Griffon 69 / Sabre VA max power comparison

[Simon Thomas]

I thought it would be interesting to compare the maximum power output vs altitude for the RR Griffon 69 and the Napier Sabre VA.

They have almost identical capacity at 2240 in³.
The Griffon has a two stage two speed supercharger, uses 100/150 octane fuel and runs 25 lb boost. Weight is 1980 lb.
The Sabre has a single stage two speed supercharger, uses 100/130 octane fuel and runs 15 lb boost. Weight is 2460 lb.
The Griffon data was from Flight Jan 10, 1946, p34. The Sabre VA data was from Aircraft Engines of the World 1949.
I was unable to locate fuel consumption, although at max power it isn't so relevant.

I was surprised that the Sabre had so much extra power down low, despite running 10 psi less boost and running on lower octane fuel.
Makes a strong case why the Spitfire was used for high altitude and the Typhoon/Tempest was used at low altitudes.

Edit: Sabre weight changed based on Flight 22 Nov 1945 p552.
Edit 2: Sabre at 3850 rpm. Griffon at 2750 rpm.

 

[Bretoal2]

I thought it would be interesting to compare the maximum power output vs altitude for the RR Griffon 69 and the Napier Sabre VA.

View attachment 761164
They have almost identical capacity at 2240 in³.
The Griffon has a two stage two speed supercharger, uses 100/150 octane fuel and runs 25 lb boost. Weight is 1980 lb.
The Sabre has a single stage two speed supercharger, uses 100/130 octane fuel and runs 15 lb boost. Weight is 2460 lb.
The Griffon data was from Flight Jan 10, 1946, p34. The Sabre VA data was from Aircraft Engines of the World 1949.
I was unable to locate fuel consumption, although at max power it isn't so relevant.

I was surprised that the Sabre had so much extra power down low, despite running 10 psi less boost and running on lower octane fuel.
Makes a strong case why the Spitfire was used for high altitude and the Typhoon/Tempest was used at low altitudes.

Edit: Sabre weight changed based on Flight 22 Nov 1945 p552.

You forgot RPM.....