# P-38 with Roll-Royce Merlins



## Marshall_Stack (Apr 3, 2006)

In Warren Bodie's book on P-38s, he feels that if the P-38 was retrofitted with the R.R. Merlin like the Mustang, it would have been a much better plane in Northern Europe. The problem with the Allison turbos in the cold and with the British fuel was a challenge to say the least.

What do you think?


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## Twitch (Apr 3, 2006)

That's not an unheard of idea but since the ship did fine in warm climes like the Med and Pacific it would have been hard to justify re-engining just the ETO planes. And depending on the time it might have been superfluous if the P-51 had debuted.


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## FLYBOYJ (Apr 3, 2006)

Many folks have mentioned this and there was always "folklore" at Lockheed that this was thought of - it wasn't that simple of just slappin Merlins on the airframe. Many things would of had to be re-designed, it might of not been worth the effort....


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## R988 (Apr 3, 2006)

The Merlin was also a heavier engine I think, The original Allison engined Mustang was considered the sweeter handling machine due to less weight on the front end, but of course, it lacked the power of it's Merlin engined siblings.

THe P-38 was already quite a good aircraft as it was, if expensive and complicated compared to other aircraft. The turbocharged version wouldn't have lacked much power compared to a Merlin if any and could in fact have been better at altitude as the turbo is theoretically more adjustable. Reliability would perhaps be the only reason for the change and I dont think there were enough problems or even enough P-38s to warrant the change, especially with the Mustang coming on stream for much less and demanding the Merlin engine.


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## syscom3 (Apr 3, 2006)

Lockheed did look at installing the Merlins on the P38 and there were indications of an increase in performance. It was also determined that the manufacturing process would have been easier, plus there would have been some room in in the booms made available for additional fuel cells.

But in the end, by the time they could have implimented the changes, it was decided the P51 was going to be the escort fighter and it just wasnt worth it to interrupt production.


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## KraziKanuK (Apr 3, 2006)

R988, how much did the Allison weigh with turbochargers?

V-1650-9 - 1,690 lbs
V-1710 G6R/L (V-1710-143/-145) - 1,595 lbs

from http://www.unlimitedexcitement.com/default.htm

The idea of putting Merlins in the P-38 was squashed by lobbying by General Motors.


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## FLYBOYJ (Apr 3, 2006)

KraziKanuK said:


> R988, how much did the Allison weigh with turbochargers?
> 
> V-1650-9 - 1,690 lbs
> V-1710 G6R/L (V-1710-143/-145) - 1,595 lbs
> ...



Where did you hear that? The Allisons used on the P-38 were "GFE" Government Furnished Equipment and in that sceniro there is little interface contractually between "Prime" (Lockheed) and the subcontractor (Allison)


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## KraziKanuK (Apr 3, 2006)

Allison was a GM company.

Btw, R-R had a P-38 delivered to Hucknall in 1944 for a trial installation of Merlin XXs in 1944. When it became known, they were told to return the a/c immediately. Seems it would be not that much trouble to replace the Allisons having experence previously with the P-51 conversion. Lockheed did extensive engineering evaluations of Merlin P-38s and would have transformed the P-38 in a simular manner to the P-51.


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## FLYBOYJ (Apr 3, 2006)

KraziKanuK said:


> Allison was a GM company.


 I know...

I doubt there was any serious lobbying by Allison. Bottom line if the decision was made to replace the Allison with Merlins the powers to be would of seen it through, just as they did on the P-51.

Back then as it is today, propulsion manufacturers must cater to the prime airframe manufacturer, not the other way around....


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## KraziKanuK (Apr 3, 2006)

Did I say Allison did the lobbying?


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## Marshall_Stack (Apr 3, 2006)

I read that Lockheed had desinged an alternate installation detail to accomodate the Merlins from the beginning.


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## red admiral (Apr 3, 2006)

One thing stopped the P-38 from receiving Merlin engines. THe production lines would have had to be shut down for two weeks in order to re-tool for Merlin installation. The loss of two weeks production was judged more important than having a better performing aircraft.


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## wmaxt (Apr 3, 2006)

I'd have to look it up to get a name but the General in charge of procurement was a former GM executive and held stock in GM. This man decided the Allison would stay in the P-38.

Lockheed designed the installation of Merlins as early as '41, as an optional power plant. It was felt that the overall performance would increase but climb would suffer. The problem here is the supercharger/prop reduction gearing which can be geared for power (climb) or speed, an example of this can be seen at the following site
http://spitfireperformance.com/ 
You will need to go to the Mustang tests you'll note MS (.42 reduction I belive these are right but there not stated on this material) and FS (.477 reduction) gear and its affect on speed/climb. Note: the pertinent test is of a P-51H, listed as a Mustang III with a Merlin 100, the test is quite far down the page.

The turbo being less dependant on RPM for power is not affected and use the middle ground. The P-38F/Spitfire tests on the following site illustrates this extremely well showing the P-38F climb right in the middle of the two Spit IXs one of each reduction ratio. 
http://prodocs.netfirms.com this is the Pro Docs page and has a huge collection of WWII aircraft info, that address doesn't always work but its all I have.

I've seen several estimates of the results of the installation form 1,000lbs added to an even swap. The drawings range from a profile like the early, more streamlined version, to a front radiator installation like the J/K/L models but without the radiators on the booms. Drag wise that would not be a big difference in drag, the front radiators are in a propeller wash area and add very little drag and the rear radiators are in the wing turbulence area and follow the "Meredeth Rule" to add a little thrust over the drag produced.

wmaxt

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## FLYBOYJ (Apr 3, 2006)

KraziKanuK said:


> Did I say Allison did the lobbying?


Several threads ago.....


KraziKanuK said:


> The idea of putting Merlins in the P-38 was squashed by *lobbying by General Motors*.





KraziKanuK said:


> Allison was a GM company.



While at Lockheed I knew several engineers who worked on the program and got to chat with them a bit. Ben Rich (he wrote the book Skunk Works, his daughter was a good friend of my ex wife) told me that there was a study done right before Pearl Harbor and again later in the war. Again, the engines were government furnished and when designated in the design phase, the government wanted to stick with the Allison, there was little complaint from Lockheed. He did say there was a problem with the rear pistions (closest to the firewall) always burning up first. This was identified to Allison...

It was also mentioned that there was a desire to keep the design "All American" although Packard eventually built the Merlin - Possible and probable...

I know the procurement folks for the AAF were out of Wright Patterson, (and are still today) and I would find it hard to believe that one general could of attempted to stop Lockheed from pursuing Merlins on the P-38. If it was true and Allison (GM) had this guy in their pocket, why not do the same when North American was planning to drop the Merlin in the Mustang?


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## wmaxt (Apr 3, 2006)

FLYBOYJ said:


> Several threads ago.....
> 
> While at Lockheed I knew several engineers who worked on the program and got to chat with them a bit. Ben Rich (he wrote the book Skunk Works, his daughter was a good friend of my ex wife) told me that there was a study done right before Pearl Harbor and again later in the war. Again, the engines were government furnished and when designated in the design phase, the government wanted to stick with the Allison, there was little complaint from Lockheed.
> 
> ...



I just pointed out where the decision was made and what the connections that man had. In response to your last question -
1. Allison was at capacity of an expanded factory.
2. A different officer was in charge of P-51 production, a colonel who had ties to a congressman.

I certainly don't know all the ins and out of this but
1. Why no second source for the P-38 until Jan, '45? Until March '44 it was the only AAF air superiority fighter with range and numbers to take the fight to the enemy of a 1:1 basis. 
2. P-38K squashed for +/- 50 airplane (~two weeks) delay?
3. Why no unified mixture/prop/throttle control that was ready for installation but denied by the WPB.

I'm sure the "All American" argument was used in '41 and the "Don't want to delay production" argument was probably used later but who really knows?

I certainly don't dispute what you are saying, just that there seems to be more to it.

wmaxt


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## syscom3 (Apr 3, 2006)

Theres always the possibilty that all Packard built Merlins were designated for the P51, so none were available.

The Merlin equiped P51's were a magnitude better in performance than the Allison equiped Mustangs, but a merlin equiped P38 only had a slight marginal improvement over the Allisons.

If I was in charge of the aircraft production board, Id veto changing the P38 line for the "umpteenth time" for such little over all improvement.


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## Nonskimmer (Apr 3, 2006)

syscom3 said:


> Theres always the possibilty that all Packard built Merlins were designated for the P51, so none were available..


Packard Merlins were also installed on Canadian built Lancasters.


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## KraziKanuK (Apr 3, 2006)

Nonskimmer said:


> Packard Merlins were also installed on Canadian built Lancasters.


 And Mossies.


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## Nonskimmer (Apr 3, 2006)

Ah yes.


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## pbfoot (Apr 3, 2006)

and the Hurricane


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## syscom3 (Apr 3, 2006)

So my point is valid. There might have not been engine availability for the P38


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## R988 (Apr 4, 2006)

syscom3 said:


> So my point is valid. There might have not been engine availability for the P38



They made a P-40F with a Merlin but had to discontinue it due to lack of available engine I think, so that is definately a valid point, that and the cost to benefit ratio would have been vetoed the idea.


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## Twitch (Apr 4, 2006)

The Allison weighed 1,345 lbs. and the Merlin 1,690 lbs. Performance wasn't the original issue in this thread was it? Wasn't the idea to improve cold/wet weather problems with the P-38? To stick them only in ETO birds would have probably been to much engineering for the results.


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## wmaxt (Apr 4, 2006)

Twitch said:


> The Allison weighed 1,345 lbs. and the Merlin 1,690 lbs. Performance wasn't the original issue in this thread was it? Wasn't the idea to improve cold/wet weather problems with the P-38? To stick them only in ETO birds would have probably been to much engineering for the results.



I've seen several quotes on the Merlin installation ranging from adding a 1,000lbs, to an even trade weight wise. 

The first Merlin conversion proposal was because they were still having a few problems with it when they originally designed it. At the time the Merlin XX was providing ~200hp more than the Allison. The second proposal was due to the engine issues in the ETO. The Problem that is never addressed is that the Aleutian campaigns P-38s did not have those engine problems even with -40 on the ground. The only difference was operating procedures.

Your right to put Merlins in ETO planes only would have required another assembly line at a minimum, nobody was willing to add that complication.

wmaxt

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## Gemhorse (Apr 4, 2006)

An interesting little aside to this arises in reading 'Confounding the Reich' by Martin Bowman Tom Cushing [ISBN 1 85260 507 3 ] on pg.23......

''At the end of August 1943, Wittering became a little crowded with the influx of of US personnel of the 20th Fighter Group, whose 77th 79th Sqn.'s moved into the satellite airfield at King's Cliffe. The 55th Sqn. was to be based at Wittering. The 20th was equipped with the P-38 Lightning. The CO, Major D.R. McGovern from Providence, Rhode Island, had served in the Pacific flying P-39 Airacobras and had destroyed 5 Jap aircraft. He and Bob Braham became friends. On the 20th September, Braham Jacko Jacobs in a Mosquito engaged in a local friendly dogfight with a P-38. Braham found that even though the Mosquito was worn-out and meant for training and with his [then] inexperience of the aircraft, it was, in his opinion, superior to the Lightning....''

At this time, RAF 141 Sqn. was converting from Beaufighters to NF.II Mosquitos, only being supplied sporadically with well-used ones from other units....

W/C John Randall Daniel 'Bob' Braham DSO,DSC**,not then 23, assumed command of RAF 141 Sqn. Dec. 1942, and had already shot down 12 enemy aircraft, 11 of them at night. He was then the youngest W/C in the RAF. He was eventually shot down captured but was one of the highest-scoring British NF pilots, up there with John Cunningham, by the finish of the War....

My point is that while the P-38 was a terrific aircraft [IMHO], the exercise of trying to improve performance by replacing Allisons for Merlins did work, as in the P-40 and later the P-51....

[ On pg.99, they did try using P-38J's for Intruder-work, working with RAF 515 Sqn.'s Mosquitos in late Mar. 1944, but it was disbanded in April after sorties revealed that single-seat fighters were unsuitable for Intruder Ops.....]


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## Glider (Apr 4, 2006)

Gemhorse said:


> An interesting little aside to this arises in reading 'Confounding the Reich' by Martin Bowman Tom Cushing [ISBN 1 85260 507 3 ] on pg.23......
> 
> ''At the end of August 1943, Wittering became a little crowded with the influx of of US personnel of the 20th Fighter Group, whose 77th 79th Sqn.'s moved into the satellite airfield at King's Cliffe. The 55th Sqn. was to be based at Wittering. The 20th was equipped with the P-38 Lightning. The CO, Major D.R. McGovern from Providence, Rhode Island, had served in the Pacific flying P-39 Airacobras and had destroyed 5 Jap aircraft. He and Bob Braham became friends. On the 20th September, Braham Jacko Jacobs in a Mosquito engaged in a local friendly dogfight with a P-38. Braham found that even though the Mosquito was worn-out and meant for training and with his [then] inexperience of the aircraft, it was, in his opinion, superior to the Lightning....''
> 
> ...



Interesting


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## wmaxt (Apr 5, 2006)

Gemhorse said:


> An interesting little aside to this arises in reading 'Confounding the Reich' by Martin Bowman Tom Cushing [ISBN 1 85260 507 3 ] on pg.23......
> 
> ''At the end of August 1943, Wittering became a little crowded with the influx of of US personnel of the 20th Fighter Group, whose 77th 79th Sqn.'s moved into the satellite airfield at King's Cliffe. The 55th Sqn. was to be based at Wittering. The 20th was equipped with the P-38 Lightning. The CO, Major D.R. McGovern from Providence, Rhode Island, had served in the Pacific flying P-39 Airacobras and had destroyed 5 Jap aircraft. He and Bob Braham became friends. On the 20th September, Braham Jacko Jacobs in a Mosquito engaged in a local friendly dogfight with a P-38. Braham found that even though the Mosquito was worn-out and meant for training and with his [then] inexperience of the aircraft, it was, in his opinion, superior to the Lightning....''
> 
> ...



That is interesting, If you go here http://prodocs.netfirms.com you'll see a P-38F (the same model the 20th was first equipped with) and a Spit IX, and Fw-190A.

wmaxt


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## V-1710 (Apr 6, 2006)

I don't think using the results of changing to the Merlin in the P-40 and P-51 would really be indicative of what would have happened had Merlins been installed in the P-38. Both the P-40 and P-51 were equipped with single-stage supercharged Allisons, while the P-38's of course were turbocharged. In the excellent book 'V's for Victory-The Story of the Allison V-1710' by Daniel D. Whitney there are many tables showing the expected performance levels attained by P-38's equipped with many different Merlins, including the XX type. It would seem that only the most advanced Merlins gave any real advantage over the V-1710-89/91's in the P-38L. In the end, the effort required to re-equip the P-38 with Merlins was not justified. The decision to stop development of the Merlin powered P-38 was handed down by Gen. Arnold himself. Another factor that may have had some bearing on his decision was that once the war was over, Packard was to start paying very expensive royalties to Rolls-Royce for continued manufacture of the Merlin. For this reason the P-82 and the P-51J were equipped with advanced V-1710's.


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## wmaxt (Apr 6, 2006)

V-1710 said:


> I don't think using the results of changing to the Merlin in the P-40 and P-51 would really be indicative of what would have happened had Merlins been installed in the P-38. Both the P-40 and P-51 were equipped with single-stage supercharged Allisons, while the P-38's of course were turbocharged. In the excellent book 'V's for Victory-The Story of the Allison V-1710' by Daniel D. Whitney there are many tables showing the expected performance levels attained by P-38's equipped with many different Merlins, including the XX type. It would seem that only the most advanced Merlins gave any real advantage over the V-1710-89/91's in the P-38L. In the end, the effort required to re-equip the P-38 with Merlins was not justified. The decision to stop development of the Merlin powered P-38 was handed down by Gen. Arnold himself. Another factor that may have had some bearing on his decision was that once the war was over, Packard was to start paying very expensive royalties to Rolls-Royce for continued manufacture of the Merlin. For this reason the P-82 and the P-51J were equipped with advanced V-1710's.



Good info - it'll go into the info bank! I knew about the P-51J and P-82s but not Arnold's involvement. I'm sure that there were at least two decisions regarding the P-38L vrs the P-51s though, they were about two years apart.

wmaxt


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## DaveB.inVa (Apr 6, 2006)

Id rather have the turboed Allison than the supercharged Merlin. The turbo setup on the P-38's Allison is much more flexable than the two speed two stage supercharger found on most versions of the Merlin. Many times youll find that because of the P-51's great leap in performance due to the installation of the Merlin, people will believe that the Allison was a much less powerful engine. Most dont consider that it was the induction system of the Merlin that made it such a great performer. If the Allison was given an induction system like the Merlin (and later Allisons did get two speed two stage superchargers) it would certainly perform much better at altitude. 

My point is that the induction system must be considered. If the Allison could get the amount of oxygen at altitude that the Merlin could then the Merlin would be a much less mystical engine today. In the case of the P-38 it could get enough oxygen at altitude and could make power at altitude because of the turbochargers. 


I also agree with wmaxt that operating procedures were the problem in the ETO. All the talk of cold air in Europe killing the turbos is unfounded. The B-17 and B-24 operated in that same cold air and you never heard of cold air killing their turbos. 

Personally I believe the wet weather is what did them in. The turbos were mounted on top of the boom and were more exposed to the weather than the turbos of bombers which were underneath the wing. Operating procedures in Alaska were obviously improved as problems were less prevalent.


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## Jabberwocky (Apr 7, 2006)

Argh, forum ate my post.


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## V-1710 (Apr 7, 2006)

DaveB.inVa said:


> Id rather have the turboed Allison than the supercharged Merlin. The turbo setup on the P-38's Allison is much more flexable than the two speed two stage supercharger found on most versions of the Merlin. Many times youll find that because of the P-51's great leap in performance due to the installation of the Merlin, people will believe that the Allison was a much less powerful engine. Most dont consider that it was the induction system of the Merlin that made it such a great performer. If the Allison was given an induction system like the Merlin (and later Allisons did get two speed two stage superchargers) it would certainly perform much better at altitude.
> 
> My point is that the induction system must be considered. If the Allison could get the amount of oxygen at altitude that the Merlin could then the Merlin would be a much less mystical engine today. In the case of the P-38 it could get enough oxygen at altitude and could make power at altitude because of the turbochargers.
> 
> ...



Good points. Also, it must be noted that the Allison V-1710 was intended to be a turbocharged engine. The P-37, P-38, and P-39 were all orginally designed to use the turbocharged Allison. Consider what a dissappointment the P-39 turned out to be without a turbocharger, and also note the performance (or lack of performance!) of the Lockheed P-322 Lightning with non-turbocharged V-1710-C15's. In addition, the XP-49 Lightning development didn't have any performance advantage with it's 1,600 h.p. Continental XIV-1430's over the P-38L. Wonder what a P-39 would have been like with a Merlin? Probably close to the P-63, which had a 2 stage supercharged V-1710.


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## Marshall_Stack (Apr 7, 2006)

Deleting the turbocharger on the P-39 cost American lives. I read that NACA (predessor to NASA) deleted it because of drag counts (the air inlet). I am a fan of the underdog; I would like to have seen what it could have done with the turbos. The life of the plane would probably have still been short due to its lack of range.


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## syscom3 (Apr 7, 2006)

Ive heard the primary reasons were due to the fact that General Electric was having a huge problem building the turbochargers and they werent available.


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## V-1710 (Apr 8, 2006)

It took General Electric quite some time to get the turbocharger perfected. I believe at least one of the XP-37's crashed due to turbo failure. As for the P-39, the U.S.A.A.C. decided that it wanted the aircraft to fill the ground attack role rather than high altitude interceptor, so the turbocharger was deleted. So, not only did the P-39 loose a lot of horsepower and high altitude capability, it also became significantly heavier, due to the addition of more armor plate. Recipie for disaster.......


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## wmaxt (Apr 8, 2006)

A good article on the P-39 regarding the turbo is at this site:
http://home.att.net/~C.C.Jordan/index.html

The prototype could hit 398 at 20,000ft, thats 1943 fighter performance!

wmaxt


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## helmitsmit (Apr 26, 2006)

Aren't turbochargers heavier then the the 2 stage 2 speed supercharger? Did they actually trial a merlin 60 series 1640hp on a p38? 

By the way the merlin XX 1480hp was a bombers engine (Lancaster) optimised for low level. 

They could have used the merlin 130 series 2000hp (De Haviland Hornet) which would have been handed.


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## Twitch (Apr 27, 2006)

My take on Allisons with turobs is simply that they obviously worked if P-38 had service ceiling of 44,000 feet! The myriad other factors simply made it a better ship for warmer Pacific ops instead of the ETO.

Also, only one of three P-82 prototypes used Allisons. Initial production aircraft were Packard V-1650-23/25s. And Packard was not hurting for building liscensed Merlins. It was a time for the company when defense contacts saw a cash flow like never before in their history.

<<BTW that's my Packard


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## helmitsmit (Apr 27, 2006)

Yeah but that might be the wing design or the streamlining of the aircraft

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## Jabberwocky (Apr 28, 2006)

wmaxt said:


> A good article on the P-39 regarding the turbo is at this site:
> http://home.att.net/~C.C.Jordan/index.html
> 
> The prototype could hit 398 at 20,000ft, thats 1943 fighter performance!
> ...



More like 1941-1942 performance.

FW-190s were doing 390mph + in 1941 in combat, so were Hawker Typhoons. The 109F4 was doing a few mph short of 400 in late 1941, as was the Mig 3. The Spitfire, 190A and 109G all exceeded 400mph in level flight in 1942. The P-38 was doing over 400mph as well.

One of the great 'mightofbeens' was the improved Spitfire proposed by Supermarine in 1939. Supermarine significantly reworked a Spitfire II into a "Mk III" with a two speed Merlin XX in 1940 and recorded a level speed of 400mph at 21,000 feet. They clipped the wings, added 14 Imp Gal (17 US gal) to the fuel tanks, strengthened the engine mounting, made the tail wheel retractable, re-arranged the landing gear and undercarriage and added more armour protection. 

However, the RAF decided that the Hurricane was in more dire need of a performance increase and the new Merlins went to them. The other consideration of the RAF was that production numbers were more important than the extra performance at the time, the Spitfire being considered superior to the 109 by the RAF. So, instead of the large step foward with the Mk III, the RAF decided to go with the incremental Mk V, which required far less changes in the production line and had an engine more readily available in the Merlin 45.

In essence, the amount of significant changes to the Spitfire design emboldened in the Mk III meant that, even despite the very real improvements in speed, roll rate and rate of climb, there were too many changes in the airframe for it to be put into production quickly. 

The RAF ended up paying for that decision over France in 1941, where a faster, stronger and more agile Spitfire could of blunted the technical advantage that the LuftWaffe enjoyed when the FW 190 appeared. Considering that the Mk III enjoyed almost identical advantages over the Mk V that the 190A did ( i.e a +20-30 mph speed advantage at most heights, better roll, better climb, better dive), a 190A vs a Spitfire Mk III would of been a far more even fight.


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## helmitsmit (Apr 28, 2006)

Jabberwocky said:


> More like 1941-1942 performance.
> 
> FW-190s were doing 390mph + in 1941 in combat, so were Hawker Typhoons. The 109F4 was doing a few mph short of 400 in late 1941, as was the Mig 3. The Spitfire, 190A and 109G all exceeded 400mph in level flight in 1942. The P-38 was doing over 400mph as well.
> 
> ...



I've got a thread on the Mk 3 if you want to join and chat? The mk 3 would have been a beautiful sight over England and France.


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## Twitch (Apr 28, 2006)

Ok everybody, how come the P-63 had decent performance? A supercharged Allison. The P-63C used a V-1710-117 of 1,325 HP that raised to 1,800 HP with water injection. Its max speed was 410 MPH @ 25,000 feet.

The P-63A used the V-1710-93 with 1,500 HP war emergencey power. It had same top speed at 25K feet and could get ther in 7.3 minutes plus had a range of 2,575 miles! It also had a service ceiling of 43,000 feet! Plans to install a V-1650-5 Packard-Merlin were abandoned as there was no need!

The Allison produced performance with a supercharger an no turbocharger.


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## helmitsmit (Apr 28, 2006)

Maybe it was that Rolls Royce were better at supercharging their engine because they had more experience then Alison?


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## chris mcmillin (Apr 29, 2006)

Twitch,
The aux supercharger on the P-63C engine was a fluid-coupling driven additional blower that fed compressed air to the engine blower at high altitude. It was a good set-up and is almost comparable to the Merlin performance. The thing about the Merlin is that the twospeed/twoSTAGE blower with intercooler/aftercooler just did such a good job it was hard to beat.
In hydroplane racing, there was a guy that made Allisons that had Merlin blowers grafted onto the rear case. They ran but didn't get a lot of testing and development before the team disappeared. An interesting idea that was to be copied by Dave Zueschel, a SoCal airplane engine guy on Mike Carroll's Airacobra racer that crashed on it's first flight. Too bad, another team that never had a chance to develop an Allison with a two stage blower. 

Allison G6 (used in the F-82) rods are used in the competitive Merlin racing engines in air racing today. These are big, smooth and well suited to racing. They require a custom bearing be made, but the stroke is the same on both the Allison and the Merlin. The Allison is a pretty well built and capable engine, there are some Yak-3's racing at Reno, and I love to hear them at 80 inches and 3200, the Yaks go about 380 mph. The super Merlins are making 140 in hg with their custom blower gears and turn 3400 rpm, the caps staying on their Allison G6 rods. Those Mustangs have gone 511mph (Dago Red, N5410V, race#4, Reno Saturday Gold Heat, 2003) around the pylon course.

Those old Rolls rods would stretch the rod bolts at the 3600 to 3800 rpm that it took to get big MP before the era of custom blower gears, and throw the caps off, hole the crankcase, then 125 inches of manifold pressure would run down the cylinder with the missing piston, pressurize the crankcase and blow all of the oil out of the hole in the case, evacuating the oil system and destroying everything else rotating. All of the oil would be deposited over the airplane, and cover the windshield with oil. The prop would go to high rpm, flat pitch because of the engine oil is no longer operating the governor, so the poor guy has a huge 11 foot four bladed air brake out there, so about 40 seconds to get it up, configured to land, and down on a runway before the thing slows from 400 kts to 100 kts. What a sight!

Cool Packard. (A guy in Chicago had one similar parked next to his Hispano HA-1112 I was negotiating for my father to purchase, right before Carl Icahn bought TWA. Dad retreated from the deal after ole' Carl came to town. The airplane had a 15 hour old Merlin 500 with the real four bladed propeller. It was in perfect shape, in Battle of Britain movie paint, stored in his expansive garage with the wings on tires right next to it. If only.)

Chris...

Oh Yeah, the poor old Kingcobra had the same wing layout as the Airacobra. Those guys couldn't get more gas in the wing because of the trike gear wheel well. The way a Mustang is made it is dang near perfect, big, huge square behind the gear well, they used huge stressed doors (like they did the B-25) to hold the wing together over such a big area, and the thing held enough fuel internal to go that much farther than everything else, so the old King was done. Bummer, I love the Bells.


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## helmitsmit (Apr 29, 2006)

that is good stuff out of interest what is the hp of the 3400rpm merlins?


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## Bullockracing (Apr 29, 2006)

OK, this is all very interesting, but how about one of the artists from here giving us a picture of how well a P-38 would look with some late-model Merlins in it, and the air scoops associated with that type of engine (a la Spiteful?). I would love to see one, perhaps with a thinner wing to eliminate the compressibility factor...


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## helmitsmit (Apr 29, 2006)

Yeah I see what you mean the wing might have made a bigger difference.


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## Twitch (Apr 30, 2006)

The Merlin supercharger was crap until Sir Stanley Hooker improved it too.

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## wmaxt (Apr 30, 2006)

Bullockracing said:


> OK, this is all very interesting, but how about one of the artists from here giving us a picture of how well a P-38 would look with some late-model Merlins in it, and the air scoops associated with that type of engine (a la Spiteful?). I would love to see one, perhaps with a thinner wing to eliminate the compressibility factor...



Of course the wing is a compromise, the original wing was designed with two criteria in mind first a high climb rate. Second ability to carry extra fuel. A thinner wing, maybe laminar flow, would hurt both those criteria but would have made it faster.

wmaxt


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## wmaxt (Apr 30, 2006)

helmitsmit said:


> Maybe it was that Rolls Royce were better at supercharging their engine because they had more experience then Alison?



The Army Air Corps settled on Turbo's in the early 20's (1922 I think) and allowed only Turbocharging research to proceed as the prime supercharger system. Elsewhere in the world mechanical supercharging was more popular.

wmaxt


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## Twitch (May 1, 2006)

The one thing about turbocharging in any engine application is that it is free, in that it take no power away from the engine in order to produce additional power. It all comes from exhaust. All the time a supercharger is not switched on it pulls power from the engine.


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## wmaxt (May 1, 2006)

Twitch said:


> The one thing about turbocharging in any engine application is that it is free, in that it take no power away from the engine in order to produce additional power. It all comes from exhaust. All the time a supercharger is not switched on it pulls power from the engine.



Thats true, another aspect of turbo's is that they are not dependant on engine speed and can give full boost from SL to 30,000ft seamlessly (depending on air quality).

wmaxt


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## Hop (May 2, 2006)

> The one thing about turbocharging in any engine application is that it is free, in that it take no power away from the engine in order to produce additional power. It all comes from exhaust.



The turbo uses exhaust thrust which in a non turbo engine can be used to augment the thrust of the propeller.

At lower speeds exhaust thrust isn't very important, but at high speeds it is, often comprising a sizeable proportion of total thrust, because prop thrust drops off with speed.


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## Jabberwocky (May 2, 2006)

On the Spitfire Mk I the exhaust from the engine was worth around 70lbs of thrust, which equated to around 70hp at 300mph. Doesn't sound like that much, but after the ejector exhausts were fitted, Spitfire Mk I performance rose from the 348-9 mph of the test machine, to 360-2 mph, despite the increase in drag from the new exhaust fairings. Thats around 20-24 mph improvement that you wouldn't necessarily see with a turbocharger.

On later marks the more streamlined 'multi-ejector' exhaust was installed, adding around another 7 mph in top speed.


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## syscom3 (May 2, 2006)

The one drawback to the P38's turbo system was it took up space in the boom, and it had a complex ducting system that gave mechanics fits.

In one Lockheed study looking at a Merlin install, they figured they could add a couple more fuel cells into the booms with attendent gains in range.


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## syscom3 (May 2, 2006)

Heres a thread that was started back in October about turbocharging and supercharging. Loads of information in it.

http://www.ww2aircraft.net/forum/2355-supercharger-vs-turbocharger.html


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## helmitsmit (May 2, 2006)

Why not use a turbo-supercharger? 

About the wing the Spitfire eliptical wing had a very low drag/lift ratio and alowed for high angles of attack. Why not use a similar wing on the P38???


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## FLYBOYJ (May 2, 2006)

helmitsmit said:


> About the wing the Spitfire eliptical wing had a very low drag/lift ratio and alowed for high angles of attack. Why not use a similar wing on the P38???


 Becuase the elliptical wing is hard to manufacture....


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## wmaxt (May 2, 2006)

helmitsmit said:


> Why not use a turbo-supercharger?
> 
> About the wing the Spitfire eliptical wing had a very low drag/lift ratio and alowed for high angles of attack. Why not use a similar wing on the P38???



The P-38 had a high aspect ratio wing - the next best thing to the elliptical wing. The high aspect ratio and the fowler flaps were essential to its turning performance. At maneuver setting the flaps on the P-38 extended and dropped 8deg, increasing lift ~25-30% with almost no drag penalty.

wmaxt


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## wmaxt (May 3, 2006)

Stats from a study by Lockheed for a Merlin XX installation.

Allison ------------------- Merlin XX
Rating Military - 1150 @ 20,000ft ----- 1170 @ 21,000ft
Criticle Altitude - 20,000ft ------------- 21,000ft
Rating continous - 1,000hp @ 20,000ft ---875hp @ 20,000ft
Gross weight -----13,500# ------------ 14,500#
Speed Criticle Alt - 425mph ------------ 431mph
Time to Climb -----5.94 to 20,000ft ---- 5min to 15,000ft

The P-38 would have been faster but climb would have dropped.

wmaxt


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## V-1710 (May 4, 2006)

That seems the be the information provided in the 'Vee's for Victory' book. The turbocharged Allison still had it's single-stage blower, so it was in effect a two-stage set up. The V-1710 was also used in early turbo-compounding experiments (where the turbocharger shaft is geared to the crankshaft to provide extra power, as on late R-3350's)


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## helmitsmit (May 4, 2006)

Yeah the turbo compounding was a great idea they should have used it on more engines.


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## FLYBOYJ (May 4, 2006)

helmitsmit said:


> Yeah the turbo compounding was a great idea they should have used it on more engines.


 There was no reason to as the jet engine came onscene and further development of recips basically halted after the war.


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## V-1710 (May 6, 2006)

Well, as far as the military combat aircraft were concerned, the emphases was certainly on jets, but both Pratt and Whitney and Wright continued to develop the piston engine after the war. Pleanty of military cargo and civilian airliners to power. Look at what the R-2800, R-3500 and R-4360 were capable of in the late 50's.


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## FLYBOYJ (May 6, 2006)

V-1710 said:


> Well, as far as the military combat aircraft were concerned, the emphases was certainly on jets, but both Pratt and Whitney and Wright continued to develop the piston engine after the war. Pleanty of military cargo and civilian airliners to power. Look at what the R-2800, R-3500 and R-4360 were capable of in the late 50's.


 There was not a lot of new innovations in recips, putting it simply the research was going into jets. With all the post war recips being operated into the late 50s, not much has changed since the 1940s.

I worked on P2Vs, an S2F, a PBY and was involved in painting a late model Connie - there was little difference in the technology that went into their powerplants, even though she had late model engines. From what I dealt with the major large recip manufacturers of the 50s (Curtiss Wright, Pratt and Whitney) they did little to their products except accommodate for post war airliner installation (DC-7, L1649)


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## syscom3 (May 6, 2006)

It was obvious in 1946 that high performace reciprocating engines were a technological dead end.


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## FLYBOYJ (May 6, 2006)

syscom3 said:


> It was obvious in 1946 that high performace reciprocating engines were a technological dead end.


 Bingo!!!


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## V-1710 (May 10, 2006)

I was thinking along the lines of turbo-compounding and fuel injection, both innovations first tried during the war, but more widely used after the war. But yes, a techical dead end. One look at the flight engineer's panel on a Super Connie, DC-7, or KC-97 and you knew it was over.


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## FLYBOYJ (May 10, 2006)

V-1710 said:


> I was thinking along the lines of turbo-compounding and fuel injection, both innovations first tried during the war, but more widely used after the war.


 That was about all that was done with recips after WW2. Pressuration and airconditioning technology was also improved with aircraft like the DC-7, and L1049, but no major engine advancements...


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## chris mcmillin (May 10, 2006)

That is kind of like saying that there haven't been any engine advancements since 1941 because the Whittle jet was flown then and we have jet engines today!

The hp increase of the postwar civil Merlin and Wright 3350 is a bit remarkable from 1945 to the late fifites.

I think there were some big advancements based on logical evolution to create more efficient, reliable and usable engines. This is similar to the evolution of the jet engine since the centrifugal flow design to the high bypass fans today.

Granted, we all are into old stuff or we wouldn't be on this site, and it is a history based interest. So progress has left the piston behind as far as development. The modern day piston manufacturers are way behind as well, mostly because of the need to remain in the FAA's certification envelope. Diesels are coming fast as seen by the cool little Diamond twin engine diesel powered airplane that has won certification here in the US. That is truly a positive direction to see manufacturer's going and it is the future of general aviation, which is mostly piston aviation. 

It isn't new technology on the face of it, but it is very evolved and refined.

Chris...


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## syscom3 (May 10, 2006)

One big problem with those high performance reciprocating engines is the need for expensive high octane fuel. The jets used cheap kerosine fuels.

Even for the 1950's when gas was cheap, fuel costs were a big componant of any commercial endevour.

Plus those big complex compound engines were expensive to maintain and repair, as compared to jet engines.


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## FLYBOYJ (May 10, 2006)

chris mcmillin said:


> That is kind of like saying that there haven't been any engine advancements since 1941 because the Whittle jet was flown then and we have jet engines today!
> 
> The hp increase of the postwar civil Merlin and Wright 3350 is a bit remarkable from 1945 to the late fifites.
> 
> ...



I think you hit the nail on the head Chris. I remember when I was in college an instructor spoke about electronic ignition and FADEC on recip aircraft engines but also said he doubted they would ever be certified by the FAA. We had seen the Feds budge a little with recip "innovations" but not much has changed since WW2 - especially on round engines.


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## Mad Dog (Jul 7, 2019)

FLYBOYJ said:


> Several threads ago.....
> 
> 
> 
> ...


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## GrauGeist (Jul 8, 2019)

The P-38 was in production and service before Packard got the contract to produce the Merlin.

Refitting the P-38 to accept the Rolls-Royce Merlin was out of the question (especially since Britain was hard pressed to supply the Merlin to her own production lines) and by the time Packard landed the contract, it was a moot point.

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## wuzak (Jul 8, 2019)

GrauGeist said:


> The P-38 was in production and service before Packard got the contract to produce the Merlin.
> 
> Refitting the P-38 to accept the Rolls-Royce Merlin was out of the question (especially since Britain was hard pressed to supply the Merlin to her own production lines) and by the time Packard landed the contract, it was a moot point.



As I understand it, Lockheed proposed installing Merlins in the P-38 three times. 

First was with the Merlin XX (V-1650-1). The proposal was after Packard was awarded the contract to build Merlins, so any Merlins for P-38s would have come from Packard.

The second proposal was the Merlin 61. And the last was with the "advanced Merlin", which was the 100-series Merlin, which included the V-1650-9 that was fitted to the P-51H.

The service introduction of P-38s was in mid-to-late 1941, though the aircraft was not considered combat ready at that time. 

Packard signed the contract to build Merlins under licence in 1940.


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## GrauGeist (Jul 8, 2019)

The P-38 was in production and started deliveries when the first V-1650 engine was bench-run in summer 1941.

There is a HUGE difference between the time a contract is signed and when the first product comes out the door.


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## wuzak (Jul 8, 2019)

GrauGeist said:


> The P-38 was in production and started deliveries when the first V-1650 engine was bench-run in summer 1941.
> 
> There is a HUGE difference between the time a contract is signed and when the first product comes out the door.



You've moved the goal post.



GrauGeist said:


> The P-38 was in production and service before Packard got the contract to produce the Merlin.




That the P-38 was in production did not stop Lockheed from considering the Merlin. It happened at various stages through the war.

The initial proposal may have been in response to the Packard contract being awarded and its requirement that 1/3 of production be for USAAF use.


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## Milosh (Jul 8, 2019)

GrauGeist said:


> The P-38 was in production and started deliveries when the first V-1650 engine was bench-run in summer 1941.
> 
> There is a HUGE difference between the time a contract is signed and when the first product comes out the door.



Wasn't the Allison Mustang also in production, yet that didn't stop the Packard Merlin being installed in the Mustang.


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## Shortround6 (Jul 8, 2019)

A few considerations, 
1. Packard was not able to build Merlins in numbers exceeding handfuls per month until the very end of 1941/ beginning of 1942.
2. The Merlin in question offered 1150 hp at 18,500ft while the turbo Allison offered about the same at 25,000ft so I am not sure where the advantage comes in.
3. The Allison powered version was supposed to do about 8% better in fuel economy when cruising.
4. Without some major changes in contracts/production every Merlin P-38 built is two P-40Fs not built.

That is just of the top of my head for the early Merlin. Granted they didn't know about some of the problems with the early turbo installations.

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## IdahoRenegade (Jul 8, 2019)

What was the power output at high altitude of the Merlin vs the turbocharged 1710? I seem to recall that by the time the P-51 was at 30k, hp was down to ~900hp, but this is going by memory and could be way off. Also, turbochargers extract "waste heat" from the exhaust to power the compressor, vs using engine output. In theory, the turbo setup should burn less fuel, all else being equal.

I always thought an intercooler package (liquid) like the Merlin got would have been an interesting update to the (Allison turboed) '38, rather than the core-type air-air intercoolers it got on the J models. The J model got considerably more power, but only a slight increase in speed due to the added drag. A new wing design to address the compressibility issue (assuming it would do so), a new intercooler design and some attention to cutting drag might have made a significant difference. The real shame is that there was only one source until the very end of the war, when Vultee finally built ~100 planes, none of which made it into service.


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## MIflyer (Jul 8, 2019)

The V-1710 of the P-38J/L weighed 1395 lb not including the turbo and intercooler and was rated at 1,475 hp at 30,000 ft. The turbo and intercooler probably weighed no more than 100lb.

The V-1650-3 of the P-51 weighed 1640 lb and was rated at 1390 hp at 20,000 ft. 

As for putting the Merlin in the P-51, the Allison Mustang/Apache was an outstanding aircraft but was not in much use by the USAAF. Stopping P-51A production to start building the P-51B was not a problem, while stopping P-38 production to build a Merlin powered version would have been a problem. I talked to a friend of mine who was a P-38 maintenance chief in WWII and he said that putting a Merlin in would not have been all that easy. The air intake for the downdraft carb would have interfered with the structure.

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## Milosh (Jul 8, 2019)

Didn't Merlins have an updraft carb?


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## syscom3 (Jul 8, 2019)

The War Production Board decided that the production line would have had to be shutdown for a while, and it was not worth it to get a marginal increase in performance. The P51 was where the AAF had its money on and they didn't want to squander the Merlins on a so-so fighter.

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## wuzak (Jul 8, 2019)

Milosh said:


> Didn't Merlins have an updraft carb?



Yes.


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## Shortround6 (Jul 9, 2019)

MIflyer said:


> As for putting the Merlin in the P-51, the Allison Mustang/Apache was an outstanding aircraft but was not in much use by the USAAF. Stopping P-51A production to start building the P-51B was not a problem,



We all know that the US took quite a while to acknowledge that the Allison Mustang was a very good airplane. We also know that the Apache/A-36 was a funding trick to keep the production line open. The contract for 500 A-36s was awarded April 16th 1942 but actual development wasn't started until June, FIrst flight of an A-36 was in Sept 1942.
With start of a new fiscal/budget year June 23rd 1942 saw a contract for 1200 Allison powered P-51As placed. This was later changed to 310 aircraft the remainder changed to P-51Bs with Melrins. 
To put a few other things into the timeline (and try to tie it back to the P-38) the last Mustang I left the production line in July of 1942 and was followed by the P-51 no letter.

Packard only hits the 800 engines a month production goal (of single stage engines) in July of 1942 (contract signed in Sept of 1940) and won't build a two stage engine until Nov of 1942 and won't build their 10th (yes 10th) two stage engine until May of 1943. 

Getting back to the P-38, the first G with 1325hp engines is delivered in July of 1942 (a very busy month) and the first H with 1425hp engines was delivered in March of 1943. Obviously orders hand been placed months earlier with development of the engines going on both before and after the order dates (in some cases the "orders" were changes to existing airframe orders) 

There are few Packard Merlins to be had in 1942-43(Packard's 1943 production was double what it's 1942 production was and it's 1944 production was over what the 1942 and 1943 combined production was.)

Trying to squeeze the Merlin P-38 into that is going to be hard, Which Merlin was going to be available when and in what numbers? And this is as the P-38 is going through several engine and turbo combinations, each one getting more powerful/capable even if there were a few hiccups along the way.

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## IdahoRenegade (Jul 9, 2019)

MIflyer said:


> The V-1701 of the P-38J/L weighed 1395 lb not including the turbo and intercooler and was rated at 1,475 hp at 30,000 ft. The turbo and intercooler probably weighed no more than 100lb.
> 
> The V-1650-3 of the P-51 weighed 1640 lb and was rated at 1390 hp at 20,000 ft.



According to this source: P-51 Mustang Performance the Merlin was at 1075hp at 30,000 ft., about 27% less than the V-1710 at that altitude per your spec.


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## b0ned0me (Jul 9, 2019)

MIflyer said:


> The turbo and intercooler probably weighed no more than 100lb.


Believe the P-38 used the B-13 turbo, which was 135lb including wastegate but excluding intercooler, ducting, and any extra items such as oil lines, mountings heat shields etc.

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## Snowygrouch (Jul 9, 2019)

MIflyer said:


> The turbo and intercooler probably weighed no more than 100lb.



The bare B2 turbo-unit itself weighs 135 lbs, according to the official cataloge, although when the Germans weighed one they
reckoned 153 lbs in actual practical form (the catalogue weight probably ignores some flanges and fittings etc). Thats without
the coolers, pipes, controllers, fluids, and so on for which read a very considerable increase.

The German report reckoned the approximate installation weight for a B2 turbo system was 150kg per engine (330lbs), so 300kg = 660lbs
for a twin engine aircraft.

=======
"Des gesamtgewicht einer Anlage mit Abgasleitung, rohrleitung und allen sonstigen dasugehörigen Teilen kann mit 150kg im durschnittangesetz werden."
======
_Ergebnisse der Beuteauswertung #34 - 1st July 1944 (Conclusions from Examination of Enemy Equiptment)_

This shouldnt be very surprising as even putting one extra blower with a chargecooler on the Merlin-60
increased its weight by 265lbs (120kg) from 1375 to 1640lbs. (Merlin III vs Merlin-61)

(snipped attached is from a photo taken by me)

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## MIflyer (Jul 10, 2019)

Intersting! I saw a video of two troops lifting a turbo unit off of a P-38. It did not look like it weighed more than maybe 50 pounds. I wonder what that 135 lb weight includes?


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## wuzak (Jul 10, 2019)

Using Google Translate I get the following:

turbine runner (complete with shaft) - 10.60kg (23.37lb)
loader impeller - 3.02kg (6.66lb)
bearing housing (completely with pump) - 8.80kg (19.40lb)
turbine housing (with radiation protection) - 28.10kg (61.95lb)
loader volute casing - 17.00kg (37.48lb)
loader rear wall - 2.15kg (4.74lb)
---------------------------------
Total weight of the turbocharger - 69.67kg (153.60lb)

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## Snowygrouch (Jul 11, 2019)

wuzak said:


> Using Google Translate I get the following:
> loader impeller - 3.02kg (6.66lb)
> loader volute casing - 17.00kg (37.48lb)
> loader rear wall - 2.15kg (4.74lb)



*FYI Lader = Compressor*

thats not google translates fault really, its one of those funny words
which was used at the time but has since passed out of use in that context in German.


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## pbehn (Jul 11, 2019)

Snowygrouch said:


> *FYI Lader = Compressor*
> 
> thats not google translates fault really, its one of those funny words
> which was used at the time but has since passed out of use in that context in German.


Like LADING in English, I have never heard it used in conversational English. It is used all the time in shipping where "a clean bill of lading" is required for most shipments. and trucks have a laden and unladen weight.


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## K5083 (Jul 12, 2019)

On the issue of weight a couple of hundred pounds would make little difference. Losing the turbo would free up space for fuel, but you probably need more fuel for the Merlin anyway.


The things that were wrong with the P-38 would not be fixed by the Merlin. The wing section. The lack of internal space. The complete dedication of the airframe design to turbo requirements, cooling, ducting, heat and so on. Prop clearance. To use much more power you need a bigger prop, and/or four blades. Look at the props on Spit 9 or P-51B-D. More clearance needs an undercarriage change. None of it is easy. 


And of course, that Brit fuel. The same fuel that worked in every other warplane based in the UK, including turbo-charged B-17, B-24s and P-47s.


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## MIflyer (Jul 12, 2019)

Actually, I quoted those V-1710 and Merlin figures to Warren Bodie back around 1992 and he replied that he had a copy of the Lockheed analyses that showed putting two stage Merlins in the P-38 would have been a good idea.

Note that later in the war Packard built Merlins were being used in Lancasters, Mosquitoes, and Spitfire XVI, as well as the P-82, so it probably would have been feasible to build enough engines for the P-38 at some point.


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## K5083 (Jul 12, 2019)

But a P-38 capable of compressibility on the level would not have been an improvement. And that means only 440mph at altitude. The engines weren't a major problem, or at least it got fixed. The baked-in problems were not fixable without major airframe mods. Also, if you look for what could be done with two late Merlins on a single-seater, try the DH Hornet. That reached speeds that no 38 could hope for. It missed the war but a version with merlin 61s was technically possible in 1942-3, had they not been building Mosquitoes instead. What-ifs can't improve the P-38 easily. And with the P-47 better at ground attack and the P-51 better at air-to-air, why pay extra to get worse.


An aside, when comparing power don't forget the Merlin 60series gets around 200hp equivalent at high speeds from exhaust thrust.

Another question though, what assumptions were made in the Merlin P-38 paper exercise as far as propellers were concerned. It seems to me you need more prop.


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## drgondog (Jul 18, 2019)

MIflyer said:


> Actually, I quoted those V-1710 and Merlin figures to Warren Bodie back around 1992 and he replied that he had a copy of the Lockheed analyses that showed putting two stage Merlins in the P-38 would have been a good idea.
> 
> *I don't have access to Lockheed analysis. That said there is a world of difference between "good idea" and actually redesigning the P-38 wing and booms to accommodate a Merlin 61. Just considering the difference between Cooling/Aftercooling radiator required for the 1650-3 from the Allison V-1710-39 and -81 for the Allison Mustangs leads to approximately 50% more radiator system and must consider placement of carb updraft plenum as well as radiator and oil cooler in the P-38 boom. If the turbo system is removed aft of the engine what does a radiator/aftercooling matrix look like to get the volume of cooling fins in the matrix and what config intake scoop? Place somewhere in front and co-exist with carb updraft system for the Merlin? Place aft of the engine (Mustang type), place dual radiators imbedded in the wings w/o interfering with 55 gal LE tanks?*
> 
> ...



Although fumbling and bumbling was evident in Material Command thinking in summer 1943 (like some knucklehead moving an order for 1000 spare 1650-1s for FY 1944 P-40L at the sacrifice of 1650-3 deliveries), AAF finally stated that Packard's 1st Priority was to deliver to the NAA demand for the P-51B/C/D. Packard Never met the actual demand as required until the very end of the war. Prior to that time RAF by agreement was to receive 50% of Packard output - which was easily met for the 1650-1/Merlin XX/28 but never for the 1650-3/-7.

Col Cass Hough, Chief of VIII ATS in 1944, pulled two P-38Js in March/1944 and issued orders to have them modified for the Merlin - but was firmly denied permission to execute the conversion. That was the last gasp for the mythical Merlin P-38.

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## MIflyer (Jul 18, 2019)

Lt Col Ward Duncan (9th PHOTO RECON SQUADRON) responded to my bringing up the idea of the Merlins replacing the Allisons with a description of all kinds of things that would have to be changed, just as described above. And perhaps the most important aspect would have been that to use Merlins would have required two different engines for the P-38 (as it did the P-82). V-1710's could be switched from right to left hand prop rotation by changing a single gear, and since the Allisons could have the gearcase removed, that could even be done in the field. For the V-1650-3 half the engines would be unique to P-38's or P-82's (all 20 of them). No doubt it would have been a harder job than on the P-40 or Mustang.

Here is a scan of Warren Bodie's letter to me:

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## pbehn (Jul 18, 2019)

MIflyer said:


> And perhaps the most important aspect would have been that to use Merlins would have required two different engines for the P-38 (as it did the P-82). V-1710's could be switched from right to left hand prop rotation by changing a single gear, and since the Allisons could have the gearcase removed, that could even be done in the field. For the V-1650-3 half the engines would be unique to P-38's or P-82's (all 20 of them). No doubt it would have been a harder job than on the P-40 or Mustang.


The Hornet had "handed" Merlins, this was achieved with an idler gear in the reduction casing.


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## wuzak (Jul 18, 2019)

pbehn said:


> The Hornet had "handed" Merlins, this was achieved with an idler gear in the reduction casing.



Not only that, Spitfire VIIIs and XIVs were trialled with contra-props in early 1944.

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## Kevin J (Jul 18, 2019)

drgondog said:


> Although fumbling and bumbling was evident in Material Command thinking in summer 1943 (like some knucklehead moving an order for 1000 spare 1650-1s for FY 1944 P-40L at the sacrifice of 1650-3 deliveries), AAF finally stated that Packard's 1st Priority was to deliver to the NAA demand for the P-51B/C/D. Packard Never met the actual demand as required until the very end of the war. Prior to that time RAF by agreement was to receive 50% of Packard output - which was easily met for the 1650-1/Merlin XX/28 but never for the 1650-3/-7.
> 
> Col Cass Hough, Chief of VIII ATS in 1944, pulled two P-38Js in March/1944 and issued orders to have them modified for the Merlin - but was firmly denied permission to execute the conversion. That was the last gasp for the mythical Merlin P-38.



I imagine something like 15,000 Packard produced Merlins must have been produced for the Avro Lancaster B.3'.


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## fubar57 (Jul 18, 2019)

Whatever Happened To The P-38K ?


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## wuzak (Jul 19, 2019)

fubar57 said:


> Whatever Happened To The P-38K ?



" At 40,000 feet, the "K" zipped along at a speed that was 40 mph faster than the current production P-38J could attain at this same height. "

Would that have caused a compressibility problem?


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## Kevin J (Jul 19, 2019)

wuzak said:


> " At 40,000 feet, the "K" zipped along at a speed that was 40 mph faster than the current production P-38J could attain at this same height. "
> 
> Would that have caused a compressibility problem?



Don't believe so. It's more of a cost problem. You can get 2 Mustangs for the same price and they fly farther. What benefit do you get out of changing the production lines? Losing production!


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## drgondog (Jul 19, 2019)

MIflyer said:


> Lt Col Ward Duncan (9th PHOTO RECON SQUADRON) responded to my bringing up the idea of the Merlins replacing the Allisons with a description of all kinds of things that would have to be changed, just as described above. And perhaps the most important aspect would have been that to use Merlins would have required two different engines for the P-38 (as it did the P-82). V-1710's could be switched from right to left hand prop rotation by changing a single gear, and since the Allisons could have the gearcase removed, that could even be done in the field. For the V-1650-3 half the engines would be unique to P-38's or P-82's (all 20 of them). No doubt it would have been a harder job than on the P-40 or Mustang.
> 
> Here is a scan of Warren Bodie's letter to me:
> 
> View attachment 545071


Interesting - I thought I had some traction with Ms LeVier in doing his bio in 2005-2006 timeframe, had arranged a trip to meet with her but was apparently shut down by her new male companion/husband?

I once engaged in correspondence with Bodie during research on a project I never finished due to lack of reliable data and reports. At one time (1990timeframe) I envisioned a Performance comparison between the F4U-1, P-51B-1, P-47D-16 and P-38J-10/-15 for escort requirements in ETO. At that time I was seeking complete Drag build ups for each airframe - but only the NAA data was complete enough. Bodie never responded to the request and my attempts to get the source data from Lockheed were never successful.

Candidly, I doubt that any reports/data on the other airframes outside the 1943-1946 NACA Drag studies for full scale tests will ever be available and consolidated. 

I respect Bodie, but his perspectives and apologies for the failures of the ETO P-38 (results to expectations) tainted an objective perspective that he could never quite overcome. Additionally, he took Kelsey's narratives to him (WRT Mustang sponsorship) at face value and never presented Kelsey animosity toward NAA as a fighter design contender in the 1938 through 1941 timeframe - or his lukewarm support for the Mustang (post XP-51 flight test at Wright) in Jan -1942. I attribute Kelsey attitude in that timeframe to his subordinate relationship to Echols - who undisputedly opposed NAA/Mustang entry into AAF inventory, then opposed Merlin allocation priority until over ridden by various folks in Plans and ultimately by Arnold himself in fall 1942 and again in summer 1943. By that time Kelsey had escaped from Material Command to Operations and may have changed his opinions at that time.

If you read this narrative from Wikipedia you need to need to hold your nose - If Kelsey had any finger on 'ordering Mustangs while Chief, Pursuit at Material Command, it was because his boss (Echols) was crushed into submission by General Muir Fairchild Chief Requirements - Plan Division AAF HQ in March 1942 to force Echols (and Mat'l Div) to place the order for the A-36. The '150 Mustang' order referenced by Wiki for 1941 was by the BPC for the Mustang IA. After the A-36 was rammed down Echols throat, he attempted to limit the A-36/(and P-51A discussions) to a max of 500 the force NAA to kill the Mustang line and convert to B-25s.

Kelsey was more influential while assigned to IX AF - but he had no direct oversight to the IX AF Engineering office until November 1944 and certainly not 'leading' design improvement recommendations for the Mustang. Enough - we should all value his service. Echols? not so much - he was a vindictive autocrat while leading Material Div until everyone in ETO noticed that insufficient testing (responsibility of MD) was leading to long delays in mod centers to ready the P-47C/D for combat and Flight testing was yanked from MD and replaced by Eglin Field group. Echols continued to champion the XP-75 turkey even after detailed criticism by Bradley proved it would never work in combat. 

Benjamin S. Kelsey - Wikipedia

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## MIflyer (Jul 19, 2019)

By the way, relative to Mr. Bodie's remarks on the dispersion problems with fuel in the Allison manifolds, that seems to be a problem mainly limited to the J and L models. The liquid cooled intercooler/aftercooler used on the Merlin 60 series had the immense advantage of having easy temperature regulation via a simple thermostat as used in automobiles. The air cooled chin intercooler used on the P-38J and L had no temperature regulation at all, and at high altitudes the fuel condensed into a liquid , with disastrous consequences. At the 9th Photo Recon in India they solved this problem by blocking off part the exit area of the intercooler cooling air flow with aluminum blocks. The photo recon mission focused on long range high altitude flights and not much in the way of jockying around with the throttle, so they could figure out the right amount of airflow and just set it that way. At least some J and L models were equipped with cowl flaps to enable the pilot to make adjustments - as if the P-38 pilots did not have enough buttons, knobs, and switches to fiddle with.

As for the "British fuels were a problem" my friend Ward Duncan said they used fuels from the same sources in India and had no problems relative to that. Not all fuels used in England were made there.

Finally Warren Bodie mentions problems with Champion spark plugs. Not long ago I was surprised to find out that the V-1650 in the Mustangs required special spark plugs, something they found out the hard way. One pilot even described having his engine quit while on an early mission over France because the standard spark plugs failed.


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## drgondog (Jul 19, 2019)

wuzak said:


> " At 40,000 feet, the "K" zipped along at a speed that was 40 mph faster than the current production P-38J could attain at this same height. "
> 
> Would that have caused a compressibility problem?



The Only flight test comparison between the single K (differing from J with different prop and gearing) was with the K at 600 pounds under combat load and J at combat load. It was slightly faster at 25K but both in the 420-425 TAS range. No results posted for higher altitudes and no reason to suspect any significant difference w/same engine/turbo just to the prop/gear ratio change.

The only time a 440mph posting for the late model J/L was made was from Lockheed marketing. Flight test results are missing .

At 30K 440mph = 0.65M well into compressibility and high total Drag rise for the P-38. With 1475 BHP in fully functional cooling/turbo system it might have been possible - but not with the K as described in the 2/44 flight test.


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## Peter Gunn (Jul 19, 2019)

So, pardon my ignorance, but what ever happened to Echols? I hope he ate a metric sh!t ton of crow after the Mustang got it's glorious career off the ground so to speak.

*EDIT* Just read Echols' bio on wikipedia, I see what you mean, couldn't get through all of it and no mention of his attempts to kill of the Mustang I see.


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## wuzak (Jul 19, 2019)

drgondog said:


> The Only flight test comparison between the single K (differing from J with different prop and gearing) was with the K at 600 pounds under combat load and J at combat load. It was slightly faster at 25K but both in the 420-425 TAS range. No results posted for higher altitudes and no reason to suspect any significant difference w/same engine/turbo just to the prop/gear ratio change.
> 
> The only time a 440mph posting for the late model J/L was made was from Lockheed marketing. Flight test results are missing .
> 
> At 30K 440mph = 0.65M well into compressibility and high total Drag rise for the P-38. With 1475 BHP in fully functional cooling/turbo system it might have been possible - but not with the K as described in the 2/44 flight test.



Do you have, or have you seen, the "2/44" flight test?

I was looking to see what the P-38J could do at 40,000ft, and it appears to be around 300mph TAS. If the P-38K was 40mph faster at 40,000ft that would put it at around 340mph TAS. Was wondering if that would be in the compressibility range?

It is also interesting to note that The P-38K was supposed to outperform existing types, but the Spitfire XIV and P-47D could both do about 400mph at 40,000ft. Maybe the P-51B could have too?

Regarding the change of gearing, wasn't that due to a larger propeller, not just a broader chord "high activity" unit? I would think that the "high activity" wouldn't require a change of gear ratio.

Looking quickly through Graham White, _R-2800, Pratt & Whitney's Dependable Masterpiece_, it would appear that all P-47Ds used the same reduction ratio on their R-2800s - before and after the "high activity" broad chord props were introduced.


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## MIflyer (Jul 19, 2019)

The profile is somewhat contradictory on the P-38K. It says the prototype K was a modified E and had -89 and -91 engines. But it also says that the K was not much of an improvement over the J and was not produced due to the scarcity of its -75 and -77 engines.

According to "Vees for Victory" the -75 and -77 engines had a 2.36:1 gear ratio between the prop and the crankshaft and had a Military Rating of 1425 hp at 3300 rpm at 54 in HG at 27,000 ft. Only 6 of -77 and 19 of - 75 were built

The -89 and -91 engines had the usual 2:00:1 gear ratio between the prop and the crankshaft and had a Military Rating of 1425 HP at 3000 RPM at an altitude of 24,500 ft. 

It seems that the -75 and -77 drove a prop that had wider blades at lower RPM. Now, would interfere with diving ability?


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## wuzak (Jul 19, 2019)

"Information in the author's hands indicates that the engine thrust line was one inch higher than the J"

That doesn't make sense to me. That means that Allison not only changed the gear ratio, they changed the reduction gear housing as well.


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## Shortround6 (Jul 19, 2019)

It was the change in the thrust line that supposedly put the cat among the pigeons. 

The gear teeth have to be certain size to handle the load and apparently they couldn't get the reduction ratio they wanted with a small pinion gear (or smaller than the standard gear/s) and a larger driven gear.
The K is supposed to have used larger diameter propellers and they wanted the reduction gear to keep the tip speed down. 
The Late P-39s used a 2.33 reduction gear and the P-63s used a 2.227 reduction gear.


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## MIflyer (Jul 20, 2019)

Yep! Recall that when they designed the C series engines they deliberately made the nose long to keep the shape sleek, on the P-40, B and C.. The higher power of the F series resulted in a new gearbox and a raised thrust line required as a result. Slowing the prop so to make it larger, broader, and more efficient raised the thrust line more.


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## drgondog (Jul 20, 2019)

Peter Gunn said:


> So, pardon my ignorance, but what ever happened to Echols? I hope he ate a metric sh!t ton of crow after the Mustang got it's glorious career off the ground so to speak.
> 
> *EDIT* Just read Echols' bio on wikipedia, I see what you mean, couldn't get through all of it and no mention of his attempts to kill of the Mustang I see.



Echols was 'promoted' to Chief Military Affairs and Asst Military Governor in Germany in 1945 and left AAF in 1946(?) to become President of AIA until he became President of Northrup.. possibly the first example of trading positions in the 'military industrial complex'. That said, my personal bone to pick with Echols was that he had a vindictive streak that clouded his otherwise excellent judgment. As I read between the lines in various autobiographies of Arnold and Spaatz, Arnold had a 'conversation' with Echols during the in-fighting between Material and Plans Division over the A-36 and P-51A in the spring 1942 - leading to capitulation on the Allison Mustang. He personally visited R-R during the tail end of development for the Mustang X along with a highly respected US Aerodynamicist (can't remember his name) to examine the Mustang Drag and Performance projections with the Merlin. By that time Arnold was 'involved' and issued orders that the P-51B be assigned very high priority.

His contributions to the War Production Board system of priorities and allocations were major - and eventually paid dividends to NAA when he personally approved the expansion of NAA production capacity and specialized tooling embedded in the NA-99 and NA-102 contracts as well as prioritizing tooling and Packard 1650-3/-7 production for the P-51B.

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## MIflyer (Jul 20, 2019)

Paul Kennedy's book, "Engineers of Victory" has a short section on the Merlin Mustang. I found it disappointing in that it did not mention Stanley Hooker's remarkable innovation of the two stage supercharger coupled with liquid cooled intercooler/aftercooler. I guess the book is "Engineers of Victory" rather than "Engineering That Brought Victory" in that it focuses more on the people than the actual technology. But his summary of the fight to get the Merlin Mustang built is pretty good.

He does repeat that old falsehood that the Allison Mustang was designed for low altitude, which was only true of the A-36. The Mustang MK1 had its best speed at around 15,000 ft and the P-51A at about 20,000 ft.

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## Shortround6 (Jul 20, 2019)

It is a nice story but some of the details don't hang together very well.

The Schweinfurt-Regensburg raid in October of 1943 (?) was not really a turning point in the P-51 story. Some sources claiming that 400 P-51Bs were ordered *Aug 26th 1942* and this order was had 1350 more aircraft added at a later date.
NAA Dallas receives and order for 1350 P-51Cs on Oct 8th 1942 (perhaps the extra 1350 aircraft mentioned above?)
Jan 1943 sees the US order over 2000 P-51Bs (or that is number on order?) in any case outstanding P-51A orders are to be completed as P_51Bs as of the Jan date. The June 1942 order for 1200 P-51As sees only 310 completed as P-51As and the rest are completed as P-51Bs.

To show how far ahead planing was compared to deliveries (or demands from combat theaters) On Feb 27th 1942 the 201st and 202nd P-51B-10s (months away from being actually built) are set aside as manufacturing prototypes for the P-51D model ( this over two months before the first production P-51B is delivered)

NAA gets a contract for 2500 P-51Ds on April 13th 1943, about 3 weeks before the first production P-51B flies, And this first production P-51B flew 2 days after another order for 2500 planes was placed with NAA Dallas (or modified an earlier order?) to comprise 400, P-51Cs, 800 P-51Ds and 1300 P-51Ks. Again months before even the Aug 1943 Schweinfurt-Regensburg raid let alone the October one.


The time it took for American aircraft to get from the factory door to combat seems to confuse many authors, The LAST A-36 left the factory in March of 1943, the FIRST combat mission by an A-36 was on June 6th 1943 for example. There was little or no "feedback loop" from combat reports to guide new versions of the Mustang. The XP-51D flying for the first time on Nov 17th 1943 which was several weeks before the first combat mission flown by P-51Bs in Europe. Any story that claims combat performance of the various P-51 versions influenced the design or equipment of later versions (except for the H? and the contract for the light weight P-51 program--XP-51F, G and J was signed July 20th 1943) should be viewed with at least some scepticism.

As for Packard and the Merlin story, most sources agree that the _initial_ contract was for 9000 engines and the British were to get 2/3rds. production was to reach 800 a month. Follow up contract details seem to be a bit thin. After struggling for a bit in early 1942 Packard ends up putting out the required 800 engines a month for five straight months in the 2nd half of 1942. Packard does deliver 850 Merlins in Dec of 1942 and 850 and 864 in Jan and Feb of 1943 respectively. Total production then drops for several months (result of tooling up for the two stage engine?). In any case Packard is producing over 1800 engines a month by the end of 1943 and peaks at 2.239 engines in June of 1944. (1114 of them are single stage engines for the British). Now in order to achieve such numbers Packard either needed divine intervention (on the order of immaculate conception) OR it needed the war production board to OK and release materials for plant expansion (concrete and structural steel) it needed more machine tools (always in tight supply) and it needed both additional labor and raw materials. You don't make 1800 crankshafts from 900 forged billets and steel supplies were controlled by the production board.

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## wuzak (Jul 21, 2019)

Shortround6 said:


> To show how far ahead planing was compared to deliveries (or demands from combat theaters) On *Feb 27th 1942* the 201st and 202nd P-51B-10s (months away from being actually built) are set aside as manufacturing prototypes for the P-51D model ( this over two months before the first production P-51B is delivered)



Feb 27th 1943?

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## Kevin J (Jul 21, 2019)

Shortround6 said:


> It is a nice story but some of the details don't hang together very well.
> 
> The Schweinfurt-Regensburg raid in October of 1943 (?) was not really a turning point in the P-51 story. Some sources claiming that 400 P-51Bs were ordered *Aug 26th 1942* and this order was had 1350 more aircraft added at a later date.
> NAA Dallas receives and order for 1350 P-51Cs on Oct 8th 1942 (perhaps the extra 1350 aircraft mentioned above?)
> ...


I think you need to check some of those dates (years) and re edit. Otherwise, good.


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## Snowygrouch (Jul 21, 2019)

MIflyer said:


> Paul Kennedy's book, "Engineers of Victory" has a short section on the Merlin Mustang. I found it disappointing in that it did not mention Stanley Hooker's remarkable innovation of the two stage supercharger coupled with liquid cooled intercooler/aftercooler. I guess the book is "Engineers of Victory" rather than "Engineering That Brought Victory" in that it focuses more on the people than the actual technology. But his summary of the fight to get the Merlin Mustang built is pretty good.
> 
> He does repeat that old falsehood that the Allison Mustang was designed for low altitude, which was only true of the A-36. The Mustang MK1 had its best speed at around 15,000 ft and the P-51A at about 20,000 ft.



With respect to that book, it might be useful to know from a veracity perspective what those references in the text "point" to (#43>#51), are they primary sources, (e.g. papers from Rolls-Royce, or Freemans letters) or are they just referencing other peoples books ? - not that there appears to be any actual gross errors, but it would be interesting to know hows its been referenced.


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## drgondog (Jul 21, 2019)

MIflyer said:


> Paul Kennedy's book, "Engineers of Victory" has a short section on the Merlin Mustang. I found it disappointing in that it did not mention Stanley Hooker's remarkable innovation of the two stage supercharger coupled with liquid cooled intercooler/aftercooler. I guess the book is "Engineers of Victory" rather than "Engineering That Brought Victory" in that it focuses more on the people than the actual technology. But his summary of the fight to get the Merlin Mustang built is pretty good.
> 
> He does repeat that old falsehood that the Allison Mustang was designed for low altitude, which was only true of the A-36. The Mustang MK1 had its best speed at around 15,000 ft and the P-51A at about 20,000 ft.
> 
> ...


This is a very good article that misses only on a few key points:

The spring of 1942 was momentous for the P-51:
The Army Close Air Support acolytes were the internal 'force', coupled with Plans Division, to drive the acquisition of the Low Altitude Pursuit (A-36) which had been under design development since Nov 1941. In parallel, Eaker, then Arnold and Spaatz visited NAA and came away impressed with the P-51 and reports from 'the field' from fighter pilots of the 20th Wing that "the Mustang was a better airplane than the P-39/40/38" as well as Kelsey flying and respecting the airplane in Jan 1942. Arnold was under pressure from 'Lovett" to create a close air support capability to rival the Luftwaffe late in 1940.

The major attributes (save the internal fuel fuselage tank) were introduced by the A-36 ---- Wing racks, internal plumbing for external fuel tanks.

General Schlatter who had Air Defense Directorate was also THE decision maker for ALLOCATIONS and assignment of US based fighters. Close friend of Echols and a P-38 bigot. Echols had a very strong 'relationship' with Burdette Wright and gave Curtiss every chance to become next generation Pursuit (XP-46 and XP-60) when the Mustang emerged from NAA. Echols' push on NAA to build P-40s was to unlock Curtiss manufacturing for the P-46. The single biggest factor of Echols' animosity toward NAA was that Kindelberger defied him. All that said, the Mustang CAS survived via the A-36 and The P-51A was the next gen CAS fighter - which a.) stripped dive bombing requirements, and b.) stipulated that the P-51A contract could be converted to P-51B Merlin powered. One of the key doctrines of CAS in 1942 was that the "pursuit" so allocated also be cable of air superiority over the battlefield (hence, exit A-24/25 and 32). THIS is how the P-51B was planned for IX AF/Invasion and 12th AF MTO campaigns to replace P-39 and P-40. Remember the 354th and 363rd and 357th were training in P-39s in 1943 destined for IX AF. The XP-51B design went full throttle in May 1943 and prevented from flying first due to reliability struggles with the 1650-3 in summer through Fall 1942.

Arnold takes personal responsibility for not getting the P-51B into operations much sooner, but a.) he did meet with Freeman, Winant and Hitchcock in London in May 1942 to discuss the Merlin Mustang - acknowledging that they didn't seem fully knowledgeable about the project. Hitchcock was key in the fall of 1942 to break through to Arnold the necessity of bringing the Mustang in production - BUT there is evidence in correspondence at Material Command that 'the boss wanted the Mustang) in July 1942. This was critical as the Merlin 61/1650-3 was allocated to NAA for NA-101 project in July 1942. IMO Arnold's only true relationship with the delay of the P-51B was not realizing that Schlatter had dedicated all Mustangs to CAS roles (MTO, ETO, CBI) which he had to fix in fall of 1943.

The drag attributes of design with second and third order curves gave the best possible lowest change to velocity gradient for the fuselage, the NACA 45-100 gave the Mustang the same drag attributes of the Spit despite a much fatter wing giving the P-51 greater internal space for fuel and armament, but the cooling system design enabled high speed Hp recovery over Spit and Hurricane schemes.

The disastrous Blitz Week late July 1943 was a key factor in that it drove Arnold to over ride Schlatter for the assignment of Mustangs as 'ground support. Concurrent with Blitz Week, NAA had already been pushed by Barney Giles (as well as Lockheed and Republic) to increase internal fuel - and flew the first 'prototype 90 gallon SS fuse tank' in July - well in advance of the P-38J and P-47D-25. Arnold's former boss Genneral Delos Emmons and Asst War Lovett were doing an inspection tour of 8th and 9th and, along with Eaker put out the plea for the P-51B and P-38. Arnold complied and beginning Aug 1942 all new P-38 groups activated were assigned to 8th AF. The battle for re-assignment of the P-51B was intense between Spaatz and Leigh-Mallory and finally resolved by temporary subordination of 354/357 and 363 to operate with 8th AF (during November through January timeframe) until late May - to then transfer back to 2TAC control. By all accounts (Doolittle, Spaatz, Arnold), dealing with Leigh-Mallory was a nightmare.

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## Snowygrouch (Jul 21, 2019)

drgondog said:


> By all accounts (Doolittle, Spaatz, Arnold), dealing with Leigh-Mallory was a nightmare.



That was also the opinion of German intelligence.... who`s dossier on British air staff includes a paragraph on him. It doesnt say anything very nice,
annoyingly I cant find the document right now on my PC to give you a quote... but most of the information in their Dossier came from interrogations of downed british airmen - so its contents are proably a pretty good reflection of general pilot sentiment.

(I would point out that the same document heaps praise on Keith Park.... so its not as if all the downed pilots were just taking the chance to spout off about "management")

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## MIflyer (Jul 21, 2019)

After being "fired" and replaced with Leigh-Mallory as a reward for winning the BoB, Park went to the Med where he put in another excellent, war-winning performance. Meanwhile, Leigh-Mallory seemed to be focused on putting large unwieldy formations of Spitfires over France, where the Germans sniped at them at leisure.

And as for the paper drop tanks, my understanding is that the 8th sent some to Wright Field to be evaluated, and then went ahead and used them successfully, while months later Wright Field reported they were unsuitable; this was ignored. However, as I understand it now the 50 gal metal drop tanks were still used on missions that did not require the range. I suppose the metal ones had the considerable maintenance advantage of not having to be defueled and thrown away if the mission was scrubbed or delayed.
I'll post the applicable notes from the book but it appears Kennedy is not relying on primary sources but on other books, although an admittedly impressive list, mostly publications I have never seen.

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## drgondog (Jul 21, 2019)

MIflyer said:


> After being "fired" and replaced with Leigh-Mallory as a reward for winning the BoB, Park went to the Med where he put in another excellent, war-winning performance. Meanwhile, Leigh-Mallory seemed to be focused on putting large unwieldy formations of Spitfires over France, where the Germans sniped at them at leisure.
> 
> And as for the paper drop tanks, my understanding is that the 8th sent some to Wright Field to be evaluated, and then went ahead and used them successfully, while months later Wright Field reported they were unsuitable; this was ignored. However, as I understand it now the 50 gal metal drop tanks were still used on missions that did not require the range. I suppose the metal ones had the considerable maintenance advantage of not having to be defueled and thrown away if the mission was scrubbed or delayed.
> I'll post the applicable notes from the book but it appears Kennedy is not relying on primary sources but on other books, although an admittedly impressive list, mostly publications I have never seen.
> ...


The most single comprehensive reference (not mentioned) is USAF Study 136 - Boylon. Ludwig (and I) drew heavily to address Material Command, AAC/AAF-HQ palace intrigue as well as the evolution of AAC/AAC doctrine of Air War Plans 1 &2.


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## MIflyer (Jul 22, 2019)

By the way, while I recognize what is required in the way of advanced planning and logistics for new systems - I was in both Log Command and Systems command as well as in Acquisition at the Pentagon - the disastrous losses of the Back Thursday and Munster raids in Oct 1943 certainly did influence the use of the Merlin Mustang for bomber escort.

Remember, the Merlin Mustang was ONLY going to the 9th Air Force, for tactical use. The new Mustang Pioneer Group of the 9th came over to the ETO in late 1943. The only reason the 8th got Mustangs is that Don Blakeslee went to the Pioneer Group and led them on their first missions. Then he came back to the 4th Ftr Group and made his famous pledge to Gen Kepner, "I'll have them in combat in 24 hours" and then told his pilots, "You can learn to fly them on the way to the target."

And learn to fly them they did, but there were teething problems. On the first Mustang bomber escort to Berlin on 4 March 1944 only 8 Mustangs made it to the target area. But they came right back on the 6th.

The RAF started using the Mustang III for tactical fighter bomber work in Feb 1944, not for long range escort..


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## Conslaw (Jul 22, 2019)

MIflyer said:


> By the way, while I recognize what is required in the way of advanced planning and logistics for new systems - I was in both Log Command and Systems command as well as in Acquisition at the Pentagon - the disastrous losses of the Back Thursday and Munster raids in Oct 1943 certainly did influence the use of the Merlin Mustang for bomber escort.
> 
> Remember, the Merlin Mustang was ONLY going to the 9th Air Force, for tactical use. The new Mustang Pioneer Group of the 9th came over to the ETO in late 1943. The only reason the 8th got Mustangs is that Don Blakeslee went to the Pioneer Group and led them on their first missions. Then he came back to the 4th Ftr Group and made his famous pledge to Gen Kepner, "I'll have them in combat in 24 hours" and then told his pilots, "You can learn to fly them on the way to the target."
> 
> ...



Are you sure the RAF started using the Mustang 3 in Feb 1943? Joe Baugher says Feb 1944, after having received them in December 1943. Quoting Baugher:

"The first RAF base to receive Mustang IIIs was at Gravesend in Kent. The Mustang III initially equipped No. 65 Squadron in late December of 1943, followed by No. 19 Squadron in March of 1944. Later the Mk. III also equipped Nos 64, 65, 66, 93, 94, 112, 118, 122, 126, 129, 165, 234, 237, 241 249, 250, 260, 268, 306, 309, 315, 316, 345, 430, 441, 442, and 516 Squadrons and No. 541 Squadron of RAF Coastal Command. These units included four Polish squadrons (306, 309, 315, 316), three RCAF, and one Free French.

The new RAF Mustang IIIs began operations late in February 1944, escorting US heavy bombers as well as both US and RAF medium bombers."

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## wuzak (Jul 22, 2019)

Conslaw said:


> Are you sure the RAF started using the Mustang 3 in Feb 1943? Joe Baugher says Feb 1944, after having received them in December 1943.



I don't believe the P-51B/Mustang III was in production in February 1943, or at least none had been completed.

So I think he has made a typo, the date supposed to be 1944.


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## Snowygrouch (Jul 22, 2019)

wuzak said:


> I don't believe the P-51B/Mustang III was in production in February 1943, or at least none had been completed.
> 
> So I think he has made a typo, the date supposed to be 1944.



The British AFDU report on the Mustang III was dated March 1944, with the request for the trials to be done being dated 28th December 1943.

Everything online just references Baugher, so looking at the actual 65 Squadron records for Dec 1943 the following is recorded:

"*14th December 1943 - The squadron recieved notification that it was to be re-equipped with Mustang III aircraft, and a technical representative of North American Aviation Ltd called to see the Squadron Commander. Speculation was rife in the squadron as to the new role to be performaned with these long range aircraft. No.65 Squadron has been honored as the first squadron to be re-equipped with these new aircraft*"....

"*17th December 1943 - One manuscript copy of the pilots notes for the Mustang III aircraft was recived and eagerly perused by the pilots who were very interested in the new type of aircraft of the Squadeon and much discussion took place in the dispersal.*"

"*23rd December 1943 - A lecture on Mustang III aircraft was given to all pilots in the briefing room by Flt.Lt Yates of No.122 airfield, no operational flying was carried out*"

"*27th December 1943 - There was again no flying due to fog...the squadron pilots had been carrying out cockpit drill and re-arming practice with the Mustang aircraft, of which 9 have been recieved to date and all were taking every advantage of chances of becoming conversant with this type of aircraft. An American technical advisor had arrived on the airfield and he was questioned as to the performance etc. and gave the squadron as much information as possible*"

"*29th December 1943 - The first flights were made in the Mustang III aircraft*"

Note: Its c;ear from the record that NO actual operational combat sorties were carried out by 65 Squadron in 1943, just some familiarisation flights around the vicinity of the airfield.

Looking at the squadron records for Jan 1944.....

"*4th January 1944 - The Squadron became non-operational in order to concentrate on training flights in the Mustang III aircraft. Trouble was experienced in obtaining oxygen fittings and getting the aircraft servicable. Pilots did further cockpit dril*l"

"*6th January 1944 - One section carried out a scramble,...vectored to 3 enemy aircraft following a mosquito home - the Mosquito was seen but there was no sign of the e/a. Eight Spitfire aircraft were ferried to Detling on being withdrawn.*"

From the aircraft log numbers on the squadron record for Jan 1944 - it appers that even in Jan 1944, no actual combat sorties were flown in the Mustang III, I dont have the Feb squadron logbook, but I would make a guess that in terms of actual OPERATIONS, the Mustang III in Britain almost certainly didnt become combat active until at least Feb 1944, so Baugher probably actually has bothered to read the log-book, or at least read something by someone who DID ! 

e.g. on 14th Jan the following planes flew, and all the plane log #s flown before 14th in 65 Squadron had Spit IX serials. (annoyingly the Jan logbook for plane serials ends at 14th Jan).

MH 851 (a Spitfire IX) - flown by R. J. C. Grant
MH 908 (a Spitfire IX) - R.L. Stillwell
MH 388 (a Spitfire IX) - R. F. Waterman
MH 378 (a Spitfire IX) - R. T. Williams
MH 824 (a Spitfire IX) - K. Gillham

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## MIflyer (Jul 22, 2019)

Of course I meant to type Feb 44. I realized that later but I've been too busy to come back and correct it.


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## Peter Gunn (Jul 23, 2019)

MIflyer said:


> Of course I meant to type Feb 44. I realized that later but I've been too busy to come back and correct it.



I'm not sure I can countenance such a terrible error when talking about the Mustang...

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## drgondog (Jul 23, 2019)

MIflyer said:


> By the way, while I recognize what is required in the way of advanced planning and logistics for new systems - I was in both Log Command and Systems command as well as in Acquisition at the Pentagon - the disastrous losses of the Back Thursday and Munster raids in Oct 1943 certainly did influence the use of the Merlin Mustang for bomber escort.
> 
> *The 'clarion call' from multiple high level sources for the Merlin Mustang began in July 1943 and orchestrated between Emmons, Eaker and Lovett following the heavy losses during Blitz Week. *
> 
> ...



*Perhaps a few fine points. First Portal agreed to delegate Mustang III to support 8th AF escort in his meetings and cables with Arnold in September 1943. Portal further ordered Leigh-Mallory to assign the 2TAF Mustang III to support the 8th through May 1944. He also initiated the transfere of the early P-51B-5-NAs to the 8th AF in December. As a note, RAF 2TAF (Mustang III) flew several intermediate range escort missions (no 85 gallon fuse tank) from February when they received an allocation of new Mustang III to replace the loaners of December. All control of RAF and 9th AF Mustangs reverted back to them from the 8th at the end of May.*

*As to the March 4th Berlin Mission. The March 3rd was more notable. The 363rd made the first victory credit on 3-3-44 north/ne of Berlin (over Grabow) and in fact were the first US fighters over Berlin. The 354th also scored near Wittenberg and some flights escorted their bombers around Berlin and toward home, breaking escort SW of Berlin. The 8th AF cited the 55th FG P-38s as the 'first' but the 8th AF had better Public Relations arm than the 9th AF. The 4th FG engaged and was occupied near Wittenburg and to my knowledge did not catch up to their assigned boxes for Oranienburg, north of Berlin. *

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## drgondog (Jul 23, 2019)

Conslaw said:


> Are you sure the RAF started using the Mustang 3 in Feb 1943? Joe Baugher says Feb 1944, after having received them in December 1943. Quoting Baugher:
> 
> "The first RAF base to receive Mustang IIIs was at Gravesend in Kent. The Mustang III initially equipped No. 65 Squadron in late December of 1943, followed by No. 19 Squadron in March of 1944. Later the Mk. III also equipped Nos 64, 65, 66, 93, 94, 112, 118, 122, 126, 129, 165, 234, 237, 241 249, 250, 260, 268, 306, 309, 315, 316, 345, 430, 441, 442, and 516 Squadrons and No. 541 Squadron of RAF Coastal Command. These units included four Polish squadrons (306, 309, 315, 316), three RCAF, and one Free French.
> 
> The new RAF Mustang IIIs began operations late in February 1944, escorting US heavy bombers as well as both US and RAF medium bombers."



So many of the FX series Mustang III were dispatched by Portal/Arnold agreement to USAAF 9th AF 354th FG at the end of December - leaving a few behind for training/familiarization until a steady stream of P-51B/C arrived to replace the snatched RAF contingent of November/December 1943.


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## pbehn (Jul 23, 2019)

drgondog said:


> *Perhaps a few fine points. First Portal agreed to delegate Mustang III to support 8th AF escort in his meetings and cables with Arnold in September 1943. Portal further ordered Leigh-Mallory to assign the 2TAF Mustang III to support the 8th through May 1944. *


 It would have been completely extraordinary if Portal hadn't, orders are needed in the military to establish chains of command. Since the RAF had been providing Spitfires from the start refusing to allocate lease lend RAF Mustangs to US missions would take a special kind of madness.

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## MIflyer (Jul 23, 2019)

"I'm not sure I can countenance such a terrible error when talking about the Mustang... "

I was much too busy too fix it even when I realized it.

I was taking a nap.

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## MIflyer (Jul 23, 2019)

Something odd I read about the daylight heavy bomber raids the RAF conducted in the Cherborg area in support of the Normandy fighting. The Lancs were escorted by Spitfires until they got midway across the Channel and then escort was done by Mosquitoes, presumably FBVI. I've never heard of a Mossie being used for daylight escort before, other than perhaps for anti-shipping strikes. They had, for example, 65 Squadron, with Mustang III's and they seemed to operate in that area quite a bit anyway. .

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## Conslaw (Jul 25, 2019)

MIflyer said:


> Something odd I read about the daylight heavy bomber raids the RAF conducted in the Cherborg area in support of the Normandy fighting. The Lancs were escorted by Spitfires until they got midway across the Channel and then escort was done by Mosquitoes, presumably FBVI. I've never heard of a Mossie being used for daylight escort before, other than perhaps for anti-shipping strikes. They had, for example, 65 Squadron, with Mustang III's and they seemed to operate in that area quite a bit anyway. .



Sounds like a topic worthy of its own thread.


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## MIflyer (Jul 26, 2019)

Yes, has anyone ever heard of Mossies being used for daylight escort, except for shipping strikes, where they were unlikely to encounter single engined fighters?

The DH98 was a wonder plane and no other equaled it in its versatility, but one on one against a single engined fighter it was not in the position to run away from, I don't think it had much of a chance. One of the RAF's top night fighter pilots was shot down by an FW-190 in daylight.


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## pbehn (Jul 26, 2019)

MIflyer said:


> Yes, has anyone ever heard of Mossies being used for daylight escort, except for shipping strikes, where they were unlikely to encounter single engined fighters?
> 
> The DH98 was a wonder plane and no other equaled it in its versatility, but one on one against a single engined fighter it was not in the position to run away from, I don't think it had much of a chance. One of the RAF's top night fighter pilots was shot down by an FW-190 in daylight.


There are cases but really exceptions that prove rules. Whatever you are in 4 x 20mm cannon and 4 MGs all firing on the same axis could spoil anyone's day. I read of one mosquito bomber evading a fw190 at altitude by a shallow dive. At high speed the mosquito had enough control to stop the FW getting a shot. If you have a 30MPH advantage and the enemy is 30 miles away it takes an hour to catch them. I don't know about an FW190 but a Spitfire couldn't run for 1 hr on full throttle.


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## Milosh (Jul 26, 2019)

One had a different mind set if one flew day or night.


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## pbehn (Jul 26, 2019)

MIflyer said:


> One of the RAF's top night fighter pilots was shot down by an FW-190 in daylight.


Is that John Braham?


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## MIflyer (Jul 26, 2019)

Yes, I believe it was Braham. And note that night fighters and intruders flew alone while day fighters almost never went out without a wingman. Two Mossies would have radically changed the equation for fighting an FW-190, but he was out doing a single plane attack. Despite all his combat time he would have had limited experience in using a combat formation. 

"Screwball" Beurling was the type that liked going out by himself in daylight, but on Malta that probably was a necessity in many cases.


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## MIflyer (Jul 27, 2019)

"Whatever you are in 4 x 20mm cannon and 4 MGs all firing on the same axis could spoil anyone's day ." 

Now there's a thought! Flying heavy bomber escort in a B-25H. Sounds better than the B-40, anyway.

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