Quote:
Originally posted by Jared Fenton
Trying to visualize mutiple transonic shockwaves affecting airflow over the wing. Thank you for the new perspective. You owe me ten minutes of life 
Would higher performance aircraft, say something like a P-38 or maybe a modern aerobatic plane have to run at even less RPM because of dives, banks and such? or is that where a variable pitch prop comes in? Obviously not on the P-38.
What sort of engine mounting, dampers? solid? would say a DC-3 have in comparison to a high performance prop? wondering just to what level of tolerance is aceptable and what is available?
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The P-51 was the first allied airplane to get near supersonic in flight and did that only in a dive. It would get near the transonic area and the flight controls would usually lock up, usually resulting in loss of the airplane.
The fighters (lumping them in because they almost all were about the same in this area) would get near supersonic on their prop tips, especially in a dive where the engine would be able to run as fast as possible. Even todays airplanes, like a Cessna C-206/7 are very loud because the prop tips are nearing supersonic on takeoff. In a dive most prop airplanes have to reduce power to keep the RPM's in the "green" range.
Regarding the engine mounts. Their were two types in the piston type of airplane. The Spit, P-51, P-38 and later FW-190's on used a "bed" type of mount as their engine was a watercooled inline V-12 that sat in a frame.
Two versions of a inline water cooled engine, the P-51 and P-38:
Notice how thin the engine nacelle is? Smaller size of the front of the engine made it thinner, which made the plane faster.
Why not all planes like that you say? One bullet from a rifle into the radiator and the plane is down. Radial engines have been known to have an entire cylinder and head shot off, blowing oil out everywhere and still return to base, plane and pilot in one piece. Any airplane used in ground support for the troops that was watercooled always was worried about the "golden bullet" that would bring them down, while the radial engined planes did not have this worry.
The P-47, F-4U, FW-190 (early radial versions) had radial engines that had conical mounts.
A better view of a aircraft radial engine on a ford Trimotor:
Finally, regarding shock waves over airplanes and props, look here:
