US Fighter production during WW2

[DesertFox]

One item I have been thinking about is just how many fighters that the United States produced to fill similar roles, many with similar characteristics as well.

 

Could fighter production have been simplified? Do all of these different designs make sense?

[Archie Pellagio]

In reality no more overlap than any other country.

 

You're generally looking at three primary types at any given stage of the war. (excluding carriers of course)

[JWB]

One item I have been thinking about is just how many fighters that the United States produced to fill similar roles, many with similar characteristics as well.

 

Could fighter production have been simplified? Do all of these different designs make sense?

The characteristics of the three types were similar but the technology of each could not be incorporated into a single type. The P-40 had the advantage of economy and reliablity. It was semi-obsolete but was also robust, easy to maintain and relatively cheap to operate making it an effective CAS plane. P-47 was extremely powerful because of the turbocharger, almost unbreakeable and very forgiving for novice pilots making it highly versatile as a a medium altitude escort and brutal long fighter bomber. P-51 had supreme aerodynamic efficiency and was highly maneuverable making it the only fighter capable of long range escort. All of these capabilities conflict and cannot be incorporated in a single airframe but at the same time all of those capabilities are vital.

[DesertFox]

Does the P-39 and P-40 serve different roles. That is one that seems able to be combined.

[Shortround6]

Does the P-39 and P-40 serve different roles. That is one that seems able to be combined.

 

They were intended for different roles. The P-40 was a quick and dirty re-engine of the P-36 to get a better (faster) fighter into production quickly.Please note the original P-40 had only two .50 cal MGs. They slowly added .30 cal MGs in the wings and finally went to the wing .50s when they changed engines to one with a different gear box that shifted the propeller shaft about 6 inchs higher.

 

The P-39 was designed to be a fast climbing interceptor with a cannon. The turbo installation was a disaster and with Turbo suitability for operations questionable (see P-37, sort of a turboed P-40)the turbo was removed. Bell seems to have seriously misjudged a few other aspects of the design causing it to be seriously over weight before armament was added.

 

Both fighters were designed before armor and self sealing tanks were added to requirements. Once this extra weight was added and the armament of both planes was increase well over the original designs the extra weight forced both aircraft into the low altitude role.

 

Both aircraft had also received large overseas orders at around the same time as the US place initial orders which meant that both factories were tooling up, expanding and buying materials for large scale production before the US got in the war. With the fall of France and Britain realizing they had been sold a bill of goods in the P-39 it left a lot of excess capacity at a time when the US needed large numbers of aircraft. Roosevelt had announced a 50,000 plane air force and the P-40 and P-39 were the only two fighters that had tooled up factories ready to go.

 

edit> It is very hard to turn programs on and off quickly. While everybody remembers that the Mustang was designed and built in 117 days few people remember that the British had actually placed orders for 620 Mustangs before the prototype was even rolled out the door without it's engine or that it took 363 days from the first flight of the prototype for the first production Mustang to arrive in Britain, or that it's first combat operation didn't happen for another 6 months.

2000 P-47s were on order before the first one flew. The orders were placed before Pearl Harbor.<edit

Edited November 9, 2010 by Shortround6

[Sardaukar]

Also, the pre-war plane aquisition program for Army air units was planned for small numbers of several types, sort of contigency plans if one type would not live up to expectations. It also helped several companies to stay in business during lean years. There was, because of this, some heated discussions when P-40 was ordered in unprecendented numbers, because of this policy.

 

Same was in Navy fighter production, where both Brewster and Grumman were receiving orders for Navy carrier fighter.

[bojan]

Soviets had couple of overlaping classes also, mostly driven by engine requirements: light Yak (Yak-1/3), heavy Yak (Yak-7/9), La series (La-5/7) and various niche designs or economy designs (MiG-1/3, two engined fighters Yak-5, Pe-3, economy measure as LaGG-3 etc). So US was not much worse - early P-40 and P-39, added heavy fighter (P-38), introduced P-47 and P-51. And don't forget that US had requirement which Soviets did not - long range escort fighter.

[Yama]

One item I have been thinking about is just how many fighters that the United States produced to fill similar roles, many with similar characteristics as well.

 

Could fighter production have been simplified? Do all of these different designs make sense?

 

It takes time to tool a factory and supply chain to produce new type. There will always be a tradeoff of whether to keep producing existing multiple types, or accept a temporary drop in production and move to less types which potentially would increase the production in the future.

 

Plus, there will always be bottlenecks - engines, most notably. From performance development standpoint, multiple designs made sense as the chance of benefitting from advances in design and technology increased.

 

Having said that, P-40 and P-38 production probably dragged on for too long...

[Sardaukar]

 

Having said that, P-40 and P-38 production probably dragged on for too long...

 

P-40 production probably, but P-38 was more ideal for Pacific conditions and not many flying mostly over Pacific Ocean was happy to trade it in for P-51.

 

Gen. Kenney of 5th AF made famous comparison between P-51 and P-38 in Pacific conditions, saying how much it helped pilot morale to know that even one of the "two big fans" in P-38 would be enough to bring pilot home, especially after flying hours over shark-infested waters (where you could actually see the sharks...). He said that let's say as plane, we rate P-51 as 100% and P-38 as 75%. But after hours flying over ocean, P-51 pilot arrives to combat with 50% morale while P-38 pilot is still 100%, making overall comparison of 150 - 175 for P-38.

 

There really was not comparable plane, maybe with ruggedness and range when P-47N was introduced, but even that had only one engine.

[ickysdad]

Let's remember too that the P-40 & P-39 gave the US an export to give the British & Soviets. The British I'm sure were glad to have the P-40's over the Western Dessert when there just weren't enough Hurricanes or Spitfires. On the Eastern Front the combat was at lower altitudes at which a P-40 or P-39 could give far more modern fighters a run for their money.

[Shortround6]

The P-38 was also designed/built to an an "Interceptor" specification. The performance requirements, as in speed, climb, endurance and weapons may have changed as the years went by or as each manufacturer submitted their proposals. Lockheed did offer much longer endurance than Bell from the start. Lockheed thought they could get the performance required from a single 1500hp engine but as no such engine was available or likely to be available in the near future they went with two 1000hp engines. The USAAC then specified the Allison so Lockheed didn't really have a choice.

The P-38 suffered from timing, as America's ONLY high performance fighter available in numbers until the spring/summer of 1943 and with every theater clamoring for all the P-38s they could get, modifications that threatened to disrupt production for even a couple of weeks were not allowed. The P-38 was forced to suffer with undersized intercoolers until the "J" model. these undersized intercoolers (and radiators) limited the useable power from the nominally more powerful engines that were installed in some of the intermediate model P-38s. they also limited the use of WER power settings. With the introduction of the "J" with it's much more effective intercoolers a new problem cropped up. The intercoolers were TOO effective in cruising flight and combines with a few other teething problems and a change in fuel blend, caused the problems that impacted the P-38s popularity in Europe. Minor changes combined with a change in cruise power settings (back to what both Lockheed and Allison had recommended all along) solved the ETO problems just in time for the Mustang to get the nod as the fighter of choice. The Mustang did turn out to be the better choice.

[Archie Pellagio]

At the end of the day requiring two engines to be produced for one fighter was never going to be a satisfactory state of affairs though.

[DesertFox]

At the end of the day requiring two engines to be produced for one fighter was never going to be a satisfactory state of affairs though.

 

How about the F7F Tigercat?

[DKTanker]

How about the F7F Tigercat?

Also the F-82 which actually did see combat.

[tankerwanabe]

I thought that these aircrafts were manufactured one after the other rather. In other words, the US was upgrading its airforce continuously as the war progress so that they don't fall behind the Germans and Japanese; and secondly to fullfil its needs as the war went on the offensive.

 

It was a natural progression during a period of extreme advances in aviation.

[Kenneth P. Katz]

So did the F7F. Both were used in the Korean War.

 

Also the F-82 which actually did see combat.

[Kenneth P. Katz]

Both the P-39 and P-40 served the USAAF well in the role of what in modern times would be called lead-in fight training (LIFT), aka taking newly winged pilots and teaching them the fundamentals of flying fighters.

[JOE BRENNAN]

At the end of the day requiring two engines to be produced for one fighter was never going to be a satisfactory state of affairs though.

Other countries also had two engine 'heavy fighters' for specialized roles (Ju-88 and Mosquito fighter versions, etc) which were bigger than the P-38, and the long range P-47 was about as big as the P-38, but I agree you can't ignore the cost of a much bigger fighter for the same role. Of course the roles of various USAAF fighters in WWII was usually pretty accidental compared to their original design concepts, and as mentioned timing is important: the P-38 was a long range fighter reasonably competitive with most single engine opponents, available a significant time interval before the P-51B or P-47N. And in general 'the iron law of mobilization' is to ramp up production of what's already in production.

 

The F7F fit more in the mold of heavy/night fighter type of twin, existed in day fighter versions but most production was night fighter models including the F7F-3N which saw combat in Korea, including a few cases of night air combat. The F-82 was envisioned in the P-38 type role as well as nightfighter (the couple of cases of F-82 air combat were nightfighter models operating in daylight in Korea, at least some and perhaps all their opponents were Yak-11 trainers). The F-82 was an interesting calculation when it came to resources, requiring pretty literally two (fairly large) single engine a/c to be built for each F-82; a pretty interesting airplane all around.

 

Joe

Edited November 10, 2010 by JOE BRENNAN

[Sardaukar]

US was pretty lucky (and also quite able to improvise) that P-38 and P-51 had different strengths and weaknesses, making them more suitable for Pacific and Europe respectively. Same thing could be seen in B-25/B-26 and in B-24/B-17.

 

If US had encountered Japanese planes who could actually perform in higher altitudes during times when things still were bit even (like Ki-61 Hien/Tony when it worked), P-47 would have been more popular in Pacific too.

 

One of the downsides of P-38 was that it was delayed about 6 months due to production/design/engineering mistakes, because Lockheed was allocating best engineers etc. to Lockheed Electra and derivative Hudson patrol/light bomber. It could have easily seen combat in spring 1942 in Pacific instead of autumn 1942 in form of P-38F.

[DKTanker]

Getting our feet wet, there is the F4U / F6F overlay. It is interesting that the F4U in 1938 was planned to have a PW 2800 and that in 1940 it exceeded 400mph. One might ask, then why was Grumman told to design the F6F? The design process for the F6F didn't start until after the F4U had first flown and at that it was initially supposed to be powered by an engine with significantly less HP. Even when the F6F was eventually powered by the PW2800 it was considerably slower than the F4U.

 

Granted, the F6F-3 had many flying qualities that initially made it superior to the F4U, but that wasn't known when Grumman was asked to design the Hellcat, so what gives?

 

 

[Kenneth P. Katz]

The P-82 was essentially the replacement for both the P-38 and the P-61, the latter being the most obscure of major USAAF fighter types.

 

The F-82 was envisioned in the P-38 type role as well as nightfighter (the couple of cases of F-82 air combat were nightfighter models operating in daylight in Korea, at least some and perhaps all their opponents were Yak-11 trainers). The F-82 was an interesting calculation when it came to resources, requiring pretty literally two (fairly large) single engine a/c to be built for each F-82; a pretty interesting airplane all around.

 

Joe

[Kenneth P. Katz]

Backup so that the Navy would have an alternative if the F4U had problems, which turned out to be an excellent decision since the F4U-1 was an unsatisfactory carrier-based fighter.

 

Granted, the F6F-3 had many flying qualities that initially made it superior to the F4U, but that wasn't known when Grumman was asked to design the Hellcat, so what gives?

[alejandro_]

Granted, the F6F-3 had many flying qualities that initially made it superior to the F4U, but that wasn't known when Grumman was asked to design the Hellcat, so what gives?

 

The Hellcat was initially designed as a Wildcat replacement. It seems that the USN tested the prototype and ordered them. No requirement as in the F4U. Corsair was more expensive and more, importantly, much more difficult to operate from aircraft carriers.

 

At the end of the day requiring two engines to be produced for one fighter was never going to be a satisfactory state of affairs though.

 

This was not the case at the start of the war, when engines supplied 1000HP. If more range/payload/firepower was needed, it was very likely that you would end up with a twin engine fighter.

 

An important factor determining the fighter availability for production was the engine. It made sense to have different fighters with different engines (Fw-190&Bf-109/110) to aboid overloading the production line.

[DKTanker]

The Hellcat was initially designed as a Wildcat replacement. It seems that the USN tested the prototype and ordered them. No requirement as in the F4U. Corsair was more expensive and more, importantly, much more difficult to operate from aircraft carriers.

None of which was known when Grumman started the F6F.

 

What do you mean, no requirement as in the F4U?

[DKTanker]

Backup so that the Navy would have an alternative if the F4U had problems, which turned out to be an excellent decision since the F4U-1 was an unsatisfactory carrier-based fighter.

How many F6Fs were flying off of carrier decks during the Korean War vice F4Us?