Post by volkerboehme on Jan 24, 2009 12:59:08 GMT -5
If you intend to print this document please consider substituting a different font and type face and tidying up page breaks before printing. It is easier to search for answers to any problems which may arise during simulation of Fiat G.18V operations if it is also retained in its original digital format.
This project has no ‘2D cockpit view’. This tail dragger simulation is controlled from the virtual cockpit for reasons explained below. If your default flight invokes Cockpit View no ‘panel’ will be visiblewhen the G.18V is selected. Choose Virtual Cockpit view from the menu.
Some gauges are realistically difficult to read accurately and may provoke confusion. This replicates the situation in the real cockpit. A few gauges in the realistic VC have ‘fixed’ values because systems for which they are indicators are not being simulated.
Within this simulation package the only things that can actually ’fail’ are things whose failure status you can control from the MSFS realism screen. Structural failures for instance. The use of vintage navigation equipment and the vintage AP is entirely optional. See ‘Navigating the Fiat G.18V.rtf’. You are free to ignore some systems simulations which are present , cowl flaps for instance. The ‘penalty’ will be unrealistic aircraft performance not engine failure. If you fail to restrain VSI to safe values no passengers will be injured. It is however more interesting to operate an aircraft within its limits and so they are explained here and repeated in the on screen handling notes
This flight simulation release enables a high degree of realism to be experienced and self imposed. It will take some effort to study and implement all the included realism. A brief comparative and development history of the Fiat G.18 follows. It is interspersed with, and followed by, a detailed explanation of the operating procedures.
DON’T PANIC. You will not suffer outright failure of engines or other systems. Failure to comply with operating targets specified below, and repeated within the on screen handling notes, may temporarily prevent a system from acting as you command, but the system will not ‘fail‘. The GEAR or FLAPS may fail to respond to commands whilst abusive drag is applied to them, but once the system is back within its safe operating limits it will accept commands again. You will therefore need to comply with the operating limits of various systems, but you will not suffer ‘engine failure‘ or ‘flight termination’ if you make an operating error. You will have unlimited opportunity to resolve the problem. Resolve the abusive situation and the system in question will respond again.
When flying the Fiat G.18V if you let airspeed get out of control, for instance on approach to land, you may need to fly a ‘go around’ and try again, just like real life, but remember nothing has ‘failed’. Once the aeroplane is back under control and inside its safe operating limits everything will respond.
Strictly speaking Fiat should be all upper case. It is the abbreviation for Fabbrica Italiana Automobili Torino, but I shall write Fiat. Aircraft designed by Giuseppe Gabrielli have G. designations. Those applied to airliners are not sequential. They indicate the maximum number of passengers that the airliner was designed to accommodate. The G.18 prototype flew in March 1935 and had up to eighteen passenger seats, but like most airliners it could not lift full payload and full fuel at the same time.
In the United States the first Douglas DC-2 flew in May 1934. The specification given to Gabrielli required rapid design of the original Fiat G.18 as a DC-2 clone which would not infringe any Douglas patents and which would be powered by cheaper less powerful engines. Italy could not obtain a licence to manufacture the Wright Cyclone which powered the DC-2 and in 1934-35 Italy had no certain supply of military grade AVGAS required by that engine. Consequently Fiat obtained a licence to manufacture the more ancient and less powerful Pratt and Whitney Hornet for which licences were readily available. In Germany BMW had been building the Hornet as the BMW 132 since 1932 and it had become the normal powerplant of the seventeen passenger Ju52/3m, so spares were already plentiful in Europe. Fiat built the P&W Hornet under the brand name Fiat A.59.
AVIO LINEE ITALIANE
As elsewhere airline competition in Italy was restricted and directed. Unlike the United States, Germany or Britain each of which had a single 'chosen instrument' of international aviation policy Italy had many 'chosen instruments' each allocated different international spheres of influence. One such airline was Avio Linee Italiane, (ALI), which had been allocated the route to Paris and later to London. ALI's largest shareholder was Fiat. ALI were allowed to buy aircraft manufactured by Fiat's competitors, but were nevertheless something of a captive market. The original Fiat G.18 was designed specifically for use on a new ALI Turin direct Paris service which passed directly over the Alps.
The altitude deemed safe for carriage of passengers in an unpressurised airliners differed from nation to nation. In 1935 the 'safe' limits were 10,000 feet in the British Empire, 12,000 feet in the United States, but 4000 metres (13,100 feet) across continental Europe. Several nations decided to supply airline passengers with a limited oxygen supply via 'breathing tubes' to allow 'safe' operation at even higher altitudes. Italy developed many airliners with such breathing tubes. A military face mask delivers a regulated supply of oxygen continuously to both nose and mouth in an enclosed space. A face mask system is safe to very high altitudes.
Airline passengers had to suck on their breathing tubes to obtain oxygen and were at risk of progressive anoxia. Such systems are potentially unsafe for many passengers, but in 1935 Italy decided that it was 'safe' to transport any passenger of any age at up to 5500 metres (18,000 feet) so long as they had continuous access to a breathing tube. The original Fiat G.18 was designed with that capability. Unfortunately since the original Fiat G.18 had only the power of a Ju52/3m that had already lost an engine it was unable to cruise at 5500 metres (FL180). The goal of high altitude cruising was only partly driven by trans alpine route requirements. In order to cruise at high velocity all aircraft must fly high in thin air, ramming fewer air molecules than at low altitude. Cruising at FL180 in unpressurised aircraft was not just about crossing mountains. It was all about high cruising velocity, but first the airliner has to have enough power to reach and sustain FL180.
During the 1930s Italy slowly acquired the ability to refine high octane military grade AVGAS. It then slowly became possible for already highly skilled Italian engineers to design aero engines which could run at high compression ratios or which could produce power outputs that were internationally competitive by other means. One promising and simple line of research was to have an engine with more cylinders. All the aviation powers were attempting to develop reliable eighteen cylinder engines. By taking an extremely conservative approach to both the manifold pressure and RPM at which the engine would be operated Fiat were able to develop the very first such mass production eighteen cylinder two row radial engine. Branded the Fiat A.80 it went into series production early in 1937, mostly for use in the Fiat B.R.20 bomber being designed by Fiat's chief aircraft designer Celestino Rosatelli.
Not surprisingly however Fiat's second design team under Giuseppe Gabrielli were ordered to redesign the original Fiat G.18 to achieve higher cruising levels and extremely high cruising velocity using the new Fiat engine. The new aircraft was to be known as the Fiat G.18 Veloce or G.18V for short. It is that redesigned G.18V 'Veloce' which entered service with ALI in December 1937 that is featured in this flight simulation release.
In order to understand the Fiat G.18V we must grasp that it is a 'pimped ride'. Two very expensive Italian engines each rated at 1000hp now replaced two very cheap American engines each rated at 660hp so that the G.18V would be able to cruise at 5500 metres instead of 4000 metres. This was not a simple redesign task. The original G.18 was a cheap, low powered, structurally weak aeroplane. It had to be beefed up a lot before its rated power could increase from 1320hp to 2000hp.
As the redesign proceeded the situation became worse and worse. All the extra strengthening caused empty weight to rise by a massive 22% from 5,900Kg to 7,200Kg. In order to fly the mission maximum weight rose almost 25% from 8,670Kg to 10,800Kg. There was an increase in useful load, but of course the heavier aircraft had (at least) pro rata increased drag since it had the same wing with the same lift to drag ratio.
Power was up by 52% but to achieve that both weight and drag had to rise by 25%. The main spar and gear were strengthened to take larger landing loads, but the original gear and flap V speed operating limits were still in place, as were the tail related structural failure limits. The G.18 Veloce could achieve high velocity (TAS) in thin enough air, but it could not withstand high profile drag (IAS).
The original G.18 lacked the power needed to cruise at high altitude. It had therefore been designed without anti icing equipment. With the empty weight of the Veloce spiralling out of control it was decided that it should have only alcohol airscrew de-icing to maintain thrust in icing conditions. To save weight the Veloce entered service with no airframe de-icing capability despite its very high design cruising level. Not surprisingly this proved to be a mistake, but it was rectified in only the sixth and final Veloce which was heavier due to the addition of Goodrich de-icing boots and controls. This flight simulation release represents the other five G.18Vs which had no airframe de-icing. This problem makes them more interesting to simulate. (See ‘Navigating the Fiat G.18.txt’).
We can understand the standard G.18V better by comparing useful loads (crew + fuel + oil + payload).
Douglas DC-2 = 1934 = (2 x 760hp) useful load = 7,711 pounds
Fiat G.18 = 1935 = (2 x 660hp) useful load = 6,107 pounds
Fiat G.18V = 1937 = (2 x 1000hp) useful load = 7,936 pounds
Fiat marketed both G.18s as 'eighteen seaters' whilst Junkers marketed the 52/3m as a 'seventeen seater' and Douglas marketed the DC-2 as only a 'fourteen seater'. However making the standard post war assumption of 200 pounds per passenger plus baggage we see above that with the same fuel loaded the DC-2 could lift 1,600lbs more payload than the original G.18, (eight more passengers and bags), but one fewer than the G.18V featured in this flight simulation release. The commercial value of these aeroplanes was a function of payload versus cost and commercially the DC-2 was the easy winner. The Fiat G.18 ended up as a DC-2 clone only in shape. High velocity cruising is attractive to passengers and can persuade them to pay more for a seat, but only ALI, owned mostly by Fiat, purchased either variety of Fiat G.18. They purchased three G.18s and six G.18Vs.
Now we must try to understand the eighteen cylinder Fiat A.80 engines which powered the Fiat G.18V. Using more cylinders to produce more power is the easiest and worst solution. It adds weight which is an especially poor choice in aeroplanes. Ideally more power is produced using higher RPM, higher manifold pressures and higher compression ratios, but that requires both high quality fuel and high quality cooling. By 1937 Italy could produce military grade AVGAS and was mass producing it for combat operations in both Spain and Africa, but Italy did not have the highest quality machine tools. High quality cooling required mass production using precision machine tools on a large scale. In 1937 military grade AVGAS was 87 Octane so to understand the G.18V we should compare the A.80 engine with those being mass produced elsewhere and compare how many cylinders were used to generate similar power using that fuel.
In Britain Rolls Royce were concentrating on liquid cooled engines to get around the lack of precision machine tools. They could get a lot of power from a few cylinders running at very high manifold pressure and very high RPM. In America Pratt and Whitney was a precision machine tool design and manufacturing company that had started to mass produce high quality air cooled aero engines running at modest RPM and modest MAP when supplied with 87 Octane AVGAS.
1937 R.R. Merlin = rated 1030hp from 12 cylinders 1937 P&W Twin Wasp = rated 1050hp from 14 cylinders 1937 Fiat A.80 = rated 1000hp from 18 cylinders
By 1937 most powerful aero engines were connected to superchargers which increased manifold pressure above sea level atmospheric pressure (1 Atmosphere = Ata). The Fiat A.80 could barely withstand running at 1 Atmosphere. Even its TOGA MAP rating was less than 1 Ata. It had an emergency rating at just over 1 Ata but that only added 30hp giving 1030hp in emergency versus 1000hp rated. The emergency power was barely useful. Civilians were only allowed to employ it if one engine failed just after take off anyway.
Providing adequate cooling for the Fiat A.80 was difficult. Unlike the single row radial British Pegasus and American Cyclone engines used in contemporary Savoia Marchetti and Cant airliners the eighteeen cylinder two row A.80 engine required pilot not flying (PNF) to vary engine drag according to power applied and current IAS (profile = cooling drag). We must vary engine drag phase by phase of the simulated flight using cowl flaps. For convenience mouse clickable status indicators are mounted above the engine temperature gauges in the central panel. The cowl levers move below on the central console and are interlinked with the status gauges. In this simulation (only) the status gauges may be used to control engine drag status.
Cowl flaps have no significant drag. They drag a huge amount of extra cooling air flow through the engine and that extra engine cooling drag adds greatly to the total drag of the Veloce. We must manage the cowl flaps carefully and in accordance with the on screen handling notes. To experience realistic performance in both climb and cruise we must vary the drag of the engines realistically.
METRIC MANIFOLD PRESSURE
The idea behind the metric system was that all (metric) nations should adopt common measuring standards for concepts such as manifold pressure. Some hope!
Whilst German aviators measured MAP in Atmospheres (Ata), Soviet aviators decided to measure MAP in decimetres of Mercury (dmHg), and Italian aviators decided to measure MAP in kilogrammes force per square centimetre and could not even agree if the abbreviation for that was C or C2. Americans refused to give up inches of Mercury (inHg) and the British refused to give up pounds per square inch of boost (PSI boost). Meanwhile metric engine designers everywhere measured MAP in millimetres of Mercury (mmHg).
Well it certainly makes real operating manuals confusing because the engine was rarely designed to run at 'round numbers' in the system of measurement the aviators of different nations insisted on using in the cockpit. To understand any Italian aeroplane we need to understand the conversion rate of C or C2 (same thing) to other systems of manifold pressure measurement. Here is the conversion rate. All the following are equal in different cockpits:
1.000 Ata (Germany) 29.92 inHg (US) 760.0 mmHg (metric engine designers) 0.000 PSI boost (UK) 1.033 C or C2 (Italy) 7.600 dmHg (USSR)
So we see that 1.0 C in an Italian cockpit is only 0.97 Ata in a German cockpit or slight negative boost in a British cockpit or 28.96 inches in an American cockpit. In American money the TOGA MAP rating of the Fiat A.80 is only 28.96 inches. The TOGA RPM rating is only 2200RPM. Any more of either causes very rapid engine overheating, but with 18 cylinders, using military grade fuel and with a compression ratio of 6.7:1 the Fiat A.80 can briefly pump out 1000hp.
A supercharger is indeed fitted, but it has automated boost control to prevent generation of more than 1.0 C. The supercharger can briefly deliver 1.0 C up to 4100 metres (13,445 feet), but it does not produce more manifold pressure unless the very weak emergency power is invoked. The extra 30hp are so worthless I decided not to model the emergency power system in this FS9 release and the automated boost system will work better than the real one.
So we can generate 1000hp briefly for take off at 1.0 C, whatever the altitude of the runway, but as soon as we have reached flap retraction speed we must throttle back to climb power which is actually 0.884 C. The strange value is due to the engine being designed using rounded millimetres of Mercury to measure MAP. The handling notes therefore cite 0.88 C for climb. We can use climb power for 30 minutes provided we keep climbing into ever colder air.
We will eventually need to trickle advance the throttles to sustain 0.88 C as we climb into ever thinner air. The engines are TOGA rated 1000hp at 1.0 C @ 2200 RPM, but they cannot sustain 1000hp. They can only sustain 0.88 C and can only sustain 2100 RPM which generates climb power of 800hp per engine.
We will generate 2 x 800hp for as long as the superchargers can cope with the ever reducing air density as we climb to design cruising level. In any weather we will reach air so thin that the superchargers cannot deliver 0.88 C, but we will always have sufficient power to reach our design cruising level of 5500 metres anyway.
Although the Fiat G.18V has oxygen tubes for the passengers to relieve anoxia, it is not pressurised and so we must restrain both rate of climb and rate of descent to prevent severe ear pain and burst ear drums. The corpulent industrialists, crime syndicate bosses, and high ranking fascist party officials in the back are not fit young fighter pilots, and it would be unwise to cause them grievous bodily harm!
The Fiat G.18V was one the first airliners with enough surplus power to climb fast enough to impose physiological damage on passengers. We can cruise at high velocity without injuring the passengers, but we must not exceed 3.5 metres/sec rate of climb or descent. Whenever we climb or descend the Fiat G.18V we will be taking great care to target a VSI reading between 2.5 and 3.5 metres/second.
Once we reach FL180 (5500M) we will enter cruise. The Instrument Flight Rules did not exist in western Europe until after WW2. There were no semi circular cruising levels to comply with. No mandatory en route levels at all. Weather permitting airliners cruised at their individual design cruise altitude, whatever the direction of flight. We will examine weather related issues in ‘Navigating the Fiat G.18V.txt’
Below the Fiat G.18V design cruising level of 5500M = FL180 it is easy to power the tail into structural failure in level flight if we apply more than design cruise power by mistake. It will be even easier to induce structural failure when we descend. When flying the Veloce we must guard very carefully against structural overspeed. We must restrain our profile drag (IAS) whilst maximising our velocity (TAS) by cruising in thin high air. Cruising below 5500M increases chances of structural failure if excess power is applied. At 5500M and above even full throttle will not induce structural failure in level flight. At design cruising level the turbines are not powerful enough to supply enough manifold pressure to induce structural failure.
However we can apply design cruise power in level flight safely at any altitude. Design cruise power is 600hp per engine. We apply it by throttling down to 0.75 C, (if more is available), and then we rev down to 1900 RPM. ALI were the chosen aviation propaganda instrument of the Italian state in France and Britain. The Veloce was not designed to cruise low and slow. The Fiat G.18 Veloce was an expensive way of carrying a few passengers very high and very fast. Think Concorde. The design cruising level of the 1937 Fiat G.18V was the same as the pressurised 1947 Convair Liner. The pressurised Boeing 307 Stratoliner of 1940 was designed to cruise 4000 feet lower than the Fiat G.18V, but like the post war Convairs its pressurised cabin provided much greater passenger safety.
Like all ‘pimped rides’ the extra power installed to drive the same wing caused the Veloce to cruise nose down at its new much higher design cruise power.
Post by volkerboehme on Jan 24, 2009 13:00:41 GMT -5
PRE WAR ROUTES
The Veloce was designed specifically to operate the flagship long haul route;
Turin - Paris - London
at very high altitude and very high TAS, but it also flew the internal bus stop extension;
Turin - Milan - Venice
at more modest altitude and TAS. As the Veloce fleet grew ALI added a second G.18V high altitude route;
Milan - Frankfurt - Cologne - Brussels
The high altitude cruising capability of the Veloce was also essential for the trans Alpine component of this new route. Finally once all six had been delivered some Venice branch line services continued onward to eastern Europe;
Venice - Belgrade - Bucharest
Venice - Zagreb - Budapest - Warsaw
Depending on the day of the week, and these long haul eastern routes were shared with other ALI airliners.
HIGH CRUISING VELOCITY
The cruising velocity of 183 KTAS universally reported for the Veloce is taken from the part of the flight test conducted at the A.80 engine’s rated altitude and assumes cruise in fairly thick air at 4100M, but that was neither the norm nor the intention. Cruising in thin air at FL180 mean cruising velocity was 188 KTAS and the Veloce was among the fastest airliners of its day. For a while it was the fastest aircraft operating the world’s most lucrative air route between London and Paris. A typical DC-2 using its lesser design cruise power could sustain only 170 KTAS in thicker air at FL120. Once it was introduced in December 1937 the Veloce could carry an extra passenger and bags at least 10% faster than a Europe based DC-2; but at a price. All that came to an end when Italy declared war on France, Britain and Greece in June 1940.
WORLD WAR TWO
On 10 June 1940 all ALI aircraft and crews were drafted for wartime service within Nucleo Comunicazioni Avio Linee Italiane (NCALI). The Turin - Paris service resumed at lower frequency after the fall of France, but obviously no longer continued to London. Most of the G.18Vs were now drafted to transport personnel to the Italian colony of Albania in support of the Axis invasion and occupation of Greece. Most were soon based at Lecce (LIBN) or further north on the Adriatic coast of Italy flying to Tirana (LATI) . The Tirana supply route eventually extended to Athens (LGTT).
After the axis invasion of the USSR in 1941 Italian logistic efforts and NCALI concentrated on Bucharest (LRBS) instead. Only two surviving ‘old model’ G.18s continued to be based in the south flying to Albania and Greece. All six G.18Vs reopened the ‘Venice’ - Belgrade - Bucharest logistic services operating that route from September 1941 until the collapse of Italian forces on the Ostfront during the spring of 1943. One G.18V was lost on operational service during 1942. To simulate WW2 Ostfront logictics flights we should base the G.18Vs at Istrana (LIPS) or Treviso (LIPH) military air bases rather than Venice airport.
When Italian forces surrendered in September 1943 one G.18V was captured south of the German lines and it joined the Allied Co-belligerant Air Force. It is likely to have been based at Lecce flying internal supply routes in the south of Italy under allied direction until 1945. Of the G.18Vs north of the German lines only three were still in a condition worth seizing for evacuating to Germany, and it is far from clear whether the Luftwaffe made any subsequent use of them. My guess is that they could not be maintained once they reached Germany.
Before WW2 ALI did not employ economical cruising when operating the Veloce. It was a contradiction in terms. Once Italy was involved in WW2 from June 1940 things changed. Italy struggled to produce enough 87 Octane fuel for combat operations and could produce nothing better. Precious 87 octane could no longer be squandered to impress foreigners. It had to be conserved and during WW2 the Fiat G.18V was cruised instead using only econ cruise power which was 2 x 460hp. We achieve econ cruise power by throttling down to 0.65 C and revving down to 1700 RPM. After we have throttle down and revved down so long as we are cruising in high cold air we can close the cowl flaps to minimise engine drag, yet still enjoy adequate engine cooling.
Deployment of economical cruise power delivers zero pitch cruising at mid cruise weight at design cruise altitude, further reducing drag and maximising economy. Long range cruise would have been achieved with even less power, but was not relevant to the routes or logistics operations flown by the Veloce during WW2.
ON SCREEN HANDLING NOTES
Now let's associate that narrative with the abbreviated on screen handling notes which we will use to apply cruise power differently before and during WW2, while FS9 is running. Max and normal fuel is 2,304 lbs of 87 Octane AVGAS.
Design Cruise: (before 6/40)
DO NOT EXCEED 320 KmIAS C = 0.75 RPM = 1900 COWLS = 5% Plan 600 PPH Yields 188 KTAS at 5500M (FL180)
Econ Cruise: (from 6/40)
C = 0.65 RPM = 1700 COWLS = CLOSED Plan 460 PPH Yields 164 KTAS at 5500M (FL180)
explains how to use the data above to calculate fuel required, including reserves, for a given route.
Now let's backtrack to the take off. Stage 1 FLAP is not mandatory from a long runway, but it helps to get the tail up quickly so FLAP 1 is normal at all weights from all runways. The aircraft will try to swing, but there is more than enough rudder authority to hold the swing. The view ahead is poor due to the exceptionally large tail down angle.
We must look sufficiently left or right from the VC. We must gently apply just enough rudder to stay parallel to the runway edge. With the yoke full forward the tail will soon come up and then we can look straight ahead, a couple of seconds after the tail comes up we can rotate firmly.
DRAG CURVE & INITIAL CLIMB
It is absolutely essential to prevent the aircraft from climbing significantly after we rotate. The aircraft must be trimmed neutral or even slightly nose down prior to take off. After unstick our operating target is Vy = 220 KmIAS we must accelerate to the 'right side of the drag curve' before we attempt to climb. We must prevent climb, we must trim to prevent climb, and we must achieve Vy before we climb.
We retain TOGA power only long enough to achieve safe flap retraction IAS. We retract the flaps as we accelerate through 180 KmIAS and we throttle down to climb C and rev down to climb RPM. We must not climb! Even though we must reject TOGA power as soon as we achieve 180 KmIAS we must continue to hold the nose down and accelerate to at least Vy = 220 KmIAS using only climb power, before we initiate climb.
In practice we will allow our profile drag to rise far above Vy = 220 KmIAS because we must prevent VSI exceeding 3.5 m/s to preclude physiological damage to our passengers. The G.18V was never used as a cargo plane. It was too expensive.
This is NOT a pressurised aeroplane. Climb and descent rates must be restricted at all times. If VSI in climb is excessive the nose must be lowered to increase profile drag (IAS) to reduce VSI. The Veloce must not be allowed to exceed 3.5 m/s VSI.
Even when departing Turin for Paris and needing to climb over the Alps we must resist the temptation to blast up to FL180 as fast as possible. We will target and sustain 3.5 m/s allowing our profile drag to exceed Vy = 220 KmIAS whilst the superchargers can deliver 2 x 800hp. At high altitude they cannot compress the outside air to 0.88 C and IAS will decay as C reduces. We must not allow IAS to decay through Vy = 220KmIAS. Once our profile drag falls to 220 KmIAS in the climb we cease to target constant VSI = 3.5 m/s and must target constant IAS = 220 KmIAS.
Departing a sea level airfield the climb to FL180 will always take about thirty minutes, during which time we will travel about 70 miles down route in nil wind. When we depart Turin in this unpressurised airliner we cannot afford to head directly for the mountains we must use a QFG procedure to climb south of the mountains before setting course. QFG procedures are explained in the 2008 Propliner Tutorial available from www.calclassic.com/tutorials.
'V SPEED' TARGETS
The ASI is quite difficult to read. Deducing where 200 KmIAS is on the dial is particularly confusing, but that is how it was. It's the real one and it was difficult to read in real life. We must nail our V speed targets above and below 200 KmIAS regardless, and that will be even trickier during the approach, but before we try to understand the approach handling and associated V speed targets let's associate the abbreviated on screen handling note content we will use within FS9 with the narrative above.
*************************************************************** Take Off:
AUTOMIXTURE = ON (in FS9 realism options) FLAP = STAGE 1 CARB HEAT = COLD COWLS = 40% TRIM = NEUTRAL LINE UP BRAKES = ON RPM = MAX THROTTLES = FULL BRAKES = OFF YOKE = FULL FORWARD to raise tail TAIL UP - wait 2 seconds - ROTATE FIRMLY POSITIVE RATE OF CLIMB GEAR = UP ACCELERATE = 180 KmIAS <= 1 metre/sec FLAP = UP Call for Climb power
**************************** Climb power:
C = 0.88 (max) RPM = 2100 COWLS = 20% ACCELERATE > 220 KmIAS <= 1 metre/sec VSI = 3.5 metres/second (MAX) IAS => 220 KmIAS (MIN) On reaching 5500 metres (FL180) Begin cruise Before 6/40 use design power From 6/40 use econ power
TIME OF DESCENT & RATE OF DESCENT
The 2008 Propliner Tutorial available from www.calclassic.com/tutorials explains in detail how to plan Time of Descent (ToD). Since we will be cruising high unless driven down by bad weather ToD planning will be unusually important in the Fiat G.18. We will examine vintage era navigation techniques and how they may affect ToD within ‘Navigating the Fiat G.18.rtf ‘which should be read next.
At ToD we must not slam the throttles shut. That would shock cool the very expensive engines. We must reduce C slowly and in steps of no more than 0.1 C per minute. We will not reduce C below 0.4 C until we cross our destination airfield boundary. The real and simulated C gauge ‘pegs’ at 0.4 C. We must keep the needel just above 0.4 C to ensure that Map does not fasll below 0.4C in flight. How long it takes to reduce to 0.4 C depends on the power applied in the cruise. It may take three minutes or four minutes from toD to reach 0.4C safely without risk of shock cooling the rear row of cylinders in our two row engines. We retain prior cruise RPM for descent. If the cowls were open for design cruising we must close them to prevent shock cooling.
Having flight planned Time of Descent based on descending at 2.5 metres/second (about 500 ft/min) we actually aim to descend at 3.5 m/s (about 700 ft/min). However we must not allow our profile drag (IAS) to threaten the structural integrity of the clean airframe. We must not allow our profile drag to exceed 320 KmIAS. Our operating target for this phase of the flight is minus 3.5 m/s, but we will actually trim the aircraft so that we do not exceed either minus 3.5 m/s or 320 KmIAS.
3.5 m/s is our operating target and 320 KmIAS is our operating limit. Our limit is not our target.
C reduce 0.1 per minute max C => 0.4 (MIN) DO NOT EXCEED 3.5 m/s DO NOT EXCEED 320 KmIAS RPM = as cruise COWLS = CLOSED ****************************
Eventually we are using our radio goniometer (see Navigating the Fiat G.18V) to track to the initial approach fix (IAF) for the instrument runway of our destination airfield, regardless of whether that is the landing runway. We will cross the IAF at or above the minimum altitude specified in the real world approach plate which we have downloaded. Else we risk collision with terrain in bad weather.
After reaching the IAF we fly the published real world approach procedure which we downloaded and after a few minutes we arrive at the Final Approach Fix (FAF for the instrument runway). We will have crossed the IAF with a profile drag something less than 320 KmIAS and not less than our prior cruise KmIAS. Our flaps and gear are still up as we cross the real world FAF at the real world altitude. The real world approach plate we downloaded does not tell us what profile drag we should reduce to before crossing the FAF, or what flap configuration we should deploy before the FAF, because those are aircraft specific variables. We consult the on screen handling notes;
Approach Circuit and Landing:
Before FAF or Circuit: OAT <= 5C CARB HEAT = HOT COWLS = 20% RPM = 2100 C => 0.4 (MIN) REDUCE = 200 KmIAS ****************************
In a Fiat G.18V we cross the FAF, or enter the circuit pattern at 200 KmIAS. We are in relatively warm air and with low profile drag (IAS) so we need to open the cowls again, but only slightly. After crossing the IAF we adjust C (but never reduce below 0.4) and rev up to 2100 RPM to achieve our first approach operating target. After we cross the FAF we descend to the minimum descent altitude (MDA) cited in the real approach plate.
FLAP is not mentioned in the handling notes which signifies that we retain a clean configuration. At any approach weight in a G.18V our pitch in level flight will not preclude an adequate view ahead with a profile drag of 200 KmIAS and we do not need to adjust aircraft pitch by altering our wing camber with flap (see 2008 Propliner Tutorial part 7).
RETRACTABLE GEAR - Vle
Back in the 1930s retractable landing gear was a new and often unreliable innovation. In real life ALI manuals required the gear to be extended descending through a height of 500 metres (1650 feet) above the runway elevation. If the gear did not come down there was then plenty of time to sort out the problem outside the airfield circuit pattern. We may wish to impose that operating instruction upon ourselves, but during the approach phase we have many V speed targets that we must achieve. The first is the 'leg extension' limit Vle which is 200 KmIAS. If we intend to extend the gear descending through 500M QFE we must first reduce to 200 KmIAS. In the Fiat G.18V we always extend the GEAR before we extend any FLAP because that is how it was designed to work and we must retain that sequence even if we delay GEAR extension.
Throughout the arrival and approach phases we make all descents between 2.5 and 3.5 m/s never exceeding 3.5 m/s. We do not have the flexibility of vertical profile operation associated only with pressurised airliners.
**************************** Downwind or final Glideslope
We must not delay GEAR selection any later than glideslope interception during a straight in approach to land on the instrument runway or later than downwind after repositioning from the instrument approach to join the circuit for the landing runway. That in turn mandates when we must reduce our profile drag to 200 KmIAS.
Within MSFS once selected the GEAR will always come down IF we have achieved our V speed operating targets specified above. If it does not deploy, or only partially deploys, our operating targets were not achieved, but as soon as we achieve our operating targets it will deploy. It won't fail, but the weak motors will not travel either gear or flaps beyond their profile drag (KmIAS) limits. If either gear or flaps suffer partial deployment we must reduce our profile drag to less than their structural limit and they will then respond to pilot demand.
USE OF FLAP - Vfe
As soon as we successfully deploy the main gear the aircraft slows and slowly pitches up. Now we need FLAP 1 to increase our wing camber to reverse that pitch change. We retain 2100 RPM but adjust C (=> 0.4) to achieve our new operating target of 180 KmIAS. Having increased our wing camber our pitch at 180 KmIAS will be about the same as it was without FLAP at 200 KmIAS. Our view ahead will be preserved as we reduce IAS. That is the primary purpose of flap.
**************************** Base Leg:
FLAP = STAGE 2 Turn final = 160 KmIAS ****************************
If we are approaching a landing runway from a circuit pattern we must achieve a new target of 160 KmIAS and sustain that operating target as we add G in the turn to final. We must increase wing camber again before we reduce to 160 KmIAS else the aeroplane will pitch up as we reduce IAS. Whenever we add flap (increase wing camber) an aeroplane may balloon (climb nose down), but adding flap = wing camber always rotates the aeroplane nose down to counter the pitch up as IAS reduces.
To prevent or minimise propensity to balloon we must deploy each stage of flap to increase the efficiency of the wing with extra camber only after we have achieved the prior IAS Vspeed target. A Vspeed target of 200 KmIAS = 200 = Vfe1 was required before deploying FLAP 1 and now Vfe2 = 180 KmIAS must be achieved before deploying FLAP 2. We must not apply G and increase our weight in the final turn without the camber and efficiency increment from FLAP 2 and even so we must not reduce below 160 KmIAS else we may lose control of our sink rate as our weight increases. Every approach has many aircraft specific operating targets to be understood and achieved.
We have achieved Vfe3 and we could extend FLAP 3 safely now, but we will delay another increase in wing camber to create even greater lift efficiency to improve our view ahead (with a substantial drag penalty) until the timing of FLAP 3 will achieve our final V speed target which is Vref.
REFERENCE SPEED - Vref
In technical terms our final approach reference speed Vref must be achieved when the altimeter registers 15 metres above runway elevation, but provided we have flown a sensible glide path then in practical terms we aim to achieve Vref as we cross the boundary fence of our destination airfield. If the runway is long enough it is OK to be a little faster, but we must not be slower.
We have no specific target speed for touchdown. Our reference speed, the wing camber changes we apply, and each IAS target are all about sustaining an adequate view ahead and sustaining a configuration and energy state from which we can make a go around if we need to.
Vref for each approach varies with the square root of our approach weight which we obtain from the weight and payload menu of MSFS. In most cases Vref will be in the 130 to 135 KmIAS range. 23,800lbs is our maximum safe landing weight.
After achieving Vref crossing the boundary fence we may finally retard MAP below 0.54 C and then we flare gently to touch down on the mainwheels sinking at minus 0.5 m/s. The aircraft is under full control. We use the yoke to FLARE to touchdown at our target sink rate. Our profile drag will be less than 135 KmIAS by the time we touch down, but profile drag is no longer a target. After the boundary fence our target has become a sink rate. Every phase of flight has one or more concurrent and specific operating targets that we must deploy skill to achieve.
The aircraft will now be travelling down the runway tail up with an excellent view ahead. We ensured that circumstance by achieving first our Vref target and then our sink rate target. While the mainwheels are down and the tail is still up we use rudder to correct our course until it is exactly parallel to the runway. It is only after we have achieved that operating target that we gently pull the tail down to runway contact. The G.18V has a very steep tail down angle so we will lose sight of the runway ahead with the tail down, but we have ensured that we are following the runway course. From the VC we look sideways and monitor that we remain parallel to the runway edge.
We pull the yoke full aft. Now we open the engine cowls fully to maximise engine drag and cooling. If we intend to use wheel brakes we must raise flaps first since the wheel brakes may induce a skid spitting stones or chunks of ice right through the fragile flaps.
On most runways the very large tail down angle of the G.18V provides so much natural aerodynamic drag that wheel brakes are superfluous. They are present mostly to manoeuvre on the ground by use of differential braking, not to arrest the landing.
***************************** After mainwheel contact:
GENTLY - PULL TAILWHEEL INTO CONTACT YOKE FULL AFT COWLS = 100% FLAP = UP BRAKES = as required *****************************
Post by volkerboehme on Jan 24, 2009 13:01:23 GMT -5
The purpose of flight simulation is to master real world skills in a virtual environment. Real aeroplanes are designed to be compliant with the specific procedures in force at the time they were designed and their own operating parameters are also highly specific. Compliant operation is achieved by following the real procedures so that everything happens at the right time and by achieving all the configuration changes in the correct sequence at the correct V speeds. When the aeroplane is operated in a compliant way it is easy to fly, because it is doing what it was designed to do. Forcing it to do random things it was never designed to do makes operating it difficult. Learning how to achieve compliant operation is difficult, but once that goal is being pursued the aeroplane starts to co-operate rather than fight what the (virtual) pilot is trying to force it to do.
REVERSED ENGINE CONTROLS
As we leave the runway we retard the RPM levers to max. In many continental European aircraft, including Italian aircraft, max throttle and max RPM are achieved with the control levers full aft. That is correctly implemented in the Fait G.18V VC of course but FS9 nevertheless requires us to drag a mouse forward to 'increase' either throttle % or RPM %, so when grabbing 'eurolevers' with a mouse we must mouse drag forward to move the levers aft in the cockpit. This may take some getting used to.
Now we must think about whether most of the turns to our parking space (parallel to the terminal) will be right hand or left hand. If left hand P1 will become pilot flying (PF). He slides back his side window and sticks his head partially out of the side window so that he can see any obstructions during ground handling operations. If most turns will be right hand P2 will become PF.
Any well designed VC allows the aircraft to be operated from either seat. To ENTER the P2 seat we press CTRL + SHIFT + ENTER. To move BACK to the P1 seat we press CTRL + SHIFT + BACKspace. We can continue those motions to stick our head partially out of either side window to conduct realistic ground handling operations. The further back we go in aviation history the more often we need to stick our head outside cockpits to operate the aircraft. That is especially true on the ground. It is only possible in a VC of course.
Simply removing a 2D panel to create a wholly unrealistic unobstructed view is no substitute for a scale VC. With a VC realism continues on the ground. From the perfectly scaled VC environment we stick our head *just far enough* outside the side window to see ahead and monitor the edge of the runway or taxiway when looking straight ahead, but with our head just sticking through the side window we can easily pan to see and use (mouse drag) the engine controls. From the VC we can therefore exercise precision control over asymmetric C and even asymmetric RPM to achieve realistic ground handling. Remember yoke should always be held full aft on the ground in a powerful taildragger. Remember to pan to check wingtip clearance in congested spaces. With a perfectly scaled VC we can exercise full ground operating flexibility from either pilot seat and we should make use of the opportunity to operate the Fiat G.18V from both pilot seats in all phases of flight. No eyepoint height adjustment is appropriate or necessary.
If you have never practiced 'head out of side window' realistic taildragger ground handling in a simulator before you should probably start by mastering that skill before flying the G.18V. A really good VC delivers exceptional realism to flight simulation users. We no longer need clunky 'video game cheat' solutions.
No the window doesn't actually slide. We do literally have to stick (half) our head through it. Since those levels of realism may be frustrating to some I have made the tailwheel steerable. It only castored in real life. We can however use the Fiat G.18V to learn the real world skills of vintage era ground handling in big taildragging aeroplanes with large taildown angles. Obviously we taxi to the runway and line up carefully using the same technique before we apply the parking brake, (not the weaker differential toe brakes), prior to TOGA throttle up.
At this point we now understand the real world inputs required, why they were what they were, the real world targets we must achieve, the operating limits we must avoid whilst making those inputs, and the variable wing camber configurations that are associated with each operating target. We also know how to navigate the G.18V in 2D on the ground, but compliant operation of the G.18V requires us to achieve compliant 4D navigation in flight and that is a much more difficult skill to acquire. Without one to one instruction it may take years of self study and applied effort. The 2008 Propliner Tutorial available from;
provides all the basics for the pioneer, vintage and classic eras of aviation history. The G.18V existed only within a vintage era aviation infrastructure and compliant 4D navigation of the G.18V requires the gauges and skills relevant to the vintage phase of aviation history. Those gauges are present. Learning the skills is up to us. The good news is that the slower the aircraft the easier it is to learn because we have more time to think. How to navigate the Fiat G.18V in a compliant way is explained within;
'Navigating the Fiat G.18V.rtf'
which you should read next and before flying the G.18V over significant distances.
Post by volkerboehme on Jan 24, 2009 13:02:16 GMT -5
This part of the Fiat G.18V package explains how to navigate the G.18V realistically using vintage era gauges and techniques. However it assumes prior knowledge of the tutorials, and prior practice of the exercises, within the 2008 Propliner Tutorial available from;
Only some of which is repeated below for reasons of narrative flow.
THE FOUR PHASES OF AVIATION HISTORY
Aviation history is about much more than aeroplanes because the things achieved by aeroplanes and those who fly them depend on a complex external infrastructure that is often ignored. The pioneer phase of aviation in each nation, or sector of aviation, was characterised by irregularity of service and high death rates due to inadequate public sector infrastructure. Aircraft were operated by pilots who had no formal training or qualifications in wireless operation or aerial navigation. They compared a road map to the scenery as it went by and often became fatally lost. Being a qualified pilot is not the same thing as being a qualified navigator or qualified telegrapher.
The vintage phase of aviation that followed, (everywhere except the Continental United States = CONUS), was characterised by large flight deck crews including a qualified wireless telegrapher. Vintage era navigation was conducted using global positioning systems (GPS) to navigate without reference to the scenery. Using GPS aircrew flew direct from departure airfield to destination arrival fix. Those vintage era GPS techniques were never adopted over the CONUS which moved directly from the pioneer phase of aviation history to the third and classic phase of aircraft navigation. On the other hand the European powers, and their associated world wide empires, progressed much sooner to the vintage phase of aircraft navigation.
How we should conduct a realistic propliner, maritime patrol, or bomber simulation within FS9 depends on;
1) crew complement
2) the avionics being simulated
By the time that the Fiat G.18V entered service with ALI in December 1937 most European empires, including the Italian empire, had already entered the vintage phase of aircraft navigation. Airlines no longer relied on seeing any scenery to maintain an airline schedule, and no longer relied on primitive post medieval navigation devices such as sextants. They used GPS.
GPS does not require orbiting satellites to generate the necessary electronic signals. SATNAV is just a characteristic of the latest global positioning system. Earlier global positioning systems were terrestrial.
THE VINTAGE PHASE - GLOBAL POSITIONING SYSTEMS
The vintage phase of aviation dawned with the arrival of highly trained and qualified wireless operators (WO), who joined the flight deck crew, and sometimes displaced pilots as captain of the aircraft. When we use any flight simulator we must always act as both pilot flying and aircraft captain. Performing other crew roles is optional. This tutorial provides a framework for piloting and captaining aircraft in the vintage phase of aviation. If you wish to role play telegrapher you will need to obtain a different tutorial.
Both Wireless Telegraphy (W/T = Morse) and Radio Telephony (R/T = Voice) pre date the powered aeroplane. Aircraft use of electronic global positioning for navigation dates from the Zeppelins of the Imperial German Navy. During the vintage phase of aviation history a wireless telegrapher asked an operator on the surface to manually direction find (D/F) the aircraft's transmissions in the High Frequency H/F waveband. The surface wireless operator, (who could be aboard a ship), used a large rotating Adcock array. The bearings supplied back were then plotted on a GPS chart by the aircraft telegrapher. Ideally three bearings from different surface D/F stations in sequence were used to triangulate present (actually recent) position, but two D/F bearings nearly at right angles might be deemed sufficient to update the GPS.
The WO updated the GPS plot manually and then handed it to Pilot Not Flying (PNF). Nobody in the aeroplane was a navigator. PNF only had to decide whether the latest GPS update showed the aircraft right or left of course. He made no calculation at all. If the aeroplane was more or less on course he did nothing. If it was right of course he reached out to the 'comparison compass' and altered Pilot Flying's (PF) assigned heading by 5 degrees to the left. If the aeroplane seemed to be left of course PNF altered PF assigned heading five degrees to the right. Headings not divisible by five were not assigned.
In western Europe unless the weather was causing severe interference the telegrapher could provide a new GPS plot about every ten minutes, but in areas with fewer surface D/F operators perhaps only every twenty or thirty minutes. Within vintage phase en route aviation infrastructure nobody was following beams, nobody was flying from radio beacon to radio beacon. and nobody was pretending to be navigating a sailing ship.
For pre war airlines 'radio silence' was a pointless way of operating airliners and it was anyway incompatible with maintaining schedules in all weathers by day and by night. In the vintage era of aviation history airlines flew direct from A to B using manually updated GPS plots created by the WO who handed the updated GPS plot to PNF who decided whether to assign a crude and rounded heading correction to PF via the comparison compass. To simulate this in FS9 we simply pop up the GPS window once every 10 or 20 minutes whilst en route to decide if the last heading we assigned to ourselves is working well enough, or should now vary by five degrees.
COMPARISON COMPASS & DEVIATION COMPASS
By 1937 most airline pilots used GPS plots to update a 'comparison compass' whose gyroscope also drove a 'deviation compass'. In some airliners including the G.18V the comparison compass gyroscope was also already able to drive a wing levelling autopilot which drove the rudder trim tab when activated. It is important to understand however that the assigned heading was always set on the comparison compass by PNF to drive the deviation compass, whether or not the wing leveller was going to be used. PNF dialled the assigned heading on the upper scale of the captain's comparison compass. The current heading revolved below. As pilot flying we must always keep them superimposed, but after dialling assigned heading into our comparison compass we actually suatin our self assigned heading using the deviation compass.
In the G.18V the comparison compass is above the P1 yoke. The deviation compass is above the P1 ASI. P2 only has a gyro compass which is the back up system if the P1 comparison compass gyro fails or topples.
Today in the 21st century PF is assigned headings by qualified radar controllers looking at a radar plan position indicator (RPPI). In the vintage era he was instead assigned headings (vectored) by PNF looking at a GPS plot which the WO was updating manually. It makes no difference at all to us as PF in FS9, or to us as CAPT in FS9, who mandates the assigned heading, or whether they are aboard the aircraft. Actually it makes no difference in real life either.
GPS UPDATE RATE
Today a GPS can update the aircraft plot in less than a second. In 1915 or 1937 it took around ten minutes to use GPS signals to update the GPS plot in an ocean liner, a battleship, or an aircraft with the relevant crew complement and H/F wireless transceiver. Most FS9 users fail to differentiate between the phases of aviation history and therefore fail to deploy GPS correctly during propliner, (and military or naval), simulation of the vintage phase of aviation history.
By 1929, in good weather, RDF updating of GPS was possible using HF stations 1200 miles away, *in any direction*. HFDF provided wide source infrastructure to vessels in transit, whether on the sea or in the air. When using wide source infrastructure, however the GPS signal is delivered and decoded, the vessel does not navigate from GPS transmitter to GPS transmitter. It receives their signals anywhere and everywhere. They are wide source, not point source. Consequently the vessel attempts to navigate directly from point of departure to its destination without zigzagging across the planet from one radio beacon to another.
That is why a Fiat G.18V could not have a DC-2 flight deck complement of just two pilots, who only knew how to find and follow a series of radio beams from one point source beacon to the next. When loaded with identical fuel a DC-2 based in the United States, which had already transitioned to the classic phase of aviation history, needed one less crew and could carry an extra passenger. If the DC-2 was exported to Europe a cabin for the required WO had to be added behind the flight deck and its payload was at least one passenger and bags worse than in the United States. GPS was inaccurate, added crew expense, and wasted payload. Using GPS for navigation was already being avoided over the CONUS, but was still necessary in western Europe. Within Europe only Germany had begun the transition to the classic phase of aviation history by 1937.
How the GPS signals were decoded at a particular date is not the point. The point is that with a large enough crew of specialists the captain of a Fiat G.12V, and pilot flying if a different individual, both had access to GPS in 1937 whilst the instrument rated crew of a DC-2 flying over the CONUS in 1937 navigating along the audio beams generated by point source radio ranges did not.
The Fiat G.18V did not use point source radio navigation (Ranges) in the en route phase. It used wide source radio navigation (GPS). Just because two aircraft existed at the same time on different continents does not mean that their operation and navigation was similar. They were not. The tiny crew complement of land based US airliners required very expensive point source public sector infrastructure which European taxpayers outside Germany refused to fund.
GPS provided a wide source infrastructure. Unlike Radio Ranges and the hardly different VHF Omni Ranges (VORs) that replaced them GPS was not associated with federal regulations, airways, en route air traffic control, or mandated en route procedures. Everywhere except over the CONUS GPS was widely available allowing multi crew aircraft to navigate above cloud without visual reference to the surface, and just as easily within cloud, or below cloud, without visual reference to heavenly bodies for astro navigation, on a scheduled basis, even in really bad weather, by day or night.
So during the vintage phase of aviation, everywhere except over the CONUS, (which never had a vintage phase), a flight in an aircraft with adequate crew resource for GPS navigation begins with a visual or instrument departure until clear of all potential obstructions. This is followed by a climb to design cruising level, whether or not design cruising level is below cloud, or above cloud, directly on track to the first arrival fix for destination. Then once every ten minutes, FS9 GPS is used to adjust heading left or right five degrees in units of five degrees until the flight reaches a position where it is deemed to be safe to descend again near to destination.
Of course any aircraft may need to climb above design cruising level to clear a mountain range, or descend below design cruising level to clear ice or avoid turbulence. Equally some stages may be so short that it is not possible to reach design cruising level.
LIMITATION OF UTILITY OF RDF
The slowly updating and somewhat inaccurate GPS used by the navigator of the Titanic in 1912 was not adequate to enter a harbour blindly in fog without reference to the local scenery. Nor was it good enough to allow aircrew to find a particular runway without visual reference to the local scenery. However, the GPS of 1912 was good enough to navigate from somewhere close to Ireland to somewhere close to New York, whether by a ship, or by aircraft. With sufficient training and skill, both undersea motionless reefs, and continental mountains, marked on a (GPS) chart could be avoided. Moving icebergs could not.
Just because the GPS systems used from 1909 to the 1990s were too poor to be used as approach aids, or could not be used to avoid collision with other moving objects, does not mean that they could not be used, or were not used, for en route navigation. Of course they were. Unless radio silence was required for combat operations GPS was the primary means of en route navigation in any vessel with a qualified crew complement and save for the CONUS continental land masses were just treated as another kind of ocean with bigger rocks and reefs projecting above their surface.
Most FS9 users never quite grasp this. Sextants are occasionally useful in aircraft with enough power to climb above all cloud, but vintage airliners needed to maintain a schedule. On many days, and on many legs, a sextant would have been as useful as a chocolate coffee pot.
NO ASTRO NAVIGATION - NO NAVIGATOR - NO DEAD RECKONING
Notice that the Fiat G.18V does not have an astrodome. There is nowhere for a crew member to stand to use a sextant. There was no sextant. There was no navigator. The G.18V was navigated using GPS, not astro-navigation, not dead reckoning. Now think about all the other airliners and aircrew flying schedules, whatever the weather, who could not rely on post medieval navigation techniques and who had no reason at all to maintain radio silence. Most of the airliners they were flying in the vintage phase of aviation history also had no astrodome, no sextant, and no navigator. When flying boats were used as airliners they often had all those things, but they also tended to lack the power required to climb above cloud to take astro shots, so they too were heavily reliant on GPS.
On the other hand military and naval aviators, if required to maintain radio silence, could not use terrestrial GPS. Military and naval aircraft tended to have a navigator with a sextant, slide rules, complicated tables, and other post medieval paraphernalia associated with sailing ships. Aircraft navigated like sailing ships were just as prone to run aground, and at very high velocity. Post medieval navigation techniques had always had a high failure rate and death toll.
Due to their co-incidental association in the MS default DC-3 FS9 users may have come to think of the comparison compass as part of a vintage era autopilot, and it may be, but that is not its primary use. The assigned heading is always bugged by PNF, and equality maintained by PF, whether or not we intend to use an autopilot to maintain the current heading. An AP is a luxury in any vintage era airliner. A comparison compass is not. Whilst en route we never bug a heading that is not divisible by five and we never attempt to navigate direct to anywhere many miles ahead. We always bug and then fly a heading that converges with direct track to destination arrival fix.
There is little point choosing to operate a vintage era airliner in a flight simulator using modern era avionics and modern era radar based ATC, but a modern avionics stack with a modern era AP is available on a pop up panel for those who cannot manage without one. The real Fiat G.18V autopilot system is simulated within the VC itself.
The gyroscope used by the real vintage AP is the gyroscope of the comparison compass. The vintage AP does NOT have separate bank and pitch modes. The vintage AP has no TURN mode. The AP master switch is under the P1 turn and bank indicator. When the vintage AP is turned on its servo motors will sustain current pitch. The vintage era AP has PITCH hold, not VSI hold, not ALT hold. If power or altitude is varied after pitch hold is invoked both VSI and ALT will vary with air density and power applied whilst the AP seeks constant pitch despite VSI and ALT variation. The AP is invoked to sustain headings and pitch attitudes that were achieved manually by PF and that there is an intention to sustain.
The vintage AP also sustains CURRENT heading at time of invocation. It will NOT seek the ASSIGNED heading on the comparison compass. The AP has no turn mode. The vintage AP can NOT be used to TURN the aircraft to capture a new heading which differs from current heading.
PF must use the deviation compass to achieve the heading PNF assigned on the comparison compass. P1 may then choose to activate the autopilot to sustain assigned heading. Whenever the AP master is activated the green light next to the deviation compass illuminates. The aircraft will also sustain the PITCH state at the moment of invocation. This is normally the pitch compatible with level flight at the current weight with current power at current altitude.
However use of the AP in climb and descent is not forbidden, but it will PITCH hold and will *not* VSI or ALT hold. VSI is always controlled with power. With PITCH HOLD invoked insufficient applied power WILL cause SINK and MAY cause STALL.
If inexperienced vintage propliner users find it necessary, both the real AP in the VC, and the modern era multi function AP on the pop up panel, can be invoked at different times in the same flight. If any MODE of the modern AP is turned ON only the modern era AP is active, *whether or not it remains visible*. To revert to use of the vintage AP, turn either AP master switch OFF and then turn the Vintage master AP switch ON. The simulation will revert to using only realistic vintage Italian AP modes.
Only the last of the six G.18Vs built had airframe de-icing. All had carb heat, pitot heat and airscrew de-icing. This release simulates the five aircraft with NO AIRFRAME DE-ICING. Make sure you turn icing on in the advanced weather menu of MSFS to experience the consequence.
We must avoid prolonged flight in cloud or fog which is above the freezing level. At 45 North, across the year, the freezing level is on average at 7500 QNH. Further north and in winter it is at surface level. We have the means to cope with prolonged flight in freezing air, but we do not have the means to sustain prolonged flight in freezing damp air. We must avoid prolonged flight in cloud, fog and all types of precipitation above the local freezing level. We must monitor OAT very carefully and avoid freezing cloud and precipitation accordingly. There is no freezing precipitation above cloud.
LOCAL INFRASTRUCTURE CONSTRAINT
Let's consider the rules of conduct for flight simulation of an ALI G.18V flying the London to Paris schedule in the winter of 1939. On this flight we can use French and British commercial aviation infrastructure which includes GPS widesource signals, but not point source Radio Range signals of the kind that were already in use in the United States and Germany. It will be cloudy and raining a lot of the time. We do not wait for clear blue sky and we do not need to climb above cloud to take sun shots. We have nowhere to stand to take sun shots with a sextant anyway. We have no sextant. We have no navigator. We do not wait for high visibility at low level because we do not intend to navigate en route by reference to the scenery using a map.
We could use ancient pioneer era, flight by visual reference to the scenery and a map, navigation techniques to locate Paris, but our track mileage will be less if we use GPS to proceed direct to our destination arrival fix at high altitude, and ALI are not paying our virtual wireless operator to provide musical entertainment. We will enjoy a much faster cruising velocity above cloud up at 5500 metres in nice thin low drag air.
If we have not installed a third party scenery of Croydon we will use nearby Redhill (EGKR) in FS9 instead. We must climb out over the local terrain to somewhere safe, potentially by reference to the scenery, potentially using a tourist map, else using the obscured arc goniometer for radio navigation, before climbing above cloud. Climbing out of Croydon or nearby Redhill that will be no problem. Climbing out of Turin for Paris it is a big problem, (see QFG procedures within the 2008 Propliner Tutorial).
Once in the cruise at an altitude of 5500M about 70 miles south of Croydon, and above cloud, cruising fast at high TAS in nice thin air, by day or night, we pop up the FS9 GPS window only once every ten minutes and make course changes of no more than five degrees in units of rounded five degrees until we reach flight plan Time of Descent which is always at least 30 minutes before Le Bourget.
At this point the classic phase techniques already in use in the United States and the vintage phase techniques in use almost everywhere else merge and become identical. En route navigation still differed greatly in 1939, but the means of terminal guidance was already becoming global. Non Directional Beacons, (transmitting in the Medium Frequency (M/F) band), were becoming common for terminal guidance both inbound and outbound (see QFG procedures). However Automatic Direction Finding (ADF) was not yet available.
Sometimes less than a third of a short haul flight undertaken in the vintage phase of aviation history will be conducted using GPS. In real life the way an aircraft is operated has nothing to do with the aircraft type or its date of manufacture. It depends on the current technology phase of the *local* aviation infrastructure. That is what we must seek to replicate and simulate within MSFS. By the winter of 1939 the R.A.F. already had fourth generation modern phase primary and secondary radar infrastructure within Britain, but British commercial aviation, which spanned a world wide empire, was stranded in the second and vintage phase of aviation history. This constrained the operation of commercial aviation over and near Britain whether the airline was British, French, Belgian, Italian, Dutch or Danish. By the winter 1939 German aircraft were unwelcome.
PLANNING TIME OF DESCENT (TOD)
From 1937 to 1945 there were no federally mandated procedures outside the CONUS and German occupied territory, so the procedures were employer (airline) mandated instead. However in general the present day federally mandated procedure everywhere is just an amalgam of the prior employer (airline) mandated procedures, many of which date back to the 1930s. They are the same thing really. So if a current NDB arrival and approach procedure is available for download, it should be downloaded and followed. Even if it appears that a modern STandard Arrival (STAR) procedure has no relevance to vintage airliner operation in the 1930s it probably does. The mountains have not moved and modern masts must be avoided anyway.
The current approach plate is always relevant. It tells us what our minimum descent altitude must be in FS9 during both the arrival and the approach phases of our flight. We must avoid masts present in FS9 whether or not they were present in the thirties and forties. The rules for planning TOD are therefore those explained in the 2008 Propliner Tutorial. In FS9 we will use GPS to navigate the G.18V until it is almost Time to Descend. Then we will switch to terminal guidance procedures. Part 3 of the 2008 Propliner Tutorial explains in detail how to fly arrivals and approaches in propliners, whether they are vintage or classic era propliners.
Vintage era airliners lacked ADF. Vintage era airliners had pilot obscured arc goniometers instead.
The standard American pilot obscured arc goniometer is called a U.S. Army Aviation Section Signal Corps Receiver (USAASSCR), or mercifully just Signal Corps Receiver (SCR) for short. It is of course a default gauge in both of the default FS9 Lockheed Vegas. It is mounted to the left of the altimeter in their VCs, immediately above their all important comparison compass. In the Fiat G.18V the European pattern goniometer is above the P2 ASI. We must be very careful, it is very easy to confuse a European deviation compass (above the P1 ASI) with a European pilot goniometer (above the P2 ASI). A European goniometer works just like the FS9 default goniometer, but I have a nasty suspicion that most FS9 users have never bothered to learn how to use either a comparison compass or a goniometer even though both are present in both default Lockheed Vegas. Shame on you! Now you have another chance, and the tutorial that Microsoft could not be bothered to supply.
An ADF is also called a radio compass. It has a 360 degree compass ring within a circular gauge. An automated system points the ADF needle at the NDB which we tuned using the avionics panel. However the vintage era goniometer is not automatic. It uses the circular MFDF loop on top of the Fiat G.18V. We tune it the same way as an ADF, and to the same frequency. The MFDF loop is mounted on a periscope stand and operated like a periscope. The telegrapher can turn the periscope until the signal minimises. Then he notes the bearing just like a submarine captain taking a bearing on a ship to the beam.
However just before ToD our WO locks the MF loop facing forward and he tunes the NDB that is the first arrival fix for our destination. Then he informs P1 and PF that the blind flying panel goniometer is tuned. Of course we must tune the goniometer to the NDB, by popping up the avionics window in FS9 (see below).
(STANDARD) BEACON (NDB) APPROACH
The goniometer has no automation. The MF loop has no automation. Pilot flying (we) now turn(s) the whole aeroplane manually until the NDB which is the IAF for our approach is on the nose, using the obscured arc goniometer to determine when it is dead ahead. Now we 'home' to the IAF, keeping the needle centred just as though we had a radio compass (ADF) even though we have only an obscured arc goniometer and a locked MF loop. Real world aircrew may wish to compensate for drift, but remember on a vintage flight deck that requires comparison of the goniometer needle to the deviation compass needle. That is complicated so non aircrew should just point the nose of the aeroplane at the terminal guidance M/F signal propagated from the non directional beacon (NDB).
We can fly any vintage era, classic era, or current era NDB arrival, holding, or approach procedure using a goniometer. ADF is a modern luxury that is not required to fly even modern era approaches. I am not going to repeat everything in Part 3 of the 2008 Propliner Tutorial here. The only difference when flying a Fiat G.18V instead of a Goose or a Convair 340 is that we use an obscured arc goniometer instead of an unobscured arc radio compass to fly the arrival, the holding pattern and the approach. We simply follow the 4D instructions on the real approach plate we have downloaded.
See www.calclassic.com/charts for URLs leading to thousands of free real world arrival/approach plates for use with vintage and classic propliners.
LORENZ (STANDARD) BEAM (LLZ = LOC) APPROACH
These days everybody calls Lorenz Beams, Localizers, but the abbreviation is still LLZ on European approach plates. During WW2 the British called them Standard Beams, because they wanted to pretend they were not reliant upon a German technology. However a Lorenz Beam Approach (LBA), a Standard Beam Approach (SBA), and a Localizer (LOC) approach are all the same thing within MSFS. Most LBA gauges use a vertical LOC/LLZ needle to find and then follow a Lorenz Beam (Approach) to a runway threshold.
Some LBA/LLZ gauges use lights to show left right deviation from the LLZ/LOC. The Fiat G.18V uses an LLZ gauge with a needle following the German pattern which eventually became the standard means of LOC indication in the UK and US too. In the Fiat G.18V the LLZ gauge is dead centre below the clock for ease of use from either seat. The world's greatest airports in places like Croydon, Templehof and Newark all had Lorenz beams to allow LLZ/LOC beam approaches before the G,18V entered service in December 1937.
Unlike an NDB, Lorenz Beams promote straight in approaches to specific runways and allow much lower minima because they are precision approaches providing terminal track guidance inside the Final Approach Fix (FAF). Consequently a Lorenz Beam Approach can be attempted without flying a holding pattern for inbound track guidance first. However before radar vectoring was introduced to create the furth and modern modern era of aviation history the LLZ was often located and intercepted using the goniometer to locate a holding pattern based on an NDB positioned on the LLZ beam. That NDB was often both Initial Approach Fix (IAF) and the Final Approach Fix (FAF) for the LBA = LLZ = LOC approach. If using such an NDB as the FAF in FS9 note the FAF IAS restrictions in the Fiat G.18V on screen handling notes.
DME v GLIDESLOPE and QFE v QNH
Not every LLZ/LOC has a co-located DME today or in 1937, but some do. In the vintage phase of aviation history none had glideslopes. It is very easy to confuse a German or Italian pattern vintage era LBA = LLZ gauge with a classic era US Bendix patent ILS gauge. In the classic and modern era American Bendix gauge the horizontal needle is a glideslope deviation indicator. It is very important to remember that the equivalent horizontal needle in an LLZ/LBA gauge is the DME needle. It is also the metric QFE target needle but I will explain that concept shortly.
In the vintage phase of aviation history gauges were analogue not digital. The LLZ/LBA gauge contains a horizontal analogue DME needle. There are five tick marks. Even though this is a metric gauge they are at 8,6,4,2, and 0 nautical miles DME. The are used only during the last 8 miles of a beam approach when the Lorenz Beam in question has co-located DME. If it has no co-located DME the needle will 'peg' at 0 DME. This is NOT a 'fly up' command. Vintage era LLZ/LBA gauges had no OFF flags.
Whilst it may seem illogical for a metric gauge to have DME in miles it is not. When an aeroplane is 1 mile from touchdown on a Lorenz Beam Approach it should be 100 metres above runway elevation. At four miles it should be 400 metres above runway elevation, and so on, and so on.
Those of you who are qualified aircrew and who understand how to convert QNH to QFE can use the LLZ/LBA gauge to deliver to yourselves a 'pilot interpreted surveillance radar approach'. When you are on the LOC at 4 DME the horizontal needle of an LBA gauge indicates 'you are 4 miles from touchdown height should be 400 metres'. In the vintage phase of aviation history all instrument approaches were flown using QFE not QNH. For metric aviators miles related directly to height in metres QFE. They still do. The LBA gauge simply assumes that the beam will be intercepted at a height (not altitude) of less than 800 metres and that there is no reason to indicate 'QFE target height' until inside 8 DME.
The propliner Tutorial provides an explanation of QNH to QFE conversion which is not repeated here. However airfields at see level have QNH = QFE (altitude = height) and we shall use that to our advantage in the next part of this G.18V operating tutorial.
Post by volkerboehme on Jan 24, 2009 13:02:49 GMT -5
Now we know where the G.18V navigation gauges are located, when to use them, and how to use them, we can substitute the G.18V for the cited aircraft within most of the NDB exercises within Part 3 of the 2008 Propliner Tutorial which provides very detailed explanations of how to use real arrival and approach plates during flight simulation.
If you have never incorporated propliner arrival and approach realism into flight simulation before you should work through those exercises using the updated Calclassic Grumman Goose with its modern avionics (including ADF) before attempting real arrivals and approaches using a goniometer and LLZ/DME receiver. If you have some experience of flying or simulating realistic arrivals and approaches you may wish to attempt a beam or beacon approach to the modern Venice airport (Venezia Tessera = LIPZ). A detailed step by step tutorial follows.
The flight should begin in Milan (LIML) followed by GPS navigation direct to the first arrival fix in the Venice STandard ARrival (STAR) procedure, *not* direct LIPZ airport. This is a domestic ‘bus stop’ route. The distance from LIML to LIPZ is only 130 miles and the direct track to the arrival fix only passes over the foothills of the Alps. It is not worth climbing to 5500M. We will flight plan at 3000M and will begin our arrival and descent over Vicenza when we are east of the Alps.
The relevant fix in the Venice STARs is the Vicenza (VIC) non directional beacon transmitting on 417 Kcs. While we are enroute using GPS to navigate we tune VIC using our EL 1 tuner on the vintage wireless operator's pop up panel any time after we begin cruise at 3000M, but in FS9 we will not get a Morse ident from the VIC until it is safe to use its signals for navigation (real life differs). To hear the ident which tells that it is time to forsake HFDF/GPS en route navigation for M/F terminal navigation we turn the EL1 signal knob to max.
The cruise phase of this flight continues until Time of Descent. The arrival phase begins as soon as we can use MF signals from VIC to drive our goniometer. We use HFDF GPS to navigate direct to VIC only until we can receive terminal guidance to VIC using M.F. As soon as we can use the VIC beacon we begin more precise terminal phase (arrival) navigation, and we do so before ToD and before we terminate cruise. The difference between the en route phase and the arrival phase, in the vintage era of aviation history, is all about how we are navigating. In FS9 the VIC NDB has a range of 75 miles so this short domestic flight barely has an en route phase.
Once we are sure we are getting a good ident signal from VIC we can turn the EL1 signal knob to minimum until we need to identify and use a different M/F beacon. We can close the vintage era WO (tuning) sub panel until we need it again.
The 2008 Propliner Tutorial explains that Time of Descent relates to our estimate for the Initial Approach Fix and in general that is true, but as it also explains near high mountains we must comply with minimum en route altitudes and as Part 3 of the 2008 Propliner Tutorial explains we cannot descend whenever we like to whatever altitude we like. Inbound to Venice from Milan we must stay high until VIC to avoid collision with the Alps. We will maintain 3000M all the way to VIC and we will initiate descent at minus 2.5 to 3.5 m/s only after passing VIC.
FIXED LOOP and OBSCURED ARC GONIOMETER
In a Fiat G.18V we only have one manual M/F loop so we can only tune and use one Non Directional M/F Beacon (NDB) at a time. We will need to use several during this arrival and approach to Venice, which of course can be flown in any weather, day or night.
We home to VIC by turning the whole aircraft until our goniometer needle (above the P2 ASI) centres. Do not confuse the goniometer above the P2 ASI with the deviation compass above the P1 ASI. When we get very close to VIC it will become difficult to centre the needle without using significant bank angles to hold it central. Don't chase the needle with significant bank angles. We have reached VIC and it is safe to descend.
C2 reduce 0.1 per minute max DO NOT EXCEED -3.5 m/s DO NOT EXCEED 320 KmIAS p RPM = as cruise COWLS = CLOSED ****************************
We cannot descend to any altitude we like on any track we like. We must now track towards a new Venice arrival beacon at Chioggia. The NDB at Chioggia (CHI) bears 142M (Magnetic) from Vicenza (VIC). We turn to QDM 142 and initiate descent. Then we tune the CHI on 408 Kcs. For a while we are just descending in the direction of CHI with no guidance. We only have one MF loop. We must use the signal from VIC until reaching VIC and only then tune CHI whilst heading in the direction of CHI.
Now we turn our EL1 signal to max and listen for the CHI ident. Once we have a clear audio signal we centre the goniometer needle and track to CHI descending. We are clear of the Alps and we can descend safely to 1000M QNH but we must not exceed minus 3.5 m/s VSI in this unpressurised propliner. Outbound flights going south will pass under us. We will pass over Padua tracking 142 QDM en route towards Chioggia descending to only 1000M, but we don't necessarily intend to proceed all the way to Chioggia on the coast. We are using the CHI NDB to descend on a safe 4D path during the arrival phase of this vintage era flight to Venice. We must not proceed directly to Venice airport. We must avoid inbound paths to military airfields, as well as other commercial airfields, and we must avoid the outbound paths from Venice to Vicenza and beyond by heading towards Chioggia. We must remain above outbound flights going south.
Our Minimum Descent Altitude (MDA) for this part of the arrival is 1000M QNH. The Initial Approach Fix (IAF) for Venice is the VEN NDB. We repeat the earlier tuning procedure. Once we are sure we are tracking towards CHI we tune VEN on 379 Kcs. After reaching 1000M QNH whilst heading for Chioggia we turn the whole aeroplane and home to VEN again using our obscured arc goniometer. We maintain 1000M QNH. We must not descend into confliction with outbound traffic.
Whilst we are inbound to the VEN NDB flying the last part of the arrival we tune the Lorenz beam and prepare to begin the approach phase from the IAF. If we have not already done so, we turn the EL1 MF tuner signal knob to min. It is time to tune the LLZ beam and listen for the LLZ beam on VHF.
It is time to use the lower EK1 tuner. Now we tune the Venezia LLZ beam on 109.95 VHF which idents VTS (Venezia Tessera). We used HF GPS navigation until we could use MF navigation and once we can use VHF we will use VHF. We turn *both* EK1 signal knobs full right. The right hand knob turns on our fan marker (MKR) receivers. We will need to hear their morse audio to know which fan we are over when we eventually fly down the LLZ beam. Each time we cross a MKR fan the red light on the LLZ gauge will illuminate too, but to know whether we are over an outer, middle or inner MKR of the beam we must learn to recognise their audio pulses. In the vintage phase of aviation history outer, middle and inner markers did not yet have individual warning lights of different colours. We are tuning the approach beam and approach markers long before we will use them. We are still en route to the IAF at VEN maintaining 1000M QNH.
When we reach VEN, we clear ourselves for an approach to RWY 04R at Venice airport. The arrival phase has ended. The approach begins with a holding pattern to align the aircraft with the final approach course. The approach phase begins. We turn to the right at rate 1 using our turn indicator to achieve and sustain rate 1 (3 degrees per second). We align the needle with the right tick mark throughout the level turn. We turn to 221M, which is the reciprocal of the runway track. We are now 'beacon outbound' in the VEN holding pattern. Our turn to the right placed us over the Venice Laguna. Once we are outbound 221M it is safe to descend below 1000M QNH. We descend to 500M QNH tracking 221M over the Laguna. Even if we are in cloud at night this is safe. The G.18V is unpressurised. We always descend at between -2.5 and -3.5 VSI.
We have already tuned the Lorenz beam, its co-located DME, and its MKRs using the EK1 tuner. As soon as we reach 500M QNH (= QFE for Venice at sea level) we turn right to intercept the beam. The actual magnetic track of RWY 04R at Venice is 041 in FS9. Of course its magnetic track varies as the North Magnetic Pole wanders hundreds of miles around Canada every decade. We must not use arrival and approach charts from the vintage era. We must use arrival and approach charts from the modern era with modern MAGVAR approximating the fixed MAGVAR in FS9 based on where the North Magnetic Pole had wandered to in 2003. In 2003 the LLZ beam and runway track were 041M.
We are going to intercept a beam whose magnetic track (in FS9) is 041. We wish to do so from the right, in a right turn, from a right hand holding pattern over the sea. We make that easy by turning right from 221M at Rate 1 to a HDG of 020M. We assign 020M on the comparison compass, but as always we monitor heading deviation and capture using the deviation compass above the P1 ASI.
Now we monitor the fully deflected LLZ vertical needle. As soon as it starts to centre we commence another rate 1 turn to the right. We adjust our rate of turn so that we centre the vertical LLZ needle. If there is no wind and no drift on the beam today the goniometer needle will also centre since the VEN NDB is on the LLZ beam. If the VEN goniometer needle is not centred but the beam is centred we track the beam with the LLZ needle. We do not need to allow for drift when following a beam. The beam goes to the runway. We just follow the beam.
However we have not lost interest in the VEN. As we came to the end of our arrival the VEN was the IAF, but the VEN is also the Final Approach Fix (FAF) for Venice. On screen handling notes often tell us we must achieve certain things before the FAF and the G.18V handling notes are no exception.
**************************** Approach Circuit and Landing:
Before FAF or Circuit: OAT <= 5C CARB HEAT = HOT COWLS = 10% C2 minimum 0.4 RPM = 2100 REDUCE = 200 KmIAS ****************************
MINIMUM DESCENT ALTITUDE (MDA) and MINIMUM DESCENT HEIGHT (MDH)
Our MDA was 500M after we went beacon outbound over the Laguna. Now that we have successfully intercepted the LLZ beam we can descend further. Our MDA becomes 300M. Only because Venice is at sea level our Minimum Descent Altitude (MDA using QNH) is also our Minimum Descent Height (MDH using QFE). QHN and QFE are equal at Venice.
The Venice LLZ has co-located DME. The horizontal needle of our LLZ receiver will indicate DME once we are inside 8 miles from touchdown. Because Venice is at sea level our altitude (QNH) and our height (QFE) relative to Venice will be identical and we will receive target heights from our LBA (LLZ/DME) receiver's horizontal needle.
However we are not allowed to use that information to control our descent until we cross the Final Approach Fix (FAF) and become beacon inbound. Our MDH is 300 metres, until we arrive back at the VEN NDB of the Venice holding pattern. This is not just for our safety, it is to reassure people living under the flight path and to provide noise abatement. The FAF at VEN is situated so that descent below 300M is again over the Laguna. It makes not the slightest difference whether we are still in cloud at night or have been able to see the airport and RWY 04R for the last ten minutes. What we are required to do is the same.
Today in the modern phase of aviation history an approach radar controller would be navigating the aeroplane in 4D with the pilot following his or her instructions. In 1937 - 1943 wireless telegraphers had to tune beacons and beams and pilots had to follow needles and comply with written procedures. They are essentially the same procedures as today, just a different way of navigating the same procedures. In fact today we would be required to turn onto the beam much higher for noise abatement because all arrivals at Venice are now assumed to be noisy turbine public nuisances. Turbine aircraft noise pollution wasn't a problem for Venetians 1937-43 and the procedures were flown at lower altitudes.
ON THE BEAM
So we have located the LLZ beam and we are following the beam towards the VEN NDB which is the FAF for Venice. We reach and maintain 300M. We reduce to 200 KmIAS. We wait to see the goniometer needle wobble as we pass the VEN and at the same time we hear the outer MKR tones and the red light on the LLZ gauge flashes. We have reached the FAF.
Apart from being our 200 KmIAS ‘speed limit point’ passing the FAF allows us to make another descent. We turned onto the LLZ beam at 500M. Once we established on the beam we were allowed to descend to maintain 300M QNH, but we must not descend below 300M until after the FAF. After the FAF we are allowed to descend to maintain 70M. We descend to maintain 70M. However we are now listening for the middle marker. If we hear the middle marker tones before we identify the approach lights to RWY 04R we must go around and initiate the missed approach. If we cannot see the approach lights from a height of 70 metres the weather is pretty bad!
We must not descend as far as we like. Maybe the cloud goes all the way to the surface of the Laguna. We must not descend below 70M and if we have not positively identified the approach lights of 04R by the middle MKR we must go around and fly the missed approach procedure. We can use the DME = 'height should be' needle to fly a smooth descent after the FAF, or we can just descend to 70M at minus 3.5 VSI, starting at no more than 200 KmIAS and reducing;
***************************** Downwind or final Glideslope
GEAR = DOWN FLAP = STAGE 1 REDUCE = 180 KmIAS
(Base Leg): FLAP = STAGE 2 Turn final = 160 KmIAS
In time to achieve Vref FLAP = STAGE 3 CARB HEAT = COLD Vref = boundary fence = 140 KmIAS (@ 23,800lbs) *****************************
We must extend FLAP 2 and reduce to 160 KmIAS before the middle marker. 'Final approach' targets are pursued after we have the runway in sight, but we have no hope of achieving 140 KmIAS at the airfield boundary if we have not achieved 160 KmIAS with FLAP 2 and GEAR DOWN on reaching 70 metres. Only deployment of STAGE 3 FLAP and the reduction below 160 KmIAS relate to whether we ever see the runway during this scheduled flight. If we see the runway ten minutes earlier it makes no difference. We are not allowed to go where we like at any height we like in aeroplanes near major airports and over built up areas. Not even in 1937.
In this worked example provided in this navigation tutorial the instrument runway we cleared ourselves to approach was 04R. On many days it will not be the landing runway, but it may still be the instrument runway. On many flights to Venice from Milan in a G.18V we will approach 04R but we will be required to land on 22L.
This requires better visibility and cloud base, but that is all. If the cloud base is above 300M after we pass the FAF for 04R we proceed until we identify 04R, whose other end is 22L, and then we join the left hand circuit pattern to land on 22L maintaining 300M. If 22L is the landing runway we won't extend FLAP 2 or reduce to 160 KmIAS until we are descending on base leg to 22L. We still cross the 04R FAF at 300M and 200 KmIAS. We extend FLAP 1 and extend the GEAR only once we are downwind for 22L having approached 04R.
The fact that Venice is landing 22L does not mean that we must (or will) approach 22L. The arrival phase, the approach phase and the landing phase are different phases. Many airfields have only one instrument runway and many other runways that we may need to use for landing, because they are into wind today. The instrument runway we approach is often not the runway we must land on. In that case we terminate our approach to the instrument runway *at or above circuit height for the landing runway* and join the circuit for the landing runway after identifying both the instrument runway and the landing runway whilst approaching the instrument runway *maintaining MDH for the landing runway*.
In this case MDH for 22L would be 300M not 70M. If Venice had many runways and none had adjacent masts or mountains the MDH would be 300M for all of them and only circuit pattern orientation would vary. Approaching the airfield from the instrument runway FAF makes it easy to 'count round' and join the correct circuit for the correct landing runway, however confusing the runway layout at our destination. In the vintage era of aviation history there was no approach radar controller to vector airliners to every runway regardless of orientation.
TUNING & RANGE & AUDIO
All the vintage era wireless navigation equipment mentioned in this tutorial is present in FS9, After we have tuned the frequency we must check that we are in range and receiving the signal by listening for its Morse audio tones by maximising the signal with the signal knob on the EL 1 and EK 1 wireless tuners as appropriate. Once we have identified the signal from beacons and beams we turn off the Morse audio tones by returning the audio signal to minimum. Marker fans are an exception. They should always have audio on (audio signal to max) and only MKR audio should be on (maxed) during any kind of instrument approach in FS9.
If we fail to test for audio reception we risk turning the whole aeroplane in endless circles seeking a signal that is out of range and that will never drive the goniometer needle or the LLZ needle. We must not attempt to use needles for guidance until we have identified audio on the relevant tuned frequency. We will often tune signals when our workload is low and the transmitter is still out of range.
(STANDARD) BEACON APPROACH
Venice is a major airport and is comprehensively equipped. Many airfields have no Lorenz beam, no DME and no MKRs. In real life they all get turned off for maintenance and every so often they fail. Not every aircraft has the relevant receivers anyway and sometimes they fail too. In many places and on many days we cannot fly a beam approach and we must fly a beacon approach.
The good news is that a beacon approach is a beam approach without a beam!
We already know how to fly an arrival to the holding pattern at Venice. We know how to go outbound and we know that the VEN, which is both the IAF and the FAF for Venice is on the beam. When there is no beam it is still on the final approach course. It is still the FAF.
When we make a beacon approach things only begin to differ after we have gone beacon outbound in the holding pattern. If there is no LLZ beam to tune and intercept we continue round the holding pattern and back to the holding fix (which in this case is also the FAF), then we become beacon inbound and descend.
When intercepting a beam approach the procedure was;
<<We are going to intercept a beam whose magnetic track (in FS9) is 041. We wish to do so from the right, in a right turn, from a right hand holding pattern over the sea. We make that easy by turning right from 221M at Rate 1 to a HDG of 020M. We assign 020M on the comparison compass, but as always we monitor heading deviation and capture using the deviation compass. Now we monitor the fully deflected LLZ vertical needle.>>
For a beacon approach that becomes;
We are going to intercept a final approach course whose magnetic track (in FS9) is 041. We wish to do so from the right, in a right turn, from a right hand holding pattern over the sea. We make that easy by turning right from 221M at Rate 1 to a HDG of 041M. We assign 041M on the comparison compass, but as always we monitor heading deviation and capture using the deviation compass. Now we monitor the fully deflected GONIOMETER needle.
With no beam we adjust our navigation back to VEN so that we approach VEN down a track of 041M, just as we did when we could use the LLZ needle, but with no LLZ beam we must use the goniometer needle. If we are instructed to hold we do this time and time again. When we clear ourselves for the approach, instead of going beacon outbound again, we cross the FAF and go beacon inbound.
ELECTRONIC TRACK GUIDANCE.
The big difference between a beam approach and a beacon approach is after the FAF. A beam provides guidance all the way to touchdown. During a beacon approach we have no track guidance at all between the FAF and the runway. The obscured arc goniometer goes off scale as we cross the FAF.
That is why we begin a beacon approach from a holding pattern established on the beacon. We go outbound from the beacon on the reciprocal track to the instrument runway so that we can 'establish' an inbound course which is the runway course (the final approach course) using our goniometer. We track 041M to the VEN beacon, and if we do that accurately we will still be tracking 041M after we cross the FAF and go beacon inbound descending in cloud with no electronic guidance at all.
This is however less accurate and more dangerous. Consequently our minima are higher. During a beacon approach to 04R our MDH is still 300M even after the FAF. We do not descend below 300M until we can identify the landing runway even if the landing runway is the instrument runway.
If 04R is a viable landing runway in today's wind we can depart Milan for Venice in 1937 even if the cloud base at Venice is 80M. But if any other runway is the landing runway at Venice we need a cloud base above 300M at Venice, and if either the Venice LLZ beam or our LLZ receiver is broken we need a cloud base above 300M at Venice because we will need to make a beacon approach. Many airfield have no beam and only offer beacon approaches (see 2008 Propliner Tutorial).
This tutorial is an addition to Part 3 of the 2008 Propliner Tutorial, not a replacement. Much that is relevant to navigating the Fiat G.18V realistically is not repeated here. If you have not attempted to include arrival and approach realism in flight simulation before practice the easier exercises in Part 3 of the 2008 Propliner Tutorial using ADF and the Calcalssic Grumman Goose before attempting this more difficult tutorial exercise with a goniometer and the Fiat G.18V.
All such step by step navigation exercises should be flown first in good weather, only later working towards lower visibility and lower cloud base controlling each with the weather menu to create a challenge appropriate to current ability. We must all determine what *our* cloud base and visibility minima are and observe them until more and more self training allows us to reach higher standards of skill. Used wisely and well the Fiat G.18V can deliver hundreds of hours of self training and skill enhancement within FS9.
SAVOIA MARCHETTI S.73
After you have been able to fly the arrival. approaches and landings on different runways at Venice, if you have not already done so you may wish to download the Savoia Machetti S.73 V2 release available from Avsim and elsewhere. It contains a further step by step worked example of a SABENA beacon approach to Oostende and LBA to Lille which can be flown in the Fiat G.18V. Of course the S.73 can also be used to fly the Venice arrival and approach step by step tutorial exercise above. Both types operated into Venice 1937-43.
TIME TO RECAP.
The real G.18V was carefully designed to utilise the freedom of inaccurate vintage phase en route 4D GPS navigation techniques and, as soon as they were available, location by location, also accurate classic phase terminal guidance techniques such as Beacon approaches and Beam Approaches. Do not confuse the wide source GPS signals used by the WO in the G.18V with the point source audio beams used by the two instrument rated pilots of a DC-2 to navigate over the Continental United States (CONUS) in the same timeframe.
Whilst en route the G.18V did not zig zag from one beacon to another beacon. The telegrapher used radio signals from a terrestrial and manual Global Positioning System whose radio source was up to 1200 miles away in any direction. Pilot Not Flying used the GPS plot the WO had created to give vectors to Pilot Flying, by altering the assigned heading on the comparison compass. PNF vectored PF just like a radar controller who looks at where a blip is on a radar screen and roughly estimates the heading required to get to somewhere else on the same radar map. En route in western Europe there was no beacon and no beam pointing to a waypoint. We use the panel clock to time our GPS updates and any consequential assigned heading updates. Updating late is OK, but allowing ourselves to update at intervals of less than 10 minutes, or allowing continuous display of the GPS is pointless. Vintage era GPS did not have that continuous and instant update capability. It could not be updated fast enough to provide terminal guidance.
With only two crew the DC-2 and DC-3 were poorly suited to European aviation infrastructure in the vintage phase of aviation history, but ideally suited to the classic phase that had already begun in the United States. No precision is required or involved during en route navigation of the Fiat G.18V or analogous aircraft. Once every ten minutes we pop up the GPS window and perhaps turn five degrees right, or five degrees left, depending on which side of the desired track we seem to be. That is all. Nothing more. Nothing less.
The key captaincy decision is Top of Descent. We must descend through cloud somewhere safe. This may be well before the coast, or well after the mountain range. It just depends on the current leg and the nature of the obstacles, (including outbound air traffic paths), that may kill us on that leg. If we download the real arrival procedures we will know when it is safe to descend and when the en route phase gives way to the arrival phase and when to switch to terminal navigation using MF;
In the vintage phase of aviation history HF GPS is still available in a Fiat G.18V below cloud and at low level because it has the crew complement of specialised aircrew needed to make use of vintage era GPS. HF signals can be received at low level but the update rate is far to low for terminal navigation. MF signals used to drive the needle of a goniometer (or later an ADF) are continuous, but may suddenly disappear if we descend below the curvature of the earth or pass behind the shadow of a mountain. They bend. They wander. They cut out. It is only safe to use goniometers (or ADF) at short range. They provide safe terminal guidance only. They are not safe to use at long range.
If possible we switch to short range terminal MF beacon guidance before Time of Descent. If possible we switch to VHF beam guidance as we intercept the approach course to the instrument runway. Often we will not intend to land on the instrument runway we approach. Often we will circle to land at circuit height after identifying both the instrument runway and the landing runway from the instrument approach.
Post by volkerboehme on Jan 24, 2009 13:03:18 GMT -5
A message from FSAviator:
The relationship of the Fiat G.18V to the Douglas DC-2 is fully explained in the release documentation along with much else that keen propliner fans may wish to know before attempting flight simulation of the Fiat G.18V. This is a complex vintage era propliner flight simulation release with innovative content to provide interesting new experiences and new depth of understanding for those who make the effort to understand the nature and limitations of 1937-45 propliner operation across most of Europe.
<<I think the FD is from FSAviator, and none of his AIR files will allow AI to turn in flight. Thus the AIR file swap is required.>>
AI flight dynamics must be immune to false inputs, cope with lack of inputs, and be immune to input timing errors. Consequently I make it as obvious as I can that my FD are too realistic to support the simplistic AI engine by preventing the AI engine from invoking change of direction. If I did not users would suffer mysterious and difficult to diagnose AI 'disappearances'.
<< I suddenly learn that this is not a plane to be used from macadam runways >>
The real 'Veloce' probably never had the opportunity to operate from surfaced runways and it had 'soft springs' to match. but like all taildraggers that have a tail wheel, rather than just a tail skid, it will cope with surfaced runways. Unfortunately not all of the airports the Veloce served in real life, (all scheduled destinations are listed in the supplied documentation), still have grass or dirt runways within FS9. Yet to understand the positives and negatives within the design of any real propliner we need to operate it over the real routes and flight plan profiles that it flew. We can of course choose to operate parallel to the modern surfaced runway, with more realistic BGL code running, and 'somewhat realistic' demonstration of the bumpy ride expected from an unsurfaced runway.
<<Here is the initial work from the maintenance department.>>
The Fiat G.18V release is best treated as an opportunity to first understand the reality of pre war propliner limitations, and then to develop the skill needed to work within them, rather than claim that the encoded realism should be eliminated as inconvenient. No relevant maintenance is required by those who wish to simulate operation of a Fiat G.18V. You are of course free to make your own changes, but realize that you are straying from what we believe was the true behavior.
It could have been released with nothing better than default DC-3 flight dynamics, but then you would not have the opportunity to learn anything about the Fiat G.18V. You would be condemned to another experience identical to that available from a thousand pre existing flight simulation releases with bogus, plagiarised, and generic flight dynamics that have little or no relationship to the limitations or operating targets of the real and specific aircraft the user is only pretending to operate.
Pretending to operate an aeroplane and learning to simulate the operation of a specific aeroplane are two different things. Only after we have learned to do what the real crew were doing in 4D to keep this specific aircraft within its operating limits, and to achieve its operating targets, can we understand the G.18Vs place in the timeline and pecking order of aviation history.
The Fiat G.18V release provides that unusual opportunity. Making use of that opportunity requires no new financial investment, but may require considerable investment of time and effort, starting with careful study of the supplied documentation in the DOCS folder.
Post by volkerboehme on Feb 25, 2010 0:46:17 GMT -5
FSAviator has contacted me - it appears it may be the MOI values, not the contact points. Here is his fix and more comments: -------------------------------------------
Tom's original thought was correct. I miscalculated G18V pitch MOI which causes the vehicle to 'porpoise' too easily, and then to be inadequately damped after porpoising begins. By way of official patch simply change the pitch MOI value from 86000 to 120000 in the aircraft.cfg.
I offer some detailed thoughts concerning earlier posts in this thread and the issue of 'porpoising' in large tail wheel aircraft.
<< did some quick test flights in both FS9 and FSX. Take-offs and touch-downs were very smooth at around 80kts on final, over the fence around 62kts, and touchdown about 59-60kts. >>
The bug cited at the top of this thread is real and is caused by my MOI calculation error. However the sim pilot, (or maybe just the third party bgl in use), has to induce 'porpoising' for the error to manifest itself. Consequently some users will never have seen the bug. I only observed it recently. The bug makes it easier to induce porpoising than it should be. However even after fixing, some tendency to porpoise should remain and so I will try to explain the nature of the mishandling which induces it. The compliant approach technique is explained in the on screen handling notes;
************************* Downwind or final Glideslope
After mainwheel contact: GENTLY - PULL TAILWHEEL INTO CONTACT YOKE FULL AFT *******************
When the Fiat G.18V is operated at Vref with FLAP 3 deployed on a minus three degree glideslope at typical approach weights its pitch is barely negative. The approach technique does not involve 'diving' down the glideslope and it does not allow positive pitch to develop either. We need to see where we are going without inducing significant positive or negative pitch. The aeroplane is caused to sink in a near level flying attitude by removal of thrust with throttle while sustaining 140 KmIAS on a minus three degree glideslope.
Vref = 140 KmIAS <=> 75 KIAS at the airfield boundary is followed by touchdown always in excess of 110 KmIAS <=> 59 KIAS after flaring progressively from about zero pitch to about plus 6 pitch over three to five seconds during the last 15 metres (50 feet) of descent *wholly inside the airfield boundary* . The aircraft should be 'held off' until 'almost' 110 KmIAS and then placed on the touchdown zone at barely negative VSI. If it is still airborne below 110 KmIAS <=> 59 KIAS that is a significant pilot error because it is likely to stall and slam into the runway, either breaking the tailwheel or bottoming the main gear oleos and cracking the main wing spar. In MSFS we see the main gear collapse instead to 'demonstrate' that we cracked the main spar by bottoming the oleos..
The final stage of the approach in all propliners with flaps is flown at Vref = Vs0 x 1.3 (<=> 140 KmIAS <=> 75 KIAS in a Fiat G.12V at 20,000lbs), until we are inside the airfield boundary, but we must then place the mainwheels on the runway before IAS decays to Vs0 = full flap stall (= 110 KmIAS <=> 59 KIAS in a Fiat G.12V at max gross).
Thereafter the on screen handling notes say GENTLY pull the tailwheel into contact, and they mean what they say. Suddenly pulling the tailwheel into contact will induce porpoising and failing to bring the tailwheel down to contact will cause excessive ground roll due to missing substantial induced drag from the wing once the tail is down.
Just landing gently is not sufficient. The touchdown must be at an appropriate IAS. That is much more important in a big taildragging aeroplane which we always land on the mainwheels with modest pitch (so we can correct drift during and after the flare), and then suddenly increase angle of attack again after touchdown (having corrected drift), as we force the tail down to increase our aerodynamic drag to shorten the landing roll. We must not use wheel brakes until the tail is down and the yoke is full aft.
Landing too fast is very likely to induce porpoising in a G18V when the tailwheel is brought down into contact, *not* because the tail 'bounces', or due to gear geometry, but because adding substantial AoA to the wing while in excess of full flap stalling speed = Vs0 (110 KmiAS <=> 59 KIAS) causes a sudden increase in lift which suddenly reduces the load (weight) on the mainwheel oleos. If touchdown is allowed at truly excessive IAS the aeroplane will actually lift off again if the tail is forced down too soon, but at intermediate excessive landing speeds the increase in lift still causes the main gear oleos to extend ('bounce') without actually causing 'lift off'. Porpoising is thus induced. The Fiat G18V has an unusually (unnecessary and badly designed) large taildown angle which requires pilot flying to rotate (flare) the wing trough a larger than usual change of angle of attack after touchdown. This induces greater than normal increase of lift and greater propensity to porpoise. We must stall the wing *with the mainwheels in contact* before we suddenly increase AoA. We must not force the tail down until IAS < 110 KmIAS, but of the approach was compliant it will be.
If the approach is compliant and the boundary is crossed at Vref on a minus three degree glidepath with more than 0.4C applied, followed by throttle closure,
****************************** Before FAF or Circuit:
then FLARE and 'hold off' to the touchdown zone, that will all happen more or less automatically, but depends on the headwind vector today. Failure to comply with engine operating parameters and IAS targets during the circuit and approach induces subsequent pilot errors at touchdown.
Once porpoising is induced by sudden increase of AoA, while the full flap wing is still unstalled (> 110 KmIAS > 59 KIAS), it takes a while for the oleo hydraulics to damp it out. In reality a ten ton vehicle of relevant length has more longitudinal inertia than I encoded and it should stop 'rocking' as quickly as any ten ton truck that just suffered a significant dynamic shock. It should not be free from the possibility of 'rocking' fore and aft when the 'shock absorbers' are 'shocked' though. My intention is to write FD which tell us when we mishandle the aeroplane, not just match a simple static case, but that makes the choice of non zero value critical. Removing the problem we must avoid prevents learning. Simulating (achieving) compliance in a Fiat G18V should not resemble simulating (achieving) compliance in a DC-3. In an art gallery the difference between them is how they look. In a flight simulator the difference between them is in the details of their compliant operation. That is what makes flight simulation of different aeroplanes interesting. There are always new skills of compliance to learn aeroplane by aeroplane and engine by engine.
<<I checked the contacts and noticed that the points for the main gear are ahead and slightly lower than the visual model...>>
Flight simulation is not the hobby of collecting and viewing animated model aeroplanes moving about under AI control even though we all like to also have that opportunity during flight simulation.All flight simulators exist only to teach and then test our ability to achieve compliant operation of a particular real aeroplane in a virtual environment. The goal of flight dynamics authors is to ensure that pilot error is measured and then demonstrated 'realistically' during flight simulation, not to deliver 'foolproof' dynamics.
Realistic flight dynamics are written to replicate the dynamic behaviour of the real full size aeroplane during pilot mishandling, not the static case of a particular modellers representation of it. The values imposed by the flight dynamics author define a dynamic range and non linearity, not a static or particular case. There is never any guarantee that the 3D modeller has modelled the maximum travel of the gear oleos under zero load (in flight) correctly, or the maximum compression of the oleos either. The relevant values, along with much else that the flight dynamics author must 'model' mathematically for all possible pilot inputs (errors) are usually wholly unknown to the creator of the 3D model however skilled he may be at 3D modelling. The flight dynamics author must deliver the dynamic behaviour of the real aeroplane when handled correctly, and just as importantly when it is mishandled, *absolutely regardless of the MDL in use*. Simple replication of dimensions (real or modelled) is not what flight dynamics authors do
During flight simulation consumers need a product which 'models' the dynamic consequence of their pilot error as mathematically accurately as possible so that they can notice their handling errors and notice when they have managed to eliminate them. They must be rewarded for achieving compliant operation of the vehicle just as they would be during a 'Grand Prix' racing game or any other type of vehicle simulation. Operating a vehicle at the wrong speed into turns, with the wrong RPM, and wrong throttle setting, and wrong aerofoil angle, and wrong braking, in the wrong gear must be evaluated and the consequence delivered to the consumer so that they have an incentive to use the correct values when they drive that particular type of vehicle around a circuit. They must be given the opportunity to learn what constitutes compliant operation.and they must notice the handling and performance improve when they bother. That opportunity is not delivered by simplistic replication of physical dimensions within the supplied dynamics and may be incompatible with those values. FD code is not 'model aeroplane cartoon animation' code. It exists to quantify and demonstrate user error.
the payware product 'Airwrench' is a spreadsheet which imposes a series of default assumptions concerning 'typical' non linearity of airframes, aero engines and airscrews. No spreadsheet can do otherwise. Those assumptions are mostly true for a very particular aeroplane, engine, and airscrew, each of which the designer of the spreadsheet considers to be 'typical', but most aircraft, engines and airscrews from history are in fact atypical in their non linearity, and do not have dynamics very close to any possible default assumptions, whatever is chosen as 'typical'. Consequently all such spreadsheets, (air file *compilers*), produce air files with substantial errors most of the time, even though they give good results some of the time for aeroplanes, engines and aircrews which match the default assumptions. They cannot do otherwise. This should also be obvious after testing a range of flight dynamics for aircraft of very different shape and size and date of manufacture created using any particular spreadsheet. Very large errors are easy to detect in most, but not in all. The utility of such products cannot be judged by their ability to be right sometimes.
Importing an MDL into some software and making the numbers in an aircraft.cfg match the static case of that little model aeroplane is simple enough, but it cannot address the non linearity of the real aeroplanes dynamics, and if that software assumes the extent of animation incorporated by a 3D modeller is actually 'real' it will almost always lead to significant errors in the modelling of the dynamics of the real aeroplane. Likewise a spreadsheet can only wrongly assume that things like stability and damping are functions of easy to measure components of the little model or real aeroplane. Even if the 3D model is perfect that assumption is false, because it does not address the distribution of masses. The result may literally be more than 100% wrong, but is anyway pointlessly stated to eight significant figures of wild guestimation.
Replicating errors and necessary assumptions in 3D model aeroplanes perfectly is not the goal of flight dynamics authors.
The only way to produce 'realistic' flight dynamics for a whole range of real aeroplanes, engines and airscrews, of greatly varying size and shape and capability, from different periods of history, which will measure and demonstrate the consequence of pilot error 'realistically' is with an air file *editor* to impose on the air file the specific non linearity which applies to that particular aeroplane, its engines, and airscrews, given the limitations of the technology of its own time. The simplistic design of the air file format itself then has its own always present percentage errors which no one can negate using any air file however it was created.
Realistic flight dynamics are anyway useless unless the consumer intends to work towards compliant operation of that particular in accordance with the on screen handling notes and any supplied tutorials. They take into account the limitations of the air file format and unavailable MSFS gauges, and unavailable aircraft systems in MSFS, when obviously the real handling notes cannot even if they are available.