Missed opportunity: US Navy land based P38D and P38E with dive flaps as a vertical dive bomber early 1942

[Shortround6]

The P-38D did have the 37mm gun, but only 15 rounds of ammo.

Basically we have to proposition that somebody in 1941 decides that the early Army P-38s, instead of going to training bases/training programs, should be refitted/modified into some sort of attack aircraft, and issued to the Navy/Marines in the spring of 1942 for base defence?
This disregards the aircraft already in the pipeline (A-20s, B-25s and B-26s) that the Army is already getting, all of which at this point in time are planes that can top out at over 300mph.
2 of the 3 have much better range, (and the A-20 won't take much modification to improve range).
Nobody yet knows the US MK 13 torpedo won't work so a frantic program to come up with a super divebomber/ship killer wouldn't have been a priority.

If by some amazing circumstances, P-38s had become available to the Navy and pilots were trained to fly them why not just hang a couple really large drop tanks on them and use them as escorts for the SBD

Pretty much hits the nail on the head. Figure out how to escort the dive and torpedo bombers you do have rather than try to come up with an attack plane that doesn't need escorts but won't perform the attack mission as well.

 

[pinsog]

the only reason I made it a Navy plane with Navy pilots is that they already had trained dive bomber pilots. The main discussion was meant to be about the P38 as a true, steep angle dive bomber, not who ordered it, bought it, paid for it and flew it. It could have been a Coast Guard plane flown by the Girl Scouts for all I care, the discussion was meant to be about the plane.

That being said, Shortround proved to me that it couldn't be reasonably done, and maybe, even probably not done at all due to the P38 being too heavy for the size of the dive flaps that could be fitted. If all it was going to be was an escort for bombers or an interceptor then of course it would have been flown by US Army pilots

 

[Barrett]

Ok...let's back up for a second here.
Rasmussen was a "wet behind the ears" Lieutenant and he he shot down two A6Ms at Pearl Harbor with his P-36, while wearing purple pajamas. Experienced pilots are ones who have met the enemy, survived, learned their tactics and used it against them later on.

In regards to your 250/255 mph faster ingress...what variant of P-38 are you using as a metric for comparison, the P-38L?
The notion of dive-flaps on the P-38 wasn't instituted until 1943 and a diving P-38 prior to that was in serious jeopardy of catastrophic failure.
The SBD cruised at 185, it's max. speed was 255 but was rock-solid in an accelerated dive, when it deployed it's dive flaps that were the extent of it's entire control surfaces.
No other dive bomber made, except for the Ju87, had the accuracy and control that the SBD did in a full dive.

+++

Points well taken. When we restored our A-24B as an SBD-5 early 70s, I consulted The Manual in addition to contributors to my first book. With flaps deployed a combat-loaded SBD made c. 240 kts in a 70 degree dive. Conventional wisdom was: "It flies like a big SNJ" which was true. Cruising you could control the bird with a thumb and two fingers on the stick. The ailerons were the factory's pride & joy, but I forget how many configurations Ed Heinemann said that Northrop-Douglas tested.

I do recall the boldface warning in the manual: The SBD-5 airplane will not maintain level flight with the dive brakes extended. So we never deployed them in flight--30 y/o seals.

Sidebar: I was oafishly proud to tell Ed something he did not know about the SBD. The holes in the flaps (all 318) were exactly the diameter of a tennis ball. How I knew that was peculiar but had to do with the fact that my brother dated one of Oregon's leading high school players...

 

[Spitlead]

I meant don't build any 322's at all. Build them as standard P38's.

I would probably have used B17's in place of the photo recon F4's, but if you have them in New Guinea I guess you could either add dive flaps to the F4's and use them as bombers or deliver them as dive bombers and also do photo recon with them, or go ahead and build F4 recon aircraft.

In fact B-17s were used for photo recon early on in the Pacific theater. If I'm not mistaken, the 22nd Bombardment Group flew B-17Es for some photo recon missions. One notable mission was of "Old 666" which flew a photo recon mission in early 1943 as a precursor to the attack on Bougainville. The pilot, Capt. Jay Zeamer, was awarded the Medal of Honor after withstanding the longest continuous dogfight in the annals of the United States Air Force when no less than twenty (20) Zeroes attacked him in turn. The dogfight lasted 40 minutes.

 

[GrauGeist]

At the start of the U.S. involvement in the Pacific War and before that, the PBY and B-17 were used for long range recon.

 

[Navalwarrior]

On supply issue: don't build any 322 models for the British. Don't build any photo recon. You wouldn't need very many to really tilt the scales in my opinion. Let's say the first 50, including all the early P38D models deemed not combat worthy, are delivered by February 1 to Pearl where they train. First deployment is Midway. Instead of barely trained Marines in Vindicators on the first attack wave, you have 36 well trained navy or army pilots flying P38's. Probably sets up a whole different Midway and probably ends without loss of Yorktown. I would not use them for everyday dive bombing, they would be dedicated carrier killers.

I think the dive flaps would prevent compressibility issues in dives from altitude, but testing would reveal what altitude was safe and practical from target spotting, dive speed etc. Those are all minor things that can be adjusted. The main point being that a 330-350 mph self protecting dive bomber operating at 20-25,000 feet would be nearly impossible for the Japanese to stop in 1942.

Resp:
Inre to Model 322s, the British insisted on non-counter rotating engines . . . because of logistic issues of getting two different engines? If so, I have never read anything about the USAAF having problems with the two counter rotation Allisons. Were any P-40s fitted with opposite rotating Allisons due to short supply? Probably not as it would require a different propeller. Thoughts?

 

[Shortround6]

The British only got 3 (or 4?) Model 322s delivered to them the other 139/140 went to the USAAC as trainers. Of those, about 100 got handed engines without turbos, so the US only had about 40 or less model 332s with both engines turning the same way. None went overseas, Most probably stayed on just few training bases.

I would also note that P-40 engines almost always used different supercharger gears than P-38 engines at any give time. Any P-40 that was "gifted" with a P-38 engine was going to have serious difficulties even in the low teens and have trouble keeping up with squadron mates once altitude got into 5 figures (10,000ft)
Any crew chief worth his stripes would have figured this out (if the different model number didn't clue him in) on the first run up of the engine when the manifold pressure didn't match the rpm.

 

[wuzak]

Resp:
Inre to Model 322s, the British insisted on non-counter rotating engines . . . because of logistic issues of getting two different engines? If so, I have never read anything about the USAAF having problems with the two counter rotation Allisons. Were any P-40s fitted with opposite rotating Allisons due to short supply? Probably not as it would require a different propeller. Thoughts?

The British and French both were to get Model 322s without the turbo and with right hand tractor engines. The British model 322 was designated Lightning I. There wewre 667 ordered by the French and British. After the fall of France, Britain took over the French orders.

Before any Lightning Is had arrived in Britain the order was changed so that the final 524 were to be delivered as Lightning II with turbo engines and handed engines.

Lightning I for RAF

 

[Navalwarrior]

The British and French both were to get Model 322s without the turbo and with right hand tractor engines. The British model 322 was designated Lightning I. There wewre 667 ordered by the French and British. After the fall of France, Britain took over the French orders.

Before any Lightning Is had arrived in Britain the order was changed so that the final 524 were to be delivered as Lightning II with turbo engines and handed engines.

Lightning I for RAF

Resp:
Thanks. I understand that both engines rotated one direction (RH) but the Lightning as designed was to have counter rotating propellers. So what was Britain's reasoning for requesting that both engines rotated a single direction? I have never read anything about the USAAF having (logistical?) issues with having two different rotating engines. Does anyone have info in this regard?

 

[Shortround6]

The British were already getting hundreds of P-40s and engines, and everything had to come by ship. I don't know the timing of things but the British had ordered 200 P & W R-1830s to power the Beauforts with as they were having a lot of trouble with the Bristol Taurus engine. Unfortunately the ship carrying the engines was torpedoed and the British were stuck using the Taurus engine. The British were very conscious of supply issues.

 

[Navalwarrior]

The British were already getting hundreds of P-40s and engines, and everything had to come by ship. I don't know the timing of things but the British had ordered 200 P & W R-1830s to power the Beauforts with as they were having a lot of trouble with the Bristol Taurus engine. Unfortunately the ship carrying the engines was torpedoed and the British were stuck using the Taurus engine. The British were very conscious of supply issues.

Resp:
Thanks. Makes sense from a logistics point of view. Do you have or know of issues this separate engine for the P-38 caused in say . . . in the CBI? P-38s, P-51As and P-40s dominated USAAF Squ there.

 

[pinsog]

Resp:
Thanks. I understand that both engines rotated one direction (RH) but the Lightning as designed was to have counter rotating propellers. So what was Britain's reasoning for requesting that both engines rotated a single direction? I have never read anything about the USAAF having (logistical?) issues with having two different rotating engines. Does anyone have info in this regard?

They wanted to use P40 engines to ease logistical/supply problems since they already had P40's.

Edit: already answered. My bad

 

[Navalwarrior]

They wanted to use P40 engines to ease logistical/supply problems since they already had P40's.

Edit: already answered. My bad

Resp:
Right, but you are talking about Allison engines . . . which were used as the basic engine for P-38s and P-51As, as well as most P-40s? So eliminating the counter rotating variant (322) of the P-38 Allison was done to simplify supply?

 

[pinsog]

Resp:
Right, but you are talking about Allison engines . . . which were used as the basic engine for P-38s and P-51As, as well as most P-40s? So eliminating the counter rotating variant (322) of the P-38 Allison was done to simplify supply?

Yes. As I understand it, the British wanted the exact same engine to fit the P38 and P40 to simplify the spare parts problem. I've never heard the Allison P51 mentioned, so I'm not sure if it was ready or being used by the British when they ordered the model 322.

 

[Shortround6]

The model 322 used the same long nose engines as the P-40_ through P-40C and the Tomahawks, The French were in on the original P-38 order or least discussions.
The Mustang I used the same short nose (-39) engine as the P-40D&E.
Things were changing fast in 1940/41.

 

[drgondog]

Yes. As I understand it, the British wanted the exact same engine to fit the P38 and P40 to simplify the spare parts problem. I've never heard the Allison P51 mentioned, so I'm not sure if it was ready or being used by the British when they ordered the model 322.

The Model 322 was ordered by AFPC in March 1940 as the discussions between AFPC were proceeding on the NAA 'P-509 Allison High Speed Pursuit' which evolved into the April 10/11 LOI for the NA-73X. Th Mustang was not a factor in the Anglo-French Purchasing Commission decision for the Model 322

 

[Peter Gunn]

A few random thoughts, long thread with a lot of interesting posts.
Shattered Sword actually supports Pinsog's contention that IJN AAA was not very good, in fact, the authors point out that flak only accounted for one SBD (maybe) out of all the attacking aircraft, all losses were to Zeros. It's just that the IJN did not have a very good AAA doctrine at the time, nor a cruising formation that would enhance AAA capability of the fleet. In fact, IJN doctrine at the time was using the ship's maneuverability to evade bombs and torpedoes, something that actually threw off firing solutions on attacking aircraft.

Also, the flak and fighters were NOT down low handling the TBD attacks when the Enterprise/Yorktown strike forces arrived, flak and fighters were aimed at the attacking force that put down the first three carriers. The timing of the attacks supports the fact that most of the TBD attacks were well and truly over when the kill force arrived.

Also, the authors make a good case that the Zero was NOT very good at handling high or low speed threats once the 20mm ammunition was expended, the two LMG's weren't a major threat to many US aircraft, especially heavy and fast medium bombers. Even the TBD was reasonably resilient v. the Zero's two LMGs.

USN AAA was pretty deadly even at this stage of the war, the USN had a defensive ring around Yorktown that literally shredded the Hiryus' attack force both times.

There are many myths surrounding the Battle of Midway, Shattered Sword puts all of them to rest with painstaking research of source documents. A must read.

Also, as long as we're into timelines, I'd lay the A-36 out as a better dive bomber than the P-38, drgondog can set me straight (or one of you other more knowledgeable than I) but I'm fairly sure the A-36 could dive at a 70 degree angle, perhaps even greater, and was no slouch in the air to air department as well. How about a flock of those at Midway?

Unfortunately, they would suffer the same issues that the P-38 or the historical aircraft at Midway did, lack of pilot training.

 

[PAT303]

Just ordered a copy of Shattered Sword after reading this thread.

 

[drgondog]

A few random thoughts, long thread with a lot of interesting posts.
Shattered Sword actually supports Pinsog's contention that IJN AAA was not very good, in fact, the authors point out that flak only accounted for one SBD (maybe) out of all the attacking aircraft, all losses were to Zeros. It's just that the IJN did not have a very good AAA doctrine at the time, nor a cruising formation that would enhance AAA capability of the fleet. In fact, IJN doctrine at the time was using the ship's maneuverability to evade bombs and torpedoes, something that actually threw off firing solutions on attacking aircraft.

Also, the flak and fighters were NOT down low handling the TBD attacks when the Enterprise/Yorktown strike forces arrived, flak and fighters were aimed at the attacking force that put down the first three carriers. The timing of the attacks supports the fact that most of the TBD attacks were well and truly over when the kill force arrived.

Also, the authors make a good case that the Zero was NOT very good at handling high or low speed threats once the 20mm ammunition was expended, the two LMG's weren't a major threat to many US aircraft, especially heavy and fast medium bombers. Even the TBD was reasonably resilient v. the Zero's two LMGs.

USN AAA was pretty deadly even at this stage of the war, the USN had a defensive ring around Yorktown that literally shredded the Hiryus' attack force both times.

There are many myths surrounding the Battle of Midway, Shattered Sword puts all of them to rest with painstaking research of source documents. A must read.

Also, as long as we're into timelines, I'd lay the A-36 out as a better dive bomber than the P-38, drgondog can set me straight (or one of you other more knowledgeable than I) but I'm fairly sure the A-36 could dive at a 70 degree angle, perhaps even greater, and was no slouch in the air to air department as well. How about a flock of those at Midway?

Unfortunately, they would suffer the same issues that the P-38 or the historical aircraft at Midway did, lack of pilot training.

Neither the P-38E/F nor the A-36 would have been available for Midway. The operational P-38E were tasked to west coast Air Defense, AAF upper echelon commanders did not even know that the P-38 could carry external Ferry tanks and the first F-4 IIRC were sent to Australia (April 1943)and P-38E Late May 1942). Had the 1st Pursuit Group been re-routed to Midway instead of sent to UK, they may have conceivably been available for the Midway opener on June 4th but not yet tested or approved for bomb operations (no sway braces for bombs). The A-36 was on the drawing Board in November 1941, Arnold was appraised in Jan-Feb 1942, the A-36 contract was let in April, first flight in November 1942, suitability testing was initiated Spring 1943 and squadron level deployment to MTO began in ~ June 1943, October for CBI.

Simply stated, and repeated. A P-38 modified as a Dive bomber would not emerge as a P-38. Fowler flaps would have been retained but the wing would completely depart from reasonable commonality - based on re-design of structure, primarily due to potential loads imposed due to adding sufficient dive brake area (estimate 2-3X of A-36) and almost certainly outside the engine envelope. Simply no room for dive brake and fowler flap and plumbing for fuel lines to co-exist inboard of the engines. I have not ever seen the wing structural analysis for maximum AoA loads during pull out but adding all that flat plate load minimally has to be placed on the aft spar - introducing very high bending and torsion loads, or near the center of pressure/aerodynamic center with unknown (to me) flight behavior.

You may recall that a.) Lockheed took far too long to solve (partially) severe pitch down compressibility issues, b.) solve for the radiator/aftercooling issues for the feed and care of Allison engines at high altitude, and c.) introducing ANY successful and widely produced variant of the P-38.

Last but not least for this 'debate' - The AAC in very late 1940 did not have a dive bombing mission. AAC then AAF was being prodded by the Secy of War to adapt and improvise based on the success of the Ju 87 in Europe - but did not even bother to emphasize the mission or insert into AWPD.1 or 2. Ergo, it was only by the brilliance of General Muir Fairchild Plans/Requirements pushing the need for a CAS/Tactical battlefield solution for the ARMY that even the XA32 then A-36 development initiated - and the P-38 was not even a remote concept for CAS at that time. It was, however, successful in that role in North Africa under AAF co-operation with Conningham tactical doctrine in mid 1942.

 

[Shortround6]

The AAC in very late 1940 did not have a dive bombing mission. AAC then AAF was being prodded by the Secy of War to adapt and improvise based on the success of the Ju 87 in Europe - but did not even bother to emphasize the mission or insert into AWPD

The Army was adopting and improvising by ordering Duantlesses as A-24s and Curtiss Helldivers as A-25s. Some of the A-24s were on their way to the Philippines when the Japanese attacked and they were diverted to Australia and/or the Dutch East Indies. The Helldiver had problems of it's own and early use by the Army was further hampered by hundreds of changes the Army wanted vs the Navy version of the plane (including larger main wheels and tail wheels). In the End the Army was not happy with the A-24s (too limited in range for the Island hopping) and the Helldivers took so long to get into production that the Army changed policy/doctrine and I don't believe any A-25s went overseas. As many as 3000 Army A-25s may have been on order in the spring of 1942 but 10th one was only completed in March of 1943. The Marines wound up with over 400 of the Army A-25s (non folding wings), I have no idea how many were actually completed.