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So how serious do you gentlemen think the actual, real world performance hit on a Volkes filter equipped Spitfire was? 10mph? 15mph?
Good info. Thank you. Too bad they just couldn't keep the weight gain under control on the P40. Wouldn't a P40E be 1,000 to 1,500 pounds heavier than a Spitfire V?
You have two basic aspects of the filter to consider.
1, is it actually stopping the dirt from getting into the engine.
2. How much performance loss is there, which can also be broken down into two parts.
A. pressure loss before carburetor .
B. Aerodynamic drag caused by larger intake/fairing.
I have no idea how well the Vokes filter worked at keeping dirt out of the engine.
as far as pressure loss goes, hard to figure but a tropical trials aircraft in England managed to keep 9lbs boost while climbing (2850rpm) to 14,000ft at 196mph TAS and to 17,400ft in level flight at 354mph while an early MK V held 9lbs to 15,000ft while climbing and to 20,100ft without snowguard at 371mph and to 18,800ft with snowguard fitted at 365mph.
Different serial number aircraft with different engines. The engine/s should have been able to provide more boost at less than the full throttle heights. The snow guard only seem to make a difference in speed at over FTH.
Good info. Thank you. Too bad they just couldn't keep the weight gain under control on the P40. Wouldn't a P40E be 1,000 to 1,500 pounds heavier than a Spitfire V?
Someone smarter than me will reply soon, but I thought I read somewhere the P40E Allison air intake was up high out of the worst dust? Wasn't the Spitfire air intake down lower where dust was worst?
And the SpitfireV coming in around 6,700. Amazing a P40E is even in the ballpark. Makes me wonder how it would have done if they could have kept the weight around 6,700.
Someone smarter than me will reply soon, but I thought I read somewhere the P40E Allison air intake was up high out of the worst dust? Wasn't the Spitfire air intake down lower where dust was worst?
In one of the posts above, (Japanese Zero vs Spitfire vs FW 190 | Page 11 | WW2Aircraft.net Forums it states that the Vokes filter cost something like 25 mph in top speed, or about 7%. This would be about a 2.5% power loss, or about 40 or 50 horsepower. This strikes me as a lot, although one would need a comparison with a different filtration system to be sure.
Bolding by me. IF tropical Spitfires were fitted with larger radiators and oil coolers than "standard" Spitfires then there is going to be additional drag even if such units fit in the original ducts/housings. There will be either more airflow or a larger pressure drop through the matrix or both.
Frontal area does not measure airflow or drag inside a duct.
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