Another take on superchargers

[Kryten]

Hello Kryten, you make a good point. I'm uncertain if I have (A.&A.E.E./Res/170). I'll look around.

Many thanks Mike.
I have been having trouble finding any reference to this, I bought books on testing at Boscombe but that proved to be no help, so other than trying the National Archives I'm stumped.

 

[wuzak]

Merlin Mustang was not outfitted with Merlin 61, but, for example the P-51D with V-1650-7, an equivalent of the Merlin 63. The -7 was making more than 1500 Hp @ 67 in Hg at 15000 ft. 67 in Hg = full throttle for 130 grade fuel. More than 67 in Hg is dangerous to push unless one has fuel that is much better than 130 grade.

The V-1650-3 was equivalent to the Merlin 63.

The V-1650-7 was equivalent to the Merlin 65/66.

The V-1650-9 was equivalent to a 100 series Merlin. There were high and low rated versions of the 100 series, and the -9 was a high rated version. The -9 had the same supercharger gear ratios as the -3.

 

[Schweik]

When the PI was attacked a P-40E pilot jumped in his airplane and shoved the throttle as far it would go and tried to build up some altitude and airspeed. Then he was shocked to see the manifold pressure was only something like 10 inches. Figuring his engine was failing, he despaired, but then gradually realized the gauge had gone all the way past 60 inches and started another circuit. Allison got V-1710's up above 80 in MP on the test stand, the limiting factor not being the engine but the bolts that held it to the test stand.

Where / what is "the PI"?

have you seen this?

http://www.wwiiaircraftperformance.org/P-40/V-1710_Service_Use_of_High_Power_Outputs.pdf

 

[Jim Daigneau]

PI=Philippine Islands? Great thread!

 

[Neil Stirling]

Many thanks Mike.
I have been having trouble finding any reference to this, I bought books on testing at Boscombe but that proved to be no help, so other than trying the National Archives I'm stumped.

Hi Kryten you can get a copy here, but you will have to pay.

Search results: British Performance Reduction Methods for Modern Aircraft | The National Archives

Another file that contains many charts and calculations.

Search results: aircraft performance data book | The National Archives


Neil.

 

[MIflyer]

Yes, PI = Philippines

And no, I am not familiar with that document. Thanks for pointing it out.

By the way, the P-40 did not get a V-1710 with an automatic manifold pressure regulator until the M model. RAF pilots occasionaly got surprised by that on the earlier models when they pushed in the throttle at low altitude and overboosted the engine. The regulator was also installed on the later P-38 Allisons, where it fought the turbo regulator, with undesirable consequences.

 

[Kryten]

Hi Kryten you can get a copy here, but you will have to pay.

Search results: British Performance Reduction Methods for Modern Aircraft | The National Archives

Another file that contains many charts and calculations.

Search results: aircraft performance data book | The National Archives


Neil.

Many thanks Neil, very helpful.