Spitfire: Fuel gauges

[Artist]

An issue has been opened at the bugtracker (here): "Fuel gage doesn't work at Spitfire."

First: It does in fact work - but the dial descends only when the upper tank is empty and the fuel level in the lower tank is falling. If you fly for an hour or so, you'll see.

Second: We had this subject, when running the bugtracker for the last patch of Maddox Games, so here's the information we collected back then:

Spitfire Mk I and Ia: Missing second fuel gauge and both should operating on button press only

Fuel gauges are incorrect in both function and appearance.

Spitfire Mk I and Ia did in fact have 2 fuel gauges in this starboard side of the cockpit - one calibrated to 37 gallons for the bottom tank (right hand side), next to it on the left was identical instrument calibrated to 48 gallons. Both operated via button as described above, e.g. reading such as TAIL ON GROUND or LEVEL FLIGHT were identical, scale have had different reading due to different calibration - 0 5 10 15 20 30 40 48 on the top scale (rather that 0 5 10 15 25 30 37) and 0 5 10 20 30 40 48 on the bottom scale (rather than 0 5 10 20 30 37). There was obviously no alloy label above the 37 instrument.

Layout visible here on a early example (iron gunsight and manual gear lever):





Source: Source: "The Pilot's Notes The Spitfire I Aeroplane Merlin II or II Engine", A.P. 1565A, Vol I, Sect. 1, §19 (Facsimilie provided with Cliffs of Dover, Collectors Edition): See Item "72" and "77".

Spitfire Mk IIa: Fuel gauge indicates without pressing button

Spitfire Mk IIa has got the correct instrument (37 gallon) showing the bottom tank only (correctly), but in normal conditions, the gauge should read zero. Reading has been obtained by pressing the button as shown. (Only then, with the button pressed, the needle would move and show the amount of fuel left in the respective tank. It would obviously move back to zero when pilot released the button).





Source: "Pilot's Manual for Supermarine Spitfire IIA and IIB", Section 1, §19: "The fuel contents gauge(46) on the instrument panel indicates the contents of the lower tank, but only when the adjacent push button is pressed."

[Sandy1942]

I thank for an explanation, Artist.

[ATAG_Monkeynut]

Thanks Artist, a very interesting post, I'd always wondered about the spit fuel gauges, particularly the left one that's always 0.

[313_FlyBoy]

Yep. Here is the evidence from the war film document about Spitfire Mk I check routine:

https://youtu.be/8HIFc9xpguc?t=5m31s

At 5:31 can be seen both gauges in wartime Spitfire Mk I and the functions.

[Karaya]

That was actually one of the details that struck me in the "Dunkirk" movie. You saw Tom Hardy checking his fuel state on a regular basis by pressing the button next to the fuel gauge in his Spitfire Mk.I