Quote:
Originally Posted by Dragoneye
Chris...is there any particular reason the Black Hawk has constant rotor speed versus the other option?
Engine efficiency, size of the aircraft? 
That's pretty cool, I never knew that! |
Here's a common sense answer.... cus I don't truly know..
But I'm guessing that it has to do with the "direct drive" transmission.
the jet engines that power the the main transmission that turns both the main rotor and the tail rotor are directly connected to the an ouput shaft from the two engines...
My guess is it's that it's more efficient/effective to have the transmission spin at a constant speed, while allowing the engines to respond to the increased or decreased loads caused by the angle of attack of the blades and rotor head... or the work the rotor head is doing...
But to be clear. the engines do spin up under increased load. but the rotor head rpm is relatively constant.
In fact there is a Main Rotor Overspeed indicator that when lit basicaly means that Aircraft is down for maintenance until the rotor can be inspected/serviced...
FWIW.