P-40L

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

MIflyer

1st Lieutenant
7,021
14,363
May 30, 2011
Cape Canaveral
This is a well worn P-40L of the 324FG 316th Sqdrn. The P-40L was the Merlin engined long tail version derived from the P-40F, lightened with only four .50 cal guns in an attempt to increase performance. Probably the biggest value of the V-1650-1 Merlin was that it had a two speed supercharger that improved high altitude performance. Around the time this photo was taken the 324th transitioned to the P-47.

Pr

P-40L324FG316Sqdrn.jpg
 
The V-1650-1 Merlin did not have a two speed supercharger. It was only single stage.
It is rather common for people to confuse Single Stage superchargers with Single Speed Superchargers. This may be because so many of the WW2 vintage articles used the terms interchangably for some reason. If you do not believe the P-40F/L had a two speed supercharger, go look at the performance curves for the P-40 in the book "America's Hundred Thousand" and you will see the characteristic stepped curves of a two speed supercharged engine, as compared to the unstepped curves of the V-1710 versions.

Allison was almost unique in that it did not develop and mass produce a two speed supercharged engine, unlike just about every other country in the world. This probably reflects the influence of the GE turbosupercharger, which was the first stage supercharger for the V-1710 in the P-38 as well as the company's development of a variable first supercharger stage as used in the P-63 and P-82.
 
It is rather common for people to confuse Single Stage superchargers with Single Speed Superchargers. This may be because so many of the WW2 vintage articles used the terms interchangably for some reason. If you do not believe the P-40F/L had a two speed supercharger, go look at the performance curves for the P-40 in the book "America's Hundred Thousand" and you will see the characteristic stepped curves of a two speed supercharged engine, as compared to the unstepped curves of the V-1710 versions.

Allison was almost unique in that it did not develop and mass produce a two speed supercharged engine, unlike just about every other country in the world. This probably reflects the influence of the GE turbosupercharger, which was the first stage supercharger for the V-1710 in the P-38 as well as the company's development of a variable first supercharger stage as used in the P-63 and P-82.

Yes. Totally true.

The Packard V-1650-1 engine is basically a Merlin XX, US built with some minor differences (prop shaft, oil filter, accessories drive...) and a Bendix PD carburetter. And Merlin XX is a ONE stage, TWO speed engine....
 
The Packard V-1650-1 engine is basically a Merlin XX, US built with some minor differences (prop shaft, oil filter, accessories drive...) and a Bendix PD carburetter. And Merlin XX is a ONE stage, TWO speed engine....
By the way, when I bring up the two speed Allison argument I often get two responses:

1. There were no examples of two speed single stage inline engines to use in Allison powered aircraft.
2. The V-1650-1 was not nearly as capable as the two stage V-1650-3 so it would have been a waste of time to put it in the P-51A. (Well, duhhh, but it would not have been a waste of time, as the P-40F/L performance shows.)
 

Users who are viewing this thread

Back