Improve That Design: How Aircraft Could Have Been Made Better

[wuzak]

In comparison to the P-59A, here is a performance chart for the Meteor I

http://www.wwiiaircraftperformance.org/meteor/meteor-chart-8june45.jpg

Range was about the same as a P-59A.

 

[wuzak]

I have always been perplexed with the huge wing area of the P-59 an I tend to think that this was one of the major reasons the p-59 was a disappointment in top speed (the meteor may also have been limited by this). Here are some comparisons of early jets wing area:
P-59 386 sq ft
Me 262 234
P-80 237
Meteor 350
I think that if they had built the P-59, which appears to me to be a clean design with better engine airframe integration than either the Me 262 and Meteor, with much smaller wings, say like the P-63 wings (248 sq ft), the AF may have been surprised with the performance of the P-59 which may have been equivalent to the Me 262 and the P-80, and been more timely implemented in countering the Me 262. Since it flew only two and a half months after the Me 262 flew its too bad they didn't try it with smaller wings, they seemed to have time to do so.

The wing span of teh Meteor was changed.

The Meteor I, III and early IV had a wing span of 43ft (45ft 6in for P-59), while later IVs and the F8 had a span of 37.2ft.

Gloster Meteor F Mk.I
Gloster Meteor F Mk.III
Gloster Meteor F Mk.IV

Was 350 sq.ft. for the standard, long span wings?

 

[wuzak]

The advantage of engine installations like the Me 262 and the Meteor over those like the P-59A was that it was easier to swap engines.

The first Meteor flight was the prototype fitted with two Halford/de Havilland H.1s, rather than the Rolls-Royce Wellands destined for production. A later prototype flew with Metrovicks F.2s.

It would have been a lot more work to fit these different engines in the P-59A - the H.1 was bigger than the Welland, while the F.2 was smaller in diameter but longer.

 

[Simon Thomas]

Re Merlin inlet

The Hornet had the inlet arranged better. No doubt it could have been done earlier, however the RR staff were already flat out with other priorities.

hornet | tailor-made power | series tailor-made | 1946 | 0165 | Flight Archive

 

[Shortround6]

Re Merlin inlet

The Hornet had the inlet arranged better. No doubt it could have been done earlier, however the RR staff were already flat out with other priorities.

hornet | tailor-made power | series tailor-made | 1946 | 0165 | Flight Archive

It also looks like the carb/fuel injection unit was flipped to be a down draft unit.

The Peregrine used a down draft carb so it was nothing new to RR. It may very well be as you say, other things were given higher priority.

 

[davparlr]

trouble is the early jets were real fuel hogs and they carried 290 gallons of fuel in the wings. Range was a whopping 240 miles at 20,000ft with a cruising speed of 298mph (?)

True, fuel was always an issue with early jets and a new wing would not hold as much as the old. About a 150 gallons of fuel would have to be carried in the fuselage. However, for just testing less fuel would be needed.

Cutting the wing area without cutting the fuel load can be done but you are going to have some short, stumpy wings.

Not necessarily. The new wing would have to be a complete redesign. Perhaps the P-63s wing could be adapted. Less wing area could make a significant difference. Depending on the manufacturing breakdown it could be as simple as a bolt-on change. They may not even need to change the landing gear. Some work, but if they could get another 100 mph out of the plane, it would be important.

Regarding the XP-59,

This requires the aircraft to be able to fly decently well with one engine out, and that means L/D has to be low enough to allow the engine to keep the plane level at high altitude, as well as land adequately at low-speed, as well as the ability to keep the plane in a straight-line, but I have a hunch power was more of a concern here, for the following reasons.

This seems not to be an issue with the He 280 or the Me 262. The 280 had less power available and slightly less gross weight than the P-59, and 262 had slightly more power available but was much heavier. Both had about 60% of the wing area of the P-59.

I'm not sure about that, the basic concept of mounting them in the roots isn't bad, but one of the following ultimately served to undermine it

1. Poor inlet design
2. Poor inlet-fuselage interface
3. Poor wing-inlet interface
4. Some mixture of the above

What you say is true. This technology would have been poorly understood in the 1941-42 timeframe that we are talking about and certainly simplified by podded engines. But all could be addressed, as was the inlet problems with the P-80, with reasonable effort. It is interesting to note these items are still an issue in modern stealth aircraft.

The problem with the P-59 was that, it was on a very quick time-table (approximately 9 months), using a new engine, and thanks to secrecy, they were not allowed access to the wind-tunnels at certain times.

They wanted to produce a design that was as simple as possible, without any unknowns.

I agree. I think one of the problems was that the US aircraft industry (except maybe Lockheed) unlike the German aircraft industry, did not understand the potential of the jet engine, and that was mainly speed. I am sure they designed it to common practices of propeller driven aircraft.

Was 350 sq.ft. for the standard, long span wings?

It was the F.8 37 foot.

The advantage of engine installations like the Me 262 and the Meteor over those like the P-59A was that it was easier to swap engines.

The first Meteor flight was the prototype fitted with two Halford/de Havilland H.1s, rather than the Rolls-Royce Wellands destined for production. A later prototype flew with Metrovicks F.2s.

It would have been a lot more work to fit these different engines in the P-59A - the H.1 was bigger than the Welland, while the F.2 was smaller in diameter but longer.

Yes, you are correct on the growth of the P-59. But these engines did not make it into the war whereas a properly designed P-59 with a -3 or -5 engine could have possibly been competitive in the war.

 

[GrauGeist]

The actual XP-59 may have held more promise as a jet fighter than the YP-59/P-59A, but it was intended to have a piston engine and was cancelled.

 

[Zipper730]

This seems not to be an issue with the He 280 or the Me 262.

Both had higher aspect ratios which can often yield more lift for the same wing-area.

What you say is true. This technology would have been poorly understood in the 1941-42 timeframe that we are talking about and certainly simplified by podded engines.

Correct

But all could be addressed, as was the inlet problems with the P-80, with reasonable effort.

Correct.

I agree. I think one of the problems was that the US aircraft industry (except maybe Lockheed) unlike the German aircraft industry, did not understand the potential of the jet engine, and that was mainly speed.

Honestly, the L-133 had serious potential. The engine design they produced was way too complicated.

 

[davparlr]

Both had higher aspect ratios which can often yield more lift for the same wing-area.

I would not have just chopped off part of that awful wing, I would have designed and installed a low drag high speed wing ala P-80/Me 262. I would have wanted to see how fast it could go. A cleaned up P-59 with optmize inlets and more thrust should be close to equal or faster than the P-80/Me 262.

 

[P-39 Expert]

Getting back to the "make it better" bit in the original post.

I think the P-61, with the intrinsic weight and drag added by the (imho) superfluous turret and gunner has the most obvious fix. Since I tend to think that turrets are fighters are nearly always completely superfluous, we could easily improve the Boulton-Paul Defiant and Blackburn Roc by getting rid of that monstrosity in both of them. Of course, the Roc has many more problems, starting with having too little engine.

The US aircraft I'd start with would be the P-39 and the P-38
For the P-39

1. The M-4 cannon was not particularly useful. Replace it with something like the 20 mm HIspano (its production problems were due to idiocy within the Army's bureaucracy, not intrinsic flaws in the manufacturing process).
2. The car-doors were dumb. I know they were fashionable (iirc, the Tempest started with the same arrangement). Sliding canopies were definitely the way to go.
3. One of the problems of the mid-engined layout is that it puts the engine, a big, heavy lump, exactly where one wants to put the fuel. While moving the engine would, in essence, change the P-39 to the P-40, fuel tankage could be increased by a small increase in wing span, and putting tanks in the wing roots.
4. The original XP-39 had such a poor turbocharger installation that it actually impaired performance at altitude by increased drag. I think this could be fixed by lengthening the fuselage to permit a proper installation.

For the P-39:

1. You have liquid-cooled engines. I believe that the automotive industry had figured out how to heat a passenger compartment by the addition of a tiny radiator with air blown through it. I suspect some engineer or another at Lockheed would have been smart enough to get this to work.
2. Using the wing leading edge for cooling. Use a real heat exchanger.
3. There wasn't much to be done about the compressibility issue short of major redesign, so that's not an issue.

Of course, the real problem with the P-38 was inadequate pilot training. It was a large, complex airplane and was, insofar as I can remember, the first large twin-engined aircraft the USAAF operated without a co-pilot and possibly even a flight engineer.

Looking in hindsight, every single aircraft put into service in WW2 had problems of one level or another. For example, a couple of USN aircraft had manually retracted landing gear. The elegant, iconic, elliptical wing of the Spitfire was a bitch to manufacture. The Ju-87 had a remarkably draggy radiator installation.

Can you expand on the 20mm Hispano idiocy? Really want to know. Thanks.

 

[P-39 Expert]

Please don't think badly of me, the opinions are my own. This is up to mid '44, after that it was a moot point.

P-38 Cancel this thing as soon as possible, use the ones you have for reconnaissance. Too much for the average pilot, too expensive, too low a mach number.
P-39 D through L reduce weight by losing the wing guns and nose armor plate. Move the radios up behind the pilot for balance. Now it will climb with the Zero and still be 40mph faster at all altitudes. Then when the 9.6 engine is available just build the N. If more fuel is needed lose the wing guns and add a fuel tank in each wing. When the two stage Allison -93 starts production in April '43 then start using that.
P-40 Cancel this one asap too, give the ones already built to our allies. Or make it 1200# lighter somehow. How? No idea. Or re-engine with the F version of the -93 in April '43.
P-47 Why not just build F8F Bearcats with more internal fuel instead. Almost as fast, much better climb and turn. Common single stage R-2800 engine. Less Expensive.
P-51 The AAF obviously needed to push this plane but initially didn't want them because they were under a British contract. More AAF/Govt politics and bungling? Engine them with Allisons, Merlins, single stage, two stage, just get them into production with the best engine available and constantly upgrade. Get two P-51s for every P-38 or P-47 cancelled.

Of course this is with 20/20 hindsight.

 

[swampyankee]

Can you expand on the 20mm Hispano idiocy? Really want to know. Thanks.

AG Williams, of Rapid Fire, has posted an article: Modifications and Attempts at Standardization. Since it's just one source, it may not be fully informative.

 

[pbehn]

P-51 The AAF obviously needed to push this plane but initially didn't want them because they were under a British contract. More AAF/Govt politics and bungling? Engine them with Allisons, Merlins, single stage, two stage, just get them into production with the best engine available and constantly upgrade. Get two P-51s for every P-38 or P-47 cancelled.
.

From what I have read in posts here it would be very difficult to get substantially more of any version, apart from just producing the fighter instead of the A-36 which was political budget thing and a choice of whats best. The AAF didn't have much interest in it even when they got one to test, its a strange story all around.

 

[wuzak]

P-47 Why not just build F8F Bearcats with more internal fuel instead. Almost as fast, much better climb and turn. Common single stage R-2800 engine. Less Expensive.

F8F was developed with war experience. If it was developed earlier it would probably end up like the F6F.

Plus the F8F engine didn't exist until 1944?

 

[P-39 Expert]

AG Williams, of Rapid Fire, has posted an article: Modifications and Attempts at Standardization. Since it's just one source, it may not be fully informative.

Very informative, thanks.

 

[drgondog]

Please don't think badly of me, the opinions are my own. This is up to mid '44, after that it was a moot point.

P-38 Cancel this thing as soon as possible, use the ones you have for reconnaissance. Too much for the average pilot, too expensive, too low a mach number.
P-39 D through L reduce weight by losing the wing guns and nose armor plate. Move the radios up behind the pilot for balance. Now it will climb with the Zero and still be 40mph faster at all altitudes. Then when the 9.6 engine is available just build the N. If more fuel is needed lose the wing guns and add a fuel tank in each wing. When the two stage Allison -93 starts production in April '43 then start using that.
P-40 Cancel this one asap too, give the ones already built to our allies. Or make it 1200# lighter somehow. How? No idea. Or re-engine with the F version of the -93 in April '43.
P-47 Why not just build F8F Bearcats with more internal fuel instead. Almost as fast, much better climb and turn. Common single stage R-2800 engine. Less Expensive.
P-51 The AAF obviously needed to push this plane but initially didn't want them because they were under a British contract. More AAF/Govt politics and bungling? Engine them with Allisons, Merlins, single stage, two stage, just get them into production with the best engine available and constantly upgrade. Get two P-51s for every P-38 or P-47 cancelled.

Of course this is with 20/20 hindsight.

20/20 hindsight, given the facts of 1939-1941 Doctrine wars within Plans Division, suggest that most of your suggestions were not feasible, and not practical.

First the Politics - Material Command Commanders Spaatz, Brett and Echols were a.) Heavily vested in long range strategic bombardment with belief that the B-17 would always get through opposition interceptors with acceptable losses, and b.) heavily vested in Curtiss first as Pursuit source. Lockheed was newcomer, Seversky built good aircraft but hated Arnold (semi-vocal about it also). NAA regarded as Trainer source, then acknowledged as light/medium bomber and in fact Explicityly excluded from solicitations for Pursuit RFP's.

AWPD-1 reflected bomber centric vision for AAC/AAF Plans but some wiser heads also reminded the senior leadership (Arnold/Emmons) that AAF was part of the Army - and Asst SecWar Lovett reminded Arnold and Emmons of that reality when Arnold became Chief AAF in June 1941. Further he continually reminded both Emmons and Arnold that the dive bomber and fast battlefield recon/fighter force over the battlefield left much to be desired in AAF CAS doctrine. Now look at the timeline. NAA by that time had delivered the XP-51 which was in test and Mustang I production was in swing at that time. NAA initiated design work on the Low Level Pursuit Attack Airplane in October with internal charge number in November. They didn't do so because they wanted to waste R&D funding. NAA was aware of the pressure from Lovett, the tides changing within both Arnold and acolytes in Plans that a.) European experience and Spain were bright posters that the 'bomber might not always get through', and that b.) perhaps they should listen a little harder to USA which very much wanted something better for tactical air support. They got the A-20, the P-39 and P-40 were in play because of their deficiencies as interceptors and reports were dribbling upward regarding the superiority of the XP-51 over P-40E, P-38D, P-39D as low to middle altitude fighter. Ira Eaker, in transit from command of west coast based 20th Interceptor Group stopped by NAA and flew the XP-51 number 2 - and was impressed, noting that the engine was the limiting factor. He informed both Eaker and Arnold of his impressions shortly before being named CO of VIII BC by Spaatz.

Politics continuing - Oliver Echols was an absolute supporter of Curtiss and pushed the XP-46, third in evaluation of the S/E Pursuit RFP summer/fall 1939, as the Selection. The reports of AFPC dissatisfaction with lack of armor plate and self sealing tanks of existing P-38 and P-39 and P-40 airframes led Echols to craft a strategy to push the XP-46 at Curtiss and off-load the P-40 to NAA to manufacture them to RAF standards including armor and fuel tanks and get Brits to pay for the improvements. NAA raising single digit salute to Echols to pursue the P-509/NA-73X in 1940 made an enemy of Echols and hence Material Command.

This is getting too long but the net of the parallel changes in thinking at AAF HQ, different from Echols/Material Command put NAA in a collision course with Echols, and fortunately General Muir Fairchild, Chief Requirements Div had bigger 'junk' and essentially forced the A-36 down Echols' throat when Echols was championing the Brewster XA-32 as the CAS offering. Nobody in AAF CAS camp thought much of A-25, 25, 31 or 32 as the solution and reports were flooding in that the P-51 was better than the P-39 and P-40 for any role.

The XP-47B and P-47B were deemed better, at high altitudes, ditto P-38D so they were the Only s/e ac remotely contemplated for escort despite range deficiencies. Neither were ever going to be cancelled then or with 20/20 hindsight

Everybody realized that the P-39 and P-40 with the same engine were inferior in speed and range and were dead ends relative to future development in mid 1942 but production continued because the tactical requirements globally demanded them. Range was always a huge elephant in the room.

 

[GregP]

First, Hello Bill Marshall! I still want a copy of your next book!

The problems with the P-59 were more involved than what I am reading. We are restoring the 10th YP-59A to flight status and we have many documents.

First, when Bell was asked to produce the jet, they were not told ANYTHING about the engine ... they got a big block of wood and were told the real engines would not be any bigger than the wood form block. But, and here's the part that most are missing, they were not told how much it would weigh, how much thrust it made, what the fuel consumption was, or where the engine mounts connected to the engines! So, the engine compartment were made too large to accommodate whatever came along as an engine.

So, they made a test-mule airframe with plenty of strong wing, almost a sailplane wing in fact, in case the engines were very heavy. It has air intakes that would do a modern jet engine proud, as far as area and air volume went, but the engines they got didn't need anywhere NEAR that much inlet area. So, a good deal of the inlet air would go in, turn static, and bleed back out around the intake mouth, creating or helping to create directional instability. They COULD have done things differently, but the US Government wasn't very big on sharing data such as the amount of intake air required at the time. Probably, they really didn't know.

We have a flight test report on our aircraft!

The plane we have has engines that burn about 575 gallons per hour combined at low altitudes. It has less than 300 gallons of fuel, excluding the extra fuel tanks. Good luck with the range! It needs auxiliary tanks to have enough fuel to get around the pattern more than two or three times! The fuel consumption could be made to drop, but you'd use up the internal fuel just climbing up to any decent height making the extended climb a thing to avoid.

If you DID get above 35,000 feet, the canopy would freeze over from the inside! If you open the canopy in flight, you can't get it closed! The roll rate was VERY slow, and would have been difficult to improve. The aileron gap seals were quite long (and still are), and the ailerons only had about 11° - 13° of movement in them at full deflection! The aileron tabs were servo tabs ... we have changed them to anti-servo tabs to get maybe a bit more roll rate at the expense of a slightly heavier stick. Our plane will be an airshow machine only, and it won't ever go very fast.

While the P-59 may not have been a very good airplane, it DID serve to introduce many WWII-era piston pilots to jet engines. And therein lies it's worth. The first squadrons of P-80 pilots were all transitioned from P-59 Airacomets, so they did their bit for us when they were in service.

We have had several pilots come through the Planes of Fame who flew the P-59 in one of it's forms, and at least 2 who flew our bird (tail number 777). More than one has said he ran out of fuel regularly when flying a P-59 and it glided well enough to get to any of several fields, where they would land, call home for fuel, and go to the nearest bar to wait for said fuel. We tend to forget that when they were flying the P-59 Airacomet, jet fuel was not standard at ANY airfield. You called for it and waited for the truck to show up. Might as well have a drink meanwhile!

There is NOTHING on the YP-59A that is easy to work on, and changing engines is not a fun task. But you would have to do exactly that at relatively short intervals. TBO on the early engines was only a bit north of 20 hours! Altogether, the YP-59A is a very interesting piece of aeronautical history that I hope to see fly within a couple of years. There are several generations of restoration volunteers who are eagerly awaiting daylight under the tires due to changing jet fuel into noise.

We think one of the I-16 engines makes about 1,600 pounds of thrust … and the other one just makes noise! Not really, but is sure seems that way! 12,500 pounds of aircraft and 3,200 pounds of thrust don't exactly make it "sprightly!" We just hope we don't destroy the fabric-covered elevators with flames from startup due to overflowing raw fuel into the bottom of the combustion chambers! So, we will have an item on our checklist to keep the stick full aft during startup! Heck, the engine igniters are a pair of old Ford "shower of sparks" units that fire a pair of spark plugs!

Cheers.

 

[Zipper730]

fortunately General Muir Fairchild, Chief Requirements Div had bigger 'junk' and essentially forced the A-36 down Echols' throat when Echols was championing the Brewster XA-32 as the CAS offering.

Wasn't the XA-32 a lemon?

 

[fubar57]

A husky brute of an attack plane, the XA-32 was terribly overweight at almost 20,000 pounds. The drag induced by its rotund shape was amplified by careless detail design, which left it festooned with bumps and lumps. It was underpowered by the Pratt and Whitney R-2800. The real problem, however, was that the XA-32 suffered from the terminally bad Brewster management system. First flight was not until 22 May 1943, two years after the design was proposed; and almost every aspect of performance fell short of the specifications. The firm was in such management shambles that it drew the wrath of Congress and actually went out of the aircraft manufacturing business. Only two examples built.

Brewster XA-32 Info​

 

[swampyankee]

Having worked in a classified project, I found it amazing what the military found necessary to classify. At the time, among other things that were classified were some of the computer programs, which were based on standard textbooks and readily available technical publications, many of which were from the USSR (there were a lot of articles from the Soviet equivalent of IEEE and APS; it was ironic that Cold War era stealth technology was so reliant on Soviet sources).