Need expert help for a variable pitch system
 

We need someone to help in determining how much power a tail rotor subsystem on a model helicopter consumes when being driven to the extreme of pitch. The tail rotor system rotates on a 5 mm shaft. Is there someone who is willing and able to quickly help us determine either the current draw (Amps) or the amount of power (watts) being consumed at approximately 10,000 RPM? The rotor diameter varies between 9" and 9-1/2" depending on the rotor blades selected and of course is variable pitch. We can supply the components.

John Beech - GM (and janitor)
407-302-3361

RE: Need expert help for a variable pitch system
 

Would this be better if posted in the R/C electric helicopter forum?

Dave

RE: Need expert help for a variable pitch system
 

Dave, I considered that, but I think I'm more likely to encounter the kind of help I want from an airplane type (I fly both, so this is not meant to cast aspersions on anybody's preference). Also, the question really has more of an application for one of the model airplane crowd experimenter-types (if you catch ym drift) since the application could be rather easily used for a variable pitch propellor equipped model at some time ni the future. You see, it's my experience that model helicopter modelers usually are excellent at building, but model airplane modelers are better at "making" . . . and that's a critical difference when we're going to have to do some making as part of the adapting to derive some power figures. Thanks for responding pal. John

RE: Need expert help for a variable pitch system
 

this is not a difficult problem to put your mind too, all you need to know is the Amps being drawn by the main motor without the tail shaft attached, read with a power analyzer/watt meter, then attach the tail shaft read again and take one from the other, you can vary the pitch and dia of the tail rotor and compare the readings as all things being equal the main motor should still be drawing the same amps. If the Heli is IC then there are HP tables out there that will tell you the HP required to turn a prop of a certain pitch and diamiter if thats what you need to know.
Mike

RE: Need expert help for a variable pitch system
 

All this is lovely theory, I was hoping for an empirical answer from a willing participant since nothing beats seeing the actual power being consumed just by the tail rotor blades! Especially since we're neglecting the losses associated with the belt drive and other mechanical forces.

RE: Need expert help for a variable pitch system
 

John, Give me a call I think I can help!