Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained) (1 Viewer)

[Shortround6]

All those planes had multiple contracts, just build out the initial contract and move on to the P-51. Same Allison engine, same propellers, North American is part of GM so facilities and $$ shouldn't be a problem.

Ir would take between 4 and 8 months to retool the factory and get the production back up to the same numbers of planes per month.

It isn't always about the money.

.

 

[pbehn]

All those planes had multiple contracts, just build out the initial contract and move on to the P-51. Same Allison engine, same propellers, North American is part of GM so facilities and $$ shouldn't be a problem.

You'll also need to keep producing one of either the P-39 or P-40 to provide to our allies since you don't want to be giving the Russians a plane with the range of the P-51. And you'll need that plane to use until the P-51 becomes operational in July '42. In July '42 neither the P-38 nor the P-47 are in combat yet.

That is pretty much what happened wasn't it?

 

[Milosh]

All those planes had multiple contracts, just build out the initial contract and move on to the P-51. Same Allison engine, same propellers, North American is part of GM so facilities and $$ shouldn't be a problem.

You'll also need to keep producing one of either the P-39 or P-40 to provide to our allies since you don't want to be giving the Russians a plane with the range of the P-51. And you'll need that plane to use until the P-51 becomes operational in July '42. In July '42 neither the P-38 nor the P-47 are in combat yet.

P-40 as it is the more versatile a/c.

 

[gjs238]

P-40 as it is the more versatile a/c.

...and less risky.
Assuming that the P-39 project is cancelled before production begins, and the P-40 is chosen as the interim aircraft of choice, can Curtis produce enough P-40s or are other avenues of production needed, such as the British Purchasing Commission attempted with NAA?

 

[fubar57]

As with other failing companies, Bell could have been tooled up to make P-40s

 

[GrauGeist]

As with other failing companies, Bell could have been tooled up to make P-40s

Bell would soon be building B-24s and B-29s, but had it's hands full with the YFM, XFL, XP-52 and P-39 before the war and ended up with several more irons in the fire by 1941.

 

[Shortround6]

As with other failing companies, Bell could have been tooled up to make P-40s

Curtiss was the only company to make P-40s. No other company, failing or otherwise, built P-40s.

Curtiss was given a contract to build P-47s and made a hash of it.

I am not sure that any USAAF fighter was made by another "company" in large numbers. Navy fighters yes.

Several of the companies making USAAF fighters opened entirely new plants , hundreds if not thousands of miles from the original plant.

Bell was given a contract for 13 YP-39s April 27th 1939,

Bell was given a contract for 80 P-39/P-45s Aug 10th 1939, so production tooling would have started not long after.

Then come the French and British orders for 675 aircraft by June of of 1940.

ON Sept 14th 1940 the Army orders 623 additional Airacobras and that pretty much seals things.

In Jan 1940 Bell had 1200 employees, In Jan 1941 they had 5000, AS of Dec 31st 1940 Bell had delivered 24 Aircraft total , that includes 11 YFM-1, YFM-1A and YFM-1B aircraft.
BY Jan 1st 1942 Bell will have over 10,000 employees and a new factory at Niagara Falls.

Switching factories around sounds good on paper years later. It might not have worked out so well in practice.

I would note that many sources claim that Republic got orders for the P-43 only to help enlarge the factory and keep the work force together.
There were four contracts for P-43s.
The first contract for 13 YP-43s on March 12th 1939, first plane delivered Sept 1940.
Now in Sept of 1940 all work stopped on the P-44 Rocket ( A P-43 with a P & W R-2180 engine) and work not only started on the P-47B but Republic was given a contract for 733 P-47s with R-2800 engines.
Since this plane only existed on paper Republic was also given a contract for 54 production P-43s in late 1940. This was followed by a separate contract for 80 additional P-43As.
On May 6th the first flight is made by the XP-47B.
On June 30th 1941 Republic gets a contract for 125 P-43A-1s for lend lease to China.
Dec 21st 1941 the first "production" P-47B is rolled off the line. Changes are needed.
In Jan 1942 1050 P-47Ds are ordered from the Evansville Indiana Plant (either unbuilt at this time or just starting construction) and 354 P-47Gs are ordered from Curtiss at Buffalo NY.

 

[fubar57]

I was referring to Post #604, ".........Assuming that the P-39 project is cancelled before production begins............."

 

[Shortround6]

Well, you need some Grand Overlord of Allied Aircraft Production (GOAAP for short) to make this decision in between May of 1939 and May 1940.

Of course at this time the US is not part of the "allies".

Even with the order in Aug of 1939 for 80 P-39s Bells financial future was in jeopardy. The French Gave Bell a check for 2 million dollars in the spring of 1940 as a downpayment/advance on their order for 165/170 planes.
The French thought they were ordering a 400mph (or 390mph) airplane and not a 350-360mph airplane (P-40).

Not sure what the reaction would be to being told the P-39 wonder plane was being canceled and everybody would have to make do with P-40 Tomahawks.

The US might be able to write off their 80 plane order if canceled early enough, once Bell has the French order things get tougher and once the British join in with their 505 plane order Bell is committed.

Most US aircraft companies in 1938-1940 were actually pretty small in floor space and employees.

North American was well known to the British due to them having started ordering Harvard MK I trainers in 1938. Noorduyn of Canada had licenced the AT-6 and started building them in early 1940.

 

[pbehn]

I don't know how the subject is so controversial. The USA wasn't at war until the December 1941. Many preparations may have been made but they are different to being at war. From the invasion of Russia the conduct of USA military procurement was completely logical. The P-39 and P-40 both had the advantage of being there at the start but were supplanted by other designs more in keeping with what was needed. From a standing start as a design for a foreign government the P-51/Mustang was adopted progressively over the P-39 and P-40 because it was a better design with more utility. The P-39 had just been rejected and being packed off to Russia when the Mustang Mk I first arrived in UK. Then the Spitfire MK IX arrived, the Typhoon was getting better, P-38, P47 etc. The P-39s chance to shine in Europe was at the very start and it missed that chance.

 

[Shortround6]

I missed something earlier when I said that the P-39 and P-40 were not what the Army wanted in 1939/40/41 but what they could get.

What I missed was that the Army didn't know that what it "wanted" wasn't necessarily what it needed.

Which lead to both the P-38 and P-47 not being suitable for long range bomber escort in 1943 (2-3 years after) they were first ordered.

Complaints about the short range of the P-47 will be filed in the circular bin, until somebody explains how a fighter with roughly twice the range of most European fighters of the time Ion internal fuel) is considered "short ranged". Yes it was not what was needed to escort B-17/24s in Europe but we are back to what was needed after several years of war vs what they thought they needed before the war (for the US) started. P-47 being ordered during the BoB.

 

[pbehn]

I

Complaints about the short range of the P-47 will be filed in the circular bin, until somebody explains how a fighter with roughly twice the range of most European fighters of the time Ion internal fuel) is considered "short ranged". .

Well you can have planes with engines and arms, even complete aerodynamic principles that didn't exist, transplanted into a different era what is the problem with a minor issue like range?

 

[Ivan1GFP]

Hello All,
Seems like we are all attempting to make radical adjustments to history with what we know in hindsight.
How about we take a slightly different approach and adjust with knowledge available at the time.

What was really so WRONG with the P-39 that made it less than successful except in Soviet service?
One problem was reliability which was solved after some time.
The other problem was that the Center of Gravity migrated too far aft and the aircraft became unstable as disposable loads were expended.

The Soviets had a different philosophy for fighter armament.
Their preference was for guns close to the centerline and their fighters tended to be more lightly armed than other Allied fighters.
They had very efficient machine guns and were satisfied with just one or two fuselage mounted MG with a motor cannon.
They removed the wing guns from most of their Airacobra.

Americans seem to want every piece of equipment onboard every aircraft and end up with some pretty heavy aircraft.
Some items such as the mooring kit and engine tool kit and other such service items probably did not need to be carried on the aircraft.
The choice of the Soviets to remove wing armament probably would not have been satisfactory because it would have only left three guns all with fairly low cyclic rates, so to make up for that, I believe it would have been a good idea to go back to the armament arrangement of the P-39C and restore the two synchronized .30 cal MG in place of the wing guns.
The armour for the propeller gearbox could be removed to partially compensate for the weight.

In addition, to help adjust the CoG forward, standard load for the .50 should be adjusted to 270 rounds per gun as the Soviets did with their Airacobra. The Radio could be moved to the area behind the cockpit above the engine without significantly affecting visibility from the cockpit. It would only block visibility into the aft fuselage because of where the pilot sits.
To reduce weight, the armour plate from the Turnover Bulkhead could be removed; The bulk of the engine is behind the pilot for protection. The armour plate for the oil tank perhaps should be removed as well because of the large moment arm it has from the aircraft CoG.

So far, this is the minimally invasive approach.
From test reports, it appears that the CoG of the Airacobra doesn't really migrate very much even on the early versions.
A heavily loaded Airacobra tends to have a CoG at around 25% MAC.
A normal loaded Airacobra tends to have a CoG at around 28% MAC.
An Airacobra without disposable loads in place has CoG at around 30% MAC.
This migration of CoG isn't very great so there is probably something else going on.
Perhaps the airfoil being used has a very odd pitching moment?
The problems in handling seem to be related to lack of stability due to CoG being too far aft.
If this is the case, then perhaps it would have made sense to redesign the outer wing panels with greater sweep as was done on the Ilyushin IL-2 when a rear gunner was added and changed the CoG.
It would also be the chance to go to a more conventional non-symmetric airfoil and possibly increase the wing area a bit to compensate for the increased weight over that of the prototype aircraft.

Thoughts?
- Ivan.

 

[GrauGeist]

There is never going to be a simple conclusion to the P-39 - seriously.
The aircraft had it's merits and it had it's shortcomings, like ALL aircraft will have.

I suspect, though, that the opinion of P-39 in American service may be along the lines of the F2A Buffalo, in retrospect.
The American pilots of the F2A were not schooled in the current day's tactics. They were also not combat veterans so when they hit the IJN fighters head-on, they had a steep learning curve ahead of them.
This too, may hold true to the USAAC pilots, who were thrust into the P-39's cockpit and given a crash-course.

The reason why I am touching on this, is because that's exactly what happened to my great-uncle, who was trained in the P-36, love his P-36 and was forever hateful that his P-36 sat idle on an auxiliary field on Oahu, 7 December 1941, lacking ammunition and fuel.
Shortly after Pearl, his P-36 was traded for a P-39 and he was rushed through training on it and he hated the Airacobra with a passion. He always stated that he would have gladly gone up to face any and all Japanese opponents in his P-36 than with a P-39...fortunately for him, he had an opportunity to train on the P-38, which he jumped at the chance and ended up flying them in the PTO for the duration.

So I am left to wonder if the characteristics of the P-39 ran contrary to his comfort zone, being experianced in the well-performing P-36 and then shoved into the cockpit of the unknown P-39, tending to cloud his judgement of the Airacobra to a certain degree.

 

[XBe02Drvr]

Well you can have planes with engines and arms, even complete aerodynamic principles that didn't exist, transplanted into a different era what is the problem with a minor issue like range?

"Don't need THAT much range; the bombers will always get through. What we need is a high altitude air superiority fighter/interceptor"

 

[P-39 Expert]

P-40 as it is the more versatile a/c.

How so? P-40 was slower, climbed slower, had a lower ceiling and about the same range. They both had one centerline external store.

 

[P-39 Expert]

There is never going to be a simple conclusion to the P-39 - seriously.
The aircraft had it's merits and it had it's shortcomings, like ALL aircraft will have.

I suspect, though, that the opinion of P-39 in American service may be along the lines of the F2A Buffalo, in retrospect.
The American pilots of the F2A were not schooled in the current day's tactics. They were also not combat veterans so when they hit the IJN fighters head-on, they had a steep learning curve ahead of them.
This too, may hold true to the USAAC pilots, who were thrust into the P-39's cockpit and given a crash-course.

The reason why I am touching on this, is because that's exactly what happened to my great-uncle, who was trained in the P-36, love his P-36 and was forever hateful that his P-36 sat idle on an auxiliary field on Oahu, 7 December 1941, lacking ammunition and fuel.
Shortly after Pearl, his P-36 was traded for a P-39 and he was rushed through training on it and he hated the Airacobra with a passion. He always stated that he would have gladly gone up to face any and all Japanese opponents in his P-36 than with a P-39...fortunately for him, he had an opportunity to train on the P-38, which he jumped at the chance and ended up flying them in the PTO for the duration.

So I am left to wonder if the characteristics of the P-39 ran contrary to his comfort zone, being experianced in the well-performing P-36 and then shoved into the cockpit of the unknown P-39, tending to cloud his judgement of the Airacobra to a certain degree.

Your great uncle's P-36 weighed 5700#. His P-39 was a ton heavier and was 50mph faster.

 

[P-39 Expert]

Hello All,
Seems like we are all attempting to make radical adjustments to history with what we know in hindsight.
How about we take a slightly different approach and adjust with knowledge available at the time.

What was really so WRONG with the P-39 that made it less than successful except in Soviet service? Weight. Soviets removed the usless .30 caliber wing guns.
One problem was reliability which was solved after some time. Generally considered more reliable than the P-40 in terms of TBO, daily readiness.
The other problem was that the Center of Gravity migrated too far aft and the aircraft became unstable as disposable loads were expended. And had no effect on normal flight. In order to have any chance of "tumbling" the nose ammo had to be expended, then a vertical climb until near stalling speed, then pull back hard on the stick. To spin or "tumble" a plane had to stall first and the P-39 had excellent stall characteristics.

The Soviets had a different philosophy for fighter armament.
Their preference was for guns close to the centerline and their fighters tended to be more lightly armed than other Allied fighters.
They had very efficient machine guns and were satisfied with just one or two fuselage mounted MG with a motor cannon.
They removed the wing guns from most of their Airacobra. Which made them lighter with much better climb/ceiling.

Americans seem to want every piece of equipment onboard every aircraft and end up with some pretty heavy aircraft. Absolutely true.
Some items such as the mooring kit and engine tool kit and other such service items probably did not need to be carried on the aircraft.
The choice of the Soviets to remove wing armament probably would not have been satisfactory because it would have only left three guns all with fairly low cyclic rates, so to make up for that, I believe it would have been a good idea to go back to the armament arrangement of the P-39C and restore the two synchronized .30 cal MG in place of the wing guns.
The armour for the propeller gearbox could be removed to partially compensate for the weight. Problem there is space for those two .30s reduced the ammunition capacity of the 37mm cannon (main armament) by 50%. Plus the added weapons that had little effect on the enemy and their rate of fire was further reduced by propeller synchronization. The .30s were the biggest problem of the P-39 and were not used on any other production US fighter.

In addition, to help adjust the CoG forward, standard load for the .50 should be adjusted to 270 rounds per gun as the Soviets did with their Airacobra. The Radio could be moved to the area behind the cockpit above the engine without significantly affecting visibility from the cockpit. It would only block visibility into the aft fuselage because of where the pilot sits.
To reduce weight, the armour plate from the Turnover Bulkhead could be removed; The bulk of the engine is behind the pilot for protection. The armour plate for the oil tank perhaps should be removed as well because of the large moment arm it has from the aircraft CoG. In my opinion the armor plate/glass was absolutely necessary except for the nose reduction gearbox armor (100#) and a couple of small plates on the turnover bulkhead outside of the rear armor glass (16#).

So far, this is the minimally invasive approach. Actually the minimally invasive approach would be for the crew chief at forward bases to remove the underpowered wing guns (and related equipment), the nose armor plate, and move the radios up from the tail cone for balance. Climb and ceiling are greatly increased with only a small reduction in firepower. This is applicable to the early P-39s (D through M). The N climb and ceiling were just fine even with the wing guns/nose armor, but removing them would just make it better.
From test reports, it appears that the CoG of the Airacobra doesn't really migrate very much even on the early versions.
A heavily loaded Airacobra tends to have a CoG at around 25% MAC.
A normal loaded Airacobra tends to have a CoG at around 28% MAC.
An Airacobra without disposable loads in place has CoG at around 30% MAC.
This migration of CoG isn't very great so there is probably something else going on.
Perhaps the airfoil being used has a very odd pitching moment?
The problems in handling seem to be related to lack of stability due to CoG being too far aft.
If this is the case, then perhaps it would have made sense to redesign the outer wing panels with greater sweep as was done on the Ilyushin IL-2 when a rear gunner was added and changed the CoG.
It would also be the chance to go to a more conventional non-symmetric airfoil and possibly increase the wing area a bit to compensate for the increased weight over that of the prototype aircraft.

Thoughts?
- Ivan.

See above.

 

[fubar57]

Your great uncle's P-36 weighed 5700#. His P-39 was a ton heavier and was 50mph faster.

On the plus side, his uncle was there, had first hand experience, knew what he was talking about and wasn't some kind of "expert"

 

[pbehn]

On the plus side, his uncle was there, had first hand experience, knew what he was talking about and wasn't some kind of "expert"

Can you give me a hand with this armour guns and ammo, we are putting them in and out again.