# WW2 without V-1710: options for the Allies?



## tomo pauk (Aug 22, 2013)

The never much liked (in some 'camps') Allison V-1710 powered many US-built fighters, flying in all the war theaters, especially until sufficient number of the Thunderbolts and Merlin Mustangs were in service. So let's say, for the sake of discussion, that somehow people at Allison really messed up their machine, so the USAF Allies must acquire it's fighters without it. What would be the best alternatives, ie. historical engines set-ups, for the USA/USAF in order to produce/purchase it's fighters both in quality and quantity, until the P-47C and P-51B arrive to the scene.

I'd kindly ask the Mods to please leave the thread in the 'Aviation' sub-forum.


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## GregP (Aug 22, 2013)

The early Allisons up through the mid models were mostly 1,000 - 1,200 HP. If the Allison wasn't an option, we'd be left with the radials or alternative engines. The Wright R-1820 and Pratt R-1830 come to mind immediately.

Likely as not the fighters so-powered would climb slightly better and be slightly slower, but they'd do just fine. The P-51 may never have been born, but the P-40 had radial-powered predecessors. Either Chrysler or Lycoming (or SOMEONE) would have had to come up with an alternate engine or the P-38 and P-39 likely would not have wound up looking much like they did in real life.


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## Glider (Aug 22, 2013)

Dare I say License built Merlin?


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## GregP (Aug 22, 2013)

I don't believe anyone thought of that until both sides wanted to try a Merlin in the P-51. If the P-51 had not come along, I'm not sure anyone would have pursued the license agreement.

Maybe, but maybe not, too.

The USA would not have considered a foreign engine for newly-designed US fighters at the time. It wasn't in the political cards. The only reason it was acceptable for the P-51 is the plane was designed to a British request to start with. If it had come from the USAAF, there very probably would never have been a Merlin engined P-51.

Things back then weren't like they are today, and USAAF / USN planes were all-American items with not a single foreign-produced component.

Of course, we weren't alone there. You didn't see any foreign parts on Spitfires, Hurricanes, Bf 109's Fw 19's, or A6M's either, did you? The only reason the British used some US-made engines and aircraft / components was the necessity dictated by war. Otherwise, fighters were symbols of national pride. May seem strange, but that's the way is was for many centuries, not just during WWI and WWII.

The only reason the Japanese bought some capital ships between WWI and WWII from the UK is they hadn't the skills or equipment yet to build their own. By the time WWII came around, they WERE building their own, including big guns.


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## davebender (Aug 22, 2013)

I second the motion.

The best engine solution was staring U.S. Army Air Corps in the face. Just need to be smart enough to recognize it.


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## GregP (Aug 22, 2013)

In hindsight I'd say you guys were right. 

But without the P-51 issue, it probably never WOULD have. The system and the various military services just didn't work like today in 1941.


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## Shortround6 (Aug 22, 2013)

The Licence agreement had nothing to do with the Mustang. The first 3000 (or so) US engines ( out of a total of 9000 engins) were the Merlin XX equivalent and were contracted for in the summer of 1940. Before the 2 stage engine was really viable. Approximately 2250 P-40s were built with Merlin engines. 

I think it depends on _when_ Allison stuffs it up in this scenario. Late 38/early 39? Only prototypes of the P-38-39-40 built so it is easy to build radial engine fighters? Late 39/early 40? P-39 is toast but P-40s can be built as P-36s with better engines. P-38s with turbo R-1830s? Start talking with Rolls-Royce sooner?


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## gjs238 (Aug 22, 2013)

Ford GAA engine - Wikipedia, the free encyclopedia
Maybe the Ford GAA engine would have been developed for aircraft.


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## wuzak (Aug 22, 2013)

GregP said:


> I don't believe anyone thought of that until both sides wanted to try a Merlin in the P-51. If the P-51 had not come along, I'm not sure anyone would have pursued the license agreement.



The Packard licence agreement was made to supply the British with Merlins. Part of the deal was that a proportion (1/3?) of production go to the US.


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## wuzak (Aug 22, 2013)

Maybe someone would have lit a fire under Continental to get the IV-1430 to production and in airframes.


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## Shortround6 (Aug 22, 2013)

The Ford GAA engine was developed _FROM_ a Ford V-12 aircraft engine that Ford spent over a year working on _AFTER_ they had the blueprints for the Merlin in their hands for several weeks and a sample engine. The Ford does have a number of differences from the Merlin but Ford was essentially starting from scratch in the late summer of 1940 in designing this engine so it would be available _when_ even if everything went right? 
Fastest "new" engine program in the US was 2 1/4 years for the Wright R-2600 from start of design to 5th engine accepted. Granted that was peace time. It took Packard 1 1/4 years to turn out their 5th Merlin. Most other new engine "radial programs went about 3 years. Allison took 10 years ( not quite accurate) but that was because of a lack of funding.


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## GregP (Aug 22, 2013)

Shortround, you and I both know those engines were never slated for front-line USAAF or USN aircraft. They were for the *British*. If it weren't for the P-51, I doubt the Merlin would have seen the inside of ANY US fighter.

If you doubt that, name me any mass-produced US fighter with a Merlin.

There were none before the P-51B/C that first flew in Nov 1942, a few P-40 F's and L's (2,280 of them ... 15 - 16% of the total, didn't come into service until 1943, well after the P-51B/C had proven the merit of the change), and maybe 1 or 2 in Curtiss XP-60 prototypes. Otherwise, no Merlins for the USAAF. If it weren't for the success with the P-51B, we might never have seen a P-40F or L or, in fact, any Merlins for the USAAF / USN.

We might HAVE, certainly ... especially if the Allison were a non-starter, but the political reality of the time says otherwise to me.


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## Shortround6 (Aug 22, 2013)

wuzak said:


> Maybe someone would have lit a fire under Continental to get the IV-1430 to production and in airframes.



That might have been the best thing that could have happened to the German Air Force. 

The Few airframes that saw it wished they didn't. The few samples that were deemed "air worthy" never came close to making rated power. A rash of accidents plagued the prototypes that tried to fly with it.

Please note that the Wiki article seems a bit biased and has a number of mistakes/inaccuracies.


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## Shortround6 (Aug 22, 2013)

GregP said:


> Shortround, you and I both know those engines were never slated for front-line USAAF or USN aircraft. They were for the *British*. If it weren't for the P-51, I doubt the Merlin would have seen the inside of ANY US fighter.



You may know it but the rest of the world doesn't seem to. The Original contract called for 9000 Merlin engines, equivelent to the MK XX. 1/3 of the production was to go to the US. Now maybe the P-40 wasn't a first line aircraft. But it freed up Allisons for P-38s and P-39s. 



GregP said:


> If you doubt that, name me any mass-produced US fighter with a Merlin.


 well, you answered yourself with the P-40 unless you consider over 2,000 planes NOT mass produced. We certainly built other models of fighters in smaller quantities with certain engine models. 



GregP said:


> There were none before the P-51B/C that first flew in Nov 1942, a few P-40 F's and L's (2,280 of them ... 15 - 16% of the total, didn't come into service until 1943, well after the P-51B/C had proven the merit of the change), and maybe 1 or 2 in Curtiss XP-60 prototypes. Otherwise, no Merlins for the USAAF. If it weren't for the success with the P-51B, we might never have seen a P-40F or L or, in fact, any Merlins for the USAAF / USN.



You may want to check your sources. First prototype P-40F was the 2nd P-40D airframe and first flew in June of 1941. Production examples started being delivered in Jan of 1942, Production of the "F" was All done by the start of 1943. P-40Fs flying with the 57th fighter group claim their 20th Victory in Nov 1942 but I guess the US has to wait until the P-51B/C flies the same month to "prove the merit of the change" after almost 1300 (?) Merlin powered P-40s had been built.


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## wuzak (Aug 22, 2013)

GregP said:


> Shortround, you and I both know those engines were never slated for front-line USAAF or USN aircraft. They were for the *British*. If it weren't for the P-51, I doubt the Merlin would have seen the inside of ANY US fighter.



Any US fighter except for the P-40.

The deal for US production of the Merlin, made prior to the XP-51 flying, possibly before its inception, was that 1/3 of Packard production would go to US aircraft manufacturers. If they weren't to be used for "front line" aircraft, then what were they for?

Certainly the Merlin supply side of the contract was used as a stick against Allison - to lift production and lift performance.

And if the Allison was experiencing serious difficulties, the Merlin P-38 may have happened.


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## wuzak (Aug 22, 2013)

Shortround6 said:


> That might have been the best thing that could have happened to the German Air Force.
> 
> The Few airframes that saw it wished they didn't. The few samples that were deemed "air worthy" never came close to making rated power. A rash of accidents plagued the prototypes that tried to fly with it.
> 
> Please note that the Wiki article seems a bit biased and has a number of mistakes/inaccuracies.



Fair point.

I wonder if it could have been worked out better and more quickly had the Allison resources been used to help the program.

Not that the program lacked resources.


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## Shortround6 (Aug 22, 2013)

All three liquid cooled engine programs in the US lacked resources. There was no long term funding. The Army contracted for and paid for incremental steps. Like one engine ( if they were lucky) to pass a certain benchmark like a 1000hp test at X number of hours. Some contracts overlaped and some didn't. If an engine blew up or broke during the test the Army didn't pay. The company was responsible for repairing/replacing the test engine at their own expense if they wanted to continue and get paid.

Continental and Lycoming were actually in worse shape. While they were major engine manufacturers in their own right ( of car, bus, truck, marine and industrial engines) their Army contracts left them as little more than experimental shops building army designs. Lycoming was a bit better in that several Continental employees, ed with how things were going at Continental, jumped ship and went to Lycoming where Lycoming coughed up about 1/2 million of their own money to work on their version of the Army engine. Continental spent little, if any, of their own money and despite running a single cylinder test engine in 1932 a full 12 cylinder version wasn't assembled until 1939. The Army kept paying for one or two cylinder test engines to "prove" the concept and many of the design features were dictated by the army. It was some of these features that hurt the engine/s. 

BTW, The Army owed Allison over 900,000 dollars in back payments by the Spring of 1939. Without GM backing Allison would have been out of business despite the money they were making from the their bearing division.


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## Aozora (Aug 22, 2013)

Maybe the US could have liberated a few Liberties from storage?? Plus the Brits wouldn't have had as many tank engines, so (hopefully) fewer Crusader "Cruiser" tanks.... 

Seriously, chances are had the V-1710 failed there might have been more pressure to develop fighters using the best available radial engines, before turning to the Merlin - after all, the navy wasn't interested in liquid cooled engines, and, by the look of things, the Army seemed a little so-so about liquid cooled engine development; thus, funding engines common to both the Army and Navy might have become a preferred option, especially with tight pre-war budgets.


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## GregP (Aug 22, 2013)

Yeah, Wuzak, I consider 2,200 P-40's to be a drop in the bucket compared with the rest of the US fighters produced for WWII. Plus or minus that many would have made ZERO difference to the USAAF. And, as you said, the P-40 wasn't exactly a front-line plane anyway.

No, without the P-51, the Merlin would have been essentially a non-starter for US production of fighters. 

We'd have gone all-radial or would have developed an alternative engine.


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## oldcrowcv63 (Aug 23, 2013)

Maybe there would be a move to develop a Lycoming or license-built RR, BMW or DB V-12 modification of the P-36 that resulted in license production of a foreign engine? Weren't the initial Bf-109s powered by RR engines? So once the idea of a P-36 with a liquid cooled engine is floated, the provider becomes who ever is building a possible engine, no? 

Alternatively, the army would have a variety of radial development options although it might have resulted in an odd mix of a/c operational on December 7, 1941. The US army could have subjected to further development and ultimately bought more upgraded P-36s and P-43s and perhaps land based F4F-3s or P-66s by December 7th, 1941 with perhaps a strictly land-based USAAF F4U variant in the wings or instead of the P38 perhaps the USAAF might push development of the Grumman XP-50 (first flight 2/18/41). I would expect the state of the US a/c industry would have inspired the BPC to go around to a number of manufactures asking them to produce something, anything but what they were currently building for the USAAF and the P-51B would have been born earlier or maybe USA built Hurricanes or Spitfires or lots and lots of Boulton Paul Defiants. Or best of all, the army might have obtained thousands of Bell FM-1s aerocudas.

For all its faults, I don't think the world is necessarily better off without the Allison.


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## wuzak (Aug 23, 2013)

GregP said:


> Yeah, Wuzak, I consider 2,200 P-40's to be a drop in the bucket compared with the rest of the US fighters produced for WWII. Plus or minus that many would have made ZERO difference to the USAAF.



But, I would figure that when they were built the 2,200 P-40Fs and Ls would have formed a significant proportion of the fighters produced in the US. They were produced over a relatively short time frame, but made up 16% of P-40s produced.

If the Allison wasn't around, for whatever reason, there would have been more Merlin P-40s.

The USAAC/F _wanted_ liquid cooled fighters.




GregP said:


> And, as you said, the P-40 wasn't exactly a front-line plane anyway.



That's not what I said.

The fact is that, at least for the early war years, the P-40 was a front-line fighter, and the best the USAAF had.




GregP said:


> No, without the P-51, the Merlin would have been essentially a non-starter for US production of fighters.



I disagree. The Army had the contract with Rolls-Royce and Packard such that some of the production was for US aircraft. They wouldn't be used for trainers, GA aircraft, bombers or Navy planes, they can only have been for USAAF fighters. And the P-51, let alone the Merlin P-51, didn't exist.




GregP said:


> We'd have gone all-radial or would have developed an alternative engine.



There was a reason why the USAAF had the contract between Packard and Rolls-Royce specify that 1/3 of production would go to US aircraft. They wanted liquid-cooled engines for US fighters, based on observations of the air war in Europe. And it helped the USAAF pressure Allison into doing a better job.

The USAAF did not want an all-radial fighter fleet. Some programs were specified with the V-1710 as the engine. If the V-1710 engine had failed or been terminated at that point they would have been looking for a replacement engine. And the Merlin would have fitted best.

As for developing alternatives, you would have to say other attempts at US liquid cooled aero engines during WW2 were failures. Some flew, but none went into series production. The Allison was the only use liquid cooled type to see series production.


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## GregP (Aug 23, 2013)

Nope, would NOT have happened without the P-51. 

You aren't from here and do not realize the political reality of the time. My mom and dad were FROM that time, along with most of their friends, and it would NOT have happened.

Since this is a contrived what-if, let's let it go, OK?


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## wuzak (Aug 23, 2013)

GregP said:


> Nope, would NOT have happened without the P-51.



You are saying that without the P-51 the 1/3 of Merlin production licence production required by contract would not have gone into anything else? Even though that term was made in 1940, before the existence of the P-51?

If they didn't intend to use them, why did they demand a proportion for their own use (and not just one or two for experimental purposes).


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## GregP (Aug 23, 2013)

As a fallback in case.


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## wuzak (Aug 23, 2013)

GregP said:


> As a fallback in case.



In case....the Allison V-1710 didn't work?

Would it stand to reason, then, that the US would have aircraft designed with the V-1710 changed over to Merlins - P-38, P-39, P-40, P-51 - and that the licence production would have been ramped up (in facilities that the V-1710 was to use as well as Packard) in the scenario from the OP?


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## GregP (Aug 23, 2013)

Wuzak, I asked you to let it go.

DO IT dammit.

It does not stand to reason in the 1940 timeframe except from an outside viewpoint (which I agree with today).


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## wuzak (Aug 23, 2013)

GregP said:


> Wuzak, I asked you to let it go.



Ok, letting go....


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## Shortround6 (Aug 23, 2013)

oldcrowcv63 said:


> Maybe there would be a move to develop a Lycoming or license-built RR, BMW or DB V-12 modification of the P-36 that resulted in license production of a foreign engine? Weren't the initial Bf-109s powered by RR engines? So once the idea of a P-36 with a liquid cooled engine is floated, the provider becomes who ever is building a possible engine, no?



The Lycoming engine was too small (not to the Army's eyes _at the time)_ and as it existed was a "flat" engine, it could have been been bent into a "V" but that adds a bit more time. It was a 1234 cu un ( 20.2 L) engine, smaller than a Kestrel or Peregrine and depended on high rpm and high boost to make it's power. It used a short stroke so the RPM may not have been a big problem. 
The German engines are pretty much non-starters unless you really push history, Not so much from the "Not invented here" stand point but from the fact that the DB 601 was pretty much "vapor ware) as far as the rest of the world was concerned in 1938. At the Paris Air show/exhibition in Dec 1938 the DB 601 was talked about but NOT displayed. RR had a Merlin X (two speed supercharger) on display and was talking about hp figures using 100 octane fuel. Information on large German engines was sketchy, to say the least. People to not take out licences on engines they don't know about. The Only BMW V12s were the old one that was pretty much two WW I straight sixes on a common crankshaft and a small experimental built to compete with the Jumo 210. 
A single 109 was powered by a RR Kestrel because the Jumo 210 had not been cleared for flight at the time. This one Kestrel may have made the "rounds" and powered not only the first JU 87 but another prototype as well. 



oldcrowcv63 said:


> Alternatively, the army would have a variety of radial development options although it might have resulted in an odd mix of a/c operational on December 7, 1941. The US army could have subjected to further development and ultimately bought more upgraded P-36s and P-43s and perhaps land based F4F-3s or P-66s by December 7th, 1941 with perhaps a strictly land-based USAAF F4U variant in the wings or instead of the P38 perhaps the USAAF might push development of the Grumman XP-50 (first flight 2/18/41).



The upgraded P-36 is a possibility but it is still well behind the world standard. Production P-36s had single speed superchargers and about 1050hp for take-off. Later (1941) R-1830s got 2 speed superchargers and other improvements and not only had 1200hp for take off but were allowed 1200hp at 5,000ft, and 1050 at 13,100ft Military ratings. Any improvement after that had to wait several more years. Vought built 178 F4us in 1942, and Land Based modification is a non-starter. Land based F4Fs and P-66s hit the engine problem too. You can't take enough weight out of the F4F to make a real difference without redesigning the whole thing and P W had trouble making enough two stage engines as it was which is why there was a F4F-3A model with two speed SINGLE stage supercharger whose performance was a little less than thrilling at altitude. FTH was 5-6,000 ft lower than than the F4F-3. 
US might push development and production of the XP-50 but since it was destroyed early in the test program it's published numbers must be looked at with a fair degree of suspicion as the XF5F missed it's estimated numbers by a fair margin. US had problems with turbo controls on ALL it's turbo charged aircraft in the early part of the war. 
P-43s come ONLY at the expense of the P-47 program. How big an expense depends on how and when you play with the program. Sept 13 1940 had the US Army place an order for 773 P-47s off the drawing board _after_ they decide the proposed (and mocked up) liquid cooled P-47A is a non-starter. 




oldcrowcv63 said:


> I would expect the state of the US a/c industry would have inspired the BPC to go around to a number of manufactures asking them to produce something, anything but what they were currently building for the USAAF and the P-51B would have been born earlier or maybe USA built Hurricanes or Spitfires or lots and lots of Boulton Paul Defiants. Or best of all, the army might have obtained thousands of Bell FM-1s aerocudas.



The BPC was limited as to what they could order. The US had gotten burned in WW I when it finally declared war and found it's factories were tooled up for an assortment of foreign weapons it didn't want and had a hard time using. IF the US PTB (powers that be) thought a foreign design was acceptable to the US Military it would be given the OK for production, if not then no production. No US company made a British tank design and the US had squat for tanks at the time. There was a set of standards for US military aircraft at the time that covered a bunch of things _aside_ from the actual performance numbers, standards for stress loadings, landing impacts, construction details (fittings and such). The US did not what a bunch of factories tooled up and producing Whitworth nuts, bolts, fittings and such.



oldcrowcv63 said:


> For all its faults, I don't think the world is necessarily better off without the Allison.



I think that is a little harsh, the _only_ real fault the Allison had was the lack of a really good supercharger between late 1940 and 1943/44. It's supercharger was no worse than the German ones in 1940-41-42. The Germans just didn't try to power 7,500-8,500lb planes with 1200hp engines. Blaming the engine doesn't seem quite fair.


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## Glider (Aug 23, 2013)

If the Allison hadn't been around and the USAAF wanted a liquid cooled engine then there only seem to be two real options, to license build either the Merlin or the DB601/5.

The risk involved in a rushed development of a new liquid cooled engine with war looming and no time for second guesses if there was a problem with the primary option, would seem to rule any other options out.

Its only a guess but if the Alison hadn't been available the US would have stuck to radial engines which they had in quantity and quality.


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## Shortround6 (Aug 23, 2013)

The DB 601-605 is pretty much a non-starter. The Germans are not trying to actively export it even in Dec of 1938 let alone licence it to any but the most trusted allies. After Sept 1939 the only option to is use captured examples and try to reverse engineer it. This requires co-operation of the British and French to ship captured examples to the US for examination. Possible but a long difficult process. It took Packard 1 1/4 years to deliver the 5th production Merlin with a pair of sample engines, full drawings and the services of two senior Rolls-Royce engineers and a stream of communications to the home factory. 

The Allison powered 792 aircraft delivered in 1940, 3519 delivered in 1941 and around 6600 in 1942. Packard averaged 800 engines a month for the last half of 1942. 

Any substitute for the Allison has to start in 1939 or there will be thousands fewer fighter aircraft delivered by the end of 1942 even if the US catches up after that.


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## drgondog (Aug 23, 2013)

GregP said:


> Nope, would NOT have happened without the P-51.
> 
> You aren't from here and do not realize the political reality of the time. My mom and dad were FROM that time, along with most of their friends, and it would NOT have happened.
> 
> Since this is a contrived what-if, let's let it go, OK?



So, your mom and dad were the secret consultants to Hap Arnold and presumably convinced General Arnold that there was no place in the USAAF planning for a high performance, fuel efficient Liquid Cooled engine in the USAAF inventory - if there was no other option, nothing in the pipeline? And compound the stupidity despite being tooled up for it and presumably be available to ramp up production?

In your opinion Arnold then turns to the USN and purchases the F4U rather than use a Brit Hybrid engine in a USAAF specified airframe?

So, your opinion is that Arnold was stupid? Seems to be a siilly opinion.


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## swampyankee (Aug 23, 2013)

davebender said:


> I second the motion.
> 
> The best engine solution was staring U.S. Army Air Corps in the face. Just need to be smart enough to recognize it.



yup. It came from companies called Wright and Pratt&Whitney: radials.


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## Shortround6 (Aug 23, 2013)

tomo pauk said:


> The never much liked (in some 'camps') Allison V-1710 powered many US-built fighters, flying in all the war theaters, especially until sufficient number of the Thunderbolts and Merlin Mustangs were in service. So let's say, for the sake of discussion, that somehow people at Allison really messed up their machine, so the USAF Allies must acquire it's fighters without it. What would be the best alternatives, ie. historical engines set-ups, for the USA/USAF in order to produce/purchase it's fighters both in quality and quantity, until the P-47C and P-51B arrive to the scene.


 
going back to the Original question it depends on _When_ Allison "messed up their machine". 

Without the Allison the P-39 is pretty much done ( Wright cyclone powered P-39 

Maybe you can build a special model Merlin. The DB 601, Continental IV-1430 and Lycoming O-1230 need not apply. They need gear sets to lower the the drive from the crankshaft to pass under the pilots sear and another gear set to bring the drive back up to the propeller. On the two American engines you have length problems to boot. 

Get Bell to licence what? P-36s? P-43s? The vast majority of US fighters built before the end of 1942 were powered by Allison engines, 2nd most used engine was the R-1830 in the F4F and strange as it may seem they built roughly the same number of F4Fs by the end of 1942 as the did Merlin powered P-40s, or within a hundred or so. Massive expansion of P&W factories even earlier? While a P-40 test mule with a R-1830 did beat the performance of the Merlin Powered P-40 it wasn't until the fall of 1942 that it did so and the plane was unarmed. 

Wright R-1820s seemed to have troubles as fighter engines in 1940-42. Problems with oil distribution while maneuvering? 

If Allison stuffs it up soon enough _maybe_ Packard can resurrect one one of their old engines but I believe their chief designer had died in an air crash in 1930(?) so some of the later engines were just derivatives of late 1920s designs.
Try to use the PT-boat engine?


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## oldcrowcv63 (Aug 23, 2013)

I guess it was late at night after a long and frustrating day resulting in my being a little too flip (especially in the nonsensical Aerocuda comment) with what I thought and think is a really interesting question. Even so, I appreciate your taking each comment seriously and elaborating on the prospect and consequences. I thought, and agreed after posting, that my last comment on the Allison was indeed a bit harsh. 



Shortround6 said:


> The Lycoming engine was too small (not to the Army's eyes _at the time)_ and as it existed was a "flat" engine, it could have been been bent into a "V" but that adds a bit more time. It was a 1234 cu un ( 20.2 L) engine, smaller than a Kestrel or Peregrine and depended on high rpm and high boost to make it's power. It used a short stroke so the RPM may not have been a big problem.



It seemed that the primary historical benefit of the early existence of the Allison were the roughly parallel developments of the P-37, -39 -40 and the P-38. and their production in late 1941 in sufficient numbers to provide an immediate core USAAF force for use in the coming war and to supply the even earlier requirements and needs of allied air forces. 

Trying to extrapolate the effect of the void existing due to the Allison's absence during a period when liquid-cooled engines seemed to be worth pursuing in a major way, I wondered whether the domestic engines that were in the shadow of the Allison might have received more developmental attention and come out of that process as better than they historically did. In other words, was the Allison analogous to the dinosaurs that prevented the emergence of higher mammalian species. Remove the dinosaurs and mammals flourish. Does, removing the Allison open the way to improving the Lycoming O-1230 or Continental I-1430, allowing them to evolve into some more suitable variant? Is the time frame just insufficient to have that happen or are their inherent deficiencies in the design of each that no amount of development would resolve. It seems you (SR6) see evidence that was the situation and they would not be suitable surrogates.

If the P-40 and other a/c are to come into existence in a scenario where no domestic liquid-cooled engine meets the required need, then is their a foreign product that might allow that to proceed in something like a historical fashion. I thought, British, German, and probably should have included the Hispano-Suiza 12Y, as well as Russian AM35 as options, no matter how unlikely. 

If no foreign product is suitable, then it would seem the USAAF is limited to Radials of equivalent power. To simply get to numbers that are roughly equivalent to the number of P-40s produced in a comparable time frame, it would seem that extending both the development and the production runs of the P-35 P-36 is nearly the only option. The only other aircraft that seems comparable and roughly in accord with an early development and production (albeit engine and factory floor space limited) would be an army variant of the F4F-3A or F2A whose development would have had to be in parallel to the USN's forcing major, early expansion in the Grumman iron works Brewster's problematic industrial capability . 

As intermediate stop-gaps, perhaps additional development of the P-43 to most quickly overcome the foreign performance gap, perforce accepting a delay in the P-47 and in desperation even considering an army F4U seem like later possibilities. None of the latter help our allies in the short run, so without an allison powered P-40 they are left with a number of very unsatisfactory options motivating them to consider some very (historically) unorthodox possibilities including early development of the P51B. At least that was the train of thought. 

Based upon your answer it seems that lack of the Allison puts both the USAAF and allied air forces at a considerable disadvantage.


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## swampyankee (Aug 23, 2013)

oldcrowcv63 said:


> I guess it was late at night after a long and frustrating day resulting in my being a little too flip (especially in the nonsensical Aerocuda comment) with what I thought and think is a really interesting question. Even so, I appreciate your taking each comment seriously and elaborating on the prospect and consequences. I thought, and agreed after posting, that my last comment on the Allison was indeed a bit harsh.
> 
> 
> 
> ...



With the last sentence, I disagree: the engines from Pratt&Whitney and Wright were quite capable of providing power for world-beating fighters. USAAF preference for liquid-cooled inlines was more due to fashion (they looked more streamlined, more modern) than to aerodynamics (the zero-lift drag coefficient of almost all fighters ranged between 0.02 and 0.025, whether powered by in-lines or radials: the Spitfire and the Corsair had quite similar zero-lift drag coefficients). There were also, of course, development efforts that were not being heavily funded, like the "Hyper" project, that could have been funded more heavily, and there were liquid-cooled engines under development by Wright and P&W.


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## oldcrowcv63 (Aug 23, 2013)

swampyankee said:


> With the last sentence, I disagree: the engines from Pratt&Whitney and Wright were quite capable of providing power for world-beating fighters. USAAF preference for liquid-cooled inlines was more due to fashion (they looked more streamlined, more modern) than to aerodynamics (the zero-lift drag coefficient of almost all fighters ranged between 0.02 and 0.025, whether powered by in-lines or radials: the Spitfire and the Corsair had quite similar zero-lift drag coefficients). There were also, of course, development efforts that were not being heavily funded, like the "Hyper" project, that could have been funded more heavily, and there were liquid-cooled engines under development by Wright and P&W.



I was really concerned with the time factor here wherein the radials producing power for a/c like the F4U and P-47 haven't yet arrived in sufficient numbers nor have the associated a/c to make a difference.


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## Shortround6 (Aug 23, 2013)

The knowledge of _how to cowl_ a radial engine was in it's infancy in 1938-40. The P-40 showed a 22% reduction in drag over a P-36. A gain of about 30-40mph in speed using similarly powered engines. This was NOT just fashion or looks. By late 1942 they had it pretty well sorted out and _prototype_ radial engined aircraft could match the liquid cooled engines for drag pretty well but that is way too late for deployed combat planes in 1941/42. 

Using exhaust thrust was also a problem on radial engines. Most radials used an exhaust collector and one or two exhaust outlets which often did NOT direct the exhaust rearward or mostly rearward. Some radial installations tried, like the B-25 with 14 lumps on each cowling over individual exhaust stacks but the drag on that is rather suspect. 

Oldcrowcv63 is quite correct on the timing of the higher powered radials. Allison built 6400 engines in 1941. P W built 1461 1850hp single stage R-2800s in 1941, over 1000 of them in the last 1/2 of the year. 2 2000hp single stage engines and 6 2000hp two stage engines. Ford had built 264 R-2800s, all single stage engines. 
The only High powered radial (over 1200hp) available in real numbers for most of 1941 was the Wright R-1600 "A" series engine of 1600hp take-off and 1400hp at 11,500ft. Most of it's extra power is going to get sucked up by it's extra weight and drag. 

The Hispano 12Y series wasn't a good option. 
The two Hyper engines had been crippled by Army design choices. They used small cylinders and high rpm which allowed for a high BMEP at the time but they also used separate cylinders instead of cylinder blocks which made for long engines for their displacement, they were at least as heavy as larger displacement, comparably powered engines. The separate cylinders also made for a weaker engine even if they did use a common cylinder head/cam box design. 
The Wright liquid cooled engine was rat hole that makes the Jumo 222 look good. 
P W asked to be let go from the liquid cooled engine development as they _thought_ they could get the R-4360 into service before any of the liquid cooled projects. It took them 3 years to get to the 5th R-4360.


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## GregP (Aug 23, 2013)

Apparently you didn't read my posts before throwing sarcasm, Bill. 

I said I agreed with the notion to use the Merlin, but the political reality was that the USA wasn't going to use a British engine in a US fighter in 1940 until and unless the war demanded it. In the end we procured some 2,200 P-40F/L models against a total production of some 60,000 fighters from May 1940 thriough August 1945 (and those numbers are missing the last 6 months for the F4F and F6F).

That is about 5% of the US fighter production minus the P-51. If it was a foregone conclusion, why isn't that number higher by a LOT?

If we really needed the Merlin, that percentage would be MUCH higher. There was nothing wrong with the Merlin and there still isn't. But inserting today's opinions into purchase decisions made in early WWII is what sounds silly to me. Mom and dad weren't close to anyone in the position to make WWII decisions, being kids at the time, but they were representative of the people around at the time who weren't flying Merlin-engine Mustangs. 

The thread asked what we would do if the Allison wasn't a viable option. I personally have NO issue with the Merlin or anything British or European, but in 1940 America, we'd have used an American engine for American aircraft ... in my opinion. 

If you feel differently, that's fine. It is a what-if and there is no right answer since it didn't happen. You are certainly welcome to believe it might have been possible. I just disagree and we'll never be able to find out, will we?


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## Shortround6 (Aug 23, 2013)

There is playing with statistics a there is playing with statistics. 

In 1942, the year in question, when Merlin Production really got started in the US, the US built 10,090 fighters. Granted the P-40L production didn't start until Jan 1943 but that leaves around 1300-1500 Merlin powered P-40s built in 1942. Or around 13-15% of production for the year. Production of the R-2800 powered planes didn't kick in until the last 4 months of the year and even F4F production didn't top 100 planes a month until May. Total production of F4Fs in 1942 was roughly the same as Merlin powered P-40s. were they a 'minor factor' in US airpower in 1942? There were only 1932 P-39s built in 1942 or roughly 50% more than the Merlin P-40s (and there would have been less of them without the Merlin P-40s). 

Allison made 1149 engines in 1940 (year deal was made to build Merlins), 6400 in 1941, 14,900 in 1942 and 21,064 in 1943. 

To put things into real perspective by the time the Merlin talks started with Packard Allison had made 3 engines in Jan 1940, 7 in each of Feb, March and April, 14 in May, 30 in June and managed to crank out 73 in July falling to 65 in August. 

Not only is having a second source of V-12 engines a good idea but the Allison is an _unknown quantity_ in the summer of 1940, there are not enough in service to KNOW if it is actually going to work or not and in fact there were some problems with the early ones. The first 288 built were operated at reduced power settings while Allison sorted out the problems on the test engines and then brought back the early engines and upgraded them at company expense. In March of 1941 there were only 16 engines left to be reworked. 
this compares to thousands of Merlins already built and flown in combat. 

Buy "American" might have been popular, it was also stupid given what was going on at the time. 

Allison (and GM) performed near miracles in sorting the V-1710 out, getting it into large scale production and developing new, improved models but that was all in the future in the summer/fall of 1940.


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## beitou (Aug 23, 2013)

GregP said:


> I don't believe anyone thought of that until both sides wanted to try a Merlin in the P-51. If the P-51 had not come along, I'm not sure anyone would have pursued the license agreement.
> 
> Maybe, but maybe not, too.
> 
> ...



Browning machine guns in the UK fighters were a US design.


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## GregP (Aug 23, 2013)

Yes the Brownings were a US design and I wish we'd have used some foreign 20 mm cannons in our planes a LOT sooner than we did in preference to the Brownings. Our own 37 mm cannon was certainly nothing to write home about.

My statements above aren't isolationist of in any way depricating of products made outside the USA. I was, rather, saying that the attituides prevalent *at the time* were to buy American, especially for critical military items. The reason the Merlin was produced over here by Packard comes down to a British request for it, not the USA seeking engines for itself. You may recall that Ford turned down the request to build the Merlin and Packard was induced to do it.

So while we DID use some Merlins, we didn't use many other than in the P-51, which I maintain would probably NOT have gotten a Merlin had it been a primary US military aircraft from its inception. Most Merlins went to the UK or to Canada.

These are statements about how I think it WAS at the time, not how I personally feel about it.


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## Shortround6 (Aug 23, 2013)

beitou said:


> Browning machine guns in the UK fighters were a US design.



So was the Bren gun and the Besa. So was the Hispano gun and so was the Bofors 40mm. So was the Browning High power pistol. British were not above using somebody else's design _if it worked._


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## Shortround6 (Aug 23, 2013)

The reason for "buying American" was to insure supply in time of war. The US was not above licencing (or coping) 20mm Hispano guns, 20mm Oerlikon guns, 40mm Bofors guns, 57mm (6pdr) AT guns and agreeing to build 4.5in artillery guns for common ammo supply with the British (although the last was a mistake).

British did request a US production line, The US would NOT agree unless it got _some_ of the production. At the time the agreement was signed (sept 1940) the US had more Merlins _on order_ than it did Allisons. However as some deliveries were several years in the future delivery dates and quantities changed, let alone later contracts.


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## GregP (Aug 23, 2013)

What is your point Shortround? Specifically?

I said if the Allison had not been a viable engine, we would have developed an alternative engine or used radials. You seem to think that means using the Merlin in quantity. I simply disagree. There's no use debating a what-if since it never happened. 

If it makes you happy, then by all means imaging scores of Merlin-engined P-38's and P-39's. In real life, it might not have been a bad idea, but it didn't happen. I'd love to see what a P-40 with a 2-stage Merlin would do at altitude. It would no doubt be a step up from the non-turbo Allison setup.

I wonder if anyone ever tried a Merlin supercharger housing on an Allison with an adapter plate. Sir Stanley Hooker was a genius with superchargers and it might have made a real winning combination. If they did, I haven't read about it as yet.


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## Piper106 (Aug 23, 2013)

Back to our regularly scheduled programing... What if there was no Allison V-1710. 

The Packard V-2500 (dismissed as a 'PT boat' engine) *could* have been developed into something comparable to the Daimler Benz and Jumo 211 engines. Seemed to have been reliable enough at 1350 HP in naval service, and was developed to 1500 HP later in the war, again for naval service. Before you jump on weight issues, most references will quote the weight for the naval version, with likely some of the major casting being iron rather than aluminum, and heavy water cooled exhaust manifolds, etc. Don't know what an aviation version would have weighed. Biggest problem would be reliability. What I think I know is that Packard's aviation engines in the 1920s and early 1930s were none too reliable. 

Another tact would have been to 'go big' and build something like the Hawker Typhoon with the doubled H-24 version of the Lycoming O-1230. That actually might have been do-able rather that the effort wasted on the proposal R-40C pushers and unconventionals. 

Finally, discussions always seem to forget the Hispano Suiza 12Y. Start with the 12Y and then spring off with some American thinking to get rid of that horrible multiple carb induction system, and a general strengthening to run at higher rpm and boost, ala the 12Z. The Klimov gang in the Soviet Union got more out of the 12Y than the French did, no reason the US could not have. For a real "outside the 9 dots" idea, license the Milukan AM-38. Having said all that, I agree 110% with earlier posters that a foreign engine would heve been a no go.


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## drgondog (Aug 23, 2013)

swampyankee said:


> With the last sentence, I disagree: the engines from Pratt&Whitney and Wright were quite capable of providing power for world-beating fighters. USAAF preference for liquid-cooled inlines was more due to fashion (they looked more streamlined, more modern) than to aerodynamics (the zero-lift drag coefficient of almost all fighters ranged between 0.02 and 0.025, whether powered by in-lines or radials: the Spitfire and the Corsair had quite similar zero-lift drag coefficients). There were also, of course, development efforts that were not being heavily funded, like the "Hyper" project, that could have been funded more heavily, and there were liquid-cooled engines under development by Wright and P&W.



The P-51 CDo was closer to .016 as a specific 'contrary' example - which was due more to the wing than fuselage But the 2nd order compound lines of the nose also helped, and was possible with the In-line Allison, and slightly modified for the Merlin.


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## swampyankee (Aug 23, 2013)

The Allison engine had a rather long history, actually starting as an engine for airship use (http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=804 ; the first V-1710 was bought by the USN: Allison ); the first USAAC use of the V-1710 was in 1932. At the time the engine's development had started, the NACA cowling was probably not yet tested (it was used quite soon, with some notably clean aircraft, such as the 1931 Lockheed Orion, with a zero-lift drag coefficient of about 0.021 [ see http://history.nasa.gov/SP-468/ch4-4.htm ]).

With the notable exception of the P-51, it seems that most WW2 fighters had zero-lift drag coefficients that were grouped between 0.021 and 0.025, regardless of engine type. We have to consider the possibility that Curtiss did not do a great job with the P-36's engine installation.


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## Shortround6 (Aug 23, 2013)

My point is trying not rewrite History.
The US wanted a second liquid cooled engine (or 3rd or 4th, army had not have given up on the Continental I-1430 yet or a few others). The Merlin was available, it was low risk. It was _already_ developed even if the two stage supercharger wasn't ready yet (or even being worked on in the summer of 1940) unlike the rest of the American contenders. It size, weight and configuration made it a relatively easy swap with the Allison. 
The US use of the Merlin in the P-40 had absolutely _nothing_ to do with it's use in the Mustang. 

I could care less about Merlin powered P-39s. The Merlin was designed with the Front gear case as part of the crankcase, I believe, meaning you would need a new crankcase casting to try to make a remote prop drive like the Allison. Not impossible but a lot more work than the Allison design. And all you are ging to fit in a P-39 is a _single stage_ Merlin _at best._ Once Allison could fit the 9.60 gears in the engine the need for a Merlin XX diminished a whole lot.
P-38 is iffy, The Merlin XX may or may not have worked any better than the early turbo Allisons in the Es and Fs and that is what we would be talking about here for starters. The Merlin may not have given the range of the turbo Allison. 

They did try using a Merlin supercharger on an Allison engine on a ground test rig. I can't remember if it was the single stage or two stage at the moment. For some reason it wiped out the bearing on the supercharger (several times), lack of rigidity in the mounting? poor cooling of the bearing ( mounted several inches away from the engine block?) or something else? 

People often forget there were some major differences between the single stage Merlins and the two stage Merlins. A few hundred pounds, the extra length and bulk of the supercharger/s, the need for larger radiators and oil coolers in addition to the inter-cooler radiator, the need for a bigger prop. Just because a particular airframe could fit a single stage Merlin doesn't always mean it could fit a two stage Merlin. The Mustang took a 7in splice in the height of the fuselage. From the bottom of the fuselage to the top, not including air scoop or height of the tail fin.


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## GregP (Aug 23, 2013)

Good points swampyankee. If they had cleaned up the radial installation in the p-36 and upped the installed power, I wonder how the performance might have been improved ...


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## Shortround6 (Aug 23, 2013)

Piper106 said:


> Back to our regularly scheduled programing... What if there was no Allison V-1710.
> 
> The Packard V-2500 (dismissed as a 'PT boat' engine) *could* have been developed into something comparable to the Daimler Benz and Jumo 211 engines. Seemed to have been reliable enough at 1350 HP in naval service, and was developed to 1500 HP later in the war, again for naval service. Before you jump on weight issues, most references will quote the weight for the naval version, with likely some of the major casting being iron rather than aluminum, and heavy water cooled exhaust manifolds, etc. Don't know what an aviation version would have weighed. Biggest problem would be reliability. What I think I know is that Packard's aviation engines in the 1920s and early 1930s were none too reliable.



Weight in PT boat form might include the flywheel, clutch, reduction gear and reverse gear box. 

There is some evidence that Packard built both a direct drive and Geared drive V-2500 in 1938/39 that offered 1500hp at 2500rpm and 1750hp at 2800 rpm but no altitude figures are given. Weight is listed as 1430lbs. 



Piper106 said:


> Another tact would have been to 'go big' and build something like the Hawker Typhoon with the doubled H-24 version of the Lycoming O-1230. That actually might have been do-able rather that the effort wasted on the proposal R-40C pushers and unconventionals.


 Maybe but for some reason they didn't stack the flat 12s but flipped them on their sides. Engine was about 2400lbs before they tried playing with two speed propeller drives. 



Piper106 said:


> Finally, discussions always seem to forget the Hispano Suiza 12Y. Start with the 12Y and then spring off with some American thinking to get rid of that horrible multiple carb induction system, and a general strengthening to run at higher rpm and boost, ala the 12Z. The Klimov gang in the Soviet Union got more out of the 12Y than the French did, no reason the US could not have. For a real "outside the 9 dots" idea, license the Milukan AM-38. Having said all that, I agree 110% with earlier posters that a foreign engine would heve been a no go.



All you need to fix the Hispano Suiza 12Y is a new intake system, new cylinder heads, a new supercharger, a new crankcase with a new crankshaft, new pistons and some new............How about a new engine? The 170mm stoke limited RPM unless you would settle for a short engine life and it's light weight construction meant that while it was a pretty good engine for 87 octane fuel it was a lousy engine to run high boost levels in without beefing up all kinds of stuff. Russians already had tooling in place to make the engine so they were sort of stuck with it. 
Please remember that the Hispano engine came out and was in service in 1932/33 and so was several years ahead of the Merlin and 4-5 years ahead of the DB 601. It is really no surprise it isn't in the same class. For the US to adopt a 6-7 year old engine in 1939 would be an act of desperation.


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## Balljoint (Aug 23, 2013)

If there had been no existing workable V-1710, it would seem that there would have been no P-38, P-39, P-40 or, for that matter, no P-51A (the British wouldn’t have signed on to shipping engines to America). Money and talent are fungible, however. With focused development on the radial engines, i.e. both Army and Navy, both the power and aero enhancements probably would have come along a bit sooner.

But then alternative futures are hard to call. Maybe the P-51 would have gone ahead if it was agreed that the Merlins for it were to be made in the US of A. American industry wasn’t that prideful as long as the British treasury had the needed wherewithal.


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## Shortround6 (Aug 23, 2013)

We don't have to wonder about the the P-36, I have posted this before. 







This plane achieved 389mph at 22,700ft in Sept of 1942. It is a very early P-40 airframe, please note no visible guns and the production batch it was taken from may mean no armor and no self sealing fuel tanks. Please note that that speed at that altitude with an indicated 1100hp form the engine works out to 8% more drag than the XP-40 doing 366mph at 15,000ft with 1090hp. (last modifications)
Please note that this plane used the last version of the two stage supercharged R-1830 and also appears to have a decent exhaust thrust set up for a radial engine. I don't know if the exhaust thrust was figured into the power or not. 

Please look at the both the Curtiss XP-42 and the Vultee Vanguard to see the numerous ( 14 different tries for the XP-42?) attempts to get inline streamlining for a radial engine in 1939-41.


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## GregP (Aug 23, 2013)

Not trying to rewrite history? A what-if is ALL abput trying to rewrite history! And if you discount the P-51, which was designed to a British specification and by British request, we used VERY few of the obviously-available Merlins.

We were building them here and hardly used any of them in comparison to the number built ... in the real world. In any case, its OK ... it never happened that the Allison didn't get built.

Would have made things ... interesting at the time.


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## Shortround6 (Aug 23, 2013)

You were trying to claim that the P-40F with Merlin would never have existed without the "demand" for Merlins created by the P-51. 

From your post #4 "I don't believe anyone thought of that until both sides wanted to try a Merlin in the P-51. If the P-51 had not come along, I'm not sure anyone would have pursued the license agreement."

from post #12 "Shortround, you and I both know those engines were never slated for front-line USAAF or USN aircraft. They were for the British. If it weren't for the P-51, I doubt the Merlin would have seen the inside of ANY US fighter."

And still from post#12 "There were none before the P-51B/C that first flew in Nov 1942, a few P-40 F's and L's (2,280 of them ... 15 - 16% of the total, didn't come into service until 1943, well after the P-51B/C had proven the merit of the change).

The US and the British signed the agreement with Packard in Sept of 1940 after a number of weeks of talks which started back in July. Packard had been doing a lot of work in the mean time and did not wait for the signing (although getting one of the sample engines and some of the drawings back from Ford Delayed things a bit.) The US was to get 1/3 of the production and the initial order was for 9000 engines. Now this is over two years before the Mustang B prototype flew. You can slice it, dice it even puree it any way you want but the use of the two stage Merlin engine in the P-51 had _NOTHING_ to do with with the original production agreement/licence. Trying to claim it did is re-writing history.


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## gjs238 (Aug 23, 2013)

.


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## pinsog (Aug 23, 2013)

Shortround6 said:


> We don't have to wonder about the the P-36, I have posted this before.
> 
> View attachment 241259
> 
> ...



Can you give more information about this aircraft? Maybe even a new thread. Looks very interesting and competitive


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## GregP (Aug 23, 2013)

Shortround, for a what-if, you are taking this to ridiculous lengths. I don't really care one way or the other since it never happened, so this time, I'll just let it go. 

Rewrite history on your own in good health. Nice pic above.


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## drgondog (Aug 25, 2013)

Greg - Shortround keep dealing in facts to base his conclusions that a.) building the Packard Merlin in the US had zero to do with the P-51B, and b.) that the AAF had placed a reserve 'hold' on the Packard Merlin Production before the P-51 was flying.

You, on the other hand had an opinion (No Way AAF would buy from Brits) supported in part by referencing your Mom and Dad, which even to those used to some of your emotional arguments was pretty strange.

In summary, SR inundated you with facts, overwhelmed you with opinions based on facts and you made your look pretty silly - at least from my perspective. I could be wrong because it is my Opinion that Shortround was entirely correct in his foundation of fact and logic following the foundation. 

Namely, if the Allison 1710 had never been built, that other substitutes would have been produced and that the Packard Merlin is the most likely substitute - and the AAF would have agreed to extend the contract for the Packard Merlin 1650.


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## wheelsup_cavu (Aug 25, 2013)

Have to agree with Greg that without the expediency of using the Merlin to solve a war time problem it would have never been used in very large numbers. There were still prejudices against the British going back to the war of 1812 which were not pushed aside until we finally entered WWII. We were still not ready to _*save_ Europe again from itself, hence the isolationist movement. Nothing from the time suggests we were ready, during peace time, to embark upon a massive utilization of a foreign powers defense equipment. Even using it as a backup during peace time would be highly suspect considering the collective mind set of the people in the US during that time period. 


Wheels

*please note the italics before you decide to blast me about the "save" part of the comment.


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## GregP (Aug 25, 2013)

Drgondog, let's say that you and I will not usually agree except only once in awhile in passing and go from there.

I don't feel in the slightest overwhelmed. I still don't see, 70 years after the fact, many Merlins used in US fighters of WWII other than the P-51, unless you're hiding them somehwere in an unpublished book. So my thoughts on it are based on what what really happened and people who were there when it went down, not some contrived what-if. 

Out of the 50,000+ fighters we built other than the P-51 and the derivative P/F-82, only about 2,200 Merlin-engined P-40's were powered by Merlins plus a handful of others, and that is enough to be obvious to most who take the time to look at it. I don't need any sources for it in this case either. Leave the P-51 out and find all the Merlin-engined fighters produced for US service. They are rather conspicuous by their low numbers.

It has already happened. The results are out there for all to see. I would certainly have left this alone going forward if not for the wording.

Oh, one more thing. 

I see you said the drag coefficient for the P-51 was .016.

I am interested and I wonder where you found that. When I check NACA report NA-46-130, dated 2/6/46, NACA reports ACR5D04, L5A30, ACR dated 10/40, ACR 3130, Air Corps Technical report 4677, and Boeing in-house drag data I see they mostly agree on a Cdo of 0.0176. 

I want to be accurate in my data files and am NOT arguing with you. I just wonder where you found 0.016, no other agenda. Maybe that value was for a specific model? If so, I have a new "lowest Cdo" candidate for the file.

I have Cdo for a few WWII fighters in a file and, to date, the lowest is the P-51D at 0.0176 and the highest is the Brewster Buffalo F2A at 0.030 (with the Bf 109E-3 next at 0.0290). Interestingly I have the Fw 190A-3 and the Spitfire IX both at the same value of 0.0220. The lowest radial-powered entry I have to date is for the P-47 at 0.0213.

The highest single-engine flat-plate drag area I have is for the F4U Corsair at 8.38 square feet and the lowest is for the P-51D at 4.10 square feet.


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## drgondog (Aug 26, 2013)

Greg - the published CD0 Is actually .0176 - my .016 was a typo dropping the "7". Having said that, here are additional references with a cross section of values for both wind tunnel and Flight Test.
1. GALCIT wind Tunnel at Cal Tech - "Wind Tunnel Test of 1/4 scale NA-73 Pursuit Airplane with and without running propeller", Guggenheim Aeronautics Library, Report # 286 September 20, 1940. An example data is at RN=1.6M, CDw=.0046 @ M= 0.14
2. Anon, "Wind Tunnel Data for XP-51B Airplane (NAA-101), North American Aviation Report -5549, October 9, 1943. At RN=1.68 @M= 0.14M, CDw=.0053 (Full scale XP-51B w/ wings clipped at GALCIT Wind Tunnel))
3. Nissan, J.M, Gadeburg, B.L., and Hamilton, W.T. "Correlation of Drag Characteristics of a Typical Pursuit Airplane Obtained from Wind Tunnel and Flight Tests" NACA Report 916, 1948 RN=15.37M, CDw=.0053 @ 0.5M 

Remember Flat Plate Drag value is such only at a specific q value - ditto CDw... both expressions of the same Total Drag value at the same speed and altitude for a given surface area. The CDo is calculated after determining the CL at that speed and GW to derive the CDi, then CDo


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## GregP (Aug 26, 2013)

Thanks Bill. Appreciate it.


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## gjs238 (Aug 26, 2013)

GregP said:


> Drgondog, let's say that you and I will not usually agree except only once in awhile in passing and go from there.
> 
> I don't feel in the slightest overwhelmed. I still don't see, 70 years after the fact, many Merlins used in US fighters of WWII other than the P-51, unless you're hiding them somehwere in an unpublished book. So my thoughts on it are based on what what really happened and people who were there when it went down, not some contrived what-if.
> 
> ...



How many Merlin-engined P-51's were produced?
If the P-51 did not exist, how would all those Merlins have been employed?


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## Shortround6 (Aug 26, 2013)

There were probably multiple agreements and modifications to the agreements and licences.

The _First_ contract, signed in Sept 1940 was for the already mentioned ( several times) 9000 engines with 1/3 going to the US although the US may have, in the end, not taken the full the 3000 V-1650-1 engines. Packard built over 26,750 single stage Merlins and in fact delivered over 400 in Oct of 1944 so obviously additional contracts had been placed. 
Packard built almost 18,600 TWO stage Merlins by the end of 1944 so again, extra contracts/agreements and licences were involved. A number of these engines did got to the British in addition to the single stage engines but the two stage engine use in Mustangs had squat to do with the original contract and Merlin use. 

Engine production was often _planned_ one to two years before actual engine delivery. Even repeat contracts called for deliveries many months in future (impart because the repeat contracts were being placed well before the existing contracts were completed.) US produced TWO stage Merlins could and did go into Spitfires, Mosquitos and Lancasters and perhaps others. If projected airframe production looked like it would not need full Packard production then Packard production would have been slowed down. Allison produced about 800 fewer engines in 1944 than it did in 1943. In part because both P-39 and P-40 Production were winding down ( and P-63 production didn't fully replace P-39 production). 

The US did build a truly astonishing amount of engines during WW II but even so there was a lot or resource management going on, there was only so much steel suitable for Crankshafts or valve springs, only so much material for bearings, only so much of other materials and while the US seldom ran short it meant that factories did not have an inexhaustible supply and could build as many engines as they wanted and wait for buyers. Even structural steel I beams for Plant expansion were controlled and allocated. 

Somewhat back on track, when the _original_ agreement was signed, the production Allison was the long nosed "C" version offering 1040hp for take-off and at 15,000ft, newer versions were in the works but with only a few hundred production engines delivered and those downrated until reworked betting your future on the Allison would have been very risky. However, Allison pulled it off and not only vastly increased production (1941 saw over 5 times the production of 1940) but the development AND _production_ of new improved models _before_ Packard could even really get into the swing of things.


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## GregP (Aug 27, 2013)

My entire point was the USA didn't USE the Merlin for anything much ... a couple of thousand P-40's out of 135,000 warplanes outside of the P-51.

So, my premise that the US wasn't going to use the Merlin if the Allison was a flop seems proven to me. We didn't use them even when we NEEDED them and they were available for the use. It is NOT that the Merlin wouldn't have been a good thing ... it is all about the attitudes at the time. The British were SURE the American Merlins would be horrible, but were pleasantly surprised that they weren't. Was this a result of good British design or American assembly line know-how?

My contention is that it was a product of both. We came together at almost the precisely right time and had the precisely right results to cement a good national partnership that lasts to this day. Did it start out that way? 

No.

Glad it went to the positive side of things. We probably SHOULD have used more Merlins ... but that's the way it went.


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## GregP (Aug 27, 2013)

Hey gjs230,

13,708 Merlin-powered P-51's counting the two conversions from P-51A to P-51B. It was a British contract at first and was available for experimentation with engines. You didn't see Merlins in P-38's, P-39's, P-61's, P-63's, and bombers, or many otehr aircraft intended for the USA. You saw them in a few (very few) P-40's and a couple of Curtiss (made the P-40) prototypes plus maybe a few one-off prototypes.

Otherwise we stuck to American engines like the British did with British engines. The only American-designed engines they had OTHER than the in P-51's were installed in American-supplied aircraft that were sold to the British (they paid us back in full finally in 2006 - not a problem). The Germans flew only German engines except for the Gnome-Rhone radial (due to excellent stocks of them). The Japanese flew only Janapese engines, though some were Japanese versions of German engines. They didn't actually HAVE many actual German engines and had to use plans. Some were designed after receiving foreign engines, but almost all were of Japanese manufacture and Japanese modification to designs, together with foreign props, some of which were license-built Hamilton-Standard props. They paid for the license pre-war and were legally entitled to make them. Most mass-produced Japanese engines were of Japanese design and Japanese made ... very few foreign engines or designs taken in their entirety. Their aircraft were ALSO of Japanese design, but were sometimes modifications to foreign designs with weaknesses designed out.

Almost all nations did that to an extent. If someone saw a design item that was good, they USED it in general.

The Italians used German engine designs. The USA made Merlins and used some. The Germans used French radials. The Russians used Hispano-Suizas redesigned to Russian standards plus some radials that were copies of US radials together with the props and spiners. The British mostly stuck to British designs and the French mostly stuck to French designs until they fell though they DID use some US radials. After that, they made German designs under force of arms, not by choice. The Spanish made Spanish designs until they needed more than they had, and then turned to German designs until the Germans lost the war, at which time the Spanish installed a British engine into a German-designed airframe to make the Hispano Ha.1112 fighters. The Czechs made the Avias that were Jumo-powered Bf 109's.

So we mostly all helped ourselves to designs that would aid us in the war.


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## tomo pauk (Aug 27, 2013)

Hi, Greg, the Soviets did used Hispano engine, but most of their Klimovs were wholesale redesigns of it. they added 2-speed supercharger starting with M-105, reinforcing the engine itself so it was better able to withstand greater boost and RPMs.
Radial engines were again redesigns of the French and US stuff, The most prominent of them, the M-82, shared with Wright Cyclone nothing but bore IIRC.
The Mikulin family of engines was drawing the genes from BMW in-lines of the interwar period, again heavily redesigned many times in the 1940s.


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## wuzak (Aug 27, 2013)

GregP said:


> 13,708 Merlin-powered P-51's counting the two conversions from P-51A to P-51B. It was a British contract at first and was available for experimentation with engines. You didn't see Merlins in P-38's, P-39's, P-61's, P-63's, and bombers, or many otehr aircraft intended for the USA. You saw them in a few (very few) P-40's and a couple of Curtiss (made the P-40) prototypes plus maybe a few one-off prototypes.



I'm not sure the NAA conversion of the P-51 to Merlin power was to a British contract. Certainly by that stage there were P-51s (or A-36s) being built for the USAAF.

For that list: the P-61 was too big and heavy an aircraft for the Merlin. And it was designed around a radial.

P-39 and P-63 were designed around in-line engines, and would not have worked vey well with radials. I know there were one or two aircraft with mid mounted radials, but they tended to be rather fat.

The Merlin was considered for the P-38 at several stages: the Merlin XX when Packard production was being started, the Merlin 60-series mid war, and the Merlin 100-series late in the war. Had the P-38 flown before the V-1710 failed, I should imagine that Merlins would be very much in the frame. R-1820s and R-1830s would not have been a very good substitute, and R-2800 power would have been a new aircraft, basically.

There were other aircraft designed around in-lines - XP-49, XP-52, XP-53, XP-54, XP-55, XP-56 (ended up with a radial), XP-58, XP-59 and XP-60. These were to be powered by the V-1710, Merlin or various experimental engines - IV-1430, H-2230, V-3420. Some of those may have been candidates for US Merlin production, had the Allison not been available.


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## Shortround6 (Aug 27, 2013)

There is a problem with the train of logic of " they didn't, therefore they wouldn't have."

The US _ordered_ all kinds of stuff they later canceled. OR they ordered stuff and then amended the contracts to different models, let alone change delivery dates. And sometimes companies really came through and built things well ahead of delivery dates. 

Allison in late 1942 was building over 1300 engines _EACH_ month, Packard was building about 800 Per month (2/3s to British?) and the Allisons being built in late 1942 were a far cry from the Allisons being built in the summer/fall of 1940. The late 1942 Allisons including the 1325hp for take-off -73s, and comparable models for the P-38 and P-39. With "over boosting", wither official or unofficial, these engines could reach power levels at low altitude comparable to the low altitude cropped impeller Merlins. The Allison with 1150hp at 15,000ft was just around the corner as were the 1425hp turbo Allisons. 
What happened was production levels reached a point where the Merlin wasn't really needed as a "'back up" (for perspective P W in 1938 built about 8,000 engines total, of 4 basic models , the 9 cylinder Wasp Junior, the 9 cylinder Wasp, the 14 cylinder twin wasp junior and and 14 cylinder twin wasp plus limited production (samples) of a few other engines). Allison had not only competed a very large new factory (before 1942) but in 1942 was subcontracting parts out to General Motors divisions. Cadillac made the vast majority of crankshafts, connecting rods and camshafts for Allison among other things. 
And the "new, improved" Allisons meant that the aircraft using them could come closer to the performance of the same plane using a Merlin XX. Balance that with the needs of the British for Merlins and it is easy to see _why_ the e US did not make more use of Merlin Historically. 
Please note that the _original_ contract agreement was signed about 7 months before lend-lease was signed. 

If Allison had been bought by Brewster in 1940 or there had been a major flaw in the design of the Allison that was not discovered until 1940 or some other thing happened then who knows???


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## swampyankee (Aug 27, 2013)

tomo pauk said:


> Hi, Greg, the Soviets did used Hispano engine, but most of their Klimovs were wholesale redesigns of it. they added 2-speed supercharger starting with M-105, reinforcing the engine itself so it was better able to withstand greater boost and RPMs.
> Radial engines were again redesigns of the French and US stuff, The most prominent of them, the M-82, shared with Wright Cyclone nothing but bore IIRC.
> The Mikulin family of engines was drawing the genes from BMW in-lines of the interwar period, again heavily redesigned many times in the 1940s.



BMW started manufacturing radials under a Pratt&Whitney license; Bramo (later absorbed by BMW) under a Bristol license.


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## Shortround6 (Aug 27, 2013)

The Soviets first built Hispanos (M-100s) on a contract dated June 14th 1934, negotiations had started in Aug 1933. This helps explain several things including the inability of the Hispano engine to progress much beyond 1200hp without _MAJOR_ revision. It is simply the oldest major V-12 Used in WW II.


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## drgondog (Aug 27, 2013)

My number for total Mustangs - all types including those produced by Aussies is 15700 and ~14100 for Merlin including P-51H plus XP-51G/F but I could have screwed up the math. The two XP-51J were Allison 1710-119 powered.

Wuzak - you are correct. The first XP-51B were drawn from P-51A line and were a US contract NA-91. The subsequent contract charge number for the two XP51B (XP-78 ) were NA-101. I have to check more thoroughly but I believe 2300 P-51A's were removed from earlier contract starting in June 1942 to initiate the design and tooling requirements for the Merlin P-51


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## CobberKane (Aug 28, 2013)

You guys are a million miles past me in dates numbers and all that jazz. From a general point of view, it's always seemed to me that the Allison engines were hard done by from existing in the shadow of the mighty Merlin. From what I have been told from better informed individuals contributing to this forum, the Allisons lack of high altitude performance was a function of supercharger technology rather than any intrinsic inferiority in the design of the engine, and I believe if was more easily mass produced and easier to maintain in front line conditions also. Open to correction on those points, though.
Re the Merlin, I believe Packard spent a lot of time and know-how on applying mass production techniques to this engine. I've read that Merlins were designed to be built by craftsmen whereas Allisons were meant to be built by high school graduates. True? Either way, I suspect the Yanks were in a position to teach the Poms a thing or two about production line assembly circa 1943. 
On the other hand, once the war is won who wants a 'made in America' Rolls Royce? I think it was tried once and no-one bought them!


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## wuzak (Aug 28, 2013)

CobberKane said:


> Re the Merlin, I believe Packard spent a lot of time and know-how on applying mass production techniques to this engine. I've read that Merlins were designed to be built by craftsmen whereas Allisons were meant to be built by high school graduates. True? Either way, I suspect the Yanks were in a position to teach the Poms a thing or two about production line assembly circa 1943.



Ford UK was building Merlins before Packard were. And they were using production lines, not craftsmen.


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## Milosh (Aug 28, 2013)

Greg, what engine would the Americans us if the V-1710 was not available?


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## vinnye (Aug 28, 2013)

Further info from Wiki about Ford Merlins ;
Early in 1940 Ford of Britain was approached by Herbert Austin, who was in charge of the shadow factory plan, about the possibility of converting an abandoned factory in Trafford Park into an aircraft engine production unit. Construction of the new factory was started in May 1940 on a 118-acre (48 ha) site. During this time Ford engineers went on a fact finding mission to Derby, where their chief engineer commented to Sir Stanley Hooker that the manufacturing tolerances used by Rolls-Royce were far too wide for them. As a consequence over a year was taken up re-drafting 20,000 drawings to Ford tolerance levels.[68]

Ford's factory, which was completed in May 1941, was built in two distinct sections to limit potential bomb damage.[nb 11] At first, the factory had difficulty in attracting suitable labour, such that large numbers of women, youths and untrained men had to be taken on. Despite this the first Merlin engine came off the production line one month after the factory's completion, and the production rate was 200 Merlins per week by 1943.[28][69][nb 12] Ford's investment in machinery and the redesign resulted in the 10,000 man-hours needed to produce a Merlin dropping to 2,727 man-hours three years later, while unit cost fell from £6,540 in June 1941 to £1,180 by the war's end. In his autobiography Not much of an Engineer, Sir Stanley Hooker states: "... once the great Ford factory at Manchester started production, Merlins came out like shelling peas. The percentage of engines rejected by the Air Ministry was zero. Not one engine of the 30,400 produced was rejected ...".[70] Some 17,316 people worked at the Trafford Park plant, including 7,260 women and two resident doctors and nurses.[69] Merlin production started to run down in August 1945, and finally ceased on 23 March 1946.[71]


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## Shortround6 (Aug 28, 2013)

Just to be clear this was "Ford of England" and NOT "Henry of Dearborn". 

Ford in America signed a deal to build P W R-2800s just about the time that Packard _signed_ the deal for the Merlins. Ford in America went on to build 57,637 R-2800s but did NO design or development of the engine _as an engine._ They did do some valuable work in figuring out new and more efficient ways to make some of the parts. 

How much interchange there was between Ford of England and Packard I don't know. What we _DO_ know is that there was a pretty good degree of interchangeability between the finished engines no matter which factory they were from. In North Africa the British gave the US around 600 British engines to be broken down and used for spare parts for the P-40Fs the US was using in that Theater. The US having for some reason, decided on only 20% spare engines instead of closer to 50% which was closer to the normal allowance of the time. There are some differences between the engines but if the majority of the parts were NOT interchangeable this would have been a pretty useless move.


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## GregP (Aug 28, 2013)

Hi Milosh,

If the ALlisons hnad not "made it." then effort would have been spent to develop amternate engine into useful production engines. I would not presume to say any particular engine would make it over the rest, but there are several candidates around.

1) Chrysler hasd the XV-2220 V-16. It was two V-8's coupled back to back, made 2,500 HP and flew in the XP-47H.

2) Continental had the IV-1430 V-12 of 1,500 HP.

3) Continental had teh V-1790 V-12. Early power was just over 700 HP and they didn;t proceed further with it.

4) Lycoming had the O-1230 flat-12 of 1,000 HP. Not sure if this could have been made into a 1,500 +HP class engine.

5) Lycoming also had the XH-2470 of 2,300 HP. This was two O-1230 engine mounted sude by side vertically driving a single gearbox.

Or they could have developed an entirely new engine to a specification.

In any case, we would have developed an American engine for our planes before adopting the Merlin unless wartime expediency had required we use Merlins. That could have been the case if the allisons had failed.


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## tyrodtom (Aug 28, 2013)

What V8 did the Chrysler XV-2220 put together to make the V-16 ?


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## Shortround6 (Aug 28, 2013)

Milosh said:


> Greg, what engine would the Americans us if the V-1710 was not available?



Greg, may have his own list or choices;

It is rather dependent on _WHEN_ the Allison goes _missing._

But basically the Allison was used in FIVE production aircraft during WW II. The P-38, P-39, P-40 and P-51 and P-63. The First three date from 1938, the P-51 from 1940 and the P-63 from May of 1941. 

The P-39 was designed around the remote gearbox Allison ( and the Allison was designed, in part, to accommodate remote gearboxes/propeller drives) so it is the hardest to find a substitute engine for. 
The P-40 is the easiest as it is nothing more than a re-engined P-36 and can be fitted with several substitute engines to a greater or lesser degree of success. Mostly lesser as the radials _at this point in history_ have much more drag. 
The P-38 may fall in between. In it's _designed_ role of high altitude interceptor the drag of the radials may not have been as much of a handicap. But the Cyclone is the worst from a drag standpoint and had some serious problems as a fighter engine in the early part of the war. Problems are both the drag of the radials and the fact that the R-1820 and R-1830 both trailed the Allison by several hundred horsepower for most of the duration of the war. 

Leaving out the radials and any of "_them thar furin ingines"_ that leaves pretty much the two Army Hyper engines to take up the slack. I don't believe either the Liquid cooled P W or Wright engines ever even flew in a test mule, besides the timing is all wrong for the first 3 fighters. The two Hyper engines were planned to be turbo-charged so their performance _without_ the turbos may be a little suspect. The Army may also have been a little optimistic in how much bending and flipping you can do to an engine. It can be done but not only requires new crankcases (and possibly crankshafts) but requires new oil and coolant pick up points and such. Easier than starting over but requiring a lot of time and effort for each different version/arrangement. This was part of the advantage of the Allison, it used one basic block/power section at a time and the nose (prop) gears _OR_ front cover for extension shaft engines fit on the same block. The production lines could be switched from P-39 engines to P-38/40 engines overnight and the factory often ran the two types of engine for several weeks at a time in alternating batches depending on need. 
The different Hyper engines (upright, flat, or inverted) might need different production lines or more time for change over. 
I am not sure when the Army decided the Lycoming O-1230 was too small and doubled it up to make the H-2470 but it may be out of the running even if you did bend it into a 60 degree V engine. It weighed 1325-1342lbs depending on source (without turbo) and was rated at 1200hp for take-off and at 25,000ft with the turbo ( but might not have ever been tested at that altitude?) and was longer than the Allison. 
The Army seemed to favor the Continental I-1430 more. They certainly _planned_ to use it in a lot more prototypes. Including the Bell P-39E, the Curtiss XP-53, The Lockheed XP-49 (re-engined P-38?) and the MacDonald XP-57. Development slipped by several years and "airworthy" examples only became available in Nov 1942 (?), if you could call the examples the XP-49 got "airworthy". Even in late 1943 they were troublesome and rarely, if ever, gave the full "specified" power, so even if development was sped up by several years you still have a questionable engine. And in it's upright remote gear box form it was about 20 in longer than the P-39s Allison which makes a direct substitution a little difficult. 

P-51 with no viable US V-12 in 1940-41? 

P-63 probably wouldn't get off paper without the Allison (or shouldn't considering the sad sagas of the XP-49 and XP-67)


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## Shortround6 (Aug 28, 2013)

tyrodtom said:


> What V8 did the Chrysler XV-2220 put together to make the V-16 ?



None, the engine was designed as a V-16 but with the "back to back" arrangement to help solve torsional vibration problems with the long crankshaft. This was not unheard of as I believe several straight eight racing engines of the 1930s were built the same way, or at least used two 4 cylinder engine blocks with the cam drives (and accessories/super charger) driven from between the blocks. The Crankshaft was also supported by a bearing on each side of the center "section". The Chrysler XV-2220 actually took the power for the propeller from the center of the engine and ran a shaft forward under the front half of the engine to the reduction gears. 

See: Chrysler IV-2220 - Wikipedia, the free encyclopedia

It didn't "fly" until 26 July 1945, developing new engines was never as easy or quick as it seemed to start with. Building large low stress engines in the late 20s/early 30s that gave 1/3 -1/2 hp per cu in of displacement wasn't that hard. Trying for 1.0 hp per cu got an awful lot harder.


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## Shortround6 (Aug 28, 2013)

A few notes/comments.



> 1) Chrysler hasd the XV-2220 V-16. It was two V-8's coupled back to back, made 2,500 HP and flew in the XP-47H.



As noted above it doesn't fly until the summer of 1945, Since Chrysler doesn't even put pencil to paper until a few weeks of the Merlin "deal" (summer of 1940) even a much faster development won't do much good. Best estimate _might_ be production examples showing up in the summer of 1943. Given the length and weight of this piece of machinery it WILL NOT substitute for the Allison in any existing airframe. 



> 2) Continental had the IV-1430 V-12 of 1,500 HP.



Continental, due to poor Government funding, doesn't build the first 12 cylinder engine until 1939. A number of single and two cylinder test rigs up until then. It doesn't get or even aim for 1500hp until well after 1940. And it needs a turbo to even attempt 1500-1600hp. It does no good for the P-38,P-39, P-40. 



> 4) Lycoming had the O-1230 flat-12 of 1,000 HP. Not sure if this could have been made into a 1,500 +HP class engine.



It is rather doubtful. It was rated at 1200hp for take off and at altitude with a Turbo. Without turbo and using a supercharger that is NOT sea level rated it may be stuck at 1150-1200hp even with 100/130 fuel. It is longer than the Allison even if bent and weighs just as much. 



> 5) Lycoming also had the XH-2470 of 2,300 HP. This was two O-1230 engine mounted sude by side vertically driving a single gearbox.



It also weighed about 2400lbs, No substitute for the Allison in existing airframes. It was also rated at 2300hp for take-off and at 1500ft Military power in low gear of a two speed single stage supercharger, but 1900hp at 15,000ft in high gear. Which gives us 950hp at 15,000ft for the O-1230 or any bent (V or inverted V) versions of it. The XH-2470 is also too late in timing for the critical 1941-42 period of Allison use/deployment.



> Or they could have developed an entirely new engine to a specification.



It take usually about 3 years minimum to develop a new engine and sometimes 3 years for a major modification of an existing engine so the Specification needs to be written in 1938 or so to have any effect (and actually 1937 or before to affect the 3 P-38, P-39 and P-40) .

A little more time line on the two hyper engines. The Lycoming, in spite of starting later and due in part to Lycoming sinking over 1/2 million dollars of their own money into the project advanced faster and in 1937 passed a 50 hour 1000hp development test was was flying in a a Vultee XA-19A test bed in 1938. 







The Continental passes a 1000hp 50hr development test in 1939. 

In 1937 the Allison had passed a 1000hp *150hour type test*. and yet still had problems in the summer of 1940 at 1040-1090hp at altitude.


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## Balljoint (Aug 28, 2013)

CobberKane said:


> On the other hand, once the war is won who wants a 'made in America' Rolls Royce? I think it was tried once and no-one bought them!



I recall reading somewhere that the Merlin royalty got to be rather substantial. Of course, once the war was won the surplus supply would have swamped what demand remained. Still the Allison P-82 still didn’t have the high altitude performance of the Merlin version.


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## Shortround6 (Aug 28, 2013)

I believe he is referring to to a car operation that was set up in 1921 in Springfield MA, and lasted until 1931. One source says that 1243 cars were built from 1926 through 1931 which is hardly "nobody bought them" for a car that could cost as much as $18,000 at the time. Many luxury car makers didn't make it through the depression.

>From Rolls-Royces own web site; " Rolls-Royce of America Inc. manufactured nearly 3000 Silver Ghosts and Phantoms before succumbing to the Depression."<


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## wuzak (Aug 28, 2013)

Just to add to what Shortround said:



GregP said:


> 1) Chrysler hasd the XV-2220 V-16. It was two V-8's coupled back to back, made 2,500 HP and flew in the XP-47H.



The IV-2220 V-16 was about 40" longer than the Rolls-Royce Griffon, which was of similar capacity and power. The Chrysler also weighed as much, or more.

Honestly, the reduced frontal area afforded by the IV-2220 was wasted in a P-47 - may have well used the H-2470 (but thta had been cancelled by then).




GregP said:


> 2) Continental had the IV-1430 V-12 of 1,500 HP.



I read once (I think it was in a Graham White book) that Continental spent more time on single cylinder development than Rolls-Royce spent on developing the Merlin to production.

In any case, when flown in the XP-49 and XP-67 it maybe made 1050hp. As the story has it, the McDonnell test pilot deliberately over-speeded the engines to destroy them. Also lost the XP-67 prototype in the subsequent fire.

There are claims that in late war testing the IV-1430 was able to make over 2200hp.




GregP said:


> 3) Continental had the V-1790 V-12. Early power was just over 700 HP and they didn;t proceed further with it.



That would seem to be a tank engine? Substantially heavier than a Merlin or Allison without a supercharger.




GregP said:


> 4) Lycoming had the O-1230 flat-12 of 1,000 HP. Not sure if this could have been made into a 1,500 +HP class engine.
> 
> 5) Lycoming also had the XH-2470 of 2,300 HP. This was two O-1230 engine mounted sude by side vertically driving a single gearbox.



Maybe it could have made 1500hp. At the same stage Merlins would be making 2000-2200hp on the same fuels.

I think it was Lycoming themselves that came to the conclusion that the O-1230 wasn't big enough or powerful enough for modern aircraft. So they doubled it.

It was a troubled engine program, and was cancelled mid war.

As SR says, not a substitute for a V-1710, but possibly could have worked for the P-47 (instead of the Chrysler).


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## Shortround6 (Aug 28, 2013)

> The IV-2220 V-16 was about 40" longer than the Rolls-Royce Griffon, which was of similar capacity and power. The Chrysler also weighed as much, or more.



Yes, the Chrysler was more a replacement for the R-2800 or R-3350 than for the Allison. 



> I read once (I think it was in a Graham White book) that Continental spent more time on single cylinder development than Rolls-Royce spent on developing the Merlin to production.



Not really Continental's fault. They were acting like a prototype shop for Wright Field who was dictating the design features and pace of development. Continental put little if any of their own money in the design and only completed projects, steps as the Army issued new contracts and paid for them. A very high degree of micro management. 



> That would seem to be a tank engine? Substantially heavier than a Merlin or Allison without a supercharger.



Got that right, it was an air-cooled engine. 2332 pounds dry, first used in the T-30 Heavy tank which showed up at Aberdeen Proving ground in April of 1948, Hardly an Allison substitute pre-WW II or in the early years. This version was gasoline fueled, later versions were converted to diesel and powered quite a number of US tanks.


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## wuzak (Aug 28, 2013)

Other types of US LC engines under development before or during the war were:

Wright R-2160 Tornado 
Pratt Whitney X-1800
Pratt Whitney XH-3130/XH-3730
Lycoming XR-7755

None of which could serve as a V-1710 replacement.


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## GregP (Aug 28, 2013)

Hey guys, 

The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs. Where the hell are you guys coming from? 

The XA-11 flew in 1936. Had it not worked, what exactly do you think they would have been doing for the next 5 years? Knitting? The Bf 109 flew in 1935 with a Rolls-Royce engine and then went through a Jumo until the DB was ready, and went to war before 1940. Are we too stupid to DO that? Right ... 

Saying it took years is RIGHT ... and we would have HAD years unless we did nothing when the Allison failed. I rather think it would have been noticed and a reaction would have been forthcoming on an alternate engine or three.

You are free to characterize us as people of non-action at the time, but I might remind you that BMW started out producing radials of US design, as did the Japanese. If the Allison had failed, there would have been a replacement coming along. Bet on it.


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## nuuumannn (Aug 28, 2013)

> In any case, we would have developed an American engine for our planes before adopting the Merlin unless wartime expediency had required we use Merlins. That could have been the case if the allisons had failed.



I agree with you there, Greg, but I don't necessarily agree that a foreign engine, such as the Merlin would not have been bought if a suitable American alternative could not be found in peacetime. There are a number of examples in aviation alone where foreign technology has been adopted by the USA outside of WW2; the Airco D.H.9, the Fokker F-VIIb, the English Electric Canberra and the Hawker Siddeley Harrier for example. Using the F-VIIb trimotor as a point, as a result of this aeroplane, trimotors became the configuration of choice for airline manufacturers and operators alike and it wasn't until the death of Knute Rockne in a F-VIIb that the trimotor fell out of favour and arguably led directly to the Boeing 247 and Douglas DC-1.

The argument that because American aircraft didn't use Merlins in large quantities is evidence that they would not have if there was no alternative is flawed; all it does is demonstrate that the USA had alternatives of its own and did not require a foreign engine. Sure, I can see the isolationist stance pre-war, but historical precedent dictates that if America has a need for something and it cannot produce it at home, it will go abroad if need be.

The thing with this particular 'what if' scenario is that stating that the USA would definitely not get a foreign engine is as unknown as predicting that it definitely would. Evidence eixsts to prove that the USA _might_ if it had to. But, yes, I agree; a home grown alternative would be examined and pursued.


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## wuzak (Aug 28, 2013)

GregP said:


> Hey guys,
> 
> The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs. Where the hell are you guys coming from?



The V-1710 was only delivered in small numbers by the outbreak of war in Europe (1939).

It was still being tweaked here and there.

Another poster suggested that Allison's finances weren't looking too clever in the late 1930s. Possibly Allison could have folded if not for GM's support.




GregP said:


> Saying it took years is RIGHT ... and we would have HAD years unless we did nothing when the Allison failed. I rather think it would have been noticed and a reaction would have been forthcoming on an alternate engine or three.



The IV-1430 was started at a similar time as the V-1710 (~ '30/'31), yet failed late in the war ~'43/'44.

Just because it was running before then doesn't mean it is going to be a success.


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## GregP (Aug 29, 2013)

Allison COULD have failed, true. Some engines DID fail. But saying we could not come up with an alternative V-12 or V-16 is ludicrous.

The Allison completed its US 150-hour type test in April 1937. The Merlin didn't.

At the end of the war, an overhaul a Merlin took the USAAF an average of 320 hours. An Allison overhaul took and average 191 hours. Source: Army Air Forces in World War II

In American service the Merlin rarely got more hours before TBO than the Allison. Can't say what the Birtish or Russian got. Source: WWII overhaulers visiting the Planes of Fame. Can't vouch for or refute what they said, but DID work for a shop overhauling ALlison for 1.5 years. We had ALlisons out tgehre FLYING with 1,100+ hours on them and still running strong. I have seen Merlins fail at 25 hours ... but have also seen ONE Allison come in with low oil pressure at 250 hours.

Turned out it was flogged at an airshow abd 60 inches of boost with only 2.5 hours on the engine. The oil pressure waws within spec, but lowered than before the aerobatic flight. We attributed this to inadequate break-in. When reworked (not repaired ... the oil pressure was still within spec) and broken in properly (under warranty despite the abuse), the engine is NOW flying fine many hundreds of hours later with no trouble.

There is nothing wrong with the Allison that the USAAF didnlt require. Allison twice offerd to make ot a 2-stage supercharged wngine and was turned down by the USAAF. Finally they allowed Allison to produce an auxiliary supercharger, but a 2-stage, engine-mounted unit similar to the 2-stage Merlin would have been both lighter and better.


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## bob44 (Aug 29, 2013)

GregP said:


> Hey guys,
> 
> The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs.



Yes, if the Allison would have been a total failure, it should have been realised well before the start of the war in Europe.
Giving time to make it right, or the possibilities of developing another inline or adapting a foreign design.


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## Shortround6 (Aug 29, 2013)

As I have said before in this "what If" When the Allison fails to show up is critical. 

Fails to be invented/designed in 1930-34 is one thing, plenty of time to come up with an alternative. 
1935-37 things get a little dicier. 
Allison is being developed and then turns to crap in 1938-39? Things get a lot more difficult for the US. 
Allison does everything just as done Historically but can only build 11,500 engines in 1942 ( which still ten times what they built in 1940) instead of 14,900 leaving the US 3400 engines short? what is the US alternative? 

Please remember that the Army paid for a NEW factory to build Continental I-1430s. The Factory wound up building P W R-1340s for several years and then switched to building Merlins in 1944. So things did not always go according to plan. 

It turned out that the Allison was a better basic engine than the Merlin but that was by NO MEANS a known fact even in the summer of 1940. By the summer of 1940 3-4000 Merlins had been built compared to under 200 Allisons and the Allison's being built had to be operated at reduced power until they could be reworked. 

Telling us how great Allisons are NOW is a waste of space. Most Allisons flying now use either the 12 counterweight crank or late production 6 counterweight cranks don't they? By 1942 Allison crankshafts were both shot peened and nitrided which add tremendously to their life over the crankshafts being produced in 1940. The basic block castings were also strengthened and even the casting process was changed to increase strength and reduce the scrap rate. Allison got rid of the early reduction gear (long nose) used on ALL early P-40 engines because it was a weak point (and they had been told so before it went into production). 

The Allison was a very good design and the Allison company (and GM) deserve great praise for both building it in the quantities they did and in improving the basic engine so the later ones were so much better than the early ones ( but don't forget that both P &W and Wright were also improving their engines). 
This doesn't change the FACTS that a number of the alternative engines were problematic and had built in flaws that could NOT be gotten rid of without MAJOR redesign and time. In fact it just helps point out how lucky/skilled/smart the Allison design team was. 

As far as the US not using British designed engines? How many US Jets used British designed (or based) engines from 1945-1960 and beyond?


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## GregP (Aug 29, 2013)

Your post is a waste of space to me, but that's not a challenge to a fight, it is a simple retort to your words. 

Passing the type test IS military acceptance of the design. It could NOT have failed in 1938 - 1939. It could have failed in April 1936 but didn't.

We're talking piston engines in WWII, not post-war cooperation on jets after we won a world war together, defeating the most powerful enemy ever created to date.

BIG difference in attitudes and possibilities. By 1940, all that was needed was more Allisons with some inevitable development associated with ALL piston engines of WWII. I just wish the development had included a government-funded, 2-stage, integral supercharger ... but it didn't. That's life. By the end of the war, the HP from a Merlin or an Allison was formidable.

Ah well, therein lies a tale of it's own.


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## wuzak (Aug 29, 2013)

Greg, you have to admit that, V-1710 aside, the development of liquid cooled engines in the US proved to be problematic.

None of them came to an acceptable standard.

btw, while the Merlin didn't complete the US 150 hour test in 1937 it didn't really have to. It was subjected to, and passed, the British equivalent (the 114 hour type test). Not sure when it first did that, though.


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## gjs238 (Aug 29, 2013)

GregP said:


> 13,708 Merlin-powered P-51's counting the two conversions from P-51A to P-51B.



So, if the V-1710 was a failure, and there was no Mustang, then what would have become of those 13,708 Merlins?


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## Shortround6 (Aug 29, 2013)

GregP said:


> Your post is a waste of space to me, but that's not a challenge to a fight, it is a simple retort to your words.



Nobody is debating if the Allison or Merlin is the better engine today or even which was the better engine in 1942. 



GregP said:


> Passing the type test IS military acceptance of the design. It could NOT have failed in 1938 - 1939. It could have failed in April 1936 but didn't.



Really? Jumo 222 passed a type test, R-R Vulture passed a type test, Napair Sabre passed a type test, Wright R-3350 passed a type test. None were anywhere near ready for squadron service. Production Allison's in 1940 were operated a higher power level than the V-1710 that passed the type test in *April 1937*.
Engine that passed the Type test in *April 1937* was rated at 1000hp/2600rpm/40 in for take-off and 1000hp/2600rpm/40 in at sea level military power. Engines in production in the Summer of 1940 were _rated_ at 1040hp/3000rpm/42in for take-off and 1040hp/3000rpm/14,300ft /41in? Military power. But hey, whats an extra 400rpm on a 1937-40 aircraft engine, right? 
The 1040hp engine used in the P-40s took 7 tries and 5 engines to pass it's 150 hour model test. It didn't pass until _August_ 1940. The engines already built were restricted to 950hp at 2770rpm for take-off, 950hp at 2770 rpm for Military power to 8,000ft and 838 hp at 2600rpm to 8,000 until brought back to the Allison Factory and re-worked. 
Please note that the V-1710-33 engine used in the early P-40s didn't pass it's model test until a point in time about 1/2 way BETWEEN initial talks Between the US, Britain, Ford/Packard and Packard signing the agreement.

Allison's success was by no means a sure thing in 1940 let alone 1937. The US was fortunate that Allison's people were as good as they were and they were able to Bring the Allison along as they did, meeting and exceeding the challenges they met on the way.


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## Shortround6 (Aug 29, 2013)

There are "type" test and "model" tests, which sometimes overlap. A "type" test is often done by a government body (Army/Navy/National aeronautics board, etc) Model tests are often done by the manufacturer but may have "observers" from the customer or regulating agency in attendance. Corrections welcome on this. 

The engine has to pass a "type" test to be 'accepted' and/or be declared "airworthy". Governing bodies can decide if engines with modifications/changes can operate on the basis of the original "type" test or if a new test is needed, changes in rated power levels would usually require a new test, changing the carburetor or magneto or something like probably wouldn't. WEP settings don't require a full 100/114/150 hour test. They do require a certain amount of time be spent at the WEP settings ( for the US that was 7 1/2 hours total at the WEP power level but done 5 min at a time with cool down periods between each "burst". 

The Merlin did "fail" it's US type test which was run between August 12, 1941 and Nov 1 1941 and included a 20hr penalty run over and above the 150hr test. The engine did complete the 150 hours but on tear down was found to have 3 cracked pistons, chrome plating coming off the cam followers, worn impeller shaft, sheared rivets in the supercharger clutch plates and a few other problems. Due to the war situation it was decided to "pass" the Merlin. The Allison's tested in 1939-40 "might" have passed a "relaxed" test but out of the 5 engines at least one broke a crankshaft and another (or 2?) cracked a block. Engine that passed had a crack in the cylinder head cooling passage. 

Building high powered aircraft engines was not an easy thing. These engines had power to weight ratios comparable to or exceeding many race car engines of the day and were built in large quantities instead of handfuls and were required to last much, much longer than the race car engines.


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## gjs238 (Aug 29, 2013)

In the absence of the V-1710, wonder if a "new" R-1830 powered fighter would have been viable.
At least until the R-2800 powered fighters came online.
Such a beautiful job was done on the P-51, wonder what those boys could have done with the R-1830.


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## Shortround6 (Aug 29, 2013)

Again, we have a moving "target" or moving "base line".

In the Spring of 1939 the XP-40 demonstrated 22% less drag than the P-36 and since the XP-40 was the 10th production P-36 airframe we can assume the differences aside from the engine were pretty minimal. By late 1942 P&W had gotten the drag difference down to about 8% on the factory test mule pictured earlier. And/or done a better job of using exhaust thrust? Better radial installations were done but they come even later. 

What kind of radial installation can you get (reasonably expect) in 1940-41 for the R-1830? somewhere in between 8 and 22% more drag than the Allison? assuming that the engine/radiator installations on the XP-40 and Allison P-51s were equal. If the P-51 installation is better that leaves the radial with further to catch up. An R-1830 powered Mustang may be a much faster plane than a P-36 but that does NOT mean it was up to world standard in 1942.


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## tomo pauk (Aug 29, 2013)

A P-51-sized airframe might be too much for the R-1830 (P-66 being a better choice?) - the R-2800 being much better alternative? The main shortcoming being the combat radius?

Another alternative might be the Mustang's prototype flying on British-supplied Merlin (III/XII/X/XX)?


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## gjs238 (Aug 29, 2013)

I didn't mean to suggest a R-1830 powered P-51, but something superior to other R-1830 powered fighters.
Something non-naval (i.e., light) and really clean (ala P-51).

PS: This would be something to supercede the P-36.


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## tomo pauk (Aug 29, 2013)

Then it's the P-66? It was about as fast as the P-40, despite the radial engine of modest power, ie. the R-1830 with single stage supercharger. Maybe we should ditch the fuselage MGs so the installation of the 2 stage R-1830 is easier, while substituting the 4 wing LMGs with HMGs?


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## Shortround6 (Aug 29, 2013)

> A P-51-sized airframe might be too much for the R-1830 (P-66 being a better choice?) - the R-2800 being much better alternative? The main shortcoming being the combat radius?



Main problem is the R-2800 is way too late in timing. 

By the end of 1942 the US built over 11,000 Allison powered fighters, almost 1700 of them P-38s, about 1900 R-1830 powered fighters and 720 R-2800 fighters. 

Even trying to use the singe stage bomber/transport R-2800 engines and _stopping all_ B-26 production is going to leave you way short of engines until late in 1942.


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## GregP (Aug 29, 2013)

I might point out that some of the possible Allison alternative engines weren't necessarily failures ... they weren't proceeded with. 

Had the Allison failed, the desired to peoceed with them might have been of somewhat higher priority.


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## Shortround6 (Aug 29, 2013)

We have been over the possible (or at least the probable) Allison alternatives. Alternatives being liquid cooled V-12s, either upright or inverted (or flat). of around 1200-1600lbs. 2200-2400lb H-24s are NOT Allison alternatives in the sense that you could re-engine a P-36/P-40 with them. Since P-40s made up about 43% of the fighters built by Jan 1st 1943 coming up with different airframes to take bigger engines would seriously impact fighter production in 1941-42 and 43. 

The Lycoming was wasn't "proceeded with", why? It didn't offer enough power without a turbo-charger ( and barely enough with one), it was longer in the power section (basic block/crankcase) than an Allison and it weighed just as much. Before we start talking about "development" consider that the Allison at 3000rpm will flow 22% more air per minute than the Lycoming will at 3400rpm. Assuming equal manifold pressures and equal breathing through the valves and manifolds it means the Lycoming needs a LOT of "development" to equal the Allison. The smaller cylinders do mean it can use a bit more boost on the same fuel but that 22% airflow gap may be too big to get around. If an Allison with 1150hp at 12,000ft wasn't considered quite good enough then 950hp at 15,000ft (about 100hp less than a Merlin III) gets you what for performance?

The Continental ***-1430 went through *SIXTEEN* different Army type numbers/models before it was not "proceeded with" how many were paper studies I don't know but the last one was a turbo-compound with the turbo-charger geared to the crankshaft so the turbine could add power to the prop. Some models had two speed prop drives or counter-rotating propellers. Since this was truly the Army's "baby" they didn't give up on it for quite some time. Even the simple versions (single prop, single prop speed, no turbo,etc) went 100-200lbs more than an Allison and were about 20in longer. Most models were rated at either 1250 or 1350 hp for take-off. Maybe if they spent a lot less time with the "tricks, bells and whistles" they might have actually got a workable engine. 

After that the field changes from "probable" to "possible". Ford, even if they pull a miracle, won't have a production engine in time for most of 1942. That kind of leaves Packard trying to build a modernized version of the V-2500 or air version of the Torpedo boat engine.

Unless I am missing something that is about it for US designs that can "substitute" for the Allison. The other Liquid cooled engines were all more like Liquid cooled substitutes for the R-2600, R-2800 and R-3350.


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## GregP (Aug 30, 2013)

Yes, you ARE missing something. The Allison didn't fail and WAS ordered. If it HAD failed, another alternate engine would have been developed and proceeded with. It NEVER happened, so I don't know which one would have been developed and neither do you ... but one would have beeen developed.


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## wuzak (Aug 30, 2013)

GregP said:


> Tes, you ARE missing something. The Allison didn;t fail and WAS ordered. If it HAD failed, another alternate engine would have been developed and proceeded with. It NEVER happened, so I don't know which one would have been developed and neither do you ... but one would have beeen developed.



Greg, the ones most likely (the IV-1430 and O-1230) didn't stop their development because the Allison was a success. The IV-1430's development continued well into the war, long after the Allison was being churned out by the thousand. The O-1230 was deemed to be too small and not have enough power, so it was doubled up as the H-2470 and continued for a few more years.

The US government built a factory in which to build the IV-1430. The IV-1430 was to built as well as the V-1710, not just as a backup.


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## GregP (Aug 30, 2013)

They only made 23 ... I say it was a "backup" engine that did not get proceeded with after the Allison had success ... but COULD have worked out just fine. I say that because development was stopped, somethinhg that might NOT have happened if the Allison had failed.

One can only wonder what engine they would have developed had the Allison failed. I wouldn';t choose one from the crowd myself ... the desisions at the time were just too policitical to predict. Purportedly they ignored warning of the attack on Pearl Harbor just to get us into the war! How crazy is that?

I guarantee it would have been SOME U.S. engine, not the Merlin, just due to attitudes at the time ... not due to the Merlin, which was and is a great engine among successful WWII engines. If we could go back with hindsight, we probably WOULD build the Merlin into our fighters ... but not at the time in any great numbers.


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## wuzak (Aug 30, 2013)

GregP said:


> They only made 23 ... I say it was a "backup" engine that did not get proceeded with after the Allison had success ... but COULD have worked out just fine.



They gave up on the IV-1430 in 1944. They started in 1932.

Basically because it did not perform as advertised.




GregP said:


> I guarantee it would have been SOME U.S. engine, not the Merlin, just due to attitudes at the time ... not due to the Merlin, which was and is a great engine among successful WWII engines. If we could go back with hindsight, we probably WOULD build the Merlin into our fighters ... but not at the time in any great numbers.



As stated previously, it depends on timing.

If the Allison is lost late in the piece, a replacement would probably be needed quickly. The quickest way was to build the Merlin in its stead. Pre war it is needed to produce P-40s for the British and French (and the Mustang I). The IV-1430 wasn't ready around that stage, so couldn't step into the breech.


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## Shortround6 (Aug 30, 2013)

GregP said:


> Yes, you ARE missing something. The Allison didn't fail and WAS ordered. If it HAD failed, another alternate engine would have been developed and proceeded with. It NEVER happened, so I don't know which one would have been developed and neither do you ... but one would have beeen developed.



I don't believe I am missing anything. *IF* the Army had chose to pursue _either_ of the hyper engines it would have been pouring money, time and effort down a rat hole. 

Look again at the O-1230 Lycoming and lets assume you can bend it into a 60 degree V with little trouble. Now compare it to the R-R Peregrine. The Peregrine was 1296 cu in instead of 1234 or 5% larger. The Peregrine was 200lbs lighter and a whole lot shorter. Peregrine could make 885hp at 15,000ft. _without_ turbos or extra supercharger stages. 
The Lycoming would turn 3400rpm which helped but basically the USAAC would have trying to turn a Peregrine into a Merlin. It was too small to do the job. No amount of flag waving can change that. 

The Army screwed up several times in the initial development of these engines. That is with the benefit of hindsight. 
One was not funding a 12 cylinder version for way too long. One and two cylinder test rigs can tell you a lot about the combustion and breathing a of a cylinder design, they tell you nothing about vibration problems. No Allison _may_ mean the Army builds a 12 Cylinder version sooner, depending on when the Allison fails in this scenario. 
Two was insisting on a 300 degree coolant temperature for too long. Good in theory, it was supposed to keep radiator size down but in practice it brought very diminishing returns over 250 degree coolant temp in actual heat transfer and shifted some of the cooling load to the oil system requiring larger oil coolers so there was NO net gain. 
Three, and probably the most important was the Army's insistence on separate cylinders like a WW I Mercedes or Liberty engine. Granted they did use a one piece head across the cylinders but this form of construction makes for wider cylinder spacing which means the engine is longer than the equivalent enbloc engine. The extra length means more weight. The extra length of the crankshaft means more problems with torsional vibration ( the cylinders further from the load/prop twist the crankshaft more when they fire and then when the cylinder/s go from power to exhaust the stress is removed) than a short crank. The assembly is weaker than the cylinder block style engine which limits the increase in power without more beefing up (weight). 

Now there is nothing to prevent the Army and Continental from taking the cylinder dimensions, piston, con rods, valves/valve train and spark plug placement and designing an enbloc engine that is shorter and lighter using those features except time and money.
That and somebody slapping the Army project officers up side the head to _STOP_ all the silly _extra features_ until they get the basic engine sorted out. 1350-1600 hp engines don't _need_ two speed propeller drives, or the choice of two different gear ratios _without_ extra parts depending on how they are assembled, or some of the other "stuff" they played with while the basic engine didn't work. 

The engine construction was a fundamental flaw that would have bitten them in the butt even if they had gotten the original engines to work as advertised. It is harder to increase the power when the better fuels become available because you are dealing with a weaker engine/crankshaft assembly. 

And as Wuzak has noted, the I-1430 was NOT dropped and the Army was signing contracts for prototype fighters using the I-1430 in the summer of 1941. 

Your faith is touching but let us also remember that P W thought they could get the R-4360 into production quicker than ANY of the liquid cooled engines they were working on. A mistake in judgment or was it actually true? 

And several projects that "looked" easy took a long time to get into operation, like the R-4360. _Just_ take the cylinders from a R-2800 and put 7 on each crank throw and then use 4 crank throws. Or the Wright R-3350, just take an R-2600 and add two cylinders to each row, from 7 to 9 and Wright was already making 9 cylinder engines. We know how long that took to sort out.


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## swampyankee (Aug 30, 2013)

Shortround6 said:


> Again, we have a moving "target" or moving "base line".
> 
> In the Spring of 1939 the XP-40 demonstrated 22% less drag than the P-36 and since the XP-40 was the 10th production P-36 airframe we can assume the differences aside from the engine were pretty minimal. By late 1942 P&W had gotten the drag difference down to about 8% on the factory test mule pictured earlier. And/or done a better job of using exhaust thrust? Better radial installations were done but they come even later.
> 
> What kind of radial installation can you get (reasonably expect) in 1940-41 for the R-1830? somewhere in between 8 and 22% more drag than the Allison? assuming that the engine/radiator installations on the XP-40 and Allison P-51s were equal. If the P-51 installation is better that leaves the radial with further to catch up. An R-1830 powered Mustang may be a much faster plane than a P-36 but that does NOT mean it was up to world standard in 1942.



The Mustang easily had the lowest zero-lift drag coefficient of any propeller fighter to see service in WW2, with a value of about 0.017 (I've seen values from 0.0163 to 0.0176). Most fighters were between about 0.021 and about 0.025 and, except for the Mustang, there was little to chose between air-cooled and liquid-cooled engines. Cooling drag is a major issue on all piston-engined aircraft, and it's one which is remarkably easy to get wrong, whether the engine is air-cooled directly, like an R-1830, or indirectly, like a Merlin. NAA did a remarkable job on the Mustang's aerodynamics; it had a zero-lift drag coefficient that was no less than 15% better than any other piston-engined fighter to see service in WW2, and most of that was probably due to excellent cooling system design.

Back to the Allison engine. As as been mentioned several times, the timing of the V-1710 failure is crucial. If the engine is a total failure in 1937, there's no chance to get a domestic replacement before about 1941; to be useful, the alternative engine would have to be started no later than 1933. The only way for that to happen would be for the Army or Navy to fund an engine with the same external dimensions, weight, and prop shaft location and rpm in about 1930. If it happens later, say after the UK shops around for US plants to license build Merlins, the answer is to use the Merlin.


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## drgondog (Aug 30, 2013)

swampyankee said:


> The Mustang easily had the lowest zero-lift drag coefficient of any propeller fighter to see service in WW2, with a value of about 0.017 (I've seen values from 0.0163 to 0.0176). Most fighters were between about 0.021 and about 0.025 and, except for the Mustang, there was little to chose between air-cooled and liquid-cooled engines. Cooling drag is a major issue on all piston-engined aircraft, and it's one which is remarkably easy to get wrong, whether the engine is air-cooled directly, like an R-1830, or indirectly, like a Merlin. NAA did a remarkable job on the Mustang's aerodynamics; it had a zero-lift drag coefficient that was no less than 15% better than any other piston-engined fighter to see service in WW2, and most of that was probably due to excellent cooling system design.
> 
> *While the cooling system design was the best or near best of the war, the wing was the dominant Drag reduction contributor..*
> 
> ...



Horkey also believed the second order curve of the upper and lower cowl lines were significant.

I do agree your 'range' of CDo as long as we recognize that when calculating actual CDo based on high speed flight tests that Sea Level speed range is less influenced by compressibility drag contribution than at 25-29000 feet. It is interesting that the P-51B-1 flight tests noted the probability that the prop tips were operating near or at supersonic velocities adding another component skewing CDo calcs.

The other complications (calculating CDo) include the constant for propeller efficiency, the percent you choose for added contribution of exhaust thrust to total thrust.. IIRC, NAA used 12% for Thrust contribution and .85 efficiency for the four blade 11ft-6" diameter prop and .479:1 Gear Reduction ratio. When using that as the base set of factors, I get .0168 for CDo without racks and .0173 with racks...


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## swampyankee (Aug 30, 2013)

Some surprisingly small changes can also have significant effect on drag. I've read that the matte black paint used on some Mosquito night fighters cost close to 20 mph in top speed.


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## gjs238 (Aug 30, 2013)

Romulan cloaking device much lighter.


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## wuzak (Aug 30, 2013)

When I started the Merlin thread, it occurred to me the main difference between Allison and Rolls-Royce was the number of products they were developing.

In the mid to late 1930s Allison was developing the V-1710 and the X-3420/V-3420, which was heavily based on the V-1710.

Rolls-Royce, on the other hand, were developing the Kestrel (late in its development), Peregrine, Exe, Vulture, Merlin, Griffon and Crecy. None of which shared much of anything with the others.


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## Shortround6 (Aug 30, 2013)

Allison was a much smaller company, While they had some work converting Liberties to air cooled engines, they specialized in bearings and gear sets/remote drives. They had built ALL the reduction gears for Packard aircraft engines in the 20s for one example. The also built supercharger parts under sub-contract to General Electric. Until 1939 the V-1710 was a sideline.


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## wuzak (Aug 31, 2013)

Shortround6 said:


> Allison was a much smaller company, While they had some work converting Liberties to air cooled engines, they specialized in bearings and gear sets/remote drives. They had built ALL the reduction gears for Packard aircraft engines in the 20s for one example. The also built supercharger parts under sub-contract to General Electric. Until 1939 the V-1710 was a sideline.



Very good point SR.


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## GregP (Sep 1, 2013)

I have been taken to task for stating in this thread that an alternative American engine would be produced if the Allison had failed. People have said that using the Merlin would be the choice that would have been made. 

Let’s take a look at that from a factual rather than emotional or logical basis. In the lists below, which are incomplete, I show 187 fighters that either tried out for service or were acutally procured, running form 1920 into WWII. I didn't even include the US Navy monoplane fighters or the Bell P-63 series.

Of these 187 real planes, not including the P-51 for reasons stated above, only 3 had foreign engines and only 2 were bought ... the P-40F and L.

ALL the rest had US-designed engines. Let's see, I have a bowl with 187 white pills in it and 3 red pills. Reach in and draw one out blind. How many would bet they had a red pill?

Facts like this are why I said the US would develop its own alternate engine if the Allison V-1710 had failed. It hasn't got naything to do with whether or not the Merlinw as a good engine, it has to do with FACTS. If I went ahead and added the Bell P-63 and the US Navy monop[lanes, the list would likey be 250 planes or more with 3 have foreign engines.

So, you guys who think we would design planes with Merlins, on what basis in historical fact would you believe that? If you answer, you might include all the foreign engine piston fighters other than the P-51 series. The list will be VERY short I think.



US Army Pursuits from 1920 – 1932:

1. Vermille VCP-1, Wright-Hispano H in prototype, re-engined with a Packard 1A-2025 V-12.
2. Dayton-Wright XPS-1, Lawrence -1 radial.
3. Curtiss PN-1, Liberty 8, L-825. 
4. Curtiss PN-1A, Wright R-1 (R-1454).
5. Engineering Division PW-1, Packard 1A-1237.
6. Engineering Division PW-1A, Packard 1A-1237.
7. Loening PW-2, Wright H.
8. Loening PW-2A, Wright H.
9. Loening PW-2B, Packard 1A-1237.
10. Orenco PW-3, Wright H.
11. Gallaudet PW-4, Packard 1A-1237.
12. Fokker V-40, Wright H.
13. Fokker PW-6, Wright H-2.
14. Fokker PW-5, Wright H-2.
15. Curtiss XPW-8, CurtissD-12.
16. Curtiss PW-8, -8A, -8B, Curtiss D-12.
17. Boeing XPW-9, Curtiss D-12.
18. Boeing PW-9, Curtiss D-12.
19. Engineering Division TP-1, Liberty 12.
20. Thomas-Morse TM-23, Curtiss D-12.
21. Thomas-Morse TM-24, Curtiss D-12.
22. Curtiss P-1, Curtiss V-1150.
23. Curtiss P-1A, Curtiss V-1150.
24. Curtiss P-1B, Curtiss V-1150.
25. Curtiss P-1C, Curtiss V-1150.
26. Curtiss P-2, Curtiss V-1400.
27. Curtiss XP-3A, Pratt Whitney R-1340.
28. Curtiss P-3A, Pratt Whitney R-1340.
29. Curtiss XP-4, Packard 1A-1500.
30. Curtiss P-5, Curtiss V-1150.
31. Curtiss XP-6, Curtiss V-1570.
32. Curtiss P-6, Curtiss V-1570.
33. Curtiss P-6A, Curtiss V-1570.
34. Curtiss P-6B, Curtiss V-1570.
35. Curtiss P-6D, Curtiss V-1570.
36. Curtiss Hawk I, Curtiss V-1570.
37. Curtiss Hawk P-6S (Cuba), Pratt Whitney R-1340.
38. Curtiss XP-7, Curtiss V-1570.
39. Boeing XP-8, Packard 2A-1530.
40. Boeing XP-9, Curtiss V-1570.
41. Boeing P-12, Pratt Whitney R-1340.
42. Boeing P-12A, Pratt Whitney R-1340.
43. Boeing P-12B, Pratt Whitney R-1340.
44. Boeing Model 100, Pratt Whitney SR-1340D.
45. Boeing P-12C, Pratt Whitney R-1340.
46. Boeing P-12D, Pratt Whitney R-1340.
47. Boeing XP-15, Pratt Whitney SR-1340D.
48. Boeing 218, Pratt Whitney SR-1340C.
49. Boeing P-12E, Pratt Whitney R-1340.
50. Boeing P-12F, Pratt Whitney R-1340.
51. Boeing XP-925A, Pratt Whitney SR-1340F.
52. Thomas-Morse XP-13, Curtiss H-1640.
53. Thomas-Morse XP-13A, Pratt Whitney SR-1340C.
54. Curtiss XP-17, Wright V-1460.
55. Curtiss YP-20, Wright R-1820.
56. Curtiss XP-22, Curtiss V-1570.
57. Curtiss XP-6E, Curtiss V-1570.
58. Curtiss P-6E, Curtiss V-1570.
59. Curtiss P-6F, Curtiss V-1570.
60. Curtiss XP-6H, Curtiss V-1570.
61. Curtiss XP-23, Curtiss V-1570.
62. Berliner-Joyce XP-16, Curtiss V-1570.
63. Berliner-Joyce Y1P-16, Curtiss V-1570.

So far, from 1920 – 1932, we have 63 airplanes trying out for the US Army and 63 US-designed engines. What about the US Navy?

1. Boeing FB-1, Curtiss D-12.
2. Boeing FB-3. Packard 1A-1500.
3. Boeing FB-4, Wright P-2.
4. Boeing FB-5, Packard 2A-1500.
5. Curtiss F6C-1. Curtiss D-12.
6. Curtiss F6C-2, Curtiss D-12.
7. Curtiss F6C-3, Curtiss D-12.
8. Bought FU-1, Wright R-790.
9. Wright XF3W-1, Pratt Whitney R-1340B.
10. Curtiss F6C-4, Pratt Whitney R-1340.
11. Curtiss XF6C-5, Pratt Whitney R-1690.
12. Curtiss F7C-1, Pratt Whitney R-1340B.
13. Eberhart FG-1, Pratt Whitney R-1340C.
14. Hall XFH-1, Pratt Whitney R-1340B.
15. Boeing XF2B-1, Pratt Whitney R-1340.
16. Boeing F2B-1, Pratt Whitney R-1340.
17. Curtiss F8C-1, Pratt Whitney R-1340.
18. Curtiss XF8C-2, Pratt Whitney R-1340.
19. Curtiss F8C-4, Pratt Whitney R-1340.
20. Curtiss XF9C-7, Wright R-1820.
21. Vought XF2U-1, Pratt Whitney R-1340C.
22. Bristol Bulldog, Bristol Jupiter VII (US Navy tested 1 aircraft).
23. Berliner-Joyce XFJ-1, Pratt Whitney R-1340C.
24. Berliner-Joyce XFJ-2, Pratt Whitney R-1340.
25. Fokker XFA-1, Pratt Whitney R-1340C.
26. Curtiss XF9C-1, Wright R-975C.
27. Curtiss F9C-2, Wright R-975.
28. Boeing XF4B-1, Pratt Whitney R-1340.
29. Boeing F4B-1, Pratt Whitney R-1340.
30. Boeing F4B-2, Pratt Whitney R-1340.
31. Boeing F4B-3, Pratt Whitney R-1340.
32. Boeing F4B-4, Pratt Whitney R-1340.

That’s 32 Navy planes with one foreign test. So far, we have 95 airplanes with 1 foreign engine that was a demo test from Bristol. What about WWII monoplane fighters? Exclusive of the P-51 series … OK …

1. Lockheed YP-24, Curtiss V-1570.
2. Consolidated Y1P-25, Curtiss V-1570.
3. Boeing Y1P-26, Pratt Whitney R-1340.
4. Boeing P-26A, Pratt Whitney R-1340.
5. Boeing 281, Pratt Whitney R-1340.
6. Curtiss XP-934, Pratt Whitney R-1340.
7. Curtiss XP-31, Curtiss V-1570.
8. Boeing YP-29, Pratt Whitney R-1340.
9. Boeing YP-29A, Pratt Whitney R-1340.
10. Consolidated P-30, Curtiss V-1570.
11. Consolidated PB-2A, Curtiss V-1570.
12. Northrop 3A, Pratt Whitney SR-1535.
13. Vought V-141, Pratt Whitney R-1535.
14. Vought V-143, Pratt Whitney R-1535.
15. Seversky SEV-3M-WW, Wright R-975.
16. Seversky SEV-1, Wright R-1820.
17. Seversky P-35, Pratt Whitney R-1830.
18. Seversky 2PA-A, Wright R-1820.
19. Seversky 2PA-L, Wright R-1820.
20. Republic P-35A, Pratt Whitney R-1830.
21. Republ;ic Guardsman (AT-12), Pratt Whitney R-1830.
22. Curtiss design 75, Pratt Whitney R-1535.
23. Curtiss design 75B, Wright XR-1820.
24. Curtiss YP-36, Pratt Whitney R-1830.
25. Curtiss P-3A, Pratt Whitney R-1830.
26. Curtiss P-36C, Pratt Whitney R-1830.
27. Curtiss P-36F, Pratt Whitney R-1830.
28. Curtiss XP-37, Allison V-1710.
29. Curtiss YP-37, Allison V-1710.
30. Curtiss 75R, Pratt Whitney R-1830.
31. Curtiss XP-42, Pratt Whitney R-1830.
32. Curtiss Hawk 75, Wright GR-1820.
33. Curtiss H-75Q, Wright CR-1820.
34. Curtiss Hawk 75A-4, Wright R-1820.
35. Bell XFM-1, Allison V-1710.
36. Bell YFM-1, Allison V-1710.
37. Bell YFM-1A, Allison V-1710.
38. Bell YFM-1B, Allison V-1710.
39. Curtiss-Wright CW-21, Wright R-1820.
40. Curtiss-Wright CW-21B, Wright R-1820.
41. North American P-64, Wright R-1820.
42. Vultee Vanguard prototype, Pratt Whitney R-1830.
43. Vultee P-66, Pratt Whitney R-1830.
44. Curtiss XP-40, Allison V-1710.
45. Curtiss P-40, Allison V-1710.
46. Curtiss P-40B, Allison V-1710.
47. Curtiss P-40C, Allison V-1710.
48. Curtiss XP-46, Allison V-1710.
49. Curtiss P-40D, Allison V-1710.
50. Curtiss P-40E, Allison V-1710.
51. Curtiss P-40F, Packard Merlin V-1650.
52. Curtiss P-40K, Allison V-1710.
53. Curtiss P-40L, Packard Merlin V-1650.
54. Curtiss P-40M, Allison V-1710.
55. Curtiss P-40N, Allison V-1710.
56. Curtiss XP-40Q. Allison V-1710.
57. Lockheed XP-38, Allison V-1710.
58. Lockheed YP-38, Allison V-1710.
59. Lockheed P-38, Allison V-1710.
60. Lockheed P-38D, Allison V-1710.
61. Lockheed P-38F, Allison V-1710.
62. Lockheed P-38G, Allison V-1710.
63. Lockheed 322, Allison V-1710.
64. Lockheed P-38H, Allison V-1710.
65. Lockheed P-38J, Allison V-1710.
66. Lockheed P-38L, Allison V-1710.
67. Lockheed P-38M, Allison V-1710.
68. Bell XP-39, Allison V-1710.
69. Bell XP-39B, Allison V-1710.
70. Bell YP-39, Allison V-1710.
71. Bell P-39C, Allison V-1710.
72. Bell P-39D, Allison V-1710.
73. Bell P-39F, Allison V-1710.
74. Bell P-39J, Allison V-1710.
75. Bell P-400, Allison V-1710.
76. Bell XP-39E, Allison V-1710.
77. Bell P-39K, Allison V-1710.
78. Bell P-39M, Allison V-1710.
79. Bell P-39N, Allison V-1710.
80. Bell P-39Q, Allison V-1710.
81. Seversky XP-41, Pratt Whitney R-1830.
82. Republic P-43, Pratt Whitney R-1830.
83. Republic P-43A, Pratt Whitney R-1830.
84. Republic P-47B, Pratt Whitney XR-2800.
85. Republic P-47B, Pratt Whitney R-2800.
86. Republic P-47C, Pratt Whitney R-2800.
87. Republic P-47D, Pratt Whitney R-2800.
88. Republic XP-47H, Chrysler XI-2220.
89. Republic XP-47J, Pratt Whitney R-2800.
90. Republic XP-47K, Pratt Whitney R-2800.
91. Republic P-47M, Pratt Whitney R-2800.
92. Republic P-47N, Pratt Whitney R-2800.

So, here is a list of 92 monoplane fighters of which 2 had Merlins, the P-40F and L. So far, we have 187 planes that either were bought by the USA or tried out for service. 3 had foreign engines and one of those was a Bristol demo unit. I haven’t added the P-63 series or the Navy monoplane fighters, but they run much the same.


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## swampyankee (Sep 1, 2013)

GregP said:


> Yes, you ARE missing something. The Allison didn't fail and WAS ordered. If it HAD failed, another alternate engine would have been developed and proceeded with. It NEVER happened, so I don't know which one would have been developed and neither do you ... but one would have beeen developed.



The OP was positing the hypothetical where the V-1710 failed. While I think there would have been hints of its failure long before 1937 or 1938 -- the development started as early as 1929 -- it's an equally legitimate question as "what would have happened had the USAAC given priority to development of mechanically, vs exhaust gas, driven superchargers?" 

Had the Allison been seen as a failure early enough, there would be an alternative funded; if it's too late, the USAAC doesn't have a domestic V-12 alternative. I think the USAAC would have had to made this sort of decision no later than late 1933 to get an engine developed in time to be available for aircraft such as the P-40.


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## swampyankee (Sep 1, 2013)

Referring to http://www.ww2aircraft.net/forum/aviation/ww2-without-v-1710-options-allies-38232-8.html#post1052886
Wright-Hispano was building Hispano-Suiza engines under license, which mildly changes your number of foreign-designed engines, but doesn't really change your conclusion.


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## GregP (Sep 1, 2013)

You are right, swampyankee. My point was that the US would have developed its own engine, not used the Merlin. The history I posted above shows taht is exactly what we did. Foreign engines weren't an option for the USA at the time. Since we had some Merlins avialble, we put them into the P-40F and L. The results didn't shown any significant performance gains and we went back to the Allisons for the balance of production in the real world.

If the V-1710 had failed, we would have developed alrernate engine of our own, just as we did from before 1920. I seriously doubt that, since we had a 25 year history of doing just that, we would somehow fall flat on our faces if the Allison had failed. It isn't reasonable under any circumstances to me.

This is not dislike of foreign engines like the Merlin on my part. It is simply what we DID back then.

If you look it up, we just didn't use foreign engines until the Merlins in the P-51 (successful) and P-40 (no improvement). It was war and we were building them for the British, so we got some and used them. The overhaul life wasn't especially good and the use of the Merlin by the USA didn't progress much father than the P-51 and a couple of models of the P-40. By the time we MIGHT have used more Merlins, the jet engine was in vogue and the pistons died out rather quickly.


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## GregP (Sep 1, 2013)

The Wright-Hispano engine was used in ONE prototype on my list (the first plane on it in fact), and it was later converted to an All-US engine.

Again, I have no problem using engines that have good power and reliability, no matter what the origin, but we didn't do that at the time to any great degree.


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## wuzak (Sep 1, 2013)

GregP said:


> If the V-1710 had failed, we would have developed alrernate engine of our own, just as we did from before 1920. I seriously doubt that, since we had a 25 year history of doing just that, we would somehow fall flat on our faces if the Allison had failed. It isn't reasonable under any circumstances to me.



Greg, as has been stated before, it depends on when the failure occurs.

If it is in 1933, there is no Melrin, so no optoion but to develop something else.
If it is 1937, the Merlin isn't too attractive a proposition.
If it is 1939/40, the Merlin is an option for licence production, but it would take a while to get going. But quicker than getting a new project or taking one of the existing hyper projects to production.


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## wuzak (Sep 1, 2013)

GregP said:


> 1. Lockheed YP-24, Curtiss V-1570.
> 2. Consolidated Y1P-25, Curtiss V-1570.
> 3. Boeing Y1P-26, Pratt Whitney R-1340.
> 4. Boeing P-26A, Pratt Whitney R-1340.
> ...



Greg, a quick look at the numbers of the aircraft in AHT (using Wiki, since I don't have access to AHT at the moment), I get:

103,034 fighters
50,125 fighters powered by liquid cooled engines ~49% of fighter production
34,821 fighters powered by V-1710s ~ 34% of production
15,304 fighters powered by Merlins ~ 15% of production, ~44% of liquid cooled fighters

The Merlin contribution was no insignificant to American fighter strength.

Some Merlins were put in P-40s - because that was the best available (USAAC/F) airframe at the time.

Studies were done to put Merlins in P-38s. One was delivered to Rolls-Royce Hucknall for a trial installation. This was blocked through political channels.
There was, IIRC, some consideration in installing the Merlin 2 stage engine in the P-63.


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## GregP (Sep 1, 2013)

If you take away the P-51, which was my premise, the Merlin is insignificant in the extreme.

It DOES NOT MATTER when the Allison would have failed, we would have come up with an engine of our own. If I extend my list, Wayne, it will reach 400 - 500 aircraft, with fewer than 5 with foreign engines. My list above didn't include Navy monoplanes, any attack planes, any torpedo planes, any observation planes, any bombers at all of 1 or more engines, or any trainers, observation, transport, or liaison planes.

You ought to know when you're wrong by sheer weight of numbers. In this case, you are.

The USA would not build an indigenous fighter with a Merlin or any other foreign engine up until the P-51. The P-40F/L was a way to use the Merlins coming off the production line and when they didn't produce better performance or better overhaul times, they were terminated in the P-40 line. ONLY the P-51 series continued with the Merlin. Remove it and you have almost nothing else to go on except an odd prototype or two.

On what would you base your assertion taht we would use the Merlin if the P-51 went away?

Wouldn't happen at the time, and that's the end of my participation in this argument. If you can't be convinced with the real numbers, then you can't be convinced at all. So be it.

We KNOW the P-51 and P-40F/L had the Merlin. Why not list all the other US-made planes with Merlins? I've done enough listing; you do this one, OK? 

Your post, should you choose to participate, will be VERY short.


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## Shortround6 (Sep 1, 2013)

Timing is everything. The US used the Hispano in and just after WW I because the US didn't have suitable "fighter" engine at the time. And BTW the Wright H2 was very definitely a Hispano derived engine. Changed from the original a bit to be sure but far from an "all American" engine. The Liberty not be considered a fighter engine at the time. 
Curtiss did come up with the K engine and then the D series and the US if not in the lead (and it may have been) was certainly in the top 2-3 liquid cooled engines in the world. However by 1926-27 the Air-cooled engines were coming on strong. Curtiss and Packard were the Major US players in liquid cooled engines and when Curtiss and Wright merged the liquid cooled engines were dropped. Not right away but very limited development was done on them. Packard lost their chief designer in an air crash and in the midst of the great depression dropped out of the aero engine business. 
By the Early 30s the US had only the Allison, and the hyper engine programs in the works. Packard was fitting a few engines into Speed boats and Curtiss-Wright was finishing of the last of the V=1570 Conqueror engines as they pushed the "new" R-1820 Cyclone (as opposed to the old R-1750 Cyclone). The air cooled engines took over the commercial market in the US. The US Army was the ONLY real customer for liquid cooled engines and with a rather small budget and an obsession with the hyper concept they managed to muck things up pretty good.

As international tensions got worse in the late 30s funding freed up a bit in some nations but in the US major increases in defense spending didn't happen until late 1938 and early 1939. Which is a bit late if it takes 3-4 years to go from initial design to quantity production. 
The US had some of the best radial engine in the world either in production or development in 1937-40. Aside from the Allison we had exactly bubkes for usable liquid cooled engines _at that point in time._
What the US might have been able to do either before or after may very well be another story. Trying to update 1920s designs may or may not work very well depending on how far you depart from the originals. In some cases considerable departure may be needed.

I do like the bit about the Merlin NOT improving the performance of the P-40 though, very 'inventive". It may not have improved the performance of the P-40 "enough" to keep it a front line fighter but to say that it didn't improve the performance is pushing things a bit. 

Below 15,000ft the P-40E was probably better, above 20,000ft the F was better. In between?? A p-40F was "supposed" to climb to 30,000ft in 19.42 minutes using 2850rpm the whole way while a P-40E took 40.1 minutes, just under twice as long, using 3000rpm for the first 5 minutes and 2600rpm for the rest of the climb. Above 20,000ft the F was about 30-40mph faster.


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## wuzak (Sep 1, 2013)

Greg, while the US _preferred_ to use their own equipment, they didn't always.

When they entered the war they used Spitfires, Beaufighters and Mosquitoes. They did this because they were available and the US didn't have their own equivalents yet, or not enough of them.

I see the situation is the same with the engines. If the V-1710, for what unlikely reason, cannot continue past 1939/40 there are two choices - develop an alternative or adopt the Merlin. Developing an alternative would probably not produce results until 1944, whereas Merlins could be rolling off the production line in 1942. In both scenarios there is a gaping hole in production of aircraft for the Allies, the difference being 2 years worth of production.

Without the V-1710 the race is on to get a replacement for the P-38, P-39 and P-40. The Merlin fits the bill quite easily, the most difficult one would be the P-39.

The fact of the matter is that the US developed and manufactured several good radials and one outstanding one (the R-2800), but only one production liquid cooled engine. That the V-1710 was excellent was important, because the next best could not even be described as "good".


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## GregP (Sep 1, 2013)

You keep thinking that. There were engines in development taht were not proceeded with, as we discusseds above, If teh Allison had failed, they WOULD have been proceeded with. The timing means nothing unless the Allison failed in 1940 and it already passed the type test years before that.

Sorry, I don't get it.

We'd HAVE a good liquid-cooled engine or produce a lot of radial-powered planes. Either way, we're OK with a US engine.


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## wuzak (Sep 1, 2013)

GregP said:


> You keep thinking that. There were engines in development taht were not proceeded with, as we discusseds above, If teh Allison had failed, they WOULD have been proceeded with. The timing means nothing unless the Allison failed in 1940 and it already passed the type test years before that.



The ones that were not proceeded with were the IV-1430 and the O-1230. The O-1230 was too small and didn't give enough power. So that went by the wayside (developed into a different class of engine as the H-2470).

The IV-1430 was "proceeded with" until 1943/44. Continental even built a factory to make them. But it was a failure, and was eventually cancelled.


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## Shortround6 (Sep 1, 2013)

GregP said:


> You keep thinking that. There were engines in development taht were not proceeded with, as we discusseds above, .



Please name them. If you come up with the O-1230 and the I-1430 please tell us when we can stop laughing. 



> The timing means nothing unless the Allison failed in 1940 and it already passed the type test years before that.



Yes it did but _THAT_ model engine was NOT the one used in ANY WW II fighter. The engine used in the P-40B/C did NOT PASS it's type test until August 1940.


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## GregP (Sep 1, 2013)

Shortround, we developed 400 - 500 airplanes without foreign engines.

There is no extrapolation of FACT that would lead any reasonable person to believe we couldn't do it again. If you think that, then YOU are the one who is crazy, not me.

In case you miss the logic, the Allison V-1710 DID NOT FAIL. If it had, then the engines in development would have been proceeded with. If not we would have used radials, but we would NOT have used a foreign engines in 1940 for a primary US aircraft. Pick one engine for yourself and laugh all the way to the nuthouse.

THIS IS A WHAT-IF. It did not happen. All of your objections are from some reasoning that the Allison failed. Since it didn't, your reasoning is faulty in the extreme and there are no correct answers.

However, with 400+ planes developed with US engines and not ONE between 1920 and WWII before the P-51/P-40 with a foreign engine except for a protoype , I'd say your reasoning is not only faulty, but rather ludicrous.

I have asked several times and NOBODY has answered. 

Name all the US-designed plane with Merlins other than the P-40 / P-51 variants that had them.

C'mon, produce a list with numbers. I can. Real damned short. You have no leg to stand on, but I give you an "A" for stubborn.


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## Milosh (Sep 1, 2013)

What American engine replaces the Allison used in American a/c Greg?


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## GregP (Sep 1, 2013)

You pick one. I pick the Allison in the real world. Haven't I made that clear yet? 9 pages and you don't GET it?

There WERE other engines in development that were not proceeded with. If the Allison had failed, one or two would have been proceeded with and I don't CARE wich ones would be picked. PICK ONE. It doesn't matter which one you pick, and go with the development or switch to radials.

They did absolutely GREAT for the Navy and the P-47. We simply would not have built US planes wioth foreign engines before the P-51/P-40F/L under any circumstances.

C'mon, stop waffling, produce a list of US planes other than the P-51/P-40F/L with Merlins (or any other foreign piston engine, for that matter) installed in production in the USA. 

Or give it up. No more bait.

Show me all the US-produced planes for US use with foreign piston engines in them. I think I've been VERY patient. Now put up or give up.


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## wuzak (Sep 2, 2013)

Greg, the fact is that there were a not insignificant number of US planes powered by the Merlin. That they consisted of only a couple of types does not matter.

The fact is that the Merlin powered P-51 was the backbone of the USAAF in the latter part of the war, and for a period after.

Another fact is that the USAAC/F requested that some of US production of the Merlin go to US aircraft. Why would they stipulate that if they didn't intend to use them?

The R-2800 really is a non-factor before 1942.

So that means the US would start the war with P-36s and P-35s. No P-38s, P-39s or P-40s.


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## GregP (Sep 2, 2013)

The fact is the P-51 was built to a British requirement and so was a viable candidiate for a foreign engine. The P-40 was an afterthought that didn't work out well and went back to the Allison.

Other than that, there weren't any and you still haven't come up with a list of Merlin-powered, US built and used airplanes, as I expected. Other Merlin-powered planes were NOT much in the cards. If the P-51 hadn't come along, we would have stayed exclusively with American engines.

If you think not, again, what evidence do you have? No more questions or emotional statements, Wayne, show me the US Merlin planes. Where are they?

The only significant US-designed and US-used Merlin plane was the P-51. If it weren't for that, the Merlin would never have been used in anything except as a wartime expedient (think P-40F), and if it didn't work out (it didn't) it would have gone away (did).

After the experience with the P-40F/L, there were no more Merlin Amerlican fighters other than the P-51. That was allowed since it DID work out. Once the war was over, the P-51 faded out and production stopped. There was no way we were going to pay $6,000 royalty for a Merlin engine, so it stopped VERY quickly.

Then pistons went way to make the matter moot.


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## wuzak (Sep 2, 2013)

GregP said:


> The fact is the P-51 was built to a British requirement and so was a viable candidiate for a foreign engine.



The P-51 was built to a British requirement, using the Allison engine.

The P-51B was not built to a British requirement.




GregP said:


> The P-40 was an afterthought that didn't work out well and went back to the Allison.



I suppose the whole P-40 program was an afterthought, since it started out as the P-36 with a radial.

Not sure that you can say that it "didn't work out well". I would suggest that the main reason the Merlin P-40 was stopped is so that Melrin production could go to another airframe - ie the P-51.




GregP said:


> Other than that, there weren't any and you still haven't come up with a list of Merlin-powered, US built and used airplanes, as I expected.



Well, there weren't any other US production aircraft with Merlins.




GregP said:


> Other Merlin-powered planes were NOT much in the cards.



Au contraire.

The USAAF delivered a P-38 to Rolls-Royce Hucknall for trial installation of the Merlin. GM lobbied Congress and the word quickly went to Rolls-Royce to stop the project and return the P-38.
Curtiss, in its never ending search for a replacement for the P-40 built the XP-53. The USAAF ordered 2 prototypes to be powered by the IV-1430. Then they expressed a desire to have a Merlin powered airframe with laminar flow wings, so one was changed to have the V-1650-1 (Merlin 28) and redesignated as the XP-60. Because of problems with the IV-1430 the XP-53 never flew. The XP-60 did, though. The XP-60 did not proceed because of the expectation of shortages in Merlin supply.
The XP-60 was later (1942) re-engined with the V-1650-3 as the XP-60D.
Don Berlin, of Curtiss, was said to have requested a V-1650-3 for installation into a P-40 airframe. But he wasn't allowed, because they were all going to P-51s.




GregP said:


> If the P-51 hadn't come along, we would have stayed exclusively with American engines.



Not sure that is true.




GregP said:


> If you think not, again, what evidence do you have? No more questions or emotional statements, Wayne, show me the US Merlin planes. Where are they?



I have tried to show you projects for Merlins. They either didn't go ahead because of politics or because of supply issues.




GregP said:


> The only significant US-designed and US-used Merlin plane was the P-51.



That s very true Greg.

But it is also true that the USAAC/F _*intended*_ to have Merlin powered aircraft. Hence Packard's licence agreement terms.




GregP said:


> If it weren't for that, the Merlin would never have been used in anything except as a wartime expedient (think P-40F), and if it didn't work out (it didn't) it would have gone away (did).



Firstly, I would like to know why you think the P-40F/L didn't work. 

Secondly, if the Allison V-1710 suddenly become unavailable around 1939/40 the USAAC/F would have used the Merlin as an expedient, as soon as they could get it into production. An alternative US designed engine would be some way off, and the British and French wanted P-40s with in-line engines.

If there was no P-51, the XP-60 may have gone ahead.


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## Shortround6 (Sep 2, 2013)

> You pick one. I pick the Allison in the real world. Haven't I made that clear yet? 9 pages and you don't GET it?



Title of thread is "WW2 with out the V-1710...."



> There WERE other engines in development that were not proceeded with. If the Allison had failed, one or two would have been proceeded with and I don't CARE wich ones would be picked. PICK ONE. It doesn't matter which one you pick, and go with the development or switch to radials.



You demand we come up with lists or follow you logic yet when we ask you to NAME which engine would replace the Allison you either refuse or come up with a waffle like the above. We have tried to explain both the timing and the FACT that the leading Army contenders had fundamental flaws. You ignore that without coming up with any other alternatives. 


C'mon, stop waffling, produce a list of US liquid cooled engines from the late 30s that _might of been used, no more post war tank engines._

Or give it up. No more bait.

Show me all the US-Liquied cooled engines. Now put up or give up.


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## Milosh (Sep 2, 2013)

GregP said:


> You pick one. I pick the Allison in the real world. Haven't I made that clear yet? 9 pages and you don't GET it?



How can you pick the Allison when the Allison is not available? 

*Thread title*: WW2 without V-1710


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## GregP (Sep 2, 2013)

Actually I am not demanding anything. My position is simple.

If the Allison had failed, we would have *developed another engine or used US radials*. I showed you 20 years of doing just that in the list and it only included fighters minus US Navy monoplane fighters ... no other types were in the list. During that 20 years none had foreign engines until the P-51 and P-40F/L. The P-51 was a prime candidate since it wasn't designed for USAAF use anyway in the beginning, so I discount it. If 20+ years of buying US engines for our aircraft with not one, single foreign engine in there doesn't tell you what we would have done, then nothing I can say going forward will help.

The P-40F/L was tried and found to offer no improvement, so they stopped making it and went back to the Allison for the last models while there were still Merlins easily available.

It doesn't matter which alternate engine would have been picked. This is a "what-if" and there are no correct answers. 

If this premise was viable (using a foreign engine in a USAAF or USN fighter), surely there will be an example or examples of it. What I say is simple in the extreme. What Merlin-powered USAAF aircraft other than these two types can you offer as example of this inevitability? We stopped making the Merlin powered P-40 during the war and the P-51 was and always will be a plane adopted by the USAAF but not designed for it from the outset.

So my contention is that we would have gone with a US-designed and manufactured engine regardless of the fate of the Allison, and I don't care what the alternate would have been ... we'd have gone with a US engine. I showed you nearly 200 examples of us doing just that, even so far as to included 2 - 3 Fokkers with US engines in the group that tried out for a contract.

If the Allison had failed, then the Vultee Vanguard (P-66) and perhaps the P-43 might have been given higher priority. They also might have developed the P-36 into a better airplane or developed alternate new models. We already KNOW the Navy had great success with their radial fighters and avoided the inlines altogether in their primary fighters. If we somehow (unvelievable to me) could not come up with an alternate liquid-cooled inline, then the USAAF would have gone radial, too.

I don't have to pick an engine and do not care which would have been the choice, but I think one would have been developed or we would have chosen US radials. This never happened and is a fabricated "what-if."

The title of the thread is "WW2 without the V-1710: Options for the Allies," not "pick an alternate engine if the V-1710 failed."

The option I pick is that we would have developed an alternate US engine or engines or used radials, and would not have used a foreign engine. That is surely a possible option and answers the thread subject.

This crap is why I haven't even read the "what if there was no Merlin" thread. The British were and are quite inventive. If the Merlin had not been developed, they would have developed ANOTHER engine. They would not have simply ceeded the air to the Axis. Anyone who thinks that is not living in the same world of reality as I am.


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## Shortround6 (Sep 2, 2013)

We could have used radials. Predominately the P&W R-1830. Wright R-1820s were a fall back and not a particularly good one in 1939-41. 

There were NO viable american liquid cooled engines available in that time period and all the flag waving you want to do does not change that. 

You are ignoring the reasons the US entered into that agreement with the British in the first place. In the summer of 1940 the Allison was _unproven_, having trouble passing it's type test and available in small numbers. The Army's "baby", the Continental I-1430 was no-where near ready for production (and never would be). The Merlin WAS the army's "fall back" plan in case the Allison fizzled. There was NOTHING else available in that category (size and power) and it would take 3-4 years to get something. 

Unfortunately the R-1830 was barely competitive in Europe in 1940-41 and falling behind after that. It was somewhat competitive in the Pacific in 1942. 
We start getting into the "what if's" of Wright R-2600 powered single engine fighters and those don't look a lot better without "what if-ing " that engine as it never had a good altitude performance and had had questionable reliability at times. 

The Allies would have survived but it would have been a much harder, longer battle. 

Predicting engine needs (types/numbers/performance) 2-3 years ahead was not easy. Allison came through with new models and with large numbers of engines (unforeseen in 1940?) which coupled with new fuel (also unforeseen) allowing higher boost pressures reduced the "need" for Merlin's in US planes. Last 5,000+ P-40s were either trainers or lend-lease ground pounders and didn't need the performance at 20,000+ ft that the Merlin gave. Changes in priorities may have had more to do with which planes got which engines rather than " we ain't goin ta put no furin ingines in Merican planes" attitude.


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## GregP (Sep 2, 2013)

I simply disagree Shortround. Surprise. If the Allison had failed its type test in 1937, we would have had 4 years to develop another engine or engines. With the units in design, that was certainly possible. Had it been required, we sould have developed any of the engines that were not proeeded with in the time available.

And I am NOT flag waving in the slightest. I already said my personal choice would have been the Merlin. For the last time, it is what I believe the choice would have been at that time given the attitudes in place in the pre-war USA, and that is all it is.


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## wuzak (Sep 2, 2013)

Greg, since a significant proportion of pre-1941 US production is geared towards the export sales to the UK and France would you expect that the attitude towards licence built foreign engines would be different?

Also, failing the type test is not the only way that the Allison goes missing. Allison wasn't very profitable, and GM may have simply decided to shut up shop.

Developing new engines - it took 10 years to get the V-1710 to production. It took Continental 7 years to run a V-12 test engine! 4 years would be a tight time-scale.

Do you think the Military shared the isolationist view of the populace during the late 1930's? I don't think that is necessarily true, since when Rolls-Royce/BPC came looking for a US manufacturer to make Merlins the contract was written to guarantee a supply of Merlins to the US.


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## wuzak (Sep 2, 2013)

GregP said:


> This crap is why I haven't even read the "what if there was no Merlin" thread. The British were and are quite inventive. If the Merlin had not been developed, they would have developed ANOTHER engine.



You should see the Merlin thread Greg, because it turns out there were quite a few British options, mostly not as good as the Merlin, but options, nonetheless.

Rolls-Royce, on their own, had more liquid cooled engines in production or under development than the US did. Then you had Napiers developing their air-cooled in-lines (Rapier and Dagger) and liquid cooled in-lines (Sabre) as well as having old faithful (Lion). Bristol had a myriad of projects - both sleeve valve and poppet valve. Plus other smaller manufacturers like Armstrong-Siddeley and others that wanted to get into the market - like Fairey.

When Rolls-Royce designed the Merlin, the Kestrel and Buzzard were only 5 years old. The Kestrel had also spawned the Goshwak (evaporative cooling Kestrel), the RR/D (Diesel sleeve-valve Kestrel), the RR/P (Petrol sleeve-valve Kestrel) and was about to start development on the Peregrine.

The Buzzard wasn't a very successful engine by itself, only a 100 made, but gave birth to the R. Consideration was given to making the Griffon I, a detuned R, but that was not proceeded with in favour of the PV12/Merlin.


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## Shortround6 (Sep 2, 2013)

1937 is almost too late. P W had an 18 cylinder R-2600 mocked up in late 1936/very early 1937 when they decided to go for 2800 cu in. in response to the Wright R-2600. First parts ordered in March 1937. 5th production engine completed March of 1940, first time production goes OVER 2 engines a month is Dec 1940. P W used 5-6 test engines, had 3500 hours on test engines when it passed it's type test ( at 1850hp) and had spent 8 million dollars. 

Starting in 1937 requires that the Army (the only real customer, both Navy and the US commercial sector are not interested) recognize/admit that the Hyper engines aren't going to be ready (let alone aren't going to work, it took the Army until 1944 to admit that one). Wright is working on the R-2600 and R-3350. Maybe they could have done it and not gotten side tracked into the R-2160 Tornado. That project sucked up about 4 years, 9 test engines/rigs and about 6.5 million between 1939 and 1943. 
Most of the many liquid cooled projects in the late 30s/early 40s were too big and complicated to be in the same class ( 1300-1500lbs, 1100-1500hp) as the Merlin, Allison, DB 600 and Jumo 211 engines. 
Perhaps somebody could have come up with a simple 25-33 liter V-12 without all the fancy stuff or perhaps Packard could have designed new blocks, crankcase and heads for their old V-2500 engine. Something like the Russians did when they went from the M-17 (BMW VI copy) to the M-34/35/38 type engines. But since about all you keep is the bore stroke and perhaps valve geometry ( and a few parts) I am not sure how much time/money you save. 

Not every maker of marine, industrial or automotive engines can make the jump to aircraft engines ( and Continental and Lycoming were MAJOR players in the commercial industrial/automotive engine field).

The two hyper engines ( in design ?) used the separate cylinder construction used by the old Packards, the Napier Lion, the BMW VI and Russian M-17. It was a weakness that showed up all to often when the engines were pushed beyond the original design limits/specs.


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## GregP (Sep 2, 2013)

Hi Wayne,

I am aware of the British options, being a LONG-TIME fan of WWII aviation. I have no favorite, but if the Merlin had not come along, one of the other options would have been used, successful or not. I think they would have worked out the bugs like they did with the Sabre. I would NOT have stick with the Sabre for so long myself.

GM would not shut up the Allison shop with a war looming. The attitudes did NOT really change. They produced war materiel for other countries for the money. Look at what Henry Ford said when asked to build the Merlin ... he said he'd build them for the USA but not for any other nation. Think he was alone in that attitude? Think again, he wasn't.

The military DID share isolationist views and was instrumental in removing the turbo from Allison use on all but the P-38 by simple order for it to happen. They didn't see any need for high-altitude equipment to defend the USA ... they were not thinking of the ETO at all. They were good about developing alternatives ... they made an Allison-powered B-17 that was faster than the radial unit, an Allison powered B-29 that was likewise faster than the radial unit, and several alternative large planes in case one failed.

I'm sorry, but I don't see any way for it to happen except for the small steps they took in rela life. You may, and you may be right, but I doubt it VERY strongly. That's OK, we have some US people in here who agee with you, but they seem to me to thinking in today's ways, not in the ways of the pre-WWII USA. I've met too many WWII vets who STILL don't like any foreign aircraft or foreign war implements. It was simply in vogue at the time. It wasn't necessarily right, but was the popular belief.

I'm sure there were a lot of British people who resented having to use US-supplied equipment (aircraft), didn't necessarily wan to fly them, and had a hard time seeing any good qualities in foreign aircraft. It's just the way it was at the time. Nothing wrong or right about it, but it was a fact that had to be dealt with.


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## Shortround6 (Sep 2, 2013)

> Also, failing the type test is not the only way that the Allison goes missing. Allison wasn't very profitable, and GM may have simply decided to shut up shop.



Which might have happened in the spring of 1939 IF the Army had not placed the sizable contracts it did. Allison, as an engine maker ( not bearings or other engineering projects) had been loosing money for a number of years. GM had loaned the division over 1/2 million dollars and the army was 900,000 dollars behind in payments for work already done. Now maybe P W could afford to develop an engine on their own ( 8,000 engines of all types sold in 1938, more in 1939?) and maybe Wright could ( over 8,000 cyclones sold from 1926 -1938, not counting Whirlwinds and others) but what sales did Allison have from 1930 to 38? 



> Developing new engines - it took 10 years to get the V-1710 to production. It took Continental 7 years to run a V-12 test engine! 4 years would be a tight time-scale.


4 years is much closer to the norm but it does require that everything go right. Allison and Continental are both well outside the norm. But getting "tricky" could cost big time, How long did it take for Bristol to get sleeve valves to be a _mass_ production item? And then there are built in delays in getting into service. The Merlin first ran in 1933 ( design started?) but wasn't suitable for production until 1936. By the time of the Munich crisis (1938) 1700 Merlins had been made but only 400 installed in aircraft. It may take 3-4 years to go from design to tested engine and first few examples. It can take another 1-2 years to get to the point of making hundreds of engines a month ( Allison, with the help of General motors AFTER GM shut/re-purposed their car plants was producing over 1200-1400 engines a month and was able to out produce ALL THREE English plants making Merlins 1943. ) In fact Ford was licensed to make R-2800s in Aug of 1940. in Nov 1941 they turn out 99 engines, Buick was licensed in Oct 1940 to Build R-1830s. They produce NONE until March of 1942 when they put out 440 engines. Studebaker was licensed to produce R-2600s in Nov of 1940 but was switched to R-1820s in June of 1941. They trickle out a few engines in Feb/March of 1942, 35 in April and 168 in May and just keep multiplying. 
Basically, even with a full set of plans for an existing, tested, approved engine you are looking at about 1 1/2 years before you can get them in any real numbers. Ceremonial role outs and 1-5 engines a month don't cut it in war time. Add another 6-9 months if you are looking for 1000 engines a month.


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## Shortround6 (Sep 2, 2013)

> GM would not shut up the Allison shop with a war looming.


 Allison had to "forgive" the Army's 900,000 dollar dept in return for permission to export Allison engines. There is only so long any company can keep going without income even with a war looming. 



> The military DID share isolationist views and was instrumental in removing the turbo from Allison use on all but the P-38 by simple order for it to happen. They didn't see any need for high-altitude equipment to defend the USA ... they were not thinking of the ETO at all.



Not this old myth again.  The Army actually had a pretty good idea how close the turbo was to _actual service use_. About 2 years from the summer of 1939. They figured that NON-TURBO p-40s/P-39s could be ready in one year. Not _knowing WHEN_ the war would start they figured that non-turbo P-40s/P-39s in squadron service in numbers beat the heck out of turbo-models still undergoing development testing. Turns out the army was wrong. The Turbo planes were still having problems in the Spring/summer of 1942. Longer than 2 years.


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## GregP (Sep 3, 2013)

It isn't a myth at all ... but I won't argue much about it.

The P-38 didn't have turbo problems ... it had intake manifold issues, European fuel different from American fuel issues, and poor pilot training. When these were addressed 9 months later, the P-38 was a solid aircraft with very few troubles other than a really piss-poor cockpit heater. They cured that one with an electric heater. By that time the P-51 was in the theater and there was no poiin t having a supply chain for two fighters for the same job ... so the P-38 got transferred to the MTO / PTO / CBI and did well.

You might remember it was the mount of our top two aces.


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## wuzak (Sep 3, 2013)

GregP said:


> It isn't a myth at all ... but I won't argue much about it.
> 
> The P-38 didn't have turbo problems ... it had intake manifold issues, European fuel different from American fuel issues, and poor pilot training. When these were addressed 9 months later, the P-38 was a solid aircraft with very few troubles other than a really piss-poor cockpit heater. They cured that one with an electric heater. By that time the P-51 was in the theater and there was no poiin t having a supply chain for two fighters for the same job ... so the P-38 got transferred to the MTO / PTO / CBI and did well.
> 
> You might remember it was the mount of our top two aces.



You are talking of a few years after the time of which Shortround speaks.

The XFM-1 had problems with turbos.
The YFM-1 had problems with turbos.
The XP-37 had problems with turbos.
The YP-37 had problems with turbos.
The XP-39 had problems with turbos.

The "European fuel" issue happened in 1943/44, IIRC. 

And P-38s did have problems with turbos - requiring a redesign of the wastegate control, as it would sometimes freeze shut.


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## GregP (Sep 3, 2013)

Yeah, they had issues with turbos, but the issues weren't necessarily the turbos, It nwas the system, which isn't the same thing.

The Airacuda as a joke and I ignore it as non-typical. There is no set of circumstances that would render it viable. 

The X/YP-37 was an experimental plane designed to investigate the use of turbochargers. If it had issues, that is what it was FOR. To investigate them. No surprise.

The XP-39 was well on its way to having any issues resolved when the turbo was removed by the war materiel board. It might have been high-drag and probably was, but WOULD have imbued the P-39 with altitude capability that it didn't otherwise have.

If that is not so, then why was the turbo installation in the P-38 any better? ... But it WAS. FDew issues with the tirbo ... So they were on the right track and could have done it if the USAAF had wanted to do so. They didn't.

Too isolationist and not-caring of events around the world to take notice. Their "high-altitude" plane was the P-38. They COULD have had a high-altitude P-39 and P-40, but didn't.

Silly, really, but simple. Bean counters made the decisions ... with pre-war attitudes in full bloom.


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## wuzak (Sep 3, 2013)

GregP said:


> Yeah, they had issues with turbos, but the issues weren't necessarily the turbos, It nwas the system, which isn't the same thing.



Sometimes it was the installation, other times it was the turbo.




GregP said:


> The Airacuda as a joke and I ignore it as non-typical. There is no set of circumstances that would render it viable.



It still had problems with the turbos. The turbo that the Airacuda used was of the older style - with the compressor intake between the turbine and compressor.




GregP said:


> The X/YP-37 was an experimental plane designed to investigate the use of turbochargers. If it had issues, that is what it was FOR. To investigate them. No surprise.



The X/YP-37s were not turbo test beds. They were used to evaluate the V-1710 in a persuit type airplane.

The XP-37 had the older type turbo, the YP-37s had the newer type, which would become the B-series turbo.




GregP said:


> The XP-39 was well on its way to having any issues resolved when the turbo was removed by the war materiel board. It might have been high-drag and probably was, but WOULD have imbued the P-39 with altitude capability that it didn't otherwise have.



The issues were resolved by NACA by dumping the turbo and tidying the aerodynamics.




GregP said:


> If that is not so, then why was the turbo installation in the P-38 any better? ... But it WAS.



The P-38 was a twin engine airplane, so the turbos didn't cause problems with space in the fuselage - as they did for the X/YP-37 and XP-39.




GregP said:


> Few issues with the turbo ... So they were on the right track and could have done it if the USAAF had wanted to do so. They didn't.



Still had problems with the turbos.




GregP said:


> They COULD have had a high-altitude P-39 and P-40, but didn't.



The P-40 was never intended to have a turbo. Basically the X/YP-37 showed them it was impractical to have a turbo at that time, so the P-40 was designed without one.


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## GregP (Sep 3, 2013)

From Don Berlin's son visiting the Planes of Fame, the P-40 WAS intended to have a turbo from the outset. It just never got one in production.

The P-37 WAS an experimental plane with one intent to investigate the turbocharger. It wasn't EVER going to be a service interceptor with the rearward cockpit position.

The issues with the P-39 were NEVER resolved by the NACA ... they did their best to clean it up when the turbo was deleted, and did a decent if not spectacular job. The turbo could have worked at LEAST to get the Airacobra to altitude if not too much faster. I think it WOULD have been solved if they had persisted. They didn't.

Don't care in the least about the Airacuda ... it was a stupid thing to start with. Somebody was a hairbrain. It happens every once in awhile ... I DO have a nice CAD drawing I did of it, but am NOT a fan. I did it for a friend who overhauls Allisons ... Joe Yancey. The Airacuda reminds me of an old 1950's sci fi prop that was used in a stupid movie. Doesn't have to live in the real world but must convey somthing different from the norm. That ... it does.


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## Shortround6 (Sep 3, 2013)

P-43s had problems with the turbos, early B-17s had problems with the turbos. Actually this wrong, the turbo itself may have been OK (?), the turbo controller was the main problem. The early controller/s (supplied by the army, NOT the engine maker or General Electric) measured the pressure in the exhaust system and tried to keep it at a constant value by adjusting the bypass/waste gate, this was supposed to keep the intake pressure at a constant value/pressure. Due to the moisture in the exhaust it did freeze up a lot. The later controls switched to sensing the intake pressure and adjusting the waste gate ignoring exhaust pressure. 
Part of the P-39s problem (and a potential problem for the P-40) was the inter-cooler. Without an inter cooler the turbo is severely limited in what it can actually accomplish. P-38 used the leading edge of the wing on the early ones. This intercooler design was not particularly space efficient but note that the space was of a size to house 55 gallons of fuel in self sealing tanks on later models. Later (or other types) intercoolers didn't use as much volume. The drag of the inter cooler and turbo cost the P-39 around 30-40 mph at altitudes below 15,000ft. 

I would like somebody to tell me _where_ the turbo and inter-cooler were supposed to go on the P-40? What 10-12cu ft of space is there in an appropriate relation to the CG for a turbo and inter-cooler? The Hawk 75 prototype with a two stage supercharger and inter-cooler used a large pod/duct under the cockpit-fuselage. The Later P&W test mule with two stage supercharger _may_ have used the space in the fuselage used by the cowl gun ammo storage, or perhaps there was more room behind the radial than there would be behind the V-12? 

For those who think the P-39 could have been _fixed_ please note that Bell themselves didn't really try, aside from a couple of add-on turbo installations (both turbo and intercooler mounted external to the _original_ fuselage contours. Instead they went to the P-39E (P-63) with a two foot longer fuselage and new wing. Granted in part to house the Armies favorite engine ( the Continental I- 1430) which was about 20in longer than the Allison but the extra room came in handy for remote 2nd stages.


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## wuzak (Sep 3, 2013)

Not sure where the turbo would go on a P-40. Not that I believe the P-40 was ever going to get one.

But the clues may be in the XP-60 and XP-60A.

Here is the XP-60 with the V-1650-1:







Quite slender and sleek.

And here is the XP-60A, with V-1710 and GE B-series turbosupercharger






Quite corpulent!

Wonder if the turbo is on the lower side of the fuselage, between the wings and just behind the radiator outlets.


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## GregP (Sep 4, 2013)

Not sure where it went on the P-40 either but, since it didn't have one in production, the question is moot.

Acording to Nr. Berlin's son, Don was allowed to build ONE turbo P-40 and I have been chasing a pic or description of it for years to no avail as yet. I hear rumors about it, and rumors about good performance at altitude, but can't confirm any of them. So they are sort of things to look into as I can find out anything about them.

At this time I would not claim that it was so, only that I have heard it said. You never know. Sometimes these things are true and sometimes they just can't be confirmed by a reliable source. Those are dying off these days and this one may simply have no evidence either way, which tends to lend doubt to the claim altogether, but that also may not be right. I can't say for sure.

Early turbochargers (or turbosuperchargers, as they were called back then) were problematic. Today they are reliable and rarely malfunction. The early issues do NOT mean that all were problematic or insoluable ... the P-38 DID perform well once the issues were ironed out. The P-39 may well have been able to develp along the same lines, though I doubt it. I would like to have seen a turbo P-63 as it certainly had the room for a good system and is a very good candidate.


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## wuzak (Sep 4, 2013)

Greg, I believe the P-60A is the closest thing to a turbo P-40. If you discount the X/YP-37s.

The P-60A had the V-1710 and GE turbo. The P-60B was to have the V-1710 and Wright turbo. The P-60C was supposed to get the IV-2220, but ended up with the R-2800. The P-60D was the XP-60 re-engined with the V-1650-3 (the XP-60 had the V-1650-1). And the P-60E had the R-2800.



> The XP-60A made its initial ground taxiing tests in late October of 1942. However, during one of these tests, a minor fire occurred in the engine due to the lack of cooling air in the shrouds surrounding the exhaust manifold. The turbosupercharger and long exhaust manifold were therefore removed from the aircraft, and short exhaust stacks were substituted. The XP-60A (42-79423) flew for the first time in this form on November 11, 1942. Empty weight was 7806 pounds, gross weight was 9616 pounds, and maximum takeoff weight was 10,160 pounds. Dimensions were wingspan 41 feet 3 3/4 inches, length 33 feet 7 1/2 inches, height 12 feet 4 inches, and wing area 275 square feet. Estimated maximum speed (never achieved in tests) was 420 mph at 29,000 feet and 324 mph at sea level. It was estimated that an altitude of 15,000 feet could be attained in 6.5 minutes. Service ceiling was 35,200 feet. The maximum speed (especially at low altitudes) and the initial climb rate were rather disappointing. The XP-60A aircraft was soon dismantled and some of its parts were used in the later XP-60C and XP-60E.



Curtiss P-60

The XP-60 had a maximum speed of 387mph. It was basically a P-40 with new "laminar flow" wings and a V-1650-1. No idea how the XP-60D went.

There could be some confusion between XP-60 and P-40, though the turbo XP-60s (A B) didn't share as much with the P-40 as the XP-60 did.


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## GregP (Sep 4, 2013)

Yes, I am aware of the P-60 series. The rumors are of a turbocharged P-40, not the XP-60 / P-60. Again, I cannot say and have no conviction about it one way or the other myself. I'd like to find out for sure, though. Who knows? Maybe sometime.

Meanwhile, back to topic.


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## Shortround6 (Sep 4, 2013)

I don't know if they built one with a turbo charger or not but the lack of _any_ pictures/drawings/test reports sure doesn't look good. 

From Joe Baugher's web site. "The designation P-40J was given to a projected version of the P-40E which was to have a turbosupercharged engine. This study was abandoned in May 1942 without anything ever being built".

Considering they can find out the serial numbers of the planes used for experimental radiators and have pictures of them the lack of information on the "turbo P-40" is mighty strange _if it existed._ Not 100% proof it didn't but.........

The letter designation is also strange _IF_ the P-40 was _designed_ for a turbo. The 8th version built gets one? 

At best you have "A P-40 was designed to have a turbo charger" which is quite different than "_the_ P-40 was designed to have a turbo charger."


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## wuzak (Sep 4, 2013)

We do know that the P-40s origins were for a non-turbo V-1710 P-36 version.



> Don Berlin, Chief Designer at Curtiss for the P-36 and P-37 aircraft, was frustrated by the continuing problems with the turbosupercharged XP-37 [models 75I and 80], and the lack of potential for the P-36. Given the urgency of the upcoming 1938 Persuit Competition, he obtained from Allison an estimate of cost and performance of an "altitude" rated V-1710 for use in a P-36 derivative.





> Using the information and the promise of 1050 bhp, on March 3 1938 Curtiss submitted to the Materiel Division a proposal for a P-36 airframe mated to this engine. It stated in part, "Wind tunnel tests indicate that (a P-36) with the Allison V-1710 (altitude rated) engine, a high sped of 350mph at 15,000 feet is possible. This is based on a modified V-1710 having a gear-driven supercharger giving 1000 bhp at 2,600 rpm at 15,000 feet. It is estimated that this engine will develop 1050 bhp at 2950 rpm at 15,000 feet with carburettor ram air..." Wright Field immediately approved Allison to proceed with the design change to the engine, and for Curtiss to proceed with the installation of the engine in the number ten P-36A airframe. Thus the P-40 series was born in teh form of Curtiss Design 75P, Air Corps designation XP-40 (AC-38-010).



From _Vees for Victory_.


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## tomo pauk (Sep 4, 2013)

Guess that settles it 

On topic: without V-1710, the Army might want a fighter with non-turbo R-2800, as a fall back if P-47B encounters delays?


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## Shortround6 (Sep 4, 2013)

Not unless you can introduce the Non-turbo R-2800 well over one year earlier than than it did show up. 

17 R-2800 single stage engines built in 1940.
1149 6402 Allison's built in 1940.

1723 R-2800 single stage engines built in 1941.
6402 Allison's built in 1941. 

10,679 (?) R-2800 single stage engines built in 1942.
14,904 Allison's built in 1942. 

Of the existing engines _only_ the R-1830 and R-1820 are available early enough to have any hope of being farmed out to other companies in time to make up even a part of the numbers needed in 1940, 41 and 42. And the decision has to be made in late 1938 or early 1939. Only about 200 Wright R-2600s had been built by Dec of 1939 and it may well require new airframes ( not the P-36/P-40 airframe) or heavily modified ones.


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## tomo pauk (Sep 4, 2013)

Thanks.
All in all - not an easy task to replace the often unloved engine.


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## Shortround6 (Sep 4, 2013)

It might have been loved a bit more if the Americans had given up on their love affair with SIX .50 cal guns. 

The Americans overloaded their 1150-1500hp fighters.


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## GregP (Sep 4, 2013)

Doesn't settle it for me.

I still have the designer's son's speech stating one was made to make me curious. That won't change.

But I won't make the claim as fact until I know it to be true.


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## swampyankee (Sep 4, 2013)

Shortround6 said:


> It might have been loved a bit more if the Americans had given up on their love affair with SIX .50 cal guns.
> 
> The Americans overloaded their 1150-1500hp fighters.



Or devoted more effort to developing a better supercharger for it. I've seen conflicting (second and third hand) reports that the superchargers on the Allison engines had efficiencies up to 10% lower than comparable units from Rolls Royce. Structurally, the Allison engine was sound (probably sounder than the Merlin). Without the Allison, the P-36 could have received a lot more development effort: the R-1830 (D=48 in; weight=1250 lb; 1,050 hp) could have been replaced by the two-stage engine installed in the Wildcat. If the R-1830 engine could be brought up to the same power/piston area as the R-1820, its output would be about 25% greater than the Wright engine. Alternatively, the R-1830 could be replaced by the R-2180 Twin Hornet.


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## swampyankee (Sep 4, 2013)

duplicate


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## wuzak (Sep 4, 2013)

swampyankee said:


> Alternatively, the R-1830 could be replaced by the R-2180 Twin Hornet.



The R-2180 was half a R-4360, so came after the R-4360, which came after the R-2800.

Prior to that, you could use the R-2000, which is a stretched version of the R-1830.


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## swampyankee (Sep 4, 2013)

wuzak said:


> The R-2180 was half a R-4360, so came after the R-4360, which came after the R-2800.
> 
> Prior to that, you could use the R-2000, which is a stretched version of the R-1830.



There were two distinct R-2180s: a pre-war Twin Hornet, and a post-war Twin Wasp E. The later was not quite half an R-4360 (there were some differences in the exhaust and intake arrangements). I did specify the Twin Hornet, which was the pre-war engine.


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## wuzak (Sep 4, 2013)

swampyankee said:


> There were two distinct R-2180s: a pre-war Twin Hornet, and a post-war Twin Wasp E. The later was not quite half an R-4360 (there were some differences in the exhaust and intake arrangements). I did specify the Twin Hornet, which was the pre-war engine.



Sorry, didn't realise.

The R-2180 was bigger in all respects than the R-1830 - bigger diameter to go along with the extra weight, capacity and power.

Wonder why they stopped it? Maybe because they started the R-2800?


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## GregP (Sep 4, 2013)

I don't believe the twin Hornet had a lot to recommend it. If it had, they would surely have built more than 30 of them.

The Twin Wasp was the reliable R-1830.


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## Shortround6 (Sep 4, 2013)

The problem with the R-2180 is that it wasn't big enough. It used cylinders the exact same size as the R-2800 which means you had the frontal area of an R-2800 ( or perhaps a bit more depending on published figures) but only 78% of the power. If the 54in diameter is correct then it had 26% more frontal area but only 19% more displacement than an R-1830. Granted cowling smooth things over a bit but the power per sq ft of frontal area doesn't look good for a 14 cylinder radial. 
OK for a slow bomber or transport engine but not so good for a fighter. None of the ones built had a a two speed supercharger although a two stage supercharger was _planed_ for one version it was not built. 

The R-2000 _historically_ came after the R-2800. The first one being completed in June of 1941 (over 2 years after the first R-2800) and 8 more in Dec of 1941 at which time P W had completed 1469 R-2800s including 6 of the two stage engines. 
Now maybe you can "what if" the R-2000 into 1939 but then it would be comparable to the 1939 R-1830 with 1350hp for take off and 1100hp at 13200ft Military power at best even with a two speed supercharger.


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## swampyankee (Sep 5, 2013)

The R-2180 Twin Hornet didn't seem much heavier than the R-2000. I don't think diameter was too much of an issue, as there were versions of the Hawk with R-1820s, which were quite a lot larger in diameter than the R-1830.


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## Shortround6 (Sep 5, 2013)

The Cyclone powered Hawks were usually a bit slower than the twin Wasp Hawks. Something like 5-15mph depending on exactly which engines were fitted as even with the same take-off rating they had different power at different altitudes. 

An R-2180 powered plane would be faster than a R-1830 powered one but some of the extra power goes into the extra drag so you don't get the full increase in power for performance. Both cowling design and exhaust thrust/systems were constantly evolving at this time and just a few years can make a big difference in drag/performance using the same basic components. 
read some of the articles in Flight magazine or some other period literature. They may have been wrong considering the knowledge we have now but engine and airframe designers _then _were almost obsessed with frontal area in regards to streamlining/drag.


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## Timppa (Sep 6, 2013)

AFAIK swedes made the the best fighter with R1820/R1830 that could compete with anything in 1939-42.


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## Shortround6 (Sep 6, 2013)

There are 3 things that complicate this chart/proposal.

The Swedish fighter was built to a lower load limit than US fighters and possibly British fighters. 6.5 "G"s service load I beleve instead of the American standard of "8" Gs.

The Swedish fighter had two armament set ups, one was two .50s and two .30s and the other was .four 50s, what was the performance difference between the two? ( climb more than speed)

The -86 engine in the charts weighs several hundred more pounds than the original engine and requires space/drag for inter-coolers. the -86 engine being the one used in later F4F Wildcats. 
Is this chart from company data or an estimate based on the published power figures vs the drag of the original engine installation?


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## GregP (Sep 8, 2013)

I've always liked the J-22 and think is an often-overlooked fighter in discussion of the war.

I've seen the analysis of the J-22 as it was but have not seen the proposed P&W R-1830 equipped version's projected numbers. Impressive for what would be a relatively low-powered fighter. Needed better guns, though.

I see in one of the aerto magazines that they are getting one flight-ready in Sweden. That will be nice to see. The landing gear looks complicated, but I've not seen anything written about it being so in real life. Perhaps it was relatively simple and only LOOKS complicated.


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## tomo pauk (Sep 9, 2013)

P-66 being a better platform for the two stage Twin Wasp, since the fuselage HMGs and their ammo could be deleted, thus providing space for engine accesories?


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## m37b1 (Feb 5, 2014)

GregP said:


> Hi Milosh,
> 
> If the ALlisons hnad not "made it." then effort would have been spent to develop amternate engine into useful production engines. I would not presume to say any particular engine would make it over the rest, but there are several candidates around.
> 
> ...



Great thread! Sorry I'm a bit late to the party.

Short answer has already been stated many times. The US AC industry would have switched to available radials. R1820, R1830 and R2600. IMHO the 2600 would have been a very capable fighter engine, if developed in that direction.

Now for the list above - All the experimental inline engines in development in 1940.

Good list, but it is missing the only one that actually made it into production.

The FORD V1650 DOHC V-12. Someone mentioned it early on, but that was the end of discussion.

"Made it into production" Missing 4 cylinders, as a V8 tank engine. The FORD GAA.

Now I know the duty cycle of a tank engine is not the same as an AC engine. In many cases it can be worse. The GAA proved itself as an extremely rugged, reliable engine. Such that the Army chose the GAA powered M4A3 to standardize on after the war.

Back to the V-12. Ford had this engine tested, production cores completed tooling ordered by mid-late 1940. 

The Ford V1650 is NOT a Merlin copy. The confusion between the V1650 and the Merlin arose because they both featured the same bore and stroke (5.4" x 6.0"), and because later in the war Ford of Britain did produce 400 Merlins per week at a factory in Urmston, England.

The Rolls Royce Merlin was a SOHC with rocker followers, whereas the Ford V-1650/GAA is a true DOHC engine with the cam lobes directly acting on mechanical buckets. 

It featured Direct fuel injection as well as two stage supercharging. Yes, it used a turbocharger to achieve this. However, it was a very compact package, designed in, as a package from the start.

The Merlin's (and Alison's) spark plugs were located on exhaust side of the head just below the exhaust ports, whereas the FORD V-1650 had its plugs centrally located in the pent-roof combustion chamber, as per modern practice. (Much better for detonation control). 

Finally, the Ford V-1650 featured a modern, one-piece block casting, while the Merlin (and Allison) featured a split block casting. 

Initially targeted at 1500 HP, this design could have been developed to 1600-1800hp, while achieving a better BSFC figure than the Merlin or the Alison.

Best of all, it was ready for aero certification and production.


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## GregP (Feb 6, 2014)

That particular engine also doesn't even make a note in the history books of engines considered for aero use.

There HAS to be a reason, but I won't speculate about it since I don't know. Since it didn't make it into aero use, maybe you know the rpm range? At what rpm was the rated power and did it alreasy have a reduction gear case in it or would thaht have needed to be designed and added?

Just curious.


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## Shortround6 (Feb 6, 2014)

As a tank engine it was rated at both 2600 and 2800rpm. It NOT was a direct copy of the Merlin but then I am not so sure about it's being test and production tooling ordered in mid/late 1940. Some sources say only a 2 cylinder test rig was running in 1941. 
Ford was approached about building the Merlin in summer of 1940 and given a sample engine and some blueprints, by Sept they not only backed out of the deal and Packard given the contract ( and gotten the materials for Ford) but Ford had signed up to make P&W R-2800s in a brand new Factory. It took until the summer of 1942 for the V-8 tank engine to show up. Grants had been being built with 9 cylinder radials, twin 6-71 diesels and the 30 cylinder Chrysler multi-bank with the same power units transferred over to the Sherman production. Seems like a long time if the Ford engine was really ready to go in V-12 form in 1940.

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## m37b1 (Feb 6, 2014)

Shortround6 said:


> As a tank engine it was rated at both 2600 and 2800rpm. It NOT was a direct copy of the Merlin but then I am not so sure about it's being test and production tooling ordered in mid/late 1940. Some sources say only a 2 cylinder test rig was running in 1941.
> Ford was approached about building the Merlin in summer of 1940 and given a sample engine and some blueprints, by Sept they not only backed out of the deal and Packard given the contract ( and gotten the materials for Ford) but Ford had signed up to make P&W R-2800s in a brand new Factory. It took until the summer of 1942 for the V-8 tank engine to show up. Grants had been being built with 9 cylinder radials, twin 6-71 diesels and the 30 cylinder Chrysler multi-bank with the same power units transferred over to the Sherman production. Seems like a long time if the Ford engine was really ready to go in V-12 form in 1940.



"Ready to go" was probably not accurate. While it had been dyno tested, full testing for aviation use would have most likely taken 6 months more or longer. 

The Tank engine didn't show up until 1942, because Ford wasn't approached and issued contract for the engine and M4A3 tank until late 1941. The first pilot rolled out the door on May 13th 1942. The cut down V8 version of the engine was ready prior to this date. While the GAA is fairly well documented, the V1650 is very difficult to trace history. I hope to have copies of the original drawings of the aero-engine from the Henry Ford Museum in the near future. (When they find them). Next step will be to compare the aero specs to a GAC tank V-12 I'm tearing down for rebuild. (Yes, Ford built some V12sduring WWII for prototype tanks). I'll post the drawings on here when I get them.


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## m37b1 (Feb 6, 2014)

Another view on it's history. While I know the person that researched and wrote this, I've not verified any of it.

Origins:

In late 1939 Edsel Ford made an agreement with Rolls Royce to produce their Merlin V12 Aircraft Engines in one of Ford’s unused factories in Michigan. About 3/5 of the projected production was for British use, mostly for Canadian produced aircraft including; Landcasters, Mosquitoes and Hurricanes. Rolls Royce sent blueprints, tooling and parts to Ford, and it appears that Ford immediately started to redesign the Merlin, two very modified enbloc engines were built in their prototype shop. 

Rolls Royce did not approve of the changes and Henry Ford’s insistence that Ford only manufacture for U.S defense caused the Merlin production to be later moved to Packard, who subsequently built about 58,000 Merlin’s.

The Ford V12 Aero Engine

Ford was a very successful Company with many innovative designs, a great engineering staff, especially in the area of large castings. And they had the aircraft engine designs from Rolls Royce. The Merlin is a very complicated engine with many, many parts, and the assigned Ford engineers thought they could improve it. Ford, knowing war was coming and there would soon be a large market for aircraft engines, continued development and had the tooling made to produce their design. 

The result was a less involved, more durable and powerful 1650 cubic inch V12 of identical bore and stroke as the Merlin, however, that is the only similarity, the balance of the engine is completely different.

The GM Allison Engine was originally designed in 1929, the Merlin in 1933, the 1940 Ford design, was a more advanced design than either of these engines. Had it been developed to its potential, we likely would have had Ford Mustangs, (P51 Fighter Aircraft, not cars) by 1943. 

The Ford GG Aero Engine was a dual overhead cam (4 total), 48 valve, 60 degree bank, aluminum V12. Unlike the multi-part units of the Merlin and Allison, the block was a very rigid monolithic enbloc unit, (similar to automotive V8s). Rods were stronger individual pieces-running in parallel on the crankshaft (like a standard V8 ) the crankshaft was held by 4 bolt main caps. Accessories were driven from the end opposite the propeller, induction was by a mechanical fuel injection pump. The heads were a pent roof 4valve per cylinder design, similar to the Miller/Offenhauser race engine. Spark plugs were in the top center of the heads between the valve sets, resulting in better fuel ignition and less flame travel than either the Allison, Merlin or Griffon. The cam train had no rockers, the cams drove directly onto “buckets” which pushed down on the valve stems. The jewel of the engine design was the cam drives which consisted of an assembly of helical and cone gears driving two angled shafts on the rear of each bank which simultaneously drove both intake and exhaust cams. This is far simpler than the much more involved arrangement of the Merlin or Allison. 
Supercharging was by a large proprietary 2 stage Turbocharger. 

The design was magnificent. Three were built; on the first test, the engine put out 1800HP! Unfortunately, the design was not ready in 1942, subsequent development was spent on Tank Engines, and the engine never flew.


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## tomo pauk (Feb 6, 2014)

There are 2 things here that might raise an eybrow or two:
1st - when the engine would be ready for production? If the answer is 'after Pearl Harbour' (or later), then it cannot fill V-1710's shoes, since it is too late.
2nd - what rpm was the engine turning and how big was the boost when engine made 1800 HP. What fuel was used? When where it did that? Was the supercharger system really a 2-stage turbo (= what abut engine stage supercharger?), or was it a turbo plus engine stage supercharger? Dimensions of superchargers?

I acknowledge that there is lot to be learned about the Ford's V-1650, however claiming performance figures without presenting sources does not look like a good research.


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## Shortround6 (Feb 6, 2014)

You are either dyno testing a full engine or you are not. 

Now several other engines started as one, two or even 9 cylinder test rigs ( first R-2800 was actually a R-1400 of 9 cylinders) but plenty of V-12s started as V-2 test rigs. 6 months is a miraculously short period of time to test an aircraft engine. P&W started work on an 18 cylinder R-2600 in Aug 1936, changed to to the R-2800 March of 1937. The 9 cylinder test rig X-80 first ran in Feb 1938, By March 1939 it had run just under 700 hours. There were at least three 18 cylinder test rigs. The engine was type tested By July 1 1939 after 3300 hours of testing, all ground running. July 12, 1939 was first flight. Feb 12 saw the completion of 5000 hours of testing and a bill of materials released to production. March 25th saw the first production engine complete model test. However only 17 engines were completed in all of 1940. These are also the 1850hp two speed (or a few single speed engines?) 

And the Ford engine was a very highly stressed, technically advanced engine. I am afraid ready to go in 1941 or even 1942 ( as an aircraft engine) are rather doubtful. Ford was aiming at 2000hp from 1650 cu in using standard _american_ (not British) 100 octane fuel in 1940 which would certainly limit the boost (manifold pressure) used. Both Allison and R-R took until 1945 to get to such power levels using much better fuels. Now a much lower rated Ford engine _might_ have made it into production sooner but Ford had a habit of promising things he could not deliver ( granted some of his factories did produce amazing quantities of war material by anybodies standard, just not near what Ford had promised to begin with).


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## Shortround6 (Feb 6, 2014)

m37b1 said:


> In late 1939 Edsel Ford made an agreement with Rolls Royce to produce their Merlin V12 Aircraft Engines in one of Ford’s unused factories in Michigan. About 3/5 of the projected production was for British use, mostly for Canadian produced aircraft including; Landcasters, Mosquitoes and Hurricanes. Rolls Royce sent blueprints, tooling and parts to Ford, and it appears that Ford immediately started to redesign the Merlin, two very modified enbloc engines were built in their prototype shop.
> 
> Rolls Royce did not approve of the changes and Henry Ford’s insistence that Ford only manufacture for U.S defense caused the Merlin production to be later moved to Packard, who subsequently built about 58,000 Merlin’s.



Commonly accepted history is that Ford (America) was NOT asked to build the Merlin until the Spring/ early summer of 1940. The deal with Ford fell through in just a few weeks and Packard was brought in just a few days, initial talks went good but actual signing of the contract was in Sept of 1940 so the wording "caused the Merlin production to be later moved to Packard" might be technical correct but paints a rather distorted picture. It took Packard over a year to deliver more than a symbolic engine or two. Ironically ford was signing contracts to build a Factory to Build the P&W R-2800 with in a day or two of Packard signing the Merlin contracts. 



> The Ford V12 Aero Engine
> 
> Ford was a very successful Company with many innovative designs, a great engineering staff, especially in the area of large castings. And they had the aircraft engine designs from Rolls Royce. The Merlin is a very complicated engine with many, many parts, and the assigned Ford engineers thought they could improve it. Ford, knowing war was coming and there would soon be a large market for aircraft engines, continued development and had the tooling made to produce their design.
> 
> ...



Again a bit of miss direction. While the Allison started development in 1929 there were quite a few changes to the engine by 1939 let alone by 1941. The Production Merlins ( or all but a few hundred?) also had a number of changes including a different cylinder head/combustion chamber than the 1933 version. While the Ford engine was , in some ways more advanced, the likelyhood of it matching the the Merlins used in the Mustangs in 1943 are pretty slim. Ford apparently lost a lot of money tooling up for an engine they never got a contract for. BTW Ford was paid 14.3 Million _just_ to build the R-2800 factory, that amount of money did not cover a single production engine. And Ford, for all their car manufacturing expertise simply copied the layout of the P&W East Hartford plant. Ford did make valuable contributions to the manufacturing processes of some R-2800 parts but that did not come until they had been building them awhile. 



> The Ford GG Aero Engine was a dual overhead cam (4 total), 48 valve, 60 degree bank, aluminum V12. Unlike the multi-part units of the Merlin and Allison, the block was a very rigid monolithic enbloc unit, (similar to automotive V8s). Rods were stronger individual pieces-running in parallel on the crankshaft (like a standard V8 ) the crankshaft was held by 4 bolt main caps. Accessories were driven from the end opposite the propeller, induction was by a mechanical fuel injection pump. The heads were a pent roof 4valve per cylinder design, similar to the Miller/Offenhauser race engine. Spark plugs were in the top center of the heads between the valve sets, resulting in better fuel ignition and less flame travel than either the Allison, Merlin or Griffon. The cam train had no rockers, the cams drove directly onto “buckets” which pushed down on the valve stems. The jewel of the engine design was the cam drives which consisted of an assembly of helical and cone gears driving two angled shafts on the rear of each bank which simultaneously drove both intake and exhaust cams. This is far simpler than the much more involved arrangement of the Merlin or Allison.
> Supercharging was by a large proprietary 2 stage Turbocharger.



The other two were 48 valve, 60 degree bank, aluminum V12s, just SOHC. As far as Rigid goes, early Merlin had to pull the cylinder block from the crankcase to do a valve job, Cylinder heads were NOT detachable from the Cylinder blocks. crank cases on Both the Merlin and Allison were beefed up a bit over the years to handle the higher power. If you use connecting rods like a car you have to stagger the cylinders. One bank is slightly forward of the other bank. The Allison and Melrin had the cylinders directly opposite. Slight difference in engine length and it may (or may not) affect vibration patterns. Allison used pent roof combustion chambers with 44 degrees between the valves. DOHC and angled valves are great for power ( if actually needed) but mean larger heavier heads. 



> The design was magnificent. Three were built; on the first test, the engine put out 1800HP! Unfortunately, the design was not ready in 1942, subsequent development was spent on Tank Engines, and the engine never flew.



Well here we have a bit of conflict. First test and they were pulling 1800hp? very confident or very foolish? and design not ready until 1942? what happened to ready to go in 1940?


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## m37b1 (Feb 6, 2014)

Please reread my second post. 

I clearly stated that I had not verified the details, including the date that conflicts with my premise. 

Thought it would be interesting for the folks here to read about an engine that is quite intriguing.


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## GregP (Feb 7, 2014)

It is, but it was never an aero engine that flew. Interesting that it MIGHT have been a player, though.

Wish they had pursued it at LEAST to flight test.


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## Shortround6 (Feb 7, 2014)

I agree, it is intriguing. But lets look at it objectively and not like either a press agent or Ford fanatic. 

4 valve pent roof combustion chambers date back to at least the 1913 Peugeot Grand Prix car if not even earlier. A number of race cars and WW I aero engines used 4 valve heads with angled chambers so it was not a "new" idea in the 1930s and _any_ engine designer worthy of the job description was aware of them. Like many items or details they have both advantages and disadvantages. 

Harry Miller designed at least two "aircraft" engines that never flew. One never made it off paper, and the other ( a straight 8 ) for use in the Tucker XP-47 ( same Tucker as the post war car) had component parts built that were used a in a few post war racers, while similar to the "normal" Miller/Offenhauser design it was different in detail and NOT just two Offenhauser engines place nose to tail. 

While intriguing they were of no practical value. 

I am not anti-Ford. The tales of the Continental IV-1430 and the Lycoming O-1230 (both chronically under funded for much of their lives) should also point out the problems with thinking you can design, develop and build aircraft engines in months instead of years. If you could bring an _new_ engine from drawing board to production in 3 years or under you were doing a great job. It often took longer and that is by aircraft engine companies with experience in aircraft engine design. I would note that both Continental and Lycoming not only built small aircraft engines but built car, bus, truck and marine power plants for a variety of customers in the 1930s. They were not small shops specializing in one or two low production engines. They were smart enough not to sink too much company money into the US Army designed "hyper" engines though. I would note again that the proposed power output of the Ford engine was _well_ into the hyper range.


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## RCAFson (Feb 7, 2014)

m37b1 said:


> Another view on it's history. While I know the person that researched and wrote this, I've not verified any of it.
> 
> Origins:
> 
> ...



Obviously Canada was not contemplating building Lancs and Mosquitos in 1939, but there was a very large investment into the CanCar Hurricane plant which was effectively crippled by Henry Ford's treachery and it lay nearly idle for lack of engines. If Ford hadn't reneged on the deal, Cdn Hurricane production would have peaked 6-12 months sooner than historically with hundreds of additional Hurricanes available to the Commonwealth prior to Pearl Harbor - just when they were needed most in North Africa, Malta, and Singapore.


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## Shortround6 (Feb 7, 2014)

I am afraid this argument doesn't hold up very well either. 

Unless someone can up with real evidence of talks starting in 1939 the time line looks like it started in the Spring of 1940, according to Danial Whitney "Vees for Victory".

May 28th 1940 
"Henry" Ford Announces that the Ford motor company stood ready to "Swing into production of a thousand airplanes of standard design a day." 
Same day William Knudsen is appointed Commissioner of Industrial production. 
Edsel Ford travels to Washington to discuss production programs.
British have been looking to source 6000 Merlin engines.
Edsel Ford announces the Merlin deal. 
3 days later Henry reneges on the deal, claiming he will not build war material for foreign powers (although a number of Ford overseas plants are already doing so). 
Knudsen flies to Detroit to talk to Ford, to no avail. 
Meanwhile the US army is concerned that they only have one supplier of v-12 liquid cooled engines and while plant expansion is going well Allison has actually delivered only 35 engine in 1940 by the end of May. 
June 17th 1940 sees General Arnold calling for co-operation with the British in manufacture of the Merlin engine _provided_ the US can get 3000 engines over an above the 6000 engine British requirement. 
June 24th 1940 sees Knudsen meeting with Packard Motors ( who had previously inquired about getting back into aircraft engine work) and initial agreements were quickly reached so that Packard started work on June 27 1940 using Drawings that had previously been shown to Ford. 
Final contracts are not sighed with Packard until Sept 13 1940. 
Aug 20th, 1940 Ford enters talks with Knudsen about building aircraft engines. Sept 17th 1940 sees Ford Break ground on a New plant to build the R-2800. Aug 23 1941 sees the First production roll of the line and Ford did NOT have to convert every single drawing/blue print from 3rd order projection to 1st order ( or the other way around, I can't remember at the moment) nor did Ford have to come up with taps, dies and gauges for a variety of British thread sizes/standards. Aid from P&W did not have to come from across the ocean to help Ford. 

Fords flip-flop, despicable as it may have been and politically motivated, did not delay Merlin Production by more than a month or so.


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## RCAFson (Feb 7, 2014)

By your own dates, Ford's treachery cost a 3 1/2 month delay - but this assumes that Ford and Packard had identical design and production facilities, when Ford had by far the greater resources(and their subsidiary in the UK was already building Merlins!) so we have to add the additional time that it took Packard to bring the Merlin into production, and I think that an additional 3 to 9 months is probable, so that means 6 to 12 months of lost production, even assuming that Ford would not have had greater productive capacity and output.


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## fastmongrel (Feb 7, 2014)

Shortround6 said:


> Fords flip-flop, despicable as it may have been and politically motivated, did not delay Merlin Production by more than a month or so.



Henry Ford might have been playing politics but he was a business man way before he was a patriot. In mid 1940 who are you going to hitch your wagon to, the Germans who have won stunning victories or the British who are down and taking the count according to bootlegger Kennedy. If Ford backs Britain and Germany wins he loses all his factories in Europe and is left with a useless factory tooled up for a design the USA probably wont buy. If he backs Germany he gets to keep his factories in Europe and possibly the Germans take over the British contract.


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## Shortround6 (Feb 7, 2014)

Please look at it again. Ford had NO existing facilities for aircraft engine production. You do NOT build aluminium 1650 cu in V-12s that weigh 1300lbs in plants that built 221-239 cubic in cast iron V-8s that weighed 400-500lbs. 
Ford of England was building Merlin's using the _standard_ British projection drawings which would have to be redone for Ford of America just like Packard had to redo them. ( Changing the order of projection used in the drawings confuses and causes mistakes in already trained machinists). Ford of England is either already using or or has ready access to Whitworth taps, dies and gauges, British fine thread taps, dies and gauges, British course thread and British pipe thread. Unless England sends tons of tooling to America Ford of America is going to have to either make this stuff themselves or find subcontractors to make it just like Packard did. 
Packard _started_ work in less than 30 days after Fords initial agreement. Where does the 3 1/2 month delay come from? 
Please look again. It took Ford just about 14 months to build a New facility and deliver more than few engines. It took Packard about 18 months to do the same thing with much less help. ( R-R did send two engineers, one if not both who died after several years of exhausting work). Ford could rely on P&W for much more support, and a much easier time of getting subcontractors to supply small parts to normal american standards. 
Ford may have had more workers, more engineers and more money than Packard but Ford had NO experience in building aircraft engines. Packards was about 10 years old. Packard was tooling up to build 2500 cu in V-12 torpedo boat engines ( based on their last aircraft engine). Packard went on to be ranked 14th out of all American companies in value of war production so it wasn't exactly a small job shop. 

To build aircraft engines you also need test cells. Rooms were _each and every_ production engine is run for several hours to check performance and do initial break in before being torn down, inspected and reassembled. Which means _every_ test cell needs test instruments, dynamometers, cooling systems or fans for air-cooled engines.

In 1942 Packard built more engines that Ford did (by about 850 engines) but Fords engines( being larger and with more cylinders) had more total HP. 

I would also note that Ford while building 4 engine bombers instead of single engine fighters just barley managed 600 planes a Month for a few months in 1944 and not the 1000 planes a day (30,000 planes a month?) he claimed he could make  

I would also note that at some point in 1940 Allison was short about 800 machine tools to fill just completed factory space despite having an A1A priority rating. Structural steel was being rationed in 1940. There may have been limits as to how fast some facotires could be built and equipped no matter how large the parent organization. 

12 months lost production is totally ridiculous. It would mean a NEW factory hitting Spring of 1942 production levels in the Spring of 1941, 6-9 months after breaking ground or signing the deal. NOBODY was anywhere near that fast. 

Please see : http://www.enginehistory.org/References/WWII Eng Production.pdf

What this article does not say is how big some of these factories were or how much they were expanded. The Ford R-2800 plant was tripled in size by mid 1944 from the original plant that started making engines in late 1941.


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## Shortround6 (Feb 7, 2014)

fastmongrel said:


> Henry Ford might have been playing politics but he was a business man way before he was a patriot. In mid 1940 who are you going to hitch your wagon to, the Germans who have won stunning victories or the British who are down and taking the count according to bootlegger Kennedy. If Ford backs Britain and Germany wins he loses all his factories in Europe and is left with a useless factory tooled up for a design the USA probably wont buy. If he backs Germany he gets to keep his factories in Europe and possibly the Germans take over the British contract.



One story has it that he hated FDR and when told the Merlin deal pleased FDR that was enough to kill it.


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## fastmongrel (Feb 7, 2014)

On the taps and dies it is often mentioned as a big problem but surely manufacture is just a case of altering the machinery that cuts and grinds the taps and dies. Whitworth threads arent so far off Unified threads as many mechanics have found to there cost.


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## sgtleehead (Feb 7, 2014)

Slightly off topic but relevant I hope. Years ago I was researching the Comet tank and the gun on it for a book I wrote. (Sadly tanks are another love of mine). What was interesting was the politics, business and lies that were involved in the production of this vehicle - Stalling, contract awarding, friends being involved in production, cronyism with awards and inaccuracies produced as facts to justify favoritism. In the case with the Comet it was stated that the tank couldn't fit the 17pdr gun so the pocket 77 was developed and used instead - it was complete bullshit. It was all about contracts and friends.

The point I am making is, its hard to tell sometimes what the real story was in politics and business during the war in relation to development and procurement.


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## tomo pauk (Feb 7, 2014)

Interesting about the Comet - what's the name of your book? We do have the General ww2 sub-forum, so if you feel posting there ...


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## Shortround6 (Feb 7, 2014)

It is not a *huge* problem but taps and dies have to manufactured out of high grade steel and heat treated, a large factory will have many sets distributed in numerous tool cribs. They do wear out and/or break with time so replacements are needed. Standard taps and dies can be ordered off the shelf from sub-contractors, no need to make in house or special order from suppliers. Nuts and bolts can be purchased from suppliers with little difficulty *IF* they are a national standard. If they are NOT the national standard ( British threads) then arrangements have to made to build in house or have suppliers make them special in batches. The XYZ bolt company is NOT going leave a number of machines set up to make British thread bolts sitting idle while they wait for the next order. Bolts and screws _can_ be made on lathes without a _lot_ of difficulty but it is a slow process compared to specialized screw machines. Specialized screw machines can take lengths of bar stock and turn them into finished screws/bolts that drop down into hoppers at high rates of production. If you are trying to make hundreds of engines a month each requiring hundreds of bolts/screws you do not what your machinists trying to make screws/bolts one a time on lathes. 

Aircraft grade bolts are different than car or general hardware bolts. There only a certain amount of permanent stretch allowed when torqued to a given amount. Some car or general hardware suppliers could NOT supply aircraft grade hardware. 

ALL this stuff can be worked out and was worked out but it wasn't worked out in a couple weeks.


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## Shortround6 (Feb 7, 2014)

As a further note on the Merlin, the Ford was noted as having 4 bolt main caps on the crank which is an impressive feature to may hot rodders and car enthusiast. No mention of the number of bolts was made for the Merlin or Allison. 

Picture of Merlin: 







Please note the row of pair bolts above the sump joint. ( I know it's a dry sump) The Merlin had a crankcase that extended well below the center line of the Crankshaft the main bearing caps/blocks had two bolts that went in from the bottom but the blocks/caps fit between webs/cheeks in crankcase and were also held in place by the _pairs_ of bolts going in each side making 6 bolts holding each block/cap in place. 

It would take a good engineer with knowledge of the different bolt sizes, materials, sizes of mating surfaces, thickness of webs/cheeks and a whole lot more to figure out which is actually better.


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## GregP (Feb 7, 2014)

Both the Allison and Merlin have fork and blade rods. The blade rods have two bolts, but the same bearing is held in palce by the fork rods, which has 4 bolts. It is essentially a 6-bolt main cap retention. The Allison rods are VERY strong and can withstand 3,850 HP and more. They make that every year at Reno where the two front-running P-51's use composite engines that started life as Merlins and are running Allison rods among other modifications. The Merlin rods won't take quite the same horsepower, but are VERY strong when compared with any stock automotive engine.

I know the NHRA Top Fuel dragsters are pushing 8,500 HP ... but it's only for about 4 - 5 seconds. Try making these engine live for even 30 minutes and you'll never get it done. And they aren't anywhere near stock engine parts. The rods in Strega and Voodoo are stock Allison G-6 rods.

If you are sticking to 2,400 HP and less, the stock Merlin rods are just fine. They might take a bit more, but you'd be pushing them hard if you do it.


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## wuzak (Feb 7, 2014)

fastmongrel said:


> On the taps and dies it is often mentioned as a big problem but surely manufacture is just a case of altering the machinery that cuts and grinds the taps and dies. Whitworth threads arent so far off Unified threads as many mechanics have found to there cost.



While they may be similar TPI and of the same basic diameters, the big difference between Whitworth and Unified Threads is the angle of the thread. The Unified Thread has an included angle of 60° (as does metric) compared to 55° for Whitworth. BA threads have an angle of 47.5°. So production of tools and dies requires new sets of grinding wheels.

Also, while automatic machines can spit out machined screws quickly - we had one that made BA screws - it is not the only way to make screws and bolts. They can be rolled - but I'm not sure when that first started. These also require dies of the correct form.


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## RCAFson (Feb 7, 2014)

Shortround6 said:


> Please look at it again. Ford had NO existing facilities for aircraft engine production. You do NOT build aluminium 1650 cu in V-12s that weigh 1300lbs in plants that built 221-239 cubic in cast iron V-8s that weighed 400-500lbs.
> Ford of England was building Merlin's using the _standard_ British projection drawings which would have to be redone for Ford of America just like Packard had to redo them. ( Changing the order of projection used in the drawings confuses and causes mistakes in already trained machinists). Ford of England is either already using or or has ready access to Whitworth taps, dies and gauges, British fine thread taps, dies and gauges, British course thread and British pipe thread. Unless England sends tons of tooling to America Ford of America is going to have to either make this stuff themselves or find subcontractors to make it just like Packard did.
> Packard _started_ work in less than 30 days after Fords initial agreement. Where does the 3 1/2 month delay come from?
> Please look again. It took Ford just about 14 months to build a New facility and deliver more than few engines. It took Packard about 18 months to do the same thing with much less help. ( R-R did send two engineers, one if not both who died after several years of exhausting work). Ford could rely on P&W for much more support, and a much easier time of getting subcontractors to supply small parts to normal american standards.
> ...



You state that Ford started work on the R-2800 in Aug/Sept (I used the Sept date for the 3.5 month figure) and Packard on June 27 1940, so Packard/Merlin had a 2-3 month lead over Ford/R2800 yet look at the production figures:







In the first 6 months of production, Ford built 947 R2800s versus only 636 Packard Merlins despite the two month Packard Lead. Push Ford's R2800 plant back two months and they then produce another 989 engines or 1936 R2800s versus only 636 P.Merlins when both start on the roughly the same date - this shows the disaster to Allied and Commonwealth fighter production caused by Ford's reneging on the deal. Of course at the same time as this is going on Ford's engineers are able to completely redesign the Merlin as the V1650 GG Aero Engine which shows the depth of Ford's resources in both the design and production departments.


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## GregP (Feb 7, 2014)

This is starting to be funny. You can "what if" history to death. It was what it was, and Ford made his choice and could not be made to do otherwise. This is the USA, not the Soviet Union.

I think Shortround is right, the delay was minimal, but nobody can say exactly what it cost as the resources were available when they were available, and not before. Even if it cost 2 - 3 months, we probably would not have gotten places overseas much sooner anyway. If we are talking 1 - 3 months of delay, what possible difference can it have made? 

The bombing campaign started when it started, and would not have been moved up unless EVERYTHING was ready. I haven't seen any proof as yet that the Allied campaign was lagging because of lack of US Merlin production, and that is what delayed things.


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## MikeGazdik (Feb 8, 2014)

Sorry, my eyes glossed over reading all the posts on this topic. Somehow, I came away from this fantasizing that if the Allison V-12 didn't make the cut, there may have been Wright R2600 P-36's running around at some point. Droooool.


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## wuzak (Feb 8, 2014)

MikeGazdik said:


> Sorry, my eyes glossed over reading all the posts on this topic. Somehow, I came away from this fantasizing that if the Allison V-12 didn't make the cut, there may have been Wright R2600 P-36's running around at some point. Droooool.




Would that have been any better than the R-1830 P-36?

Sure, there is more power but there is also a lot more weight and a larger frontal area.


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## Shortround6 (Feb 8, 2014)

MikeGazdik said:


> Sorry, my eyes glossed over reading all the posts on this topic. Somehow, I came away from this fantasizing that if the Allison V-12 didn't make the cut, there may have been Wright R2600 P-36's running around at some point. Droooool.



Not to mention trying to fit a prop about 1 ft larger in diameter which means longer landing gear which means.................


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## stona (Feb 8, 2014)

Shortround6 said:


> Not to mention trying to fit a prop about 1 ft larger in diameter which means longer landing gear which means.................




........as always, things are easier to write than do.

Cheers

Steve


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## m37b1 (Feb 8, 2014)

Shortround6 said:


> I agree, it is intriguing. But lets look at it objectively and not like either a press agent or Ford fanatic.
> 
> 4 valve pent roof combustion chambers date back to at least the 1913 Peugeot Grand Prix car if not even earlier. A number of race cars and WW I aero engines used 4 valve heads with angled chambers so it was not a "new" idea in the 1930s and _any_ engine designer worthy of the job description was aware of them. Like many items or details they have both advantages and disadvantages.
> 
> ...



Reason for detailing the head/chamber design was to point out plug location. A big deal when detonation is a key factor in determining performance potential. It is probable that this engine would not have been ready any sooner than the GAA Tank V8 was. Dec 41- Jan 42. So that would put the Ford out of the running for this exercise. Maybe I should have chimed in on the "What if no US built Merlins" Thread.

Any how, I'm in the final legal phase of securing loan of the Ford V12 Tank engine GAC, for tear down and study. A photo essay will be published in a magazine that I write for. However, if anyone here is interested, I can present it in much greater detail after published.


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## MikeGazdik (Feb 9, 2014)

Hey, this is a fantasy, don't throw facts and reality in the way!!!!  As a hot rodder, first you put the big engine in, then you figure out all the other stuff. How about a nice thick cord prop, stretch the diameter to as much as can be handled. Put the P-40K airframe behind it with the larger fin area. 

Which if that happend, then when the British asks North American to produce the airplane, and North American counters, we have a R2600 P-51A. Yum. 

Sorry, ranting.


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## RCAFson (Feb 9, 2014)

I found this on the web:



> In article ,
> 
> 
> > (RON) writes:
> ...



So Ford's involvement did begin in 1939 and Ford engineers had had previous experience with the Merlin, both in terms of design and production; thus Ford USA was ideally situated to begin production of the Merlin under license.


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## Shortround6 (Feb 9, 2014)

Not really, Ford of France had a look and a few Ford of America engineers helped them look. Now you have the reverse problem, trying to turn the British drawings ( and thread sizes) into metric drawings and measurements. Now the American engineers go back to America with what? No computers so ALL drawings are done by hand and there were thousands ( if not tens of thousands) of drawings involved so the American engineers would have needed numbers of crates to get _any_ number of any short of drawings back to the US. There is no fax, etc. The actual drawings (or hand made copies or photographs) had to be physically shipped even from Ford of England. 

There is also some dispute about the two piece cylinder blocks. Some people say Packard designed them and others say Rolls-Royce did. Packard, because they were tooling up a _new_ production facility was in a better position to _start_ producing the 2 piece cylinder blocks since there was NO existing tooling to change over and no delay or loss of production like would have occurred in the English plants making the Merlin at the time. 

And having a few engineers who looked at the Merlin in terms of French production may or _may not_ help you when planning American production. My father was a production engineer for Colt in 1960s and 70s and not only worked on the US Colt production but helped set up factories in Korea and the Philippines to make M-16s. They often had to design different jigs and fixtures because the two oriental factories not only used different machinery than the home plant but different machinery from each other due to different monthly production goals and different goals (future production) after the initial rifle contracts were completed. 
Not sure what Ford of France had for production machinery or what they planned to buy to equip production line vs what Ford of America had available. Please remember that many lathes (for example) that could handle a small V-8 car crankshaft would be entirely too small to handle 5-6 foot long V-12 aircraft engine crankshaft. Casting cast iron is a different skill than casting aluminium.


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## GregP (Feb 9, 2014)

The people most familiar with casting aluminum back then, other than engine companies, were washing machine and sewing machine makers. Many aluminum parts for WWII engines were cast by Singer and Maytag. Singer was familiar with precision machining of steel,too, and made many precision parts for engines and weapons in WWII. Even Tiffany Jewelers in Mew York City got into war material produciton. They made the gold-plated amuinum disks used in late war throat microphones for interplane chat in B-17's and B-24's.

So it wasn't just the British that diversified production of war material, the US did it, too.


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## m37b1 (Feb 9, 2014)

RCAFson said:


> I found this on the web:
> 
> 
> 
> So Ford's involvement did begin in 1939 and Ford engineers had had previous experience with the Merlin, both in terms of design and production; thus Ford USA was ideally situated to begin production of the Merlin under license.



This makes a lot of sense. If we ignore the V-1650 GG V-12 aero-engine and just look at the GAA V-8 tank engine. This would explain how this high-tech engine was ready for production in Dec 41/Jan 42. I doubt Ford could have come up with this design form a clean sheet. This would point to inspiration from an existing design. 

Just a guess. The Merlin inspired the GG which in turn, inspired the GAA. 

If, (and this is a big if) The Henry Ford Museum can provide the test parameters used in the GG, I will attempt to reproduce them with my dyno run of the GAC Tank V-12.


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## GregP (Feb 9, 2014)

Good luck!

When we tried something as simple as getting some prop pitch specs for a WWII 6-bladed club propeller from Hamilton Standard, we were told "These data were produced for and at the request of the US Army Air Force. Since you are not the USAAF, the data will not be transmitted in any fashion to you. They are the property of the USAAF."

Explaining to them that the USAAF was no longer in existence and the USAF didn't care (we even included a letter from the USAF to that effect on official USAF letterhead to that effect) in the least did not do any good and they simply ignored us going forward. We came up with our opwn pitch data and now use that prop to break in just-overhauled Allisons. It was easier than we thought. We simply chose a pitch and ran the Allison at break-in power, noted the rpm possible, and adjusted until we achieved the desitred rpm. That pitch works for all Allison model at break-in and results in rapid piston ring seating.

The companies these days are more worried about potential laibility if the restored equipment breaks in a test they can be shown to have helped with than they are about preserving a historic piece of equipment in running condition.


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## Shortround6 (Feb 9, 2014)

Running an engine at part RPM ( even 90%) or so solves a few problems and ripping the supercharger off solves a whole bunch more. Lowering the _average_ pressure in the cylinders to a third ( or less) or what they were expecting from the airplane engine (for the GAA) certainly makes things a whole lot easier. 

Chrysler started work on their IV-16 2200cubic engine in the summer of 1940, it didn't _fly_ until the summer of 1945.

P&W started work on both the R-2800 "C" series engine and the R-4360 (used R-2800 cylinders) in 1940. The R-2800 "C" series doesn't see combat use until the fall of 1944 and a _short_ History of the R-4360 is here. 

http://www.enginehistory.org/P&W/R-4360/R-4360History.pdf


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## m37b1 (Feb 9, 2014)

Shortround6 said:


> Running an engine at part RPM ( even 90%) or so solves a few problems and ripping the supercharger off solves a whole bunch more. Lowering the _average_ pressure in the cylinders to a third ( or less) or what they were expecting from the airplane engine (for the GAA) certainly makes things a whole lot easier.
> 
> Chrysler started work on their IV-16 2200cubic engine in the summer of 1940, it didn't _fly_ until the summer of 1945.
> 
> ...



Understood. However, If I can get the test data. I'll add manifold pressure, using an external source to equal that used in the original tests. Of course this will only be done if tear down inspection and rebuild provides confidence in the mechanical integrity of the test engine.

BTW - Nice write up on the R4360! Love that engine!


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## m37b1 (Feb 9, 2014)

GregP said:


> Good luck!
> 
> When we tried something as simple as getting some prop pitch specs for a WWII 6-bladed club propeller from Hamilton Standard, we were told "These data were produced for and at the request of the US Army Air Force. Since you are not the USAAF, the data will not be transmitted in any fashion to you. They are the property of the USAAF."
> 
> ...




Ran into the same problem with Lockheed in obtaining the blueprints for the P-38. It took some time, but they finally sent them.


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## ohogain (May 6, 2014)

I only joined yesterday, and I haven't taken the time yet to go through all the posts on this thread, so I apologize in advance if I cover some ground already covered.

I agree with others that the US would not have adopted a foreign engine.

The USAAC dropped its support for the Curtiss V-1570 in 1932. I think it is reasonable to assume that if the Allison V-1710 had not come along Curtiss would have developed a new engine as they did when the D-12 came to the end of its functional development. 

Even if Curtiss hadn't, as has been posted by many others in this thread, there were other manufacturers, such as Lycoming and Continental, that were already building aircraft engines that would have been more than willing to develop a new generation of engines back in the early 1930s that would have been fully developed by the beginning of WW2.

As it was, both Continental and Lycoming began development of hyper-engines under Army direction in the early 1930s. Continental built the O-1430 in 1938 and successfully tested it in 1939, which would have been too late for any production of any of the V-engined US aircraft (P-38, P-39, P-40, etc.). Likewise, Lycoming's O-1230 first flew in 1940.

Packard's last aircraft engine that I can find prior to the V-1650 Merlin was the experimental 5A-2500 of 1930 rated at 1500 hp. While the xA-2500 was an "old" engine dating back to 1924, it is possible that Packard may have continued development of aircraft engines if Allison had not emerged.

The emphasis on the hyper engine by the US Army greatly hampered the development of water-cooled in-line aircraft engines, in my opinion. The Army began working on the development of hyper-engines in 1932, the same year that they cut the funding of the Curtiss V-1570. The Allison V-1710, which flew in 1930, before the Army switched to researching hyper-engines, was the last US design of water-cooled in-line engine prior to WW2.


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## Shortround6 (May 6, 2014)

The trouble was financing development. Few companies were willing to design and develop an engine purely on speculation without some idea or prospect of sizable orders. In the US _only_ the army was interested in liquid cooled engines for most of the 1930s and the Army wasn't buying very many airplanes per year. This resulted in the "gap" in liquid cooled engine development. 
The Army alone was not responsible for Curtiss dropping development of the V-1570, Curtiss had merged with Wright and found itself with 2 engine divisions competing against each other. The only real competition was P&W and Packard and Packard, in numbers produced, was pretty much small potatoes. The Navy's decision _not_ to use anymore liquid cooled engines pretty much ended Packard's primary market. The death of Packard's head designer after the diesel diversion along with the depression pretty much finished off Packard during the early and mid 30s. Curtiss-Wright didn't think it was very profitable to compete with itself and bailed out of the liquid cooled business as the airlines weren't interested in liquid cooled engines and they were a bigger market than the Military. 
Military contracts during the 30s were much different than today. Contracts spelled out each step and payment was _only_ made upon _successful_ completion of a test or task, and even then payment could be late (sometimes very late). If a test engine broke _before_ the test was finished the Army (or Navy) not only didn't pay for repairs but didn't pay _anything_ until the engine was repaired and completed the required test. During the depression this meant few companies were willing to get involved in development of large complicated engines _just_ for the army. 

The Allison did NOT fly in 1930, It first flew on Dec 14th, 1936 in a converted Consolidated A-11.


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## Balljoint (May 6, 2014)

In terms of “what if”, without the Allison there would have been no P-40 as we know it. The British want NA to build P-40s but were talked into an “improved” version, i.e. the P-51. But even for the initial P-51 there was no question –or option- other than the Allison. 
Asking what would have transpired without the Allison is a bit like asking what intelligent life would look like if the dinosaurs hadn’t been rendered extinct.


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## ohogain (May 6, 2014)

My error. According to Wikipedia, the V-1710 was first *run* in 1930, which is not the same as flown, but:

"The USAAC purchased its first V-1710 in December 1932. The Great Depression slowed development, and it was not until December 14, 1936 that the engine next flew in the Consolidated XA-11A testbed. The V-1710-C6 successfully completed the USAAC 150 hour Type Test on April 23, 1937 at 1,000 hp (750 kW), the first engine of any type to do so." (Wikipedia: Allison V-1710)

This implies that it flew at some point earlier. Not that it really matters from a practical point of view.

Your argument explains a lot. I had assumed that the lack of alternative engines was due to the Army's fixation with hyper-engines, but your explanation clarifies that if the Army wasn't buying aircraft, there wasn't a market for in-line water-cooled engines, so no one was building them.


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## gjs238 (May 6, 2014)

ohogain said:


> The emphasis on the hyper engine by the US Army greatly hampered the development of water-cooled in-line aircraft engines, in my opinion. The Army began working on the development of hyper-engines in 1932, the same year that they cut the funding of the Curtiss V-1570. The Allison V-1710, which flew in 1930, before the Army switched to researching hyper-engines, was the last US design of water-cooled in-line engine prior to WW2.



Not to sound silly, but perhaps the Army should have/could have better supported Allison and pursued the hyper-supercharger.
I suppose in a way they did - the turbocharger.
Still, with more support, a "better" supercharger could have been developed for the V-1710.


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## wuzak (May 6, 2014)

gjs238 said:


> Not to sound silly, but perhaps the Army should have/could have better supported Allison and pursued the hyper-supercharger.
> I suppose in a way they did - the turbocharger.
> Still, with more support, a "better" supercharger could have been developed for the V-1710.



At the start Allison was using supercharger impellers from General Electric, who also made the turbos. This was also the case for Wright and Pratt Whitney. Each of them eventually took supercharger design in-house and were able to make significant improvements thereafter.


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## Shortround6 (May 6, 2014)

I think we have been over this one a few times too. 

During the 30s you had kind of a chicken and egg thing going on. In the early 30s you had 80 octane fuel and it just won't take much supercharging. Even 87 octane is only good for about 4-6lbs boost in most engines. Please remember that it is not only the boost but the rise in temperature due to the boosting that causes detonation ( along with some other things). Until you had better fuel you couldn't use a high pressure supercharger and since the superchargers that were available could provide all the boost required (or allowed) by the fuels being used there wasn't much research being done on improving them.
In the US this was compounded by General Electric having almost a monopoly on supercharger design. Wright, P W and Packard actually had small design staffs in the 1920s and early 30s and rather than spend time working on superchargers they ALL went to GE and bought not only supercharger designs but supercharger parts (like impellers) if not entire superchargers. I am talking about mechanical superchargers not turbos. Even some Auto racers ( Like Henry Miller) went to GE for advice on car superchargers. So basically you had *one* supercharger design team in the entire United States and they had a few things wrong with their basic design. Nobody knew it because of the lousy fuel. 
By 1937-38 87 octane was common, 91 octane was coming on the scene in America and 100 octane was being used in experiential batches and for record setting. With both Wright and P&W competing on the world scene and having larger design staffs than they had in the late 20s and early 30s they both realized that the GE superchargers left something to be desired and started designing their own. Accounts differ about Wright with either the R-2600 or the R-1800 G-200 series engines being the first to use a Wright designed supercharger (Kenneth Campbell). P W _might_ have been a little faster on the draw but not by much. P W then got into the 2 stage supercharger business. 
Allison may have designed their supercharger in house but Allison during the 30s did a lot of sub-contract work for GE making supercharger parts (like impellers) as they sure weren't making any money selling engines until 1939. 
The US learned a lot about superchargers and centrifugal compressors during WW II but it took awhile. The Supercharger on a Wright R-2600-8 as used in a Grumman Avenger only supplied about 7 to 7.5lbs of manifold pressure at 12,000ft compared to the 6-6.25lbs the Merlin III supercharger (Pre Hooker) would provide at 16,250ft. 

You can have the "idea" of a two stage supercharger. Getting it to work is the big problem. Allison tried to go cheap on the first go round and use identical diameter impellers.

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## vikingBerserker (May 6, 2014)

GregP said:


> Good luck!
> 
> When we tried something as simple as getting some prop pitch specs for a WWII 6-bladed club propeller from Hamilton Standard, we were told "These data were produced for and at the request of the US Army Air Force. Since you are not the USAAF, the data will not be transmitted in any fashion to you. They are the property of the USAAF.".



Sometimes the "logic" used by others just scares the hell out of me.


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