How fast do helicopter blades spin in mph?

At the extreme, the theoretical top speed for a rotary winged aircraft is about 225 knots (259 mph; 417 km/h), just above the current official speed record for a conventional helicopter held by a Westland Lynx, which flew at 400 km/h (250 mph) in 1986 where its blade tips were nearly Mach 1.

How fast do helicopter blades spin in a second?

Depending on the model and size of the helicopter, a helicopter’s blades, which are between 40-60ft long, spin from about 225 RPM to 500 RPM. Speed is determined by the power of the rotor and the length of the blade.