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Post by connieguy on Apr 9, 2019 7:30:39 GMT -5
With BOAC Constellations over the Atlantic 1946-c.1950.
The Prelude:
As the Second World War was drawing to a close it was evident that the development of four-engined aircraft during it would facilitate post-war transatlantic and other long range passenger flights of a type that had not been possible previously. Consequently, a number of airlines were eager to be quick off the mark. The first Lockheed Constellation, Lockheed Construction Number 1961, had made its first flight on 9th January, 1943. The American Air Force ordered a number of the production models as the C-69, but by the end of May 1945 all but 69 had been cancelled and it only actually took delivery of 15, Construction Numbers 1961-74 and 1979. However, all of these were eventually declared surplus to requirements and ended up in civilian ownership, 1961 returning to Lockheed and being used for development of later types. This left Lockheed with a number of C-69s in the process of construction and the decision was taken to adapt these into commercial airliners as a temporary expedient pending the development of a fully commercial Constellation. These aircraft, which had begun life as C-69s or would-be C-69s, were construction numbers 1961-80 (see above) and 2021-44 (1981-2020 were never built). By November 1945 orders had been received from TWA, Pan Am, American Overseas Airlines, Eastern Air Lines and Panagra in the U.S., and from Air France and KLM in Europe, TWA receiving its first aircraft on 14th November and Pan Am on 5th January, 1946. A month later, on 5th February 1946, the first scheduled air service with the Constellation was inaugurated when T.W.A's Star of Paris took off from La Guardia at 14:21 Local Time and landed at Paris Orly at 15:57 Local Time the following day after stops at Gander and Shannon - elapsed time 19 hours 46 minutes, flying time 16 hours 38 minutes. On 11th February Star of Rome inaugurated the first US airline service to Italy. Pan Am and American Overseas followed suit, the latter having flown a Constellation to the official opening of London's Heathrow airport on 31st May, 1946 and putting the type into transatlantic service on 23rd June.
At this point the Constellation was the only game in town. The DC-4 was slower and unpressurized, the DC-6 not yet available and the Avro Tudor, the first pressurized British airliner, a failure despite its descent from the Lancaster and Lincoln bombers. Thus, B.O.A.C. had little choice but to order Constellations too, despite a considerable reluctance in some quarters to sanction the purchase of American aircraft, and was given permission to do so (it was a state airline) on 15th April, 1946. Thus, five former C-69s, construction numbers 1975-8 and 1980, were delivered to them at Montreal-Dorval, Canada in May-July 1946. The first of 10 proving flights was made on 16 June, 1946 and the final one on Sunday June 23rd, returning from New York a week later. Scheduled service began on 1st July, although interrupted by the grounding of all Constellations between 11th July and 30th August. The tenth proving flight is of particular interest because it was the subject of two extremely informative articles which appeared in Flight on July 11th and July 18th, 1946 and can be downloaded from the online Flight archive. The early Constellations produced from modified C-69s had a maximum take-off weight of 86,250 lbs, rather lighter than their successors, and a climb performance which no subsequent propliner (as far as I know) equalled, being able to climb straight to 20,000 feet with a full fuel load (edit: it can do so, but the best initial cruising height after take off with a full fuel load is FL180 - see later posts). According to the Flight article a full B.O.A.C, passenger load in 1946 was 42, although the accompanying plan shows 47 seats, and this was the standard for the type 26 (the number denoting the interior accommodation) with 7 crew and 445 cu ft for cargo. This may mean that B.O.A.C. chose to limit the number of passengers to 42, because it was not possible to carry any more with a full fuel load and a crew of 7 and stay within the limit for the maximum take-off weight of 86,250 lbs. The 049 made by the Connie Team can be adapted to these figures. They provide an aircraft.cfg which can easily be modified to 86,250 lbs and I have also altered it to represent a smaller full passenger load and a bigger crew as follows; //For L049-46 early model (see manual for other subtypes) station_load.0= "1623.000, -30.000, 0.000, 0.000, Pax-load rear" // from 1804 station_load.1= "1562.000, 22.000, 0.000, 0.000, Pax-load front" // from 1738 station_load.2= "1665.000, -8.000, 0.000, 0.000, Pax-load center" // from 1850 //For L149 with increased weight modifications and 6 tanks configuration //station_load.0= "2134.000, -30.000, 0.000, 0.000, Pax-load rear" //station_load.1= "1738.000, 22.000, 0.000, 0.000, Pax-load front" //station_load.2= "2250.000, -8.000, 0.000, 0.000, Pax-load center" station_load.3= "1000.000, 0.000, 0.000, 0.000, Cabin crew" //871.000 station_load.4= "0.000, -8.000, 0.000, 0.000, Cargo" Not all will be interested in B.O.A.C., but there are good repaints of the 049 available for TWA, Pan Am, American Overseas, Air France and KLM, some of them by Frank Gonzalez. That being so, it will not be difficult for those who wish to fly along as this thread develops.
It remains to say that the earliest of these commercial aircraft had the Wright 739-C18BA-1 or 745-C18BA-1 engines, but that in the late summer of 1946 the 745-C18BA-3 engine became available, with two-speed superchargers and direct fuel injection. It was also possible to lean the engines below Auto-Lean. Once fitted with these engines the Constellation became the Lockheed type 049-46 (46 indicating this type of engine), and the B.O.A.C. machines seem to have been converted to the type 049-46-26 as quickly as possible, as were those of other airlines. Having established all this, it will soon be time for the results of proving flights before we attempt to cross the Atlantic properly ourselves... The fleet:
Construction Number 1980, 'Baltimore', G-AHEN, in the fine repaint of the 1946 livery by Frank Gonzalez.
Construction Number 1976, 'Berwick', G-AHEK, in the later white top livery. Modified by myself using the 049 paint kit from a repaint of the Connie Team 749 Constellation by Tim Scharnhop.
Virtually all the information in this post derives from the second edition of Peter Marson's book on the Constellation, clearly the result of a lifetime's work.
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Post by Tom/CalClassic on Apr 9, 2019 9:21:02 GMT -5
Nice history, thanks.
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Post by connieguy on Apr 10, 2019 6:20:58 GMT -5
Flying the 049 and Proving Flights It should be noted that the Connie Team say that their model has been simplified in some respects to facilitate FS operation by one man of a machine which was in reality operated by at least three. Nevertheless, flying it is a rich experience. On the real aircraft the throttles were advanced by the flight engineer during take-off after the captain commanded 'Maximum Power', and during blower shift Nos. 2 and 3 were shifted together and then 1 and 4 separately. As manifold pressure and rpm must both be reduced, first one and then the other, there are few if any FS rigs which would be able to do this, as one would need 4 separate controls for the manifold pressure and four separate ones for rpm. I use a throttle quadrant with dual throttle controls mapped to 1 and 4 and 2 and 3, and dual rpm controls mapped similarly. With the mixture controls, however, I simply use the second for all four engines. The closest I can get to the 049 procedure is therefore to move 2 and 3 together and then 1 and 4 together. I have done this with the Super Constellation for some time, and it does produce a very smooth shift. I have also done a number of proving flights with the 049, with occasionally unexpected results. The one I regarded as the most significant was climbing to 20,000 feet after take-off with a full fuel load and the payload adjusted as in my previous post, and then cruising at that height. Gross weight on start-up was 86,090 lbs, slightly below the maximum of 86,250. The Connie Team engine information gauge showed c/g to be 25.69%. Weather was turned off and the flight took place in July. Climb was impressive. With a climb BMEP of 144 at 2300 rpm it took 6 minutes to reach 5,000 feet, and 12 minutes 39 seconds to reach 10,000. At 12,000 feet the climb rate was still 700 feet per minute and 600 feet per minute at 14,500 when I changed to high blower. At 17,000 feet the throttles were fully advanced but climb rate was still 600 feet per minute and 400 feet per minute at 19,500 as I prepared to level off at 20,000. Gross Weight was 84,500 as I started cruise, so taxi, take-off and climb had used 1,590 lbs of fuel. It was cruise where the slightly unexpected happened. In the Super Constellation I concluded some time ago that there is not a great deal to be gained by cruising above 18,000 feet and have therefore seldom done so. There are detailed real world performance charts available for that aircraft which the Connie Team model gets extremely close to, and when it has come to leaning the mixture a fuel to air ratio of 0.064 or very close to it has always produced the right results. There are three ways of adjusting the mixture - my physical throttle quadrant control, which by this stage is deep into Idle Cut Off, the four mixture controls on the flight engineer's panel, which can be moved together by clicking at the right spot, and the keyboard controls Shift Control F2 (lean) and Shift Control F3 (enrich). It is often a combination of the latter two which eventually gives the right result. With the 049 at a gross weight of 80,000 lbs (in fact I was above this) the Connie Team manual suggested a Maximum Cruise BHP of about 1150 (i.e. half way between the actual figures it gives of 1200 at 18,000 feet and 1107 at 22,000 feet). The problem was that a fuel to air ratio of 0.064 would not produce this BHP, but 0.083 did. Both enriching and leaning resulted in power dropping away, so this was apparently the 'best power' setting sometimes referred to in manuals for later Constellations. However, the engine gauge showed mixture to be 19%, well below the level of Auto Lean. To be precise the settings at this point with an OAT of -23C were BHP 1150, RPM 2208, BMEP 123, Fuel flow 576 (slightly above what the manual suggests it should have been), Mixture 19 and KTAS 237 (slightly below what the manual suggests). At 80,601 lbs gross weight similar results were produced with a fuel to air of 0.077, KTAS now being 240. At 80,300 lbs I pushed the throttle fully forward and with a mixture of 17 obtained a BHP of 1145, a f/a of 0.073, and a fuel flow of 546 (the lowest yet), while KTAS remained at 240. At this point the aircraft was flying with a Red (negative) trim of 0.8. I look forward to eventually examining these matters more fully during complete flights. On the crucial matter of descent there is more solid information. It is always better to leave plenty of time for the descent rather than not enough. The figures that follow assume that the aircraft was loaded with fuel and payload in the manner indicated earlier and that at this point there is about 6,000 lbs of fuel left. Variations in this would be less significant than variations in the distribution of the payload, which would produce a different c/g. As cruise comes to an end cruise trim is likely to be Red 2.4 or 2.5. Descent is initiated by reducing manifold pressure and rpm, the former by no more than three inches at a time. As the aircraft passes below 10,000 feet I return the blower levers to low blower and push the mixture lever forward into Auto Lean. As the destination comes closer it is necessary to trim the nose up in order to bring the airspeed down to the point where we can go to Flaps 60. These alterations in trim must be gentle or the nose of the aircraft will rise and it will begin to climb rather than descend. The ideal is to keep climb/descent rate at 0 but of course while doing so you will not be descending at all. By the time trim is Red 1.2 it is possible to go to Flaps 60, at an rpm of about 2000 and manifold pressure of about 23. This is probably also the point at which the mixture should be increased to Auto-Rich. The effect of lowering flaps is to cause the nose of the aircraft to rise quite significantly, and therefore as the flaps begin to move the mouse should be placed on the trim wheel and the trim lowered to Red 1.7. As the aircraft settles into the new attitude it can and should then be brought back to Red 1.4. At this point the aircraft's rate of descent can often be controlled by variations in rpm alone. When the gear is lowered trim will need to be Red 0.1, rpm 2300 and manifold pressure 27. Once at Flaps 80 the trim should be adjusted to 1.3 Green, which is landing trim. At this point at 2300 rpm variations in manifold pressure probably will be needed to control the descent rate. Going to Full Flaps requires no further adjustment to trim.
It is difficult for a description like this to convey the beautiful precision with which this aircraft behaves if trim and power settings are got right, and these settings need to be more or less memorised so that it can all be done almost automatically, because you may well have other things to take care of during the descent.
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Post by Defender on Apr 10, 2019 15:35:19 GMT -5
From memory the team didn't have a full real world manual for this version, only the single speed C-69 USAF manual, flight notes on "Flying the Constellation", a L049D, from Marson's book and a USAF manual for the C121A which was more powerful so some interpolation and guesswork was needed. It's possible that the tables show what was thought to be the true performance rather than what the model was capable of.
Manual leaning would not really be possible at extremes of weight/altitude/power and the fallback was always autorich. And to accomplish a 10% BMEP drop you would need to start well below full throttle so as to be able to restore the target BMEP.
Descent. Keep in mind that the 3" per minute is a limit, not a command. A variety of profiles is possible depending on terrain, traffic or time. You could just maintain cruise power with a long descent taking care not to exceed Vno, then slow down once at initial approach altitude when shock cooling should be less of a risk. Or you might need a steep descent in which case you need to slow even before starting down.
Bill
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Post by connieguy on Apr 11, 2019 12:02:06 GMT -5
Bill, Marson's section on flying the 049 is a little curious because he does not state what his sources are, and in fact at points quotes almost verbatim from the first 1946 Flight article, for example on the steady drone of the engines having an almost soothing effect. I have two manuals for the 049. One is available for download on the French Aviatechno site, where it is stated to be a manual for the L749. This is incorrect. It is a Lockheed Flight Engineer's manual for the 049, undated, but I guess from 1946, because the engine performance charts, starting on p. 27, are for the BA engine with single blowers, not the BA-3. These charts give the type of information for BHP at different weights which is the sort of thing one likes to see, although you will probably be able to get a lot more out of them than I can. I guess that this manual goes back to the earliest Air France Constellation, Construction Number 2072, registered as F-BAZA, delivered to them in July 1946, some time before the rest of the Air France order, and almost certainly before the installation of the BA-3 engines, hence the engine data given in the manual. I also have a Lockheed Report 5817 for the Model 49-46, bought at some expense from eFlightManuals.com. The title page carries a date of approval of 22nd October, 1946, but there are revisions to October, 1954. It is not without points of interest, but the sort of engine performance tables available in the Aviatechno one are not there, perhaps because there were so many changes to the type over the years, or because there were different manuals for flight engineers. A quick scan suggests that there is no reference to flying with mixtures set on less than AutoLean. I know that there are many different ways of doing things with these aircraft - that is one of the fascinating things about them - but what I was doing in my previous post was showing one way of descending for those who may never have flown a propliner simulation as complex as this before, rather like my thread on navigating using a sextant. As the recent Auto-Mixture thread has shown, there are those who prefer classic flight simulation to be not too demanding and those who prefer it to be as realistic/difficult as possible within the limits of a one-man crew in FS. I am firmly in the latter camp and that is why I spend all my time with the Connie Team's aircraft. Had it not been for them I suspect that I would have given up classic flight simulation some time ago, Best wishes, Ken aviatechno.net/constellation/documents/flight_engineers_handbook_l749.php
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Post by Defender on Apr 11, 2019 16:51:38 GMT -5
Thanks for the reminder about the Aviatechno manual/s. I've got two, both from there I think, one called "Constellation - Flight Engineers' Handbook" which as you say is the L049 but the BA1 engine. The other one, in French, is "Manuel D'utilisation L749" for the BD1 engine.
So neither perfect except by interpolation and Luis Pallas' huge knowledge of how these engines work. But I'm still not sure we had these when developing and testing the L049 model.
Bill
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Post by connieguy on Apr 12, 2019 15:17:20 GMT -5
Bill, I have mentioned this elsewhere, but the second Flight artice says that on the return trip from Shannon to Heathrow, when the Constellation was flying light, 'the take-off and climb were particularly impressive. Measured with watch and pocket altimeter the initial climb to 2,000 feet took only 1 min 24 sec.' I have tried taking off with only 6,000 lbs of fuel onboard and the model replicated this almost precisely. Another point I will mention from the Lockheed Report 5817, because it surprised me, is the section on cross-feeding fuel. On page 36 it says that in the event of the two bigger tanks containing more fuel than the two smaller ones the crossfeeds should be used to equalize it, but not on both sides of the aircraft at the same time. The 049's fuel management was therefore rather less straightforward than one might have thought.
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Post by connieguy on Jul 30, 2019 13:54:38 GMT -5
Here is the promised report on a westbound transatlantic crossing by one of these early Constellations. It was originally my intention to replicate the earliest flights to New York via Shannon and Gander, but on reflection I decided to go for the later mid-Atlantic route, partly in the hope that the winds in that area would be less extreme than those further north; also, even in Flight Simulator, Bermuda is a great deal more attractive than Gander. The aircraft I flew is the L049 Construction Number 1976, which B.O.A.C. gave the registration G-AHEK and (eventually) the name Berwick. My version was produced using the Connie Team paintkit and adapted, with modified alpha channels, from an excellent L749 B.O.A.C. livery made by Tim Scharnhop. G-AHEK flew the inaugural London-Azores-Bermuda-Kingston service in April 1950 and was converted to All-Tourist 65 seater L049D standard in 1952 and to 049E standard in 1953, conversions which must have blunted its originally fine performance in order to obtain heavier payloads. Fortunately, I shall fly it in its original form. As classic a sight as one could wish. G-AHEK over the English Channel, September 1950. The schedule, taken from the B.O.A.C. timetable for July 1950, operated the flight which left London at 13:15 Local time on Wednesday, 13th September and then flew to Havana via Lisbon, Sancta Maria in the Azores, Bermuda and Nassau. I was assisted by my usual Voice Bot flight crew of Bill as co-pilot and Stuart as flight engineer, with Beatrice (the utterly convincing Microsoft Zira) as stewardess. I would rather listen to her gentle transatlantic tones than the cut-glass upper-class English accent which would almost certainly have been used by a real B.O.A.C. stewardess of that period. Beatrice does, however, refer to the aircraft as a 'ship'. Whether she will ladder her stockings in the galley as frequently as Kathryn, who is part of my Air France flight crew, remains to be seen, but I suspect that this was a problem that Lockheed never really solved. The first leg was due in Lisbon at 17:30 Local Time, both London and Lisbon being one hour ahead of GMT. Navigation was by radio beacons, so there was no need for the sextant just yet, and I used a dynamic FS Global Real Weather file for the equivalent time and date in 2018. With a passenger payload of 4,123 lbs the aircraft was only two-thirds full, which I believe accurately reflects the likely position at the time, and I loaded 13,167 lbs of fuel, which as it happens was rather too much and did not take sufficient account of the fact that during cruise the engines of this aircraft are rather more economical than those of later Constellations. I have flown to Lisbon a number of times and knew that there might be consistent headwinds, but in fact the FS Global weather report showed that at 20,000 feet there would be a large element of side wind in them, whose effect would be reduced as we crossed the Bay of Biscay and turned more southerly. I checked that the winds at lower altitudes would not be significantly more favourable, but in fact in this case they would not. Departure from the London Airport was a straightforward take-off on runway 28R and there needed to be only a moderate change of heading as we turned to 230 magnetic for the beacon at Southampton. As the payload was so light I used the lower cruise climb setting, 2300 rpm amd 134 BMEP in low blower, with 123 BMEP in high blower. I reached FL190 in 21 minutes 36 seconds and then flattened out to cruise at FL200 at an initial gross weight of about 68,000 lbs. I decided that maximum cruise of about 1150 BHP was not necessary (and was just about right, see below) so initial settings were BHP 950, RPM 2008, BMEP 112, fuel to air ratio 0.064, Mixture 14, Fuel Flow 413 pph and a true airspeed of 232 knots. The weather was good and at 20,000 feet I was above the dense cloud, with occasional patches above me. I have never liked landing in Lisbon. There is no beacon in the centre of the airport, but NDBs off both ends of the main runway, and on the approach to runway 03 from the south - and a lot of them seem to be - it is not easy to pick out the airport from the surrounding ground textures (purely an FS9 issue, of course). In fact on this occasion I landed on R03 at 14:50 local time without too many issues, and with 6,150 lbs of fuel still on board. The onward flight to Sancta Maria was also straightforward. I departed exactly on time at 18:45 local time (UTC+1)and landed at 20:17 (UTC-1), 28 minutes ahead of schedule. Cruise on this occasion was at FL120 because the forecast for FL200 suggested the winds would be less favourable at that height and the distance was a relatively modest 767 nm. Night fell as we flew west and by the time I reached the vicinity of my second waypoint the stars were out and it was possible to use the sextant. The Plough was off the starboard quarter and this allowed me to find Arcturus dead ahead to the west and Polaris, the Pole Star, to the north. Scorpio was also visible to the south-west. The plot placed me just beyond the waypoint and slightly to the north of it - 8nm to the north, according to the Plan G breadcrumb trail. As I wanted to approach Sancta Maria from the north anticipating a landing on R18 this was fine, and I simply adjusted the heading from 269 to 267. Some time later we then picked up the Sancta Maria NDB just off to port, ATIS did indeed advise me of a landing on R18 and I followed the same course all the time until the needle was near to 180, at which point I turned. I left descending for 8 minutes after picking up the NDB and this turned out to be almost exactly right. The landing was so gentle I didn't even feel the wheels touch and I took the clear skies to be a good omen for the long leg to Bermuda, leaving at 22:00 local time. As it turned out, this was too optimistic. To be continued.
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Post by connieguy on Aug 2, 2019 10:47:48 GMT -5
As the flight from the Azores to Bermuda was the first time I had crossed the Atlantic at night using a sextant I had looked forward to it with some anticipation. BOAC scheduled it to leave Sancta Maria at 22:00 (UTC-1) and to arrive at Bermuda at 06:40 (UTC-3), the distance being 1955 nm. I again used a reduced payload but took off with full tanks. As on similar flights in the past I used a FSGRW dynamic weather file for the right time of day and year - 22:36 UTC on 13th September, 2018 - and plotted a number of intermediate waypoints into the Plan G flight plan. I also extracted a weather forecast from FSGRW which suggested that there was going to be no significant headwind at FL220; this turned out to be correct. We took off a minute late with a trim of +7 (+9 would have been better in maintaining an IAS of 150) and reached FL100 in 12 minutes 29 seconds. I shifted into high blower at FL145 and the throttles were against the stops at about FL165, but the climb rate was still about 500 fpm. It maintained itself well until up to FL200 but thereafter fell significantly. The comments that follow are based on this flight and a second test flight a few days ago. Both experiences suggest that FL220 is too high for this aircraft as an initial cruise height above a gross weight of 80,000 lbs. It is, for one thing, as far as I could discover, impossible to achieve the 119 BMEP suggested by the Team Connie manual. 113 BMEP was the nearest I could get with a fuel to air ratio of 0.083. On the test flight, with full tanks at take-off and a full payload, I could not lean below Auto-Lean, and on both flights the aircraft flew nose up, a fairly definite indication that the cruise level was too high. On the test flight I descended to FL200 and was able to achieve settings nearer to the manual apart from the airspeed, which was too low by about 10 knots. This suggests that a better initial cruise height would have been FL180, and I shall try this on the next long flight I do.
In terms of navigation the largely clear weather on the flight to the Azores had to led to a degree of optimism about the coming night which proved groundless. I flew out on the reciprocal of the Sancta Maria NDB, which got me off to an accurate start, but cloud closed in before the first waypoint and I was not able to use the sextant until I was near the third, by which time I had travelled 750 nm. Using Polaris to the north and Vega dead ahead the plot suggested that I was some way beyond the waypoint and about 30nm to starboard - not too bad in the circumstances, though it was fortunate there had not been a strong wind from the side. As a result I changed my heading from 279 magnetic to 275 and had I been able to take a shot at the next waypoint the Plan G breadcrumb later showed that I would have found myself still to starboard but only by half as much. By the time I got to the next waypoint I was able to use the sextant again. Some things are more difficult in FS than in real life and I am fairly sure that identifying stars is one of them. However, I had the program Stellarium running on my laptop and as a result of decreasing the number of stars it shows was able to recognise both Cygnus and Aquila, with Polaris still to the north. I also benefited at this point by picking up Ocean Station Echo, although unfortunately I did not log when this happened. The sextant plot showed me to be near the waypoint but south of the track. I accordingly changed heading to 280 magnetic but there was now a northerly wind which kept me south of the track but parallel to it. At the final waypoint I was 30 nm south of it but I knew that I was almost there by this stage and picked up the Bermuda NDB and ATIS soon afterwards. I started the descent at 07:07UTC, which was a little late, and I had to put in a descent loop before making a decent straight-in landing on Runway 30 at 04:45 local time, almost two hours ahead of schedule. The favourable winds may not have been the only reason for this. I used Maximum Cruise all the way and later flights suggested that BOAC schedules for this aircraft in this area were based on saving fuel through utilising Normal Cruise. As it was, I still had 10,040 lbs of fuel on board.
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Post by Defender on Aug 2, 2019 15:39:47 GMT -5
Hi Ken,
Nice shots and lovely account of a long ocean trip but just to add some explanation.
Cruise height. Yes the 049 had an remarkable climb to initial cruise ability and could get to the high blower range at near max weight. But there's a certain degree of misunderstanding about optimum cruise heights. Winds, icing conditions and any need for celestial navigation came into the desired flight level equation but generally eastbound gave rewarding conditions at higher altitudes for all these factors, whereas westbound was a more complicated choice and many flights were at low blower levels throughout. Somewhere on the web, there's an interesting 1962 frequency survey of traffic routes and altitudes on the North Atlantic.
Throttle settings etc. It's a distant memory now but I do recall many exchanges about the FDE performance versus the real world charts during beta testing and in some cases it was decided that the handling notes could be based on real world if the FDE got within 10%. In fact I hardly ever found any of Luis Pallas' work more than 2 or 3% away. The problem is that adjusting settings to match one area of the performance spectrum sometimes gives the wrong results in another area. It's a computer programme, not a machine of course!
Nose up etc. I think Volker mentions this in some but maybe not all the Connie series notes but the real Connies normally cruise nose up, anything from around + 2 degrees at fast or normal settings up to + 4 using long range settings. Probably to do with the wing angle of attack. So don't attempt zero pitch flight.
Anyway, all that aside, I'm sure we all enjoy your reports and suggestions for getting the most fun out of these models.
Bill
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Post by Defender on Aug 2, 2019 16:29:17 GMT -5
Just found the flight level survey I mentioned above. So the Atlantic east/westbound altitudes are as follows, All stats civil and military piston aircraft only, at 30 degrees west, about half way Gander/Shannon, so initial cruise might be even lower, final cruise higher. Eastbound. Highest frequency 17,000', next 15,000'. Westbound. Highest frequency 10,000', next 12,000' For the full survey here's the link, babel.hathitrust.org/cgi/pt?id=mdp.39015020237262&view=1up&seq=8Bill
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Post by Tom/CalClassic on Aug 2, 2019 20:17:14 GMT -5
Wow, nice resource.
Thanks,
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Post by connieguy on Aug 3, 2019 10:22:57 GMT -5
Bill, I write these reports partly because I enjoy writing them, partly because I want to give others some sort of insight into what I find the most rewarding form of flight simulation, and partly because I know that there is always a good chance that you will make contributions which leave most of the rest of us knowing a great deal more than we did before. Although Lockheed issued manuals for the different aircraft of the Constellation series which at least in the case of the L049 included one specifically for flight engineers, it is clear that at least some operators felt the need for more detail in certain areas and created their own. Some of these are available on the net. Air France produced a manual (in French) for the L749 which can be found on the aviatechno website, together with the Lockheed flight engineer's manual for the version of the L049 with the BA1 engines. TWA produced their own manual for the Starliner available from Avialogs and it refers to a separate Power Chart Manual which unfortunately is not available. Above all, the United States Air Force had their own manual for the C-121C and C-121G, available from Mach One Manuals, and this contains tables which give detailed power settings for different altitudes. If you are in Low Blower at FL120, for example, as demonstrated by a flight test in September 1965, an RPM of 2340 and BMEP of 171 should produce 1700 BHP at 10% Lean and using Spark Advance; if you are in High Blower it will need an RPM of 2360 and BMEP of 170. Or you might go for Long Range Cruise at a lower speed. Detailed tables for a range of gross weights provide the High and Low Blower rpm and bmep settings for altitudes between 3000 and 23000 in 1000 feet steps. The wonderful thing about all this is not only that we have this information, but that the Connie Team's Super Constellation flies either right on these settings or very near to them. If we had such a manual for the L049 with the BA3 engines it seems very likely that the Luis Pallas flight model would turn out to do exactly the same. It will be evident from that I said about cruise altitude that I was under the impression that these aircraft always cruised high unless there were good meteorological reasons not to do so. This was partly because of their climb performance, but also because I knew that in June 1946 Flight reported that 'Balmoral' had carried out a non-stop proving flight from New York to London in 11hrs and 24 mins at an average height of 21,000 feet. The immensely valuable FAA report to which you link shows the true situation and is the most informative thing I have ever seen in terms of showing how transatlantic flights were really conducted. I shall need time to absorb it properly but it seems impossible to download it in its entirety unless you are a member of their organization. While searching for an alternative version I did, however, find on the Internet Archive a subsidiary report which contributed to it, a study of North Atlantic traffic for one day - 25th August, 1961 - by the same author; this is downloadable. Many thanks again.
PS Having now looked at the full report the downloading of a few single pages, which is possible, is probably enough for most purposes, including mine. Some of the illustrations in the full report are in any case taken from the study of 25th August. The crucial statistic is the one Bill gave - that aircraft travelling west flew lower, and quite a lot lower than one might have thought.
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Post by chris_c on Aug 3, 2019 17:53:18 GMT -5
Don't have anything technical to add really but have been really engrossed in this thread and never tire of the threads where Forum Members share their vast knowledge for the benefit of the rest of us. Thank you.
According to the book Fly with the Stars (Susan and Ian Ottway Sutton Publishing, UK) BOAC management really wanted the Connie because they saw its revenue potential and performance as vastly superior to AVRO's offering, the Tudor Mk.1. The Ministry of Civil Aviation (MCA) wanted the three British national airlines, BEA, BOAC and BSAA to use exclusively British aircraft but many of these were unsuited for profitable use particularly for the long-haul routes. Hence BOAC got permission to buy the Connie and the Canadair North Star (Argonaut in BOAC service). So while the politicians wanted "Britain First" they also wanted their airlines to make money and this could not be done on the Empire and Atlantic routes using Yorks, Lancastrians and later, albeit in limited numbers, Tudors for passenger service.
Repeated failures, delays, setbacks and cost-overruns in the Tudor program and the chronic under-performing of the Handley Page Hermes pretty much ensured that BOAC got its American designs. In the face of failure of British industry to build a revenue-producing piston engine airliner, BSAA management stuck absolutely to the "Fly British" policy even though BOAC's experiences with the Connie and Argonaut are almost certainly the reason that the company became profitable on its long-haul routes. Sticking to the British Only policy (which were relaxed to suggestions and then guidelines and finally nationalist wishful-thinking) helped to doom BSAA, the company never made a profit and the Tudor crashes of 1948 were the final nail in their corporate coffin.
The MCA put all of its airliner marbles into the Comet and Brabazon baskets and when they failed there was little choice but to buy American. BSAA could not use the Comet because the early versions lacked the necessary range and the stubborn refusal of BSAA Chief Operating Officer, former Air Vice Marshal Donald Bennett, to even consider the Connie helped to doom his company from the start. After BSAA was forcibly merged with BOAC, the Argonaut safely flew the South Atlantic routes and apparently made money on them although AVM Bennett, dismissed from BSAA before the BOAC takeover, never stopped asserting the British airliners were in every way superior to those from the States. But by then nobody was listening to him...
Chris
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Post by Erik on Aug 3, 2019 20:51:20 GMT -5
never tire of the threads where Forum Members share their vast knowledge for the benefit of the rest of us. Thank you. I second that, these are highly appreciated contributions. Thanks very much. Erik
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