Interestingly, the plane uses contra-rotating propellers, which rotate so fast that the tips move faster than the speed of ...

Noise levels of propeller-driven aircraft are higher and amplified at ... is achieved when the aircraft's speed exceeds the speed of sound. To achieve supersonic speed, the airframe must withstand ...

It was noisy to the extreme. The aircraft never broke the sound barrier in flight, but the large squared-off propeller blades would travel constantly faster than the speed of sound at around 900 ...