On 2011-01-12 12:50:59 -0800, Eric Stevens said:

On Tue, 11 Jan 2011 18:13:33 -0800, Savageduck
wrote:

On 2011-01-11 17:13:09 -0800, John Turco said:

Savageduck wrote:

On 2010-12-22 19:16:49 -0800, Eric Stevens said:

heavily edited for brevity

So I am not sure just what proportion of Packard built Merlins
ended up in RAF aircraft. The Merlin 61 was built in the US & the UK
but used the Packard designed split head and ended up in Spitfire Mk IX
and P-51s. The later Spitfires used the RR Griffon not the Merlin.

English built Merlins came out of 3 RR plants and one English Ford
factory. There were just too many variants of the Merlin made for a
wide array of aircraft, ranging from all of the British bombers, The
Beaufighter, Mosquito, the Hurricane, & Spitfire. All were different.
Once the move to replace the Allison in the P-51 was made, it only made
sense to build those engines in the US rather than have them make a two
way trip across the Atlantic.

They needed them anyway.

Yup! I guess the got them.


Well, from what I recall reading, the Allison engine's real drawback was
its lack of a supercharger. The P-51's manufacturer (North American) had
built the plane to British specifications, and the latter had originally
intended the aircraft as a low-level "rhubarb fighter."

Hence, North American decided against the supercharger; such an omission
severely crippled the Allison's high-altitude performance, unfortunately.

Not quite right. The Allison V-1710 always had a single stage
supercharger, it just didn't perform well above 15,000 ft.
The English variant "Mustang" MkI, MkII, MkIII were powered by the same
single stage supercharged Allison V-1710 used in the Bell P-39, P-40,
and the English P-38, the "Lightning" MkI & MkII. All had performance
issues above 15,000 ft.
The US Lockheed P-38, was powered by 12 cylinder Allison V-1710 engines
fitted with top secret turbo-superchargers to supplied with the English
order. The variant of P-38 exported for RAF use was fitted with
non-Turbo-supercharged "right-side" single stage supercharged Allison
V-1710's and was ultimately rejected by the RAF. By specifying their
order for the "Lightning" MkI & MkII, with "right-side" engines, they
lost the benefit of counter rotating props.
The reason for using the "right side" Allison V-1710 was, that was the
engine, with single stage supercharger, used in the UK lend-lease
P-40's, & "Mustang" MkI, II, & III

I've always understood that at the stage of the war the US would not
allow turbocharged engines to be sold to any foreign government. hence
the British were forced to take the unturbocharged engines which, as
you say, turned the Lightning into rather a dog.



Eric Stevens

Correct with regard to the Turbo-supercharger, but the UK "Lightning"
MkI had the single stage supercharger and Allison V-1710-39. It was the
turbo-superchargers fitted to the US P-38, which was powered the
Allison V-1710-111, and the P-47 which were on the prohibited list.

The Allison V-1710-37/39 as fitted to the P-39, The Commonwealth P-40B
& P-40C, UK "Mustang" MkI, MkII, & MkIII, and the UK "Lightning" MkI &
MkII, all had the single stage supercharger which worked reasonably up
to 15,000-16,500 ft, any higher and they were asthmatic dogs. They
mostly ended up as ground attack fighters, though the Russians were
pretty successful with the P-39 as fighter. The "Mustang" MkI & MkII
never got P-51 designation. They were designated USAAF A-36
Apache/Invader.

Later the RAF, Australians, NZ, South Africans in the Desert Air Force
got 330 of the P-40F's fitted with the Packard Merlin V-1650 as fitted
to the P-51, Lancaster, & Mosquito.

The Russians got the P-39's as is and never got the P-63 KingCobra with
the turbo-supercharged V-1710-117.


--
Regards,

Savageduck