Originally Posted by
buffo
Umm... I think you've got your wires crossed, Randy. Elevator control on a helicopter is accomplished with cyclic pitch control, just like roll control is. Neither one is really affected by rotor RPM, provided you have enough RPM to remain airborne of course. I think you're confusing the airplane term "elevator" with "lift" on a helicopter, as lift is definitely a factor of RPM on a fixed-pitch bird, but the elevator on an airplane is a control surface on the tail that causes the airframe to pitch up or down.
Dude - really?
I'm pretty sure I know what I was referring to ... talking about copters or airplanes is not my first rodeo with the models OR the real ones
"Elevator", in quotes, is referring to the similarity, or lack thereof, between altitude pitch control of airplanes - the elevator - and the equivalent control combination on helicopters. Intentionally simplified the comparison for someone who doesn't have much experience with collective-pitch helicopters.
I'm very aware that helicopter pitch & altitude control is a combination of both cyclic & collective pitch.
(And surprisingly, some helicopters do have actual functioning elevators - the AH-1 uses them as an aid primarily for high-speed / diving flight)
Without collective pitch, the only way you can maintain a climb setting - "up elevator" - on a fixed-pitch helicopter is to increase the rotor RPM, which increases the lift of the entire main rotor system. Yes, cyclic pitch is a factor with any helicopter, but without an increase in RPM of a fixed-pitch rotor system, the copter can't maintain a climb.
Collective pitch does it by increasing the blade pitch of all blades simultaneously, with a relatively constant RPM setting that is maintained "behind the scenes" with fuel controls on the real aircraft, or throttle / pitch curve mixing on CP models using a programmable computer radio.
Also, keep in mind that a true helicopter - model or real - does NOT need cylic input to climb vertically.
True vertical takeoff is all about the vertical lift generated by the rotor system, whether by collective pitch or rotor RPM increase.
For this mode of flight, cyclic control is merely being used to stabilize the copter horizontally.
Mostly everything you just said in the post prior to this one, I just started out with a more simplified approach to make make my initial comparison.
Kind of a leftover trait from being an instructor / test pilot when flying for Uncle Sam ~
Start out simple, but pile on the details when it's time for a check ride...
Last edited by Stuka; 04-08-2014 at 10:57.
RR
Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
1979.
Sweet.....