Mistakes in Aviation

[kool kitty89]

I think the P-38 was a very good multi-role a/c. (in the top 5 of the war if not the top 3) The crasing of the XP-38 delayed things by about a year though... But if you look at overall capabilities the F4U could do about the same. The F4U-1D and later models could cary 4,000 lbs of bombs and dive bomb very accurately the range of the F4U (on Reinarch's figures, with wing tanks) was better than the pre J p-38. This switched when the P-38 got the wing tanks.

I kind of mis spoke though, and that statement was a bit wrong, but the Early P-38 (Pre-J) had alot more problems than the P-47 or F4U of the same period. I was just trying to think in Renrich's case. It had it's advantages and overall ended up a more capable than almost any other single seat fighter. (it could level bomb, te Corsair didn't, the F4U could dive bomb the P-38 didn't...) But that discussion belongs more on the most versitile a/c thread. Plus there was that F4U vs P-51 vs P-38 vs P-47 thread iirc.


But Why jump on me when Renrich mentioned it first! He said the P-38 and P-47 and the F6F in the Navy should be replaced by the F4U due to the performance of the XF4U, with Republic, Lockheed, Grumman etc license bulilding the Corsair. And the only other fighter to use

Which I don't think is true even with hindsight, and certainly not at the time. (kind of an all eggs in one basket situation)

 

[kool kitty89]

Blech I read that quote a little more carefully and that's not right at all...

I was trying to think form Renrich's post PoV and it screwed it up.

What I should have said that in the case of the P-38 it was a good a/c with excelent multirole capabilities, but the P-47 and F4U were as well, and they cost less and were roughly as capable. (the bomb loads and ranges were very close) For long ranges in warmer temperatures (PTO, MTO, N Africa) even the early models were manageable. And the lack of torq would make long range flight a bit easier on the pilot.

The only real problem (besides the extra cost and maintenence) was the compressibility issues. (dive flaps adressed this but held speed to .68 mach which was well below the competition, ~.82 on the P-47) And on the cockpit, though the heating problems were solved and it was comfortable enough, the instrument layout was a bit complecated, much more crouded than the other single seaters. (though some of this would obviously be necessary due to the 2x engines)

 

[kool kitty89]

We kind of had that discussion going on in the best PTO fighter thread. (P-38 vs Corsari, not the build the corsair instead one)

 

[renrich]

Vought was a very small company. For instance, after Boone Guyton came on board he, one pilot, did all the test flights for the Corsair. The development program went slowly because the performance of the Corsair was so cutting edge and because Vought was getting the bugs out of a new engine and a new prop as well as the air frame. A development program for a land based version by Lockheed and or Republic would have advanced the program much faster. The first design change for a version without carrier capability would have meant deleting the tail hook and wing fold. How much weight and drag would go away from that change? Structural changes may have been made because the AC would no longer have to endure the controlled crash of carrier landings. How much weight savings there? The airplane was optimised for performance from sea level to around 25000 feet where sea warfare took place. The later F4U4 and 5 had very good high altitude performance with bigger and better superchargers. By the way, the F4U5 was all metal. The big advantage the Corsair in 42-43 had over the P47 was in range. The F4U1 had a capacity of 361 gallons of internal fuel and could carry drop tanks too. How nice would it have been to have escort fighters in the 8th in 42-43 with a combat radius of a couple of hundred miles further? Bubble canopies, some Corsairs had them. The reason the P51 would have been desirable as a stable mate for the Corsair was that it combined very long range but retained good fighting qualities.

 

[FLYBOYJ]

But Why jump on me when Renrich mentioned it first!

Because i read your post first!

He said the P-38 and P-47 and the F6F in the Navy should be replaced by the F4U due to the performance of the XF4U, with Republic, Lockheed, Grumman etc license bulilding the Corsair. And the only other fighter to use

Actually look at the XF4U performance - it was great but the developing fighters had the some potential and it wasn't till the F4U-4 where it started walking away from the "competition" for the most part.

Which I don't think is true even with hindsight, and certainly not at the time. (kind of an all eggs in one basket situation)

Agree....

 

[kool kitty89]

I wonder how much faster development would have been for the P-38 had the XP-38 not crashed.

Obvioulsy further testing could have the discovery of some problems earlier on, but there were fundemental differences between the XP-38 and the YP-38's and subsequent production a/c. The construction was very different, and the XP-38 was made largely of stainless steel and much heavier construction. There may have benn structural differences as well and the XP-38 was basicly hand built with some very tight tolerances iirc.

 

[FLYBOYJ]

I wonder how much faster development would have been for the P-38 had the XP-38 not crashed.

Obvioulsy further testing could have the discovery of some problems earlier on, but there were fundemental differences between the XP-38 and the YP-38's and subsequent production a/c. The construction was very different, and the XP-38 was made largely of stainless steel and much heavier construction. There may have benn structural differences as well and the XP-38 was basicly hand built with some very tight tolerances iirc.

The XP-38 was hand built - stainless steel? Maybe on the firewall!

 

[kool kitty89]

Hmm, Lockheed XP-38 Lightning

it was the first to make extensive use of stainless steel

And it's all over google XP-38 stainless - Google Search

but none seems to be more specific to the usage of stainless steel other than it was "used extensively in its structure" so what is that about???


There's also claims that the crash of the XP-38 delayed the program by 2 years. P-38 Lightning

That first XP-38 proved to be capable of a level speed of 413 m.p.h., and had a terrific climb rate. In fact, throughout the war, the P-38 remained one of the fastest climbing American fighters. Unfortunately, the first prototype lasted only 16 days. The testing program had barely begun when the Army decided to use it in a record setting cross-country flight that ended with a landing short of the runway, which wrote off the prototype. Tony LeVier (Lockheed Chief Test Pilot) later estimated that disaster set the program back nearly two years. It also probably cost many brave American aviators their lives when their inferior and obsolescent planes came up against advanced Axis fighters like the Zero and ME 109.

One thing that I didn't know was taht not only was the prototype not designed for mass production, but the original plan and specification didn't include it either! P-38 Lightning

It started in January of 1937, when the Army Air Corps circulated to aircraft manufacturers a specification for a new pursuit plane for the "interception and attack of hostile aircraft at high altitude". They wanted a max. speed of 360 m.p.h. at 20,000 ft., and climb from takeoff to 20,000 ft. in 6 minutes. There were other details, but the point is that the demand was for a high performance interceptor. The government anticipated on order for a maximum of 50 planes, so suitability for mass production was not a consideration. Lockheed was one of the companies that entered the competition to design and build the new fighter. ... As alluded to earlier, the P-38 was not designed for mass production. In fact, it was intended to virtually build each of the 50 originally anticipated aircraft by hand. Many, many production problems had to be solved before the Lightning could be produced in quantity. As well as some serious engineering problems.

 

[KrazyKraut]

The Heinkel He 100 was too late to compete with the Bf 109. Even the He 112 was too late to compete with it in the early versions.

I agree. The Bf 109 beat the He 112 fair and square. Politics sure played their part but especially in this case they swing both ways: Messerschmitt had some LW staff on his side, but, far more important, he had Milch against him. Milch hated Messerschmitt with a passion.

The He 112 simply wasn't as good as the Bf: The 109 with Jumo outperformed the equally powered He 112 and that in the end won Messerschmitt the competition. Even then Udet was smart enough to ask Heinkel for a zero series for further analysis. Some of these were tested against the already procured 109 over a period of ~5 months... and they were simply not as good. After reading up on the trial process, in my personal opinion, there was nothing dodgy about the decision.

The He 100 is a different matter: While it showed some superiority over the contemporary 109s, it also had a very novel and unproven cooling system. Also the performance estimations by Heinkel proved to be far too optimistic after armament etc. was installed. I still have to read up on the subject, but my first impression is, that it simply wasn't worth replacing the 109 (whose production was just gearing up) with an only marginally better, unproven design.

 

[evangilder]

I think we only need to take a look at the success of the 109 to see that the proper decision was made on the choices. I have read similar things about the 112/109 debate and seen the same conclusions. The 109 was simply better.

 

[FLYBOYJ]

And it's all over google XP-38 stainless - Google Search

but none seems to be more specific to the usage of stainless steel other than it was "used extensively in its structure" so what is that about???

I suspect that was an exaggeration - I could see stainless being used on the firewalls and forward nacelles. The Budd RB-1was the first all stainless steel aircraft and that wasn't started until 1942 or 43 if I remember right. Stainless steel could be used for a good aluminum replacement for the most part but it is expensive. I'd bet areas around major structural components were stainless, the rest were aluminum.

There's also claims that the crash of the XP-38 delayed the program by 2 years. P-38 Lightning

Yes it did - there were a lot of plans for the P-38 that Lockheed wanted to recommend to the government - although we always hear about the "Merlin Myth" I personally think it was more of a study than anything else. you see, when the government ordered the YP-38s they dictated certain pices of equipment and one of those were the engines, so after the prototype stage Lockheed was stuck by contract with the Allison. I was also told that Kelly Johnson looked in replacing the yoke with a stick.

One thing that I didn't know was taht not only was the prototype not designed for mass production, but the original plan and specification didn't include it either! P-38 Lightning

That is true. People who I worked with at Lockheed who were there at that times also thought that the prototypes were going to be the only "production" P-38s built. They too were also hand built.

 

[HoHun]

Hi Flyboyj,

>The Budd RB-1was the first all stainless steel aircraft and that wasn't started until 1942 or 43 if I remember right.

Hm, it's my impression that it was pre-empted in 1915 by the Junkers J 1, the world's first all-metal cantilever monoplane aircraft. It was not a success due to being too heavy for the engines available at the time, but it still was 30 km/h faster than the contemporary Fokker Eindecker.

Regards,

Henning (HoHun)

 

[evangilder]

The Junkers J1 was made mostly of duraluminum, not stainless steel.

 

[FLYBOYJ]

Hi Flyboyj,

>The Budd RB-1was the first all stainless steel aircraft and that wasn't started until 1942 or 43 if I remember right.

Hm, it's my impression that it was pre-empted in 1915 by the Junkers J 1, the world's first all-metal cantilever monoplane aircraft. It was not a success due to being too heavy for the engines available at the time, but it still was 30 km/h faster than the contemporary Fokker Eindecker.

Regards,

Henning (HoHun)

Aluminum - not stainless steel.

 

[kool kitty89]

I don't think the Merlins would have been much of an advantage over the turbocharged Allisons. (they jst needed to wok out the bugs with the system, particularly the intercooler problem, iirc there were some problems with the turbos ceasing at high alt as well)

Another problem was that until late war there weren't Models of the Merlin developed for "hande"/counter rotating props for twins. Opposed to the Allison design where this was realitively easy to do.

Another feature of the V-1710 design was its ability to turn the output shaft either clockwise or counter-clockwise by assembling the engine with the crankshaft turned end-for-end, by installing an idler gear in the drive train to the supercharger and accessories and by installing a starter turning the proper direction. So, there was no need to re-arrange the ignition wiring and firing order, nor the oil and Glycol circuits to accommodate the direction of rotation.

Throughout the war the power output levels were similar for both engines as well.


The only real limitation for the P-38's development compared to the contemporary P-51 and (especially) P-47 was the realatively low Mach limit (.68 with dive flaps) and it would have taken a redesign of the wing to fix it. (entire new airfoil)
And as often stated, the P-38's problem was particularly bad since it was a very clean design and could easily exceed the limit in a dive above 20,000 ft and not slow fast enough once it had reached denser air. (and the P-38L could come very close to the limit in level flight)

Kind of like the F-84G Thunderjet, a very clean design, such so that even with similar thrust to the F-80C, and at ~25% more weight (25% thrust/weight) it could exceed its critical mach of .8 at SL (entering pitch up stall), the airfoil again being the limit. (and the P-80 actually haveing a high critical mach number, ~.84 iirc, with limit of .82)

 

[HoHun]

Hi Evan,

>The Junkers J1 was made mostly of duraluminum, not stainless steel.

Steel is correct for the J 1 of 1915 vintage. It took Junkers about two years to come up with an all-metal light alloy aircraft, and I'm sure you are thinking of the Junkers J-I - the former was the Junkers-internal designation, and the latter was the Fliegertruppen designation in which the "J" did not stand for "Junkers", but for "Infanterieflugzeug" (ground attack plane - "J" was habitually substituted for an initial "I" in German typesetting tradition). According to the Junkers count, the J-I was the J 4, but it was a completely different aircraft from the J 1. You're right that it was mostly a duraluminium aircraft, it was only the armour tub for engine and crew that was from steel.

Velius posted a short description of the type (complete with photograph) here:

http://www.ww2aircraft.net/forum/aviation/aircraft-technological-firsts-13099.html

Though I'm not a Wikipedia fan, here the link to the article on the J 1:

Junkers J 1 - Wikipedia, the free encyclopedia

Here the article on the J.I - the picture is interesting as it highlights the completely different layout compared to the J 1:

Junkers J.I - Wikipedia, the free encyclopedia

The J 1 due to its prototype nature is not a well known type, but was quite a milestone in aviation - it even hat a jet radiator with diffusor and jet nozzle to exploit what was later termed the "Meredith effect".

Regards,

Henning (HoHun)

 

[Graeme]

Hi HoHun.

My understanding is that the Junkers J1 (aka the "Tin Donkey") was made with sheet iron over an iron tube framework. No aluminium.

From the site you posted...

"Junkers had to use sheets of heavier electrical steel instead for his first all-metal aircraft designs, similar to the types of ferrous sheet metals used in laminated-core AC electrical transformers".

Turner and Nowarra in their book "Junkers" state that at the time aluminium was so "precious", that he could not acquire any for his project and that many thought the all-metal design as "frivolous".

(edited. Apologies, re-read your post, this is actually your point. J1 confusion!)

 

[pbfoot]

I know that in the early 1900's aluminium was a rare metal I've heard it was up to several hundred dollars a pound .One of the reasons being that few places had the electric power able to supply large quantities for the refining/smelting of Aluminium.

 

[evangilder]

Good catch Henning. I misread that same Wikipedia article, and swore I read that it was made of duraluminum. After re-reading, I see that is not the case.

 

[FLYBOYJ]

Yes indeed, but remember, we were talking about stainless steel, a little different animal.