Spitfire question (Supermarine not Triumph)

[Dr Jekyll]

One of the links on the mystery instrument thread refers to a Spitfire using a gallon of fuel a minute on tickover!

Is this right? I'd have thought a gallon a minute in flight would be more like it. Or does it take just as much fuel to tick over as to run normally?

[Eric Mc]

Sounds a bit high BUT there were many versions of Spitfires using a variety of Merlin and Griffon engines - all with different fuel consumption figures.

[Tango13]

I've read in James Gilberts' "The Great Planes" that on full throttle they use just over a gallon of 80 octane a minute but this makes no mention of which mark of Spitfire or engine type.

I'd imagine this consumption is for an early Merlin engined aircraft as the Griffon was a much larger capacity engine producing much more horsepower and therefore needing more fuel.

[aeropilot]

Dr Jekyll said:

One of the links on the mystery instrument thread refers to a Spitfire using a gallon of fuel a minute on tickover!

Is this right?

No.

A RR Merlin 24, for example had a fuel consumption rate of 100/130 fuel of about 3 gallons per minute at max take off power and about half that at typical cruise power settings.

On that basis, at idle, it's likely to be significantly less than a gallon/minute.

[DieselGriff]

Tango13 said:

I've read in James Gilberts' "The Great Planes" that on full throttle they use just over a gallon of 80 octane a minute but this makes no mention of which mark of Spitfire or engine type.

Just on the octane - the Spit initially used 90 octane fuel and then very early on (around May\June 1940 IIRC) they switched to 100 octane - an important difference when comparing performance of German and British\American aircraft as German aircraft were limited to 80 something (I can't remember) fuel throughout most of the war.

[Tango13]

DieselGriff said:

Tango13 said:

I've read in James Gilberts' "The Great Planes" that on full throttle they use just over a gallon of 80 octane a minute but this makes no mention of which mark of Spitfire or engine type.

Just on the octane - the Spit initially used 90 octane fuel and then very early on (around May\June 1940 IIRC) they switched to 100 octane - an important difference when comparing performance of German and British\American aircraft as German aircraft were limited to 80 something (I can't remember) fuel throughout most of the war.

I did think that it was a bit low when I was typing it. The Germans overcame their poor quality fuel by using GM-1 better known as Nitrous Oxide and MW-50 a 50:50 mix of water and methanol.

[2 sMoKiN bArReLs]

Didn't the ME have fuel injection rather than carb to avoid fuel starvation cut out?

[Eric Mc]

2 sMoKiN bArReLs said:

Didn't the ME have fuel injection rather than carb to avoid fuel starvation cut out?

The Daimler Benz 600 family as fitted to the 109E and later variants of the 109 had mechanical fuel injection which had been developed in the pre-war Mercedes grand prix cars.

[Tango13]

/\ What he said altough I'm not sure if it was directly injected into each cylinder or the inlet manifold.

[aeropilot]

Tango13 said:

/\ What he said altough I'm not sure if it was directly injected into each cylinder or the inlet manifold.

DB601/603/605 series engines were direct injection.