1938-1940 Allison and P&W Engines Question.

[Akuma]

Was a two stage or two speed supercharger available for the Allison and P&W engines in use by the U.S military before 1940?

 

[pbehn]

There was an Allison V1710 made but only post war.

 

[Shortround6]

The two stage Allison entered production in the summer of 1943. It was used in the P-63. It didn't exist even as a prototype until 1940 and in 1940 had some very serious design flaws.

Some question as to the Allison engine power section stand up to two stage supercharging in 1940.

Two P & W two stage engines were at the USAAC fighter trials in Jan 1939 but they had some troubles.
Production started in May of 1949 but only 98 two stage engines were built in 1940. About 3545 single stage, single speed and two speed engines were built in 1940.
These 1940 engines (-76) had some problems with compressor mismatch and there a number of complaints about rumbling in the ducts and other problems.
The F4F-4 changed to the -86 engine near the end of 1941.

 

[Akuma]

There was an Allison V1710 made but only post war.

Sorry the info I got was wrong about the model. I'll re-edit my original question.

 

[Shortround6]

For the Allison the two speed engine was almost entirely post war.

P & W was late to the two speed game (Wright had gotten in 1938) and while they made 1917 two speed engines in 1940 they only started in April with 2 engines, 23 in May, 113 in June and so on.

 

[OldGeezer]

Allison put together a very informative overview of the relative performance characteristics of 8 different kinds of engine options, including single- and 2-stage supercharging. Some fundamentals of aircraft engine design (with particular reference to the requirements for performance at varying altitudes)

 

[OldGeezer]

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