Post by Tom/CalClassic on Aug 9, 2008 0:10:17 GMT -5
Re: B-314 Throttle problem
« Reply #13 on: Jul 17th, 2008, 8:42am » Quote Modify
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Hi,
And here is a reply from FSAviator:
One the great advantages of downloading files from Calclassic .com is that most have all the necessary documentation explaining how to actually use what was downloaded. The learning curve may however be steep. All the information required to operate a B314A 'realistically' is in the Calclassic download. Some of it is repeated below. Some of what follows applies to all flying boats and may be of wider interest. It does not repeat the information in the aliased thread I posted the last time the same problem arose from installation of mismatched B314A files.
My B314A aircraft.cfg explains;
>>>>>>>>>>>>>>>>
performance= These flight dynamics by FSAviator integrate the panel by Ken Mitchell with the Boeing Clipper MDL by Mike Stone and the operating procedures within Briefing.txt enclosed. Some data by Mike Stone and Ken Mitchell retained in this file. Download the aircraft and panel from their original upload locations and install as instructed before adding these files.
[fuel]
Max fuel was about 5400 USG usable, but for everything except trans Atlantic crossings 4000 USG was more usual. Unusable fuel is in the APS weight. In reality there were more than 2 tanks.
fuel_type = 1
number_of_tank_selectors = 1
electric_pump = 1
LeftMain = 0, -12, 0, 2700, 0
RightMain = 0, 12, 0, 2700, 0
[weight_and_balance]
reference_datum_position = 0.000, 0.000, 0.000
empty_weight_CG_position = 0.000, 0.000, 0.000
max_gross_weight = 100000 //BOAC war emergency only - PAA war emergency gross was 97000
This allows wartime emergency overload operation but the default at anchor weight represents commercial certification of the B314A at 84,000lbs which allowed full tanks with zero payload.
empty_weight = 50000 ;Aircraft prepared for service with unusable fuel, 300 gallons of engine oil, etc. Up to a thousand pounds heavier after the war with more seats fitted.
station_load.0 = "1600,0,0,0, 8 crew + kit" ;8 or fewer crew on BOAC boats but PAA boats had 10 to 12 crew until 1942
station_load.1 = "0, 0, 0, 0, payload" ;Certification allowed full fuel only with zero payload.
By default these FD have full fuel tanks so that you can fly any flight that the B314A actually flew including propaganda flights with no payload. When simulating airline flying, before and after the war, increase the payload and reduce the fuel by the same amount using the payload menu of FS9. To simulate war emergency operations just add or subtract payload until you cannot take off without exceeding the flap limit in the prevailing wave and wind state or you reach 97,000lbs PAA / 100,000lbs BOAC.
>>>>>>>>>>>>>
These extracts from the supplied Briefing.txt then go on to explain;
>>>>>>>>>>>>
INSTALLATION
After renaming the existing aircraft.cfg to aircraft.old, and panel.cfg to panel.old, move all the provided files, including this one, into the relevant folders where you have previously installed Mike Stone's Boeing Clipper and Ken Mitchell's Clipper panel. Download and install the BOAC textures, or delete the relevant section from the top of the aircraft.cfg.Copy (not move) the gauge cabs from the default DC-3 and the default Lockheed Vega into the folder where you have already installed Ken Mitchell's B314A panel, (*not* your gauges folder), else some replacement gauges may not appear.
PANEL ISSUES.
To make use of these files which are intended to allow ‘realistic’ operation of the B314A, using the simulation notes below, users will need a fully functional panel integrated for use with these dynamics and those handling notes. The enclosed air file will only work properly with the specified panel and in association with the enclosed panel.cfg and aircraft.cfg. You may of course add additional liveries, effects, etc to that aircraft cfg.
.........
The cowl flap gauges in the B314 panel by Ken Mitchell cannot control engine drag. If you wish to have functional cowl flaps you will need to substitute, within the overhead panel, the fully functional cowl flap controls from his DC-6 panel. If you choose to use cowl flaps you must become the FE as well. Use CHT and oil temperature as your reference. Simply avoid the yellow arcs on all gauges except as a transient. Do not use cowl flaps during simulation unless you add functional gauges to the panel.
These files allow individual control of each engine to simulate realistic water handling. You may find this cumbersome and under some circumstances you may find it difficult to switch between single engine and all engines mode. If so there is a gauge you can download from Avsim.com (rcbse-10.zip) which solves this problem. If you do not have the problem you do not need to add that gauge.
...........
A photo indicating the sparse nature of the real panel is here;
www.zpub.com/sf/history/boeing314.html
The revised cockpit environment has a suitably reduced complement of gauges on the main panel, but gains a clock so that you can fly published procedures.
..........
BMEP gauges containing the real world formula should indicate BMEP correctly if the relevant data is stated correctly in the aircraft.cfg. However in my opinion BMEP had little relevance to operation of the B314A. It may have had relevance in the original B314. It is of no consequence since if nobody knows the BMEP avoid ranges, for either aircraft, any gauges provided are just eye candy anyway and cannot contribute to the simulation. Knowing the rpm avoid ranges is not enough to calculate the BMEP avoid ranges so the aircraft must be operated using the rpm gauges. Feel free to run oversquare if simulating US operations. I think it is unlikely that BOAC took any notice of oversquare mythology.
Continued in next post...
IP Logged
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Tom Gibson
California Classic Propliners: www.calclassic.com/
AlcoHauler Locomotive Page: www.calclassic.com/alco/
Freeflight Design Shop: www.freeflightdesign.com/
Tom Gibson
Forum Administrator
Jets are for Kids!
Posts: 2874
Re: B-314 Throttle problem
« Reply #14 on: Jul 17th, 2008, 8:44am » Quote Modify
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MSFS and FLYING BOATS.
MSFS has the viscosity of water hard coded to an excessive value. However the weight limit for this and most other hydroplanes is not limited by that bug. The limit is usually the structural strength of the flaps. Full details of flap operation using these FD are below. For the moment note that you must reject an
attempted take off if you have not achieved unstick approaching the twenty degree flap drag limit which is 105 KIAS. How much before 105 KIAS you must abort depends on your skill at restraining the boat to <= 105 KIAS after unstick whilst the FE raises the flaps.
Remember the length of the take off run depends on wind and wave state. As in real life you can create an effective increase in wave state by longitudinal rocking of the boat with the elevators. Due to the viscosity bug it is impossible to write aircrew code that accelerates the boat correctly in both air and water. Air must take precedence. The landing distance is shorter than it should be. The take off run and time are unlikely to be within 5% of reality.
The real B314A lacked a water rudder. It also lacked outboard floats which could be dug into the water with a 'wheel over'. Consequently on the surface you can only manoeuvre using asymmetric power. If it is too much trouble just use the slew controls when on the surface.
MSFS has another bug afflicting elevator trim in all aircraft. This bug allows the trim setting to override applied elevator. It is essential to trim correctly for take off. This is especially true for flying boats at marginal unstick weights.The operating weights in these FD are by default those of the airline certification and apply to commercial usage in peacetime public transport service. In that default condition the B314A will unstick in a flat calm, under ISA conditions,
but only if you follow the operating guide below. Read it carefully. Do not use guidance provided elsewhere.
*************** BOEING B314A 'Clipper' OPERATING GUIDE **********************
I believe that the inputs promulgated below are within 5% of reality. The FD will anyway deliver output within 5% of reality when the promulgated inputs are made.
The B314A was not designed to be flown in compliance with the IFR, or on Airways. Unlike other U.S. propliners of the late 1930s it was designed to cruise climb off airways, in unregulated airspace, even in IMC. This was possible because it always departed over an ocean with no obstructions and outside the tightly regulated environment over the CONUS. Consequently step climb procedures do not apply to this boat.
Whilst everything that follows is specific to the B314A the generic principles may be adopted for the trans oceanic operation of all hydroplanes in MSFS. They override the propliner tutorial, but only for trans oceanic departure and cruise, and only for hydroplanes. Boats operated across a land mass, on riverine and/or inter lake services should be flown in accordance with the propliner tutorial. For such services weight should be reduced to ensure that operational ceiling (see propliner tutorial) exceeds the altitude of the highest obstruction en route by not less than 1500 feet.
When operating a hydroplane over the ocean you will often have the intention to exceed operational ceiling since your operational ceiling may be below sea level. Service ceiling has no practical relevance in aircraft with airscrews.
The take off procedure is simulated thus.
Before take off set mixture to automatic in the FS9 realism menu, set carb heat cold and longitudinal trim to plus 15. Set the screws fully fine.
The real aircraft had what amount to press to travel flap controls like those fitted in many real Cessna singles. Any flap angle could be selected. Tables were used to calculate the optimum angle based on sea state and weight. Since these tables are not available I have coded the flaps in stages operated with the F7 and F6 keys in the usual way. It is not pilot flying who operates the flaps. It is the FE. Use the F6 and F7 keys to tell the FE what angle to set and leave him to fiddle with the flap controls. Setting precise flap angles is not your job as PF. Your job is commanding the change at the right moment.
This is an aircraft from the vintage era, not the classic era. The flaps were very frail.
Always take off into wind. Steadily apply full throttle. On reaching 60 KIAS extend FLAP 1. On reaching 85 KIAS extend FLAP 2. At 95 KIAS attempt unstick. If the boat will not unstick commence longitudinal rocking until it does. If it will not rock off before reaching 105 KIAS you must abort and await a more favourable headwind, lower temperature, lower air pressure, or a more favourable wave state.
Extending the flaps at the right moments in the procedure is an essential part of the process of breaking the surface tension, getting the boat to hydroplane on the chined step, and eventually unsticking. Once free of the water the boat will accelerate quickly in TOGA power. This effect is overstated in FS9 by comparison to the excessive drag of the over viscous FS9 water. Use back pressure to restrain any tendency to sink back onto the water whilst FE retracts the flaps. Do not exceed 105 KIAS with flap extended. Pitch the boat up as necessary to prevent drag on the flaps exceeding 105 KIAS. The flaps may suffer (asymmetric) structural failure at higher drag with fatal consequences. I decline to steal copyright photos and upload them to the internet so please view the photo at;
www.zpub.com/sf/history/boeing314.html
which gives a good impression of required attitude post unstick whilst retarding IAS to the fragile flap limit.
Only after the FE (use the keyboard) has retracted all flap allow drag to rise to 120 KIAS.
Never intentionally allow drag to exceed 155 KIAS with flaps up. The tail may suffer structural failure. FS9 will autocalculate the probability and kill all aboard as appropriate. How accurately this works will depend on the quality of the weather data you imported.
On achieving 120 KIAS retard to METO power = 2300/37.5 and climb to 1000 feet at 120 KIAS.
Now retard to 2100 rpm for the cruise climb which will be conducted in max cruise power, *not* climb power. Climb power is not really a relevant concept in this boat, (or most other vintage boats). In the B314A it overheats the engines, requires you to add engine drag via the cowl flaps, and reduces the already far too short overhaul interval.
Reduce to 35 inches MAP. Finally allow drag to rise to 135 KIAS and then cruise climb with max cruise power = 2100/35 set on all engines and with the drag pegged at 135 KIAS. Trim can never command a pitch; it can only command a drag (IAS). Following a max gross departure at 84,000lbs plus 4 longitudinal trim will command 135 KIAS in ISA regardless of aircraft pitch or power.
Constantly adjust the four throttles to sustain exactly 35 inches from each engine as you climb. Once above FL60 the turbines cannot generate 35 inches. You cannot supply the turbines with enough power. Thereafter use full throttle and 2100 rpm for the cruise climb. Remember full throttle has little correlation with full power. MAP and power will fall as you climb at full throttle into ever thinner air and the boat will accelerate and accelerate and accelerate, to higher and higher velocity (TAS), as the power reduces, with the drag pegged at 135 KIAS.
There is no target rate of climb. Under war overload conditions it will eventually be minimal and may appear to be zero. You have no ATC assigned level. Just peg the drag at 135 KIAS with the trim wheel. Once you have set the trim to demand the target drag it will command that drag whatever happens to power, air pressure or air temperature. In any aircraft pitch will vary as the trim commands the target drag. There is no such thing as pitch trim. That's why the Sperry AP had to be invented. To command a pitch it has to alter trim. Consequently you must NOT use the pitch mode of the Sperry AP. You must target constant drag using constant trim, not constant VSI, or constant pitch using an AP. You can only maximise acceleration in any aircraft by going uphill with reducing power.
You may however use the HDG hold mode of the Sperry AP at any time when the flaps are fully up.
As weight changes the trim required to peg the drag at 135 KIAS varies, but equally slowly. You may need to make a minor adjustment every 15 minutes or so.
Continued in next post...
Tom Gibson
Forum Administrator
Re: B-314 Throttle problem
« Reply #15 on: Jul 17th, 2008, 8:45am » Quote Modify
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Design cruise altitude of the B314A was FL110. PAA and PAA crews flying USN boats proceeded accordingly, but see also relevant sections of the propliner tutorial concerning 4D flight planning and navigation if you intend to import winds into the simulation. Under US certification do not exceed FL120 for more than 30 minutes per flight (and only if necessary to avoid bad weather).
On achieving flight plan cruise altitude Sperry AP pitch hold may be engaged to prevent further climb. BOAC were governed by Ministry of War, (and later BCAR), regulations concerning flight without oxygen and consequently did not exceed FL100 by day or FL80 by night, (for more than 30 minutes per flight). Cruise BOAC boats accordingly. Your encounters with icing will reduce.
Do not attempt to land a commercial flying boat at night. Night departures are dangerous too, but may be necessary. Plan your departure taking account of planetary rotation so that your arrival up to 16 hours later is always in daylight.
It will normally take under an hour to cruise climb to design cruise altitude (FL110) at peacetime weights, but it depends on the weather. If you do not allow your drag to drop below 135 KIAS you should not need to augment engine drag by cowl flap opening. Don't use the cowl flaps to increase engine drag unless the CHT, or oil temperature, is in the yellow caution arc. Augmentation of engine drag via use of cowl flaps may sometimes be necessary for engine cooling during a cruise climb under tropical conditions. It will depend on the weather, but the whole idea is to avoid that requirement by conducting a cruise
climb with high natural engine drag at modest and reducing power. Do not use cowl flaps unless you have added functional cowl flap gauges that increase drag.
Eventually you must undertake some parts of the flight engineer function as well as the roles of PF, PNF, captain, radio operator and navigator. On reaching final cruising level the FE must prevent drag rising above 135 KIAS by very slowly trickle reducing MAP, hour after hour after tedious hour. Ideally you would trickle reduce rpm whilst running at full throttle instead, but these poorly designed airscrews suffer terribly from harmonic vibration between 2050 and 1750 rpm so you must sustain an uneconomical 2100 rpm and throttle the engines. It's bad news for engine maintenance and renders the BMEP gauge irrelevant.
The early B314 boats had been fitted with alternative airscrews that did not have this horrendous avoid range. The problem was that those screws limited the engines to 1500 bhp at best. The throttles of the B314 had to be gated at 42 inches and the rpm levers at 2300rpm. These handling notes are for the B314A.
Many, many hours later the boat's weight will have reduced to 65,000lbs. Now you will normally be light enough to sustain a drag of 135 KIAS using full throttle and 1700 rpm. As usual it depends on the weather. If you are not maintaining your own flight plan, use the FS9 Aircraft / Fuel & Payload menu to monitor current weight. On reaching 65,000lbs reduce to economical cruise power which is 1700 rpm and 29 inches. At this point your fuel burn will be down to 1600 PPH. The goal in nil wind is to sustain 135 KIAS, (see propliner tutorial for headwinds and tailwinds). When cruising at < 65,000lbs if drag rises above 135 KIAS trickle reduce rpm below 1700, hour by tedious hour, to prevent any such increase.
With a significant headwind, in any piston engined aircraft, you must always increase your fuel burn and drag or you will run out of fuel. If you lack real world aircrew experience use the Propliner Tutorial to understand how to manage both power and altitude when flying a propliner in real weather. You must make all the appropriate captaincy decisions. Controlling the miles per gallon is your job not mine. Avoiding ditching because you made the wrong captaincy decisions concerning applied power and flight plan cruising level is your job not mine.
In the event of headwinds, under ISA conditions, max cruise power is available up to FL60, but max altitude for max cruise power will vary with the weather. Remember if you run into headwinds you may need to reduce both cruising altitude and cruising velocity to increase cruising speed. If concepts such as increasing fuel burn to prevent running out of fuel, or reducing velocity to increase speed seem odd you should never import real weather into your simulation. The navigation of aircraft is not a 2D process. The Propliner Tutorial is essential reading (for non aircrew) before attempting to operate propliners with realistic flight dynamics in real weather. The B314A is not a special case except that however great the headwind you must limit the desired increase in drag (IAS) to only 20 extra knots (less than 15% increase).
The weak redesigned tail (see B314_history.txt) is this boat's Achilles' heel. Operation into headwinds is more than usually dangerous. The weak tail may prevent you from adding enough extra fuel burn (PPH), or sufficient drag (IAS), to overcome the headwind, since if drag is in danger of exceeding 155 KIAS you must reduce below max cruise power. The risk of ditching is therefore abnormally high. Consequently the need to reduce velocity (TAS) by cruising at lower altitudes to increase speed (GS) with higher drag (IAS) is greater than usual. If the power required due to headwinds is not available at your chosen
flight plan altitude descend until it is available. There is no high speed cruise setting.
After the first few minutes of each flight, by cruise climbing, you will have reduced fuel burn to around 2200 PPH. If you follow the procedures above burn will reduce to less than 2000 PPH by top of cruise climb and about 1500 PPH by top of descent. With full tanks you have about 16 hours practical endurance with the drag pegged at 135 KIAS which will deliver an average cruising velocity in excess of 155 KTAS allowing legs of around 2500 miles in nil wind, but only if you operate the boat in accordance with the guidance given above.
Remember unless operating the boat under war emergency powers full fuel can only be loaded with no payload at all. For every pound of payload you put aboard you must remove one pound of fuel using the FS9 menu (*never the aircraft.cfg*). This boat was designed to fly 800 or so miles from Baltimore to Bermuda with a large payload and little fuel, but only BOAC used it that way. PAA commercial services could carry only very limited payload especially on long hauls such as KSFO - PHNL. For such routes you must calculate your air miles per gallon carefully taking into account the forecast wind vector and delay your departure for as many hours or days as may be necessary.
In the event of engine failure return to your point of departure or continue to destination, whichever delivers the lesser air miles, with the remaining engines in climb power = 2100/37.5. This is the only time that climb power will ever be relevant. METO power is available of course, but over the ocean will never be needed on commercial flights even following engine failure.
At flight plan top of descent, (see propliner tutorial), begin to reduce MAP at about one inch per minute to coddle the engines. Descend at less than minus 700 VSI and less than 155 KIAS. During descent both AP modes may be employed until just before first use of flap when the AP must be disconnected. If you are simulating operation of the boat by US aircrew you will wish to fly oversquare (MAP => rpm/1000) until you are downwind in the pattern. This does not apply to BOAC boats.
If you wish to fly instrument approaches in this boat use the Signal Corps Receiver which must be tuned by the radio operator or navigator from the appropriate pop up cockpit panel. If you are accustomed to using a proper radio compass with a full compass ring you may find the deliberate obscuration of
most of the compass arc by U.S. Government decree annoying, but if you want to fly with post war instruments, or contrary to US regulations which inhibit area navigation, by withholding bearing information, you should simulate the operation of post war or non US aircraft.
Once you get used to using a U.S. Signal Corps Receiver you will realise that it really poses no problem. It forces you to intercept any published course TO a signal source as though you were intercepting a LOC and only withholds bearing information you might use to cut corners. It never makes it harder to fly the mandated procedure; it just makes it harder not to, and that was the whole idea.
Whether or not from an instrument approach, enter a standard visual circuit for the aquadrome in question. Early downwind advance the screws to full fine. Disconnect the AP if in use and reduce drag below 105 KIAS. Then by turns deploy the first two stages of flap. Extend downwind for a long final. Extend two further stages of flap only after you are lined up with the into wind landing lane and only after reducing drag below 91 KIAS. Always confirm that the company launch has swept the marked lane of flotsam. This is not possible at night. Do NOT attempt to fly a modern airliner 3 degree glideslope and flare.
Make a long shallow final descent to less than 50 feet over the sea at 80 KIAS and then in level flight cut the throttles. Allow the boat to sink slowly through the surface effect onto the water in a slightly nose up attitude with speed hardly decaying at no more than minus 100 VSI. If ditching at very high weights, or following engine failure, aim for 85 KIAS instead. These boats did not normally land at more than 65,000lbs unless ditching, though 80,000lbs is acceptable with care.
The boat will decelerate more rapidly, and bounce fewer times, than in real life due to the excessive water viscosity in MSFS.
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Continued in next post...
Posts: 2874
Re: B-314 Throttle problem
« Reply #16 on: Jul 17th, 2008, 8:48am » Quote Modify
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A heavy aircraft must cruise below design cruise altitude until it reaches design cruise weight. This precludes acceleration to design cruise velocity (158 KTAS). If you decide to overload the aircraft in accordance with war emergency regulations you may not be able to reach design cruise altitude or design cruise velocity during the first eight hours of the flight, but at public transport weights it will normally take less than an hour of careful energy state management to accelerate the boat to design cruise velocity without using more than max cruise power.
These 'realistic' FD allow the boat to be up to 19% overloaded as operated under war emergency powers. For reasons that I have explained above there is however no guarantee that you will have the weather and sea state to achieve take off at that war overload weight on any particular day within FS9, because there was no such guarantee in real life. Use the FS9 menu to add up to 16,000lbs of extra payload for BOAC war emergency operations, or 13,000lbs extra for US Navy war emergency operations. You cannot add fuel. There is nowhere to put it. Increase the longitudinal trim values at overload weights or you will not unstick in FS9.
..............
Payload and fuel should only ever be altered using the FS9 on screen menu never the aircraft.cfg. Information within an aircraft.cfg should be altered only to vary an aircraft type from e.g. L049A to L049E or L149, not to vary the load on the original aircraft type. That is what the FS9 menu is for.
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For the B314A the situation was that if it was light enough to unstick, in the prevailing wind and wave state, without exceeding the fragile flap limit, it was also light enough to break free from surface effect and achieve design cruise drag (135 KIAS) using max cruise power. That of course in no way implies that it could achieve design cruise velocity (158 KTAS) before running out of fuel trying to reach the necessary design cruise altitude. That depended on the payload, the route length and the weather.
The real problems that dogged this boat, precluding significant production, and causing half the US owned boats to be laid up almost as soon as they were delivered, are explained in B314_history.txt. It will help you to understand this complicated aircraft better if you appreciate the gulf between the propaganda and the truth about this aircraft and the real problems that limited its production and utility before you simulate its operation in detail, but be warned this is not an aircraft whose real flight dynamics, instrumentation, and operating procedures will please anyone with limited flight simulation experience. It is however potentially educational.
I will try to answer questions arising from these FD and handling notes in the calclassic forum.
>>>>>>>>>>>>>>>>>>>>>
All the above is just extracted from the supplied documentation.
All of the original problems cited in this latest thread were once again the result of using the aircraft.cfg from one release with the air file from another. That will never work. The answers to the outstanding questions are as follows;
''Speaking of "necessary fuel"-- how come there are only two tanks when there are gauges for four?''
The panel was created by Ken Mitchell to support Mike Stone's original flight dynamics. The real aircraft had many tanks. It is only the total fuel we decide to load for the flight that matters anyway. Two tanks are sufficient to model the dynamic inertia consequence of fuel distribution in this particular aircraft.
''The MSFS flight planner also calls for more gas than the plane can carry to get to Hawaii, too.''
The MSFS flight planner is useless for fuel planning. They all are. Hence the need for contradictory guidance in the Propliner Tutorial and the eventual production of the Calclassic Planning Tool now being beta tested as part of the Calclassic Notepad package.
'' While I understand the concept behind FS Aviator's "Classic Fuel Planning" it's tough to do when there's no guage to tell you how much fuel the plane is using (at least I havn't seen one). BMEP is not, as far as I know, a measure of fuel usage.''
Fuel planning takes place before flight. Gauges are irrelevant to planning. The real aircraft had no fuel flow flow gauges. NAV asked the FE for the current contents every 20 minutes and calculated PPH accordingly. Those who flight plan in full will do the same every 20 minutes to calculate route fuel exhaustion time and will compare it to ETA as both vary.
The required planning information is in the supplied Briefing.txt. The most relevant extracts are;
<<[fuel] Max fuel was about 5400 USG usable, but for everything except trans Atlantic crossings 4000 USG was more usual.>>
<<This allows wartime emergency overload operation but the default at anchor weight represents commercial certification of the B314A at 84,000lbs which allowed full tanks with zero payload.>>
<<After the first few minutes of each flight, by cruise climbing, you will have reduced fuel burn to around 2200 PPH. If you follow the procedures above burn will reduce to less than 2000 PPH by top of cruise climb and about 1500 PPH by top of descent. With full tanks you have about 16 hours practical endurance with the drag pegged at 135 KIAS which will deliver an average cruising velocity in excess of 155 KTAS allowing legs of around 2500 miles in nil wind, but only if you operate the boat in accordance with the guidance given above.
<<On reaching 65,000lbs reduce to economical cruise power which is 1700 rpm and 29 inches. At this point your fuel burn will
be down to 1600 PPH.>>
So we start with up to 32,400lbs of AVGAS for pre war propaganda flights with little or no worthwhile payload until we are authorised to attempt take off > 84,000lbs under war emergency powers. We decide our take off weight. We decide when the boat will be down to 65,000lbs. Our PPH starts at 2200 and is down to 2000 about an hour later once we are full throttle cruising well above rated altitude. It declines to 1600 PPH when we reach 65,000lbs.
The mean burn will be => 1800 PPH while we are reducing weight, from whatever we started at, to 65,000lbs and 1600 PPH reducing to 1500 PPH thereafter. If we assume a mean burn of 1900 PPH prior to the availability of low RPM cruising and we depart at the commercial certification maximum of 84,000lbs it will take (84000-65000) / 1900 hours = 10 hours to reach 65,000lbs and initiate low RPM cruising at <= 1600 PPH.
If we use 1900 * 10 = 19,000 lbs in the first 10 hours we have 13,400lbs remaining to dry tanks which we will burn at <= 1600 PPH so it will last just over another eight hours to dry tanks. Endurance using commercial power settings is around 18 hours to dry tanks. Mean cruising velocity will be just a little slower than the design cruise velocity of 158 KTAS which applies to mid cruise weight. Nil wind we can expect around 18 hours * 155 KTAS = 2800 miles to dry tanks. KSFO to PHNL is only about 2100 miles. The automated flight planners used with MSFS are useless for fuel planning! They make a series of false assumptions by design and the design of the default MS planner is particularly bad.
There is more than enough tankage to lift a small payload to Honolulu for propaganda purposes in nil wind, or even with a minimal (potentially unsafe) pre war headwind reserve, but the B314A was explicitly designed to fly less then 800 miles from Baltimore (or New York) to the British offshore banking centre of Bermuda; carrying a large payload of whatever those who purchased the very expensive tickets wished to remove from scrutiny by U.S. authorities. The boats designed to fly the PAA Pacific routes were the three Martin M-130 China Clippers. The Boeings were driven into the Pacific by the war in Europe. The Boeing B314A Clipper was designed for Atlantic short hauls.
The document B314_History.txt supplied within the Calclassic download explains further and will help anyone who really wants to understand the commercial failure, and the real operating difficulties, of the B314 and B314A to do so. Finally the 2008 Propliner Tutorial is now supplemented by the Savoia Marchetti S.73 V2 release hosted at Avsim and elsewhere which explains use of pilot goniometers, (such as the U.S. Army Signal Corps Receiver in the B314A), in more detail than the Propliner Tutorial. The S.73 release also contains the relevant goniometer training aids.
Those supplied training exercises feature Oostende (EBOS) in Belgium. They can be flown using the B314A. We can fly the approach to the instrument runway at pre war EBOS. Once below all cloud and certain of our position over EBOS aerodrome, even in bad weather we can use pioneer era techniques to navigate to the coast and follow it eastward at low level into the Wester Schelde estuary, following the shore to Antwerp, before landing in the sheltered swept lane outside the port of Antwerp. Then we can transpose those training exercises to Shannon, or Baltimore, or Lagos, or Lisbon so that we can locate the relevant sheltered and swept B314A hydroplane landing lanes (usually just outside the port), anywhere in bad weather after an instrument approach; potentially to an instrument runway on land.
The B314A's pilot goniometer can also be used to fly the Grumman Goose instrument approach exercise into Greenville aquadrome (3B1_NDB_14 available in Part 4 of the Propliner Tutorial). Transpose that training to other aquadromes which have their own instrument approach to the aquadrome visual circuit pattern.
BOAC allowed their pilots access to ADF from first delivery in 1941 and I expect the US Navy war emergency procedures allowed contracted PAA pilots access to ADF from 1942.
The more realism we learn to incorporate the more interesting flight simulation becomes. MSFS is extremely versatile in what it can be used to simulate and we can discover a great deal about pre classic era aviation. However I am afraid there is no way round it. The price of realism is complexity and understanding that complexity may require substantial effort to study and understand lengthy supplied documentation.
FSAviator.
« Reply #13 on: Jul 17th, 2008, 8:42am » Quote Modify
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Hi,
And here is a reply from FSAviator:
One the great advantages of downloading files from Calclassic .com is that most have all the necessary documentation explaining how to actually use what was downloaded. The learning curve may however be steep. All the information required to operate a B314A 'realistically' is in the Calclassic download. Some of it is repeated below. Some of what follows applies to all flying boats and may be of wider interest. It does not repeat the information in the aliased thread I posted the last time the same problem arose from installation of mismatched B314A files.
My B314A aircraft.cfg explains;
>>>>>>>>>>>>>>>>
performance= These flight dynamics by FSAviator integrate the panel by Ken Mitchell with the Boeing Clipper MDL by Mike Stone and the operating procedures within Briefing.txt enclosed. Some data by Mike Stone and Ken Mitchell retained in this file. Download the aircraft and panel from their original upload locations and install as instructed before adding these files.
[fuel]
Max fuel was about 5400 USG usable, but for everything except trans Atlantic crossings 4000 USG was more usual. Unusable fuel is in the APS weight. In reality there were more than 2 tanks.
fuel_type = 1
number_of_tank_selectors = 1
electric_pump = 1
LeftMain = 0, -12, 0, 2700, 0
RightMain = 0, 12, 0, 2700, 0
[weight_and_balance]
reference_datum_position = 0.000, 0.000, 0.000
empty_weight_CG_position = 0.000, 0.000, 0.000
max_gross_weight = 100000 //BOAC war emergency only - PAA war emergency gross was 97000
This allows wartime emergency overload operation but the default at anchor weight represents commercial certification of the B314A at 84,000lbs which allowed full tanks with zero payload.
empty_weight = 50000 ;Aircraft prepared for service with unusable fuel, 300 gallons of engine oil, etc. Up to a thousand pounds heavier after the war with more seats fitted.
station_load.0 = "1600,0,0,0, 8 crew + kit" ;8 or fewer crew on BOAC boats but PAA boats had 10 to 12 crew until 1942
station_load.1 = "0, 0, 0, 0, payload" ;Certification allowed full fuel only with zero payload.
By default these FD have full fuel tanks so that you can fly any flight that the B314A actually flew including propaganda flights with no payload. When simulating airline flying, before and after the war, increase the payload and reduce the fuel by the same amount using the payload menu of FS9. To simulate war emergency operations just add or subtract payload until you cannot take off without exceeding the flap limit in the prevailing wave and wind state or you reach 97,000lbs PAA / 100,000lbs BOAC.
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These extracts from the supplied Briefing.txt then go on to explain;
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INSTALLATION
After renaming the existing aircraft.cfg to aircraft.old, and panel.cfg to panel.old, move all the provided files, including this one, into the relevant folders where you have previously installed Mike Stone's Boeing Clipper and Ken Mitchell's Clipper panel. Download and install the BOAC textures, or delete the relevant section from the top of the aircraft.cfg.Copy (not move) the gauge cabs from the default DC-3 and the default Lockheed Vega into the folder where you have already installed Ken Mitchell's B314A panel, (*not* your gauges folder), else some replacement gauges may not appear.
PANEL ISSUES.
To make use of these files which are intended to allow ‘realistic’ operation of the B314A, using the simulation notes below, users will need a fully functional panel integrated for use with these dynamics and those handling notes. The enclosed air file will only work properly with the specified panel and in association with the enclosed panel.cfg and aircraft.cfg. You may of course add additional liveries, effects, etc to that aircraft cfg.
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The cowl flap gauges in the B314 panel by Ken Mitchell cannot control engine drag. If you wish to have functional cowl flaps you will need to substitute, within the overhead panel, the fully functional cowl flap controls from his DC-6 panel. If you choose to use cowl flaps you must become the FE as well. Use CHT and oil temperature as your reference. Simply avoid the yellow arcs on all gauges except as a transient. Do not use cowl flaps during simulation unless you add functional gauges to the panel.
These files allow individual control of each engine to simulate realistic water handling. You may find this cumbersome and under some circumstances you may find it difficult to switch between single engine and all engines mode. If so there is a gauge you can download from Avsim.com (rcbse-10.zip) which solves this problem. If you do not have the problem you do not need to add that gauge.
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A photo indicating the sparse nature of the real panel is here;
www.zpub.com/sf/history/boeing314.html
The revised cockpit environment has a suitably reduced complement of gauges on the main panel, but gains a clock so that you can fly published procedures.
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BMEP gauges containing the real world formula should indicate BMEP correctly if the relevant data is stated correctly in the aircraft.cfg. However in my opinion BMEP had little relevance to operation of the B314A. It may have had relevance in the original B314. It is of no consequence since if nobody knows the BMEP avoid ranges, for either aircraft, any gauges provided are just eye candy anyway and cannot contribute to the simulation. Knowing the rpm avoid ranges is not enough to calculate the BMEP avoid ranges so the aircraft must be operated using the rpm gauges. Feel free to run oversquare if simulating US operations. I think it is unlikely that BOAC took any notice of oversquare mythology.
Continued in next post...
IP Logged
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Tom Gibson
California Classic Propliners: www.calclassic.com/
AlcoHauler Locomotive Page: www.calclassic.com/alco/
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Tom Gibson
Forum Administrator
Jets are for Kids!
Posts: 2874
Re: B-314 Throttle problem
« Reply #14 on: Jul 17th, 2008, 8:44am » Quote Modify
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MSFS and FLYING BOATS.
MSFS has the viscosity of water hard coded to an excessive value. However the weight limit for this and most other hydroplanes is not limited by that bug. The limit is usually the structural strength of the flaps. Full details of flap operation using these FD are below. For the moment note that you must reject an
attempted take off if you have not achieved unstick approaching the twenty degree flap drag limit which is 105 KIAS. How much before 105 KIAS you must abort depends on your skill at restraining the boat to <= 105 KIAS after unstick whilst the FE raises the flaps.
Remember the length of the take off run depends on wind and wave state. As in real life you can create an effective increase in wave state by longitudinal rocking of the boat with the elevators. Due to the viscosity bug it is impossible to write aircrew code that accelerates the boat correctly in both air and water. Air must take precedence. The landing distance is shorter than it should be. The take off run and time are unlikely to be within 5% of reality.
The real B314A lacked a water rudder. It also lacked outboard floats which could be dug into the water with a 'wheel over'. Consequently on the surface you can only manoeuvre using asymmetric power. If it is too much trouble just use the slew controls when on the surface.
MSFS has another bug afflicting elevator trim in all aircraft. This bug allows the trim setting to override applied elevator. It is essential to trim correctly for take off. This is especially true for flying boats at marginal unstick weights.The operating weights in these FD are by default those of the airline certification and apply to commercial usage in peacetime public transport service. In that default condition the B314A will unstick in a flat calm, under ISA conditions,
but only if you follow the operating guide below. Read it carefully. Do not use guidance provided elsewhere.
*************** BOEING B314A 'Clipper' OPERATING GUIDE **********************
I believe that the inputs promulgated below are within 5% of reality. The FD will anyway deliver output within 5% of reality when the promulgated inputs are made.
The B314A was not designed to be flown in compliance with the IFR, or on Airways. Unlike other U.S. propliners of the late 1930s it was designed to cruise climb off airways, in unregulated airspace, even in IMC. This was possible because it always departed over an ocean with no obstructions and outside the tightly regulated environment over the CONUS. Consequently step climb procedures do not apply to this boat.
Whilst everything that follows is specific to the B314A the generic principles may be adopted for the trans oceanic operation of all hydroplanes in MSFS. They override the propliner tutorial, but only for trans oceanic departure and cruise, and only for hydroplanes. Boats operated across a land mass, on riverine and/or inter lake services should be flown in accordance with the propliner tutorial. For such services weight should be reduced to ensure that operational ceiling (see propliner tutorial) exceeds the altitude of the highest obstruction en route by not less than 1500 feet.
When operating a hydroplane over the ocean you will often have the intention to exceed operational ceiling since your operational ceiling may be below sea level. Service ceiling has no practical relevance in aircraft with airscrews.
The take off procedure is simulated thus.
Before take off set mixture to automatic in the FS9 realism menu, set carb heat cold and longitudinal trim to plus 15. Set the screws fully fine.
The real aircraft had what amount to press to travel flap controls like those fitted in many real Cessna singles. Any flap angle could be selected. Tables were used to calculate the optimum angle based on sea state and weight. Since these tables are not available I have coded the flaps in stages operated with the F7 and F6 keys in the usual way. It is not pilot flying who operates the flaps. It is the FE. Use the F6 and F7 keys to tell the FE what angle to set and leave him to fiddle with the flap controls. Setting precise flap angles is not your job as PF. Your job is commanding the change at the right moment.
This is an aircraft from the vintage era, not the classic era. The flaps were very frail.
Always take off into wind. Steadily apply full throttle. On reaching 60 KIAS extend FLAP 1. On reaching 85 KIAS extend FLAP 2. At 95 KIAS attempt unstick. If the boat will not unstick commence longitudinal rocking until it does. If it will not rock off before reaching 105 KIAS you must abort and await a more favourable headwind, lower temperature, lower air pressure, or a more favourable wave state.
Extending the flaps at the right moments in the procedure is an essential part of the process of breaking the surface tension, getting the boat to hydroplane on the chined step, and eventually unsticking. Once free of the water the boat will accelerate quickly in TOGA power. This effect is overstated in FS9 by comparison to the excessive drag of the over viscous FS9 water. Use back pressure to restrain any tendency to sink back onto the water whilst FE retracts the flaps. Do not exceed 105 KIAS with flap extended. Pitch the boat up as necessary to prevent drag on the flaps exceeding 105 KIAS. The flaps may suffer (asymmetric) structural failure at higher drag with fatal consequences. I decline to steal copyright photos and upload them to the internet so please view the photo at;
www.zpub.com/sf/history/boeing314.html
which gives a good impression of required attitude post unstick whilst retarding IAS to the fragile flap limit.
Only after the FE (use the keyboard) has retracted all flap allow drag to rise to 120 KIAS.
Never intentionally allow drag to exceed 155 KIAS with flaps up. The tail may suffer structural failure. FS9 will autocalculate the probability and kill all aboard as appropriate. How accurately this works will depend on the quality of the weather data you imported.
On achieving 120 KIAS retard to METO power = 2300/37.5 and climb to 1000 feet at 120 KIAS.
Now retard to 2100 rpm for the cruise climb which will be conducted in max cruise power, *not* climb power. Climb power is not really a relevant concept in this boat, (or most other vintage boats). In the B314A it overheats the engines, requires you to add engine drag via the cowl flaps, and reduces the already far too short overhaul interval.
Reduce to 35 inches MAP. Finally allow drag to rise to 135 KIAS and then cruise climb with max cruise power = 2100/35 set on all engines and with the drag pegged at 135 KIAS. Trim can never command a pitch; it can only command a drag (IAS). Following a max gross departure at 84,000lbs plus 4 longitudinal trim will command 135 KIAS in ISA regardless of aircraft pitch or power.
Constantly adjust the four throttles to sustain exactly 35 inches from each engine as you climb. Once above FL60 the turbines cannot generate 35 inches. You cannot supply the turbines with enough power. Thereafter use full throttle and 2100 rpm for the cruise climb. Remember full throttle has little correlation with full power. MAP and power will fall as you climb at full throttle into ever thinner air and the boat will accelerate and accelerate and accelerate, to higher and higher velocity (TAS), as the power reduces, with the drag pegged at 135 KIAS.
There is no target rate of climb. Under war overload conditions it will eventually be minimal and may appear to be zero. You have no ATC assigned level. Just peg the drag at 135 KIAS with the trim wheel. Once you have set the trim to demand the target drag it will command that drag whatever happens to power, air pressure or air temperature. In any aircraft pitch will vary as the trim commands the target drag. There is no such thing as pitch trim. That's why the Sperry AP had to be invented. To command a pitch it has to alter trim. Consequently you must NOT use the pitch mode of the Sperry AP. You must target constant drag using constant trim, not constant VSI, or constant pitch using an AP. You can only maximise acceleration in any aircraft by going uphill with reducing power.
You may however use the HDG hold mode of the Sperry AP at any time when the flaps are fully up.
As weight changes the trim required to peg the drag at 135 KIAS varies, but equally slowly. You may need to make a minor adjustment every 15 minutes or so.
Continued in next post...
Tom Gibson
Forum Administrator
Re: B-314 Throttle problem
« Reply #15 on: Jul 17th, 2008, 8:45am » Quote Modify
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Design cruise altitude of the B314A was FL110. PAA and PAA crews flying USN boats proceeded accordingly, but see also relevant sections of the propliner tutorial concerning 4D flight planning and navigation if you intend to import winds into the simulation. Under US certification do not exceed FL120 for more than 30 minutes per flight (and only if necessary to avoid bad weather).
On achieving flight plan cruise altitude Sperry AP pitch hold may be engaged to prevent further climb. BOAC were governed by Ministry of War, (and later BCAR), regulations concerning flight without oxygen and consequently did not exceed FL100 by day or FL80 by night, (for more than 30 minutes per flight). Cruise BOAC boats accordingly. Your encounters with icing will reduce.
Do not attempt to land a commercial flying boat at night. Night departures are dangerous too, but may be necessary. Plan your departure taking account of planetary rotation so that your arrival up to 16 hours later is always in daylight.
It will normally take under an hour to cruise climb to design cruise altitude (FL110) at peacetime weights, but it depends on the weather. If you do not allow your drag to drop below 135 KIAS you should not need to augment engine drag by cowl flap opening. Don't use the cowl flaps to increase engine drag unless the CHT, or oil temperature, is in the yellow caution arc. Augmentation of engine drag via use of cowl flaps may sometimes be necessary for engine cooling during a cruise climb under tropical conditions. It will depend on the weather, but the whole idea is to avoid that requirement by conducting a cruise
climb with high natural engine drag at modest and reducing power. Do not use cowl flaps unless you have added functional cowl flap gauges that increase drag.
Eventually you must undertake some parts of the flight engineer function as well as the roles of PF, PNF, captain, radio operator and navigator. On reaching final cruising level the FE must prevent drag rising above 135 KIAS by very slowly trickle reducing MAP, hour after hour after tedious hour. Ideally you would trickle reduce rpm whilst running at full throttle instead, but these poorly designed airscrews suffer terribly from harmonic vibration between 2050 and 1750 rpm so you must sustain an uneconomical 2100 rpm and throttle the engines. It's bad news for engine maintenance and renders the BMEP gauge irrelevant.
The early B314 boats had been fitted with alternative airscrews that did not have this horrendous avoid range. The problem was that those screws limited the engines to 1500 bhp at best. The throttles of the B314 had to be gated at 42 inches and the rpm levers at 2300rpm. These handling notes are for the B314A.
Many, many hours later the boat's weight will have reduced to 65,000lbs. Now you will normally be light enough to sustain a drag of 135 KIAS using full throttle and 1700 rpm. As usual it depends on the weather. If you are not maintaining your own flight plan, use the FS9 Aircraft / Fuel & Payload menu to monitor current weight. On reaching 65,000lbs reduce to economical cruise power which is 1700 rpm and 29 inches. At this point your fuel burn will be down to 1600 PPH. The goal in nil wind is to sustain 135 KIAS, (see propliner tutorial for headwinds and tailwinds). When cruising at < 65,000lbs if drag rises above 135 KIAS trickle reduce rpm below 1700, hour by tedious hour, to prevent any such increase.
With a significant headwind, in any piston engined aircraft, you must always increase your fuel burn and drag or you will run out of fuel. If you lack real world aircrew experience use the Propliner Tutorial to understand how to manage both power and altitude when flying a propliner in real weather. You must make all the appropriate captaincy decisions. Controlling the miles per gallon is your job not mine. Avoiding ditching because you made the wrong captaincy decisions concerning applied power and flight plan cruising level is your job not mine.
In the event of headwinds, under ISA conditions, max cruise power is available up to FL60, but max altitude for max cruise power will vary with the weather. Remember if you run into headwinds you may need to reduce both cruising altitude and cruising velocity to increase cruising speed. If concepts such as increasing fuel burn to prevent running out of fuel, or reducing velocity to increase speed seem odd you should never import real weather into your simulation. The navigation of aircraft is not a 2D process. The Propliner Tutorial is essential reading (for non aircrew) before attempting to operate propliners with realistic flight dynamics in real weather. The B314A is not a special case except that however great the headwind you must limit the desired increase in drag (IAS) to only 20 extra knots (less than 15% increase).
The weak redesigned tail (see B314_history.txt) is this boat's Achilles' heel. Operation into headwinds is more than usually dangerous. The weak tail may prevent you from adding enough extra fuel burn (PPH), or sufficient drag (IAS), to overcome the headwind, since if drag is in danger of exceeding 155 KIAS you must reduce below max cruise power. The risk of ditching is therefore abnormally high. Consequently the need to reduce velocity (TAS) by cruising at lower altitudes to increase speed (GS) with higher drag (IAS) is greater than usual. If the power required due to headwinds is not available at your chosen
flight plan altitude descend until it is available. There is no high speed cruise setting.
After the first few minutes of each flight, by cruise climbing, you will have reduced fuel burn to around 2200 PPH. If you follow the procedures above burn will reduce to less than 2000 PPH by top of cruise climb and about 1500 PPH by top of descent. With full tanks you have about 16 hours practical endurance with the drag pegged at 135 KIAS which will deliver an average cruising velocity in excess of 155 KTAS allowing legs of around 2500 miles in nil wind, but only if you operate the boat in accordance with the guidance given above.
Remember unless operating the boat under war emergency powers full fuel can only be loaded with no payload at all. For every pound of payload you put aboard you must remove one pound of fuel using the FS9 menu (*never the aircraft.cfg*). This boat was designed to fly 800 or so miles from Baltimore to Bermuda with a large payload and little fuel, but only BOAC used it that way. PAA commercial services could carry only very limited payload especially on long hauls such as KSFO - PHNL. For such routes you must calculate your air miles per gallon carefully taking into account the forecast wind vector and delay your departure for as many hours or days as may be necessary.
In the event of engine failure return to your point of departure or continue to destination, whichever delivers the lesser air miles, with the remaining engines in climb power = 2100/37.5. This is the only time that climb power will ever be relevant. METO power is available of course, but over the ocean will never be needed on commercial flights even following engine failure.
At flight plan top of descent, (see propliner tutorial), begin to reduce MAP at about one inch per minute to coddle the engines. Descend at less than minus 700 VSI and less than 155 KIAS. During descent both AP modes may be employed until just before first use of flap when the AP must be disconnected. If you are simulating operation of the boat by US aircrew you will wish to fly oversquare (MAP => rpm/1000) until you are downwind in the pattern. This does not apply to BOAC boats.
If you wish to fly instrument approaches in this boat use the Signal Corps Receiver which must be tuned by the radio operator or navigator from the appropriate pop up cockpit panel. If you are accustomed to using a proper radio compass with a full compass ring you may find the deliberate obscuration of
most of the compass arc by U.S. Government decree annoying, but if you want to fly with post war instruments, or contrary to US regulations which inhibit area navigation, by withholding bearing information, you should simulate the operation of post war or non US aircraft.
Once you get used to using a U.S. Signal Corps Receiver you will realise that it really poses no problem. It forces you to intercept any published course TO a signal source as though you were intercepting a LOC and only withholds bearing information you might use to cut corners. It never makes it harder to fly the mandated procedure; it just makes it harder not to, and that was the whole idea.
Whether or not from an instrument approach, enter a standard visual circuit for the aquadrome in question. Early downwind advance the screws to full fine. Disconnect the AP if in use and reduce drag below 105 KIAS. Then by turns deploy the first two stages of flap. Extend downwind for a long final. Extend two further stages of flap only after you are lined up with the into wind landing lane and only after reducing drag below 91 KIAS. Always confirm that the company launch has swept the marked lane of flotsam. This is not possible at night. Do NOT attempt to fly a modern airliner 3 degree glideslope and flare.
Make a long shallow final descent to less than 50 feet over the sea at 80 KIAS and then in level flight cut the throttles. Allow the boat to sink slowly through the surface effect onto the water in a slightly nose up attitude with speed hardly decaying at no more than minus 100 VSI. If ditching at very high weights, or following engine failure, aim for 85 KIAS instead. These boats did not normally land at more than 65,000lbs unless ditching, though 80,000lbs is acceptable with care.
The boat will decelerate more rapidly, and bounce fewer times, than in real life due to the excessive water viscosity in MSFS.
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Continued in next post...
Posts: 2874
Re: B-314 Throttle problem
« Reply #16 on: Jul 17th, 2008, 8:48am » Quote Modify
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A heavy aircraft must cruise below design cruise altitude until it reaches design cruise weight. This precludes acceleration to design cruise velocity (158 KTAS). If you decide to overload the aircraft in accordance with war emergency regulations you may not be able to reach design cruise altitude or design cruise velocity during the first eight hours of the flight, but at public transport weights it will normally take less than an hour of careful energy state management to accelerate the boat to design cruise velocity without using more than max cruise power.
These 'realistic' FD allow the boat to be up to 19% overloaded as operated under war emergency powers. For reasons that I have explained above there is however no guarantee that you will have the weather and sea state to achieve take off at that war overload weight on any particular day within FS9, because there was no such guarantee in real life. Use the FS9 menu to add up to 16,000lbs of extra payload for BOAC war emergency operations, or 13,000lbs extra for US Navy war emergency operations. You cannot add fuel. There is nowhere to put it. Increase the longitudinal trim values at overload weights or you will not unstick in FS9.
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Payload and fuel should only ever be altered using the FS9 on screen menu never the aircraft.cfg. Information within an aircraft.cfg should be altered only to vary an aircraft type from e.g. L049A to L049E or L149, not to vary the load on the original aircraft type. That is what the FS9 menu is for.
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For the B314A the situation was that if it was light enough to unstick, in the prevailing wind and wave state, without exceeding the fragile flap limit, it was also light enough to break free from surface effect and achieve design cruise drag (135 KIAS) using max cruise power. That of course in no way implies that it could achieve design cruise velocity (158 KTAS) before running out of fuel trying to reach the necessary design cruise altitude. That depended on the payload, the route length and the weather.
The real problems that dogged this boat, precluding significant production, and causing half the US owned boats to be laid up almost as soon as they were delivered, are explained in B314_history.txt. It will help you to understand this complicated aircraft better if you appreciate the gulf between the propaganda and the truth about this aircraft and the real problems that limited its production and utility before you simulate its operation in detail, but be warned this is not an aircraft whose real flight dynamics, instrumentation, and operating procedures will please anyone with limited flight simulation experience. It is however potentially educational.
I will try to answer questions arising from these FD and handling notes in the calclassic forum.
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All the above is just extracted from the supplied documentation.
All of the original problems cited in this latest thread were once again the result of using the aircraft.cfg from one release with the air file from another. That will never work. The answers to the outstanding questions are as follows;
''Speaking of "necessary fuel"-- how come there are only two tanks when there are gauges for four?''
The panel was created by Ken Mitchell to support Mike Stone's original flight dynamics. The real aircraft had many tanks. It is only the total fuel we decide to load for the flight that matters anyway. Two tanks are sufficient to model the dynamic inertia consequence of fuel distribution in this particular aircraft.
''The MSFS flight planner also calls for more gas than the plane can carry to get to Hawaii, too.''
The MSFS flight planner is useless for fuel planning. They all are. Hence the need for contradictory guidance in the Propliner Tutorial and the eventual production of the Calclassic Planning Tool now being beta tested as part of the Calclassic Notepad package.
'' While I understand the concept behind FS Aviator's "Classic Fuel Planning" it's tough to do when there's no guage to tell you how much fuel the plane is using (at least I havn't seen one). BMEP is not, as far as I know, a measure of fuel usage.''
Fuel planning takes place before flight. Gauges are irrelevant to planning. The real aircraft had no fuel flow flow gauges. NAV asked the FE for the current contents every 20 minutes and calculated PPH accordingly. Those who flight plan in full will do the same every 20 minutes to calculate route fuel exhaustion time and will compare it to ETA as both vary.
The required planning information is in the supplied Briefing.txt. The most relevant extracts are;
<<[fuel] Max fuel was about 5400 USG usable, but for everything except trans Atlantic crossings 4000 USG was more usual.>>
<<This allows wartime emergency overload operation but the default at anchor weight represents commercial certification of the B314A at 84,000lbs which allowed full tanks with zero payload.>>
<<After the first few minutes of each flight, by cruise climbing, you will have reduced fuel burn to around 2200 PPH. If you follow the procedures above burn will reduce to less than 2000 PPH by top of cruise climb and about 1500 PPH by top of descent. With full tanks you have about 16 hours practical endurance with the drag pegged at 135 KIAS which will deliver an average cruising velocity in excess of 155 KTAS allowing legs of around 2500 miles in nil wind, but only if you operate the boat in accordance with the guidance given above.
<<On reaching 65,000lbs reduce to economical cruise power which is 1700 rpm and 29 inches. At this point your fuel burn will
be down to 1600 PPH.>>
So we start with up to 32,400lbs of AVGAS for pre war propaganda flights with little or no worthwhile payload until we are authorised to attempt take off > 84,000lbs under war emergency powers. We decide our take off weight. We decide when the boat will be down to 65,000lbs. Our PPH starts at 2200 and is down to 2000 about an hour later once we are full throttle cruising well above rated altitude. It declines to 1600 PPH when we reach 65,000lbs.
The mean burn will be => 1800 PPH while we are reducing weight, from whatever we started at, to 65,000lbs and 1600 PPH reducing to 1500 PPH thereafter. If we assume a mean burn of 1900 PPH prior to the availability of low RPM cruising and we depart at the commercial certification maximum of 84,000lbs it will take (84000-65000) / 1900 hours = 10 hours to reach 65,000lbs and initiate low RPM cruising at <= 1600 PPH.
If we use 1900 * 10 = 19,000 lbs in the first 10 hours we have 13,400lbs remaining to dry tanks which we will burn at <= 1600 PPH so it will last just over another eight hours to dry tanks. Endurance using commercial power settings is around 18 hours to dry tanks. Mean cruising velocity will be just a little slower than the design cruise velocity of 158 KTAS which applies to mid cruise weight. Nil wind we can expect around 18 hours * 155 KTAS = 2800 miles to dry tanks. KSFO to PHNL is only about 2100 miles. The automated flight planners used with MSFS are useless for fuel planning! They make a series of false assumptions by design and the design of the default MS planner is particularly bad.
There is more than enough tankage to lift a small payload to Honolulu for propaganda purposes in nil wind, or even with a minimal (potentially unsafe) pre war headwind reserve, but the B314A was explicitly designed to fly less then 800 miles from Baltimore (or New York) to the British offshore banking centre of Bermuda; carrying a large payload of whatever those who purchased the very expensive tickets wished to remove from scrutiny by U.S. authorities. The boats designed to fly the PAA Pacific routes were the three Martin M-130 China Clippers. The Boeings were driven into the Pacific by the war in Europe. The Boeing B314A Clipper was designed for Atlantic short hauls.
The document B314_History.txt supplied within the Calclassic download explains further and will help anyone who really wants to understand the commercial failure, and the real operating difficulties, of the B314 and B314A to do so. Finally the 2008 Propliner Tutorial is now supplemented by the Savoia Marchetti S.73 V2 release hosted at Avsim and elsewhere which explains use of pilot goniometers, (such as the U.S. Army Signal Corps Receiver in the B314A), in more detail than the Propliner Tutorial. The S.73 release also contains the relevant goniometer training aids.
Those supplied training exercises feature Oostende (EBOS) in Belgium. They can be flown using the B314A. We can fly the approach to the instrument runway at pre war EBOS. Once below all cloud and certain of our position over EBOS aerodrome, even in bad weather we can use pioneer era techniques to navigate to the coast and follow it eastward at low level into the Wester Schelde estuary, following the shore to Antwerp, before landing in the sheltered swept lane outside the port of Antwerp. Then we can transpose those training exercises to Shannon, or Baltimore, or Lagos, or Lisbon so that we can locate the relevant sheltered and swept B314A hydroplane landing lanes (usually just outside the port), anywhere in bad weather after an instrument approach; potentially to an instrument runway on land.
The B314A's pilot goniometer can also be used to fly the Grumman Goose instrument approach exercise into Greenville aquadrome (3B1_NDB_14 available in Part 4 of the Propliner Tutorial). Transpose that training to other aquadromes which have their own instrument approach to the aquadrome visual circuit pattern.
BOAC allowed their pilots access to ADF from first delivery in 1941 and I expect the US Navy war emergency procedures allowed contracted PAA pilots access to ADF from 1942.
The more realism we learn to incorporate the more interesting flight simulation becomes. MSFS is extremely versatile in what it can be used to simulate and we can discover a great deal about pre classic era aviation. However I am afraid there is no way round it. The price of realism is complexity and understanding that complexity may require substantial effort to study and understand lengthy supplied documentation.
FSAviator.