Re: OT: helicopter question (lyledriver)
quote:[HR][/HR]In your average passenger helicopter, how fast does the main rotor spin? Do they use a turboprop system and keep the engine at a constant RPM? I just saw a trafficopter fly by pretty close and it made me curious.
Main rotor RPM varies from helicopter to helicoper, however it is typically between 300 and 500 RPM. Main rotor RPM is "controlled" via the collective, which is a stick on the pilot's left side, typically positioned like an emergency-brake lever. Raising and lowering the collective changes the pitch of the main rotor blades, which effects how fast the main rotor can spin. In flight, main rotor speed is not controlled via the engine throttle; the throttle is set at 100% before takeoff and typically remains in that position throughout the flight.
Helicopters with turbine engines use a "turboshaft" configuration, rather than the turboprop you referred to. The main differences being that turboshaft engines are designed to produce more shaft power (as opposed to hot-gas thrust) and have significantly different gearing.
I flew a Robinson R22 once. That was a blast... anyone who hasn't flown before should definitely give it a try. Go down to your local airport; you can typically get an introductory lesson for around $60. In the end, I decided to fly fixed wing planes, simply because it's cheaper. I do work with helicopters though and am constantly amazed by them... what ingenious machines!