Non veni pacem mittere, sed gladium.
Radial engine porn.
Wow! Thirty six cylinders displacing 7757 cubic inches, making 5000HP. Very cool.Today a single 8 cylinder Top Fuel Drag engine exceeds that HP rating. https://en.wikipedia.org/wiki/Lycoming_XR-7755
The drag motor runs at full power for 4 seconds tops and less than 1000 revolutions total then it needs a complete rebuild.. The Lycoming would have been run for 100 hours at least between overhauls.
Aircraft engines are both efficient and reliable. Believe it or not, aircraft engines designed in the late 1930's have a BSFC (fuel consumption per hour per HP) that matches the best engines today. Those engineers were brilliant and truly did understand what they were doing. Today's turbine engines produce far more power, and are exceedingly reliable. But they are not more efficient.