Assertion: rotor's speed | /r/HasProperty | about 225 knots
Facets:
value: at the extreme
type: OTHER
Source sentences:
text: 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.