Hello,
I am writing an essay on Reginald Mitchell and one of the assignments is to talk about environment when it comes to his invention, so I decided to compare the fuel consumption of his Spitfire MK I and Stukas. The problem is that the sources I found for the TSFC seem funny.
In this source, the fuel consumption for the Spitfire at 7000ft 2133m at 200mph322 km/h is 24 Gallons per hour, which roughly translates to 90 litres per hour.
The source for the Ju 87 B-2 claims that the the consumption is 275 litres per hour over the speed of 200 km/h.
Is my German wrong or does the German plane need 3 times more fuel than its British counterpart?
Thanks.
The Spitfire MkI had a loaded weight of 5935 pounds and a top speed of 348 miles per hour. The Stuka B-2 had a loaded weight of 9500 pounds and its top speed was only 210 miles per hour. Now, I see you are asking to compare the Spitfire at 200 miles per hour, which is slightly higher than its most efficient cruising speed, to a Stuka at 200 kilometers per hour, which is even closer to the Stuka's cruising speed. Double check your source. If the Stuka is consuming 275 liters per hour at 200 miles per hour, that makes more sense, because that is close to the Stuka's top speed. Aircraft that fly close to their top speed burn a lot more fuel than a plane that is flying at its cruising speed.
Now if you are really trying to compare fuel consumption of a Spitfire at 200 miles per hour to a Stuka at 200 kilometers per hour, then that does not sound right. The Stuka is 3465 pounds heavier and has a fixed landing gear, compared to the Spitfire's retractable landing gear. The Stuka should burn more fuel than the Spitfire, but not that much more at its cruising speed. However, if the Stuka is flying a 200 miles per hour, which is close to its top speed, then it having a much worse fuel economy makes sense.
Fighter pilots during World War II were told to limit their maximum throttle setting during dog fights to less than 20 minutes, because they burned fuel much faster at their top speed and could quickly cause the engine to overheat and oil pressure to drop.
The Stuka link goes to the whole 383 page manual... What page did you find your source for fuel consumption?
Edit: Okay, I found at the bottom of p. 12 where it says 275 l/h, but that is for an altitude of 5,500 m, which is roughly 18,000 ft, so the comparison with Spitfire data at 7,000 is a little off, perhaps. The speed given for the Stuka is "VR", and I didn't immediately see what that reference corresponds to in km/h or mph.
But it's not impossible that the Stuka does consume considerably more fuel than the Spitfire - they have similarly-sized V12 engines, but the MTOW of the Stuka is nearly double that of the Spitfire (11,000 lb to 6,700 lb).