Quote:
Originally Posted by Karl
I've always been amazed how essentially the same engine in a Spitfire and a P51D sounds so completely different-However both spine tingling.
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Several different things can cause the difference in sound, the most common of which might be propeller blade style, number of blades, blade length, pitch setting, RPM, and even the aerodynamic load on the propeller at any given time. Also, the material the blades are made from (some Spit propellers have wooden core blades that special machinery pressed a hard metal mesh coating and cellulose sheet over the entire propeller) can have an effect on resonance of the blades at speed. Some earlier Spitfires had three-bladed propellers.
A close second factor might be differences in exhaust, like stack length, shape, and even the angle or direction that the stacks exhaust into the slipstream.
Common P-51 blade shape and exhaust stack configuration below.
3-bladed propeller, and exhaust stackson early Spit!
Note the narrow blade profile (compared to P-51), and distinct exhaust stack shape on this Mark VIII Spit.
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