The P-38J and L in the European theater.

[Shortround6]

Hindsight is 20/20, but why didn't the initial British order for P-51s specify the Merlin XX. It did wonders for the P-40F, imagine what it would have done for the early P-51 pending the introduction of a two stage engine. At half the cost of a P-38.

Just maybe, the British didn't order the initial Mustangs with Merlin XX engines because they ordered them on May 29th 1940 and Packard didn't sign the deal to make Merlins until Sept of 1940?????

And just maybe they were right because NA managed to build 138 Mustangs in 1941 while Packard only built 45 Merlins in 1941 and the British were already getting 2/3rds of them for other aircraft??????????

You not only need hindsight, you need a time machine shuttling back and forth between mid 1942 and late 1941 to deliver the engines.

 

[pbehn]

Hindsight is 20/20, but why didn't the initial British order for P-51s specify the Merlin XX. It did wonders for the P-40F, imagine what it would have done for the early P-51 pending the introduction of a two stage engine. At half the cost of a P-38.
.

That would give you a slightly better but possibly later P51 but it would just replace Hurricanes with P51s.

 

[Shortround6]

I would note that while you would get better Mustangs, they would arrive late ( they only had 4 squadrons of Allison Mustangs in Service at Dieppe In Aug 1942) and you would be short hundreds of other aircraft, whether they were Hurricanes, P-40Fs, 4 engine bombers or whatever the British were shoving Packard built Merlins into.

 

[pbehn]

I would note that while you would get better Mustangs, they would arrive late ( they only had 4 squadrons of Allison Mustangs in Service at Dieppe In Aug 1942) and you would be short hundreds of other aircraft, whether they were Hurricanes, P-40Fs, 4 engine bombers or whatever the British were shoving Packard built Merlins into.

You also wouldn't get P51B/C mustangs any earlier, the engines had just started to become in service. I just suggested less hurricanes as the lowest down the tech "food chain".

 

[swampyankee]

The only counting the leadership of the Eighth was concerned with was the difference between the number of bombers setting out and the number which returned.

They'd probably be counting the escorts that were unable to complete a mission due to engine failurs and the number of pilots who became casualties because of poor cockpit heating. The P-38 was not succeeding in Europe. It was better than nothing, but not as good as the single-engined aircraft that replaced it.

And cost lest to operate and procure.

 

[Shortround6]

You also wouldn't get P51B/C mustangs any earlier, the engines had just started to become in service. I just suggested less hurricanes as the lowest down the tech "food chain".

to borrow from another thread how about the Merlin XX used in the Defiant II

In reality it would take weeks of engineering (drawing. fabrication and testing) to change from the Allison to the Merlin XX and then it would take pretty much all the engineering time it took historically to change to the two stage Merlin from the single stage Merlin (heavier engine, bigger heavier propeller, larger radiator and oil cooler plus intercooler, needed larger duct) and so on.

 

[redcoat]

They'd probably be counting the escorts that were unable to complete a mission due to engine failurs and the number of pilots who became casualties because of poor cockpit heating. The P-38 was not succeeding in Europe. It was better than nothing, but not as good as the single-engined aircraft that replaced it.

And cost lest to operate and procure.

But there is no historical evidence that what you stated in your last comment played any role in the replacement of the P-38, you are merely making an assumption.

 

[pinehilljoe]

I good reference is Warren Bodie's book on the P-38. Mr Bodie wrote a 13 or 14 part article in Wings/Airpower in the 80s on the P-38 and the book is largely a collection of the articles.
)
IMHO it wasn't performance, it was other factors. The P-38 had demonstrated the range to escort to Berlin, and pilots like Robin Olds (8 claimed, 5 confirmed kills) showed the 38 could perform with the best of the Luftwaffe.

The 5th AF demand for the Lightning IMHO was the factor. In 42 and 43 the 38 was the only fighter that could fly the long range missions routinely in South Pacific.

 

[P-39 Expert]

Just maybe, the British didn't order the initial Mustangs with Merlin XX engines because they ordered them on May 29th 1940 and Packard didn't sign the deal to make Merlins until Sept of 1940?????

And just maybe they were right because NA managed to build 138 Mustangs in 1941 while Packard only built 45 Merlins in 1941 and the British were already getting 2/3rds of them for other aircraft??????????

You not only need hindsight, you need a time machine shuttling back and forth between mid 1942 and late 1941 to deliver the engines.

So the P-51 (Allison) was in production in 1941 and the MerlinXX was in production in 1941, both in the USA, but there is no way they could have been used together? To get a fighter in production before the P-38 got into combat in very late 1942?

 

[drgondog]

So the P-51 (Allison) was in production in 1941 and the MerlinXX was in production in 1941, both in the USA, but there is no way they could have been used together? To get a fighter in production before the P-38 got into combat in very late 1942?

Simple answer - No. First, the AAF was not interested in the Mustang until very late 1941, and the interest expressed first was for the A-36 with combination of Mustang IA - both with Allisons.

Second, the re-tooling for Mustang XX/28/1650-1 was significant because it imposed a re-design of the radiator/cooling design, engine mount changes, etc and did not solve the high altitude requirement for escort which was just starting to surface as 8th AF started bombing ops over Germany.

Third, the contract for the 1650-3 was just beginning, along with the engineering changes for the two speed/two stage supercharger at the end of 1941.

Fourth, NAA did not at that time have a high enough priority at War Production Board to warrant diversions from either Packard delivery obligations to British or the P-40F. AAF Mat'l command did not allocate any more than two of Packard's early production 1650-3 until July 1942 while both the RAF Mustang X and XP-51B were well into design change stage. And that required Arnold to approve and push the allocation. Barney Echols resisted but was overcome by Muir and others in mid 1942 when the CAS arm of AAF held sway. In fact, the Merlin 1650-3 Mustangs were originally DEDICATED to 9th AF to replace P-39 for ETO. That is why the 354th, 357th and 363rd FG were all slated to receive the P-51B first.

Fourth - it took Packard until July, 1943 to keep pace with NAA delivery of complete airframes of P-51B-1=NA

On your other comments about "Lack of external fuel tanks for Day Fighter Arm", the first approval for C/L 80 gallon tanks began with introduction of Bf 109G-4 in September 1942. Note - that date is 3 months prior to first 8th AF raid on Germany on January 27, 1943.

 

[Shortround6]

So the P-51 (Allison) was in production in 1941 and the MerlinXX was in production in 1941, both in the USA, but there is no way they could have been used together? To get a fighter in production before the P-38 got into combat in very late 1942?

Ah.........no.

Please note that as of Jan 1 1942 there had been 207 P-38s built for the US forces and 138 Mustangs built for the British. Also note that Lockheed was building , at a minimum 100 P-38s a month for most of 1942 (August was an exception) Lockheed built way more P-38s in 1942 than NA built Mustangs (in part because the Mustang had not been ordered in the numbers that that P-38 had been)

Changing the goalposts and comparing apples to oranges doesn't help discussions.

You asked about the initial British order for Mustangs. It was placed 2 1/2 months before the deal with Packard was signed although Packard had been working for several weeks prior to the actual signing. The British ordered an additional 300 Mustangs in Sept of 1940, during the BoB. At this point it seemed that the Hurricane needed the Merlin XX to stay competitive as a front line fighter. This idea went out the window When the 109F showed up. However that is 4-6 months further along. Allison engines are already ordered for the Mustangs, playing switcharoo with the engines at this point is difficult. Sticking Allisons in Hurricanes would be a disaster from a performance point of view.

Now you want to change things to some air force (US?) getting Merlin XX powered planes in production and/or initial service BEFORE the P-38 sees combat.
These are two different things. And the contention that the P-38 didn't see "combat" until late 1942 is also somewhat mistaken.

April 16th 1942 sees F-4 photo Lightnings flying recon missions over Eastern New Guinea and new Britain (they used 75 gallon drop tanks to get to Australia )

May 29th 1942 sees P-38Es start their deployment to Alaska.

The 1st Fighter Group is playing ping-pong flying back and forth across the Country, initially deployed from their base in Michigan (Selfridge field) to the west coast after Pearl Harbor they headed east in April to get ready for deployment to England, They got their older P-38s replaced by P-38Fs. June sees them heading West again because of Midway. They are turned around before they get there and go back to Maine (jumping off point for the transatlantic flight). Over the Summer two P-38 fighter groups (six squadrons ?) cross the Atlantic by air. Early Sept sees a number of sorties over France as the groups work up but with no contacts (combat?) Oct 15th sees the first B-17 escort mission. Oct 31st sees all P-38s in England withdrawn from operations for use in Operation Torch.

In the Pacific the 67th fighter squadron with a mix of P-38s and P-39s arrives at Henderson field On Aug 22nd. Oct 31st sees the 339th squadron with P-38s arrive at Henderson field. Perhaps you define that as very late 1942?

Now perhaps our mythical Merlin XX Mustang could have been built by the hundreds in spring/summer of 1942 (and the P-40Fs built as additional P-40Es?)
But they would not have been able to fly the Atlantic. Would they have been able to fly from England to North Africa once the ground troops took a few airfields like the P-38s did?

The British Mustangs flew their first operational mission on May 10th 1942, shooting up a German Airfield just across the Channel. As stated before the British have 4 operational squadrons in the middle of Aug 1942 at which point both NA and RR are working on building prototypes of Mustangs with two stage engines.

There is often a 4 to 6 month delay between a fighter going into production and it seeing squadron use (in it's first squadron let alone large numbers) with combat often taking several months more.

There is alo the need to allocate resources (like engines) so they get the highest number of effective aircraft rather than a lesser number of great fighters.
This was the whole Spitfire vs Hurricane II debate. The Hurricane II got the better engine because they felt that without it the Hurricane ( being built in larger numbers than the Spitfire) would be obsolete without it and the Spitfire (in the MK II version) was good enough in the interim.


Would a few hundred Merlin XX Mustangs (or even 500) made up for not having the P-40F? Would the Merlin XX Mustangs have been sent to NA to provide top cover/support for the P-40E/Ks and not used to escort B-17s in any case?

Yes a Merlin XX Mustang would have been better than the P-40F but you can't have them in unlimited quantities and something has to take the place of the P-40Fs and Ls or the Allison P-40s despite how well they might have done at low altitude are going to get pounced on from above more often.

 

[P-39 Expert]

Simple answer - No. First, the AAF was not interested in the Mustang until very late 1941, and the interest expressed first was for the A-36 with combination of Mustang IA - both with Allisons.

Second, the re-tooling for Mustang XX/28/1650-1 was significant because it imposed a re-design of the radiator/cooling design, engine mount changes, etc and did not solve the high altitude requirement for escort which was just starting to surface as 8th AF started bombing ops over Germany.

Third, the contract for the 1650-3 was just beginning, along with the engineering changes for the two speed/two stage supercharger at the end of 1941.

Fourth, NAA did not at that time have a high enough priority at War Production Board to warrant diversions from either Packard delivery obligations to British or the P-40F. AAF Mat'l command did not allocate any more than two of Packard's early production 1650-3 until July 1942 while both the RAF Mustang X and XP-51B were well into design change stage. And that required Arnold to approve and push the allocation. Barney Echols resisted but was overcome by Muir and others in mid 1942 when the CAS arm of AAF held sway. In fact, the Merlin 1650-3 Mustangs were originally DEDICATED to 9th AF to replace P-39 for ETO. That is why the 354th, 357th and 363rd FG were all slated to receive the P-51B first.

Fourth - it took Packard until July, 1943 to keep pace with NAA delivery of complete airframes of P-51B-1=NA

On your other comments about "Lack of external fuel tanks for Day Fighter Arm", the first approval for C/L 80 gallon tanks began with introduction of Bf 109G-4 in September 1942. Note - that date is 3 months prior to first 8th AF raid on Germany on January 27, 1943.

Whole point of my initial P-51XX post was to substitute that production for P-38 production.
Yes, the AAF would need to get more interested in P-51 production, again to replace P-38 production. They sure got interested in the P-51 production with the Merlin 61.
No retooling for the P-51XX since it would have been ordered that way from the beginning. Probably less retooling for the Merlin 61 (P-51B/C) since the P-51 would have already been designed for a Merlin.
Doesn't replace the P-51B/C, just gets a Merlin P-51 (with slightly lower performance) in production sooner, at the expense of P-38 production and P-40F (MerlinXX) production.
If nothing else, just put the XX into the P-51 instead of the P-40F.

 

[Shortround6]

Whole point of my initial P-51XX post was to substitute that production for P-38 production.
Yes, the AAF would need to get more interested in P-51 production, again to replace P-38 production. They sure got interested in the P-51 production with the Merlin 61.
No retooling for the P-51XX since it would have been ordered that way from the beginning. Probably less retooling for the Merlin 61 (P-51B/C) since the P-51 would have already been designed for a Merlin.

Cutting US total fighter production by several hundred aircraft in late 1941/early 1942 would have done what?
You don't stop making P-38s on saturday and start making P-51s on Monday.

What part of the two stage Merlin was longer and heavier than the single stage engine and needed bigger radiators/oil coolers and an additional inter-cooler radiator aren't you getting?

Engine mount designed for a 1510lb 1300hp engine (and suitable prop) may NOT be the engine mount you design for a 1700lb 1600hp engine with a prop around 100lbs heavier.
Engine mount has to keep the engine/prop attached to the plane during a 8 G turn/pull out with a safety margin.
Just because a few bolt holes will line up doesn't mean it is suitable.

 

[P-39 Expert]

Ah.........no.


Please note that as of Jan 1 1942 there had been 207 P-38s built for the US forces and 138 Mustangs built for the British. Also note that Lockheed was building , at a minimum 100 P-38s a month for most of 1942 (August was an exception) Lockheed built way more P-38s in 1942 than NA built Mustangs (in part because the Mustang had not been ordered in the numbers that that P-38 had been)

Please remember in my hypothetical situation P-51XX is replacing P-38 production.

Changing the goalposts and comparing apples to oranges doesn't help discussions.

You asked about the initial British order for Mustangs. It was placed 2 1/2 months before the deal with Packard was signed although Packard had been working for several weeks prior to the actual signing. The British ordered an additional 300 Mustangs in Sept of 1940, during the BoB. At this point it seemed that the Hurricane needed the Merlin XX to stay competitive as a front line fighter. This idea went out the window When the 109F showed up. However that is 4-6 months further along. Allison engines are already ordered for the Mustangs, playing switcharoo with the engines at this point is difficult. Sticking Allisons in Hurricanes would be a disaster from a performance point of view.

Order the P-51 with the Merlin XX from the beginning.

Now you want to change things to some air force (US?) getting Merlin XX powered planes in production and/or initial service BEFORE the P-38 sees combat.
These are two different things. And the contention that the P-38 didn't see "combat" until late 1942 is also somewhat mistaken.

April 16th 1942 sees F-4 photo Lightnings flying recon missions over Eastern New Guinea and new Britain (they used 75 gallon drop tanks to get to Australia )

Photo recon is not combat.

May 29th 1942 sees P-38Es start their deployment to Alaska.

Not much combat there either.

The 1st Fighter Group is playing ping-pong flying back and forth across the Country, initially deployed from their base in Michigan (Selfridge field) to the west coast after Pearl Harbor they headed east in April to get ready for deployment to England, They got their older P-38s replaced by P-38Fs. June sees them heading West again because of Midway. They are turned around before they get there and go back to Maine (jumping off point for the transatlantic flight). Over the Summer two P-38 fighter groups (six squadrons ?) cross the Atlantic by air. Early Sept sees a number of sorties over France as the groups work up but with no contacts (combat?) Oct 15th sees the first B-17 escort mission. Oct 31st sees all P-38s in England withdrawn from operations for use in Operation Torch.

Show me the combat. Torch began November '42.

In the Pacific the 67th fighter squadron with a mix of P-38s and P-39s arrives at Henderson field On Aug 22nd. Oct 31st sees the 339th squadron with P-38s arrive at Henderson field. Perhaps you define that as very late 1942?

Yes October 31 is very late 1942.

Now perhaps our mythical Merlin XX Mustang could have been built by the hundreds in spring/summer of 1942 (and the P-40Fs built as additional P-40Es?) Yes hypothetically.
But they would not have been able to fly the Atlantic. Would they have been able to fly from England to North Africa once the ground troops took a few airfields like the P-38s did? Since they had more range than a P-38 they would have flown anywhere the P-38 could have flown.

The British Mustangs flew their first operational mission on May 10th 1942, shooting up a German Airfield just across the Channel. As stated before the British have 4 operational squadrons in the middle of Aug 1942 at which point both NA and RR are working on building prototypes of Mustangs with two stage engines. P-51XX operational by May '42 would have been great.

There is often a 4 to 6 month delay between a fighter going into production and it seeing squadron use (in it's first squadron let alone large numbers) with combat often taking several months more. Yep, and Mustang production began in the last half of 1941.

There is alo the need to allocate resources (like engines) so they get the highest number of effective aircraft rather than a lesser number of great fighters.
This was the whole Spitfire vs Hurricane II debate. The Hurricane II got the better engine because they felt that without it the Hurricane ( being built in larger numbers than the Spitfire) would be obsolete without it and the Spitfire (in the MK II version) was good enough in the interim.


Would a few hundred Merlin XX Mustangs (or even 500) made up for not having the P-40F? Would the Merlin XX Mustangs have been sent to NA to provide top cover/support for the P-40E/Ks and not used to escort B-17s in any case?

Yes 500 MustangXXs would have more than made up for not having the P-40F. Why waste the Merlin XX on the P-40 when we could have had the 40mph faster and much longer range MustangXX. Range was the whole point, no?

Yes a Merlin XX Mustang would have been better than the P-40F but you can't have them in unlimited quantities and something has to take the place of the P-40Fs and Ls or the Allison P-40s despite how well they might have done at low altitude are going to get pounced on from above more often.

Yes a MustangXX would have been better than the P-40F. Just put the P-40F engines in the Mustang.

 

[billrunnels]

I think the P-38 could have provided bomber stream support. However, I am partial to the P-51 simply because I witnessed their performance first hand. It was outstanding.

 

[pinehilljoe]

Simple answer - No. First, the AAF was not interested in the Mustang until very late 1941, and the interest expressed first was for the A-36 with combination of Mustang IA - both with Allisons.

1943.

I believe Ben Kelsey and the AAF was interested in the Mustang from the start of the NA 73 program and knew its performance was superior. The A-36 was out of necessity. Fiscal Year '42 dollars for fighters were committed to other types, but there were FY dollars left for ground attack bombers, and the A-36 was built to at least get some Mustang into the war as soon as possible.

 

[tomo pauk]

Hindsight is 20/20, but why didn't the initial British order for P-51s specify the Merlin XX. It did wonders for the P-40F, imagine what it would have done for the early P-51 pending the introduction of a two stage engine. At half the cost of a P-38.
...

Let's not blame the British for what was the American mistake - AAF lost too much time neglecting the whole Mustang/XP-51 program for more than a year.
But yes, the 'Mustang XX' would've give a 420+ mph fighter for 1942-43, above 20000 ft, with capability for long range, no vices (rate of roll, compressibility, heating, training...) , no problems with size and shape the P-38 had - if the AAF made that decision in early 1941.

So the P-51 (Allison) was in production in 1941 and the MerlinXX was in production in 1941, both in the USA, but there is no way they could have been used together? To get a fighter in production before the P-38 got into combat in very late 1942?

As above - yes, technically it was feasible, but decision need to be made much earlier than US entering the war as it historically did.

BTW - all of the above has no bearing on the P-38.

 

[Shortround6]

Yes a MustangXX would have been better than the P-40F. Just put the P-40F engines in the Mustang.

Nobody is arguing that a MustangXX wouldn't be better than the P-40F.

However that is not the question.
There were about 1550 P-40F/ Kittihawk IIs built and it took from Jan of 1942 till Dec/42-Jan/43 to build them.

The question is whether the allies would have been better off replacing a large number of those P-40Fs with MustangXXs and building additional P-40E/Ks instead?
Curtiss built about 2300 Allison powered P-40s during the same time frame. The vast majority of P-40Fs went to North Africa/Med. It was well known that the P-40E could not stand up to the 109 by itself (or with support of the P-39) and needed Support/top cover from P-38s, P-40Fs and Spitfires.
Improving the P-40 was a priority for the US as it was the fighter being built in the largest quantity in the US in 1942 and followed by the P-39. They built more P-40s in 1942 than P-38s and P-39s put together and you could even throw in about 1/2 the production of either the P-47 or Mustang.

You are also not going to get 1500 MustangXX's in 1942 without seriously screwing up some other production line as they only built around 900-950 mustang airframe in 1942 (including A-36s).

Replacing P-38s with MustangXX Production means serious changes in events, like no Yamamoto shoot down? No flying fighters across the atlantic in 1942. No flying fighters from England to North Africa for operation Torch. Supporting the invasion of Sicily from bases in North Africa?

people seem to think that the MustangXX is some sort of P-51B lite. At just over 23,000ft the Merlin XX engine is down to around 940-950hp with no RAM compared to the 1330hp of the Merlin V-1650-3. Having about 72% of the power at that altitude really makes the plane a bit lite as while it will be lighter than the P-51B it sure won't be only 72% of the weight of the P-51B.

you can pretty much forget stuffing fuel tanks in the rear fuselage of the MustangXX as with a power plant weight over 300lbs lighter the cg problems of putting fuel in the rear fuselage are going to be that much worse.

 

[drgondog]

I believe Ben Kelsey and the AAF was interested in the Mustang from the start of the NA 73 program and knew its performance was superior. The A-36 was out of necessity. Fiscal Year '42 dollars for fighters were committed to other types, but there were FY dollars left for ground attack bombers, and the A-36 was built to at least get some Mustang into the war as soon as possible.

That belief would Not be correct.

The AAF test pilot that first flew the Mustang I/XP-51 wrote a hatchet job, five liner on behalf of Material Command evaluation that stated 'crappy airplane" at Echols orders. Echols tried to force NAA to disengage from Mustang production, scrap tooling and convert Inglewood production to B-25. Echols despised NAA for disobeying his wishes to shut up and build P-40s

Kelsey was an unabashed supporter of Lockheed and the P-38 and NEVER got behind the Mustang. It was only after the CAS side of AAF got the Mustang evaluation away from Material Command/Wright Field to Eglin Field for evaluation, that AAF recognized what a good airplane the Mustang was in comparison with P-40, P-39, P-38 and P-47

Echols and Kelsey tried to re-write history post WWII, but nobody at NAA bought in. Col. Ben Bradley was a key facilitator in mid 1943 for AAF Mat'l Command and he had to be very careful to point out (when necessary) to his boss MG Echols that even the XP-75 which Echols championed - was a dangerous Turkey.

 

[Shortround6]

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