aerocharger

Hi Guys,

The weirdness continues...

I rebuilt the helicopter with a new tail gearbox and a new belt, double checked everything again and then set the helicopter into a little test stand I made for it which allows me to run it without worrying about it flying away. The stand allows me to yaw the helicopter to observe the tail rotor response.

I have full travel of the rudder servo and tail rotor blades, and yes, they are turning in the correct direction and the linkage is traveling in the correct direction, etc. What I observed this time around is that as the rotor rpm increases up to its normal speed of around 1,700 rpm, the tailrotor linkage stops moving to its full travel, and only moves about 1/8th the total travel as it does when the engine rpm is low. This only seems to happen due to rpm, not stick travel; in other words, if the engine is in idle hold, and I move the throttle stick all the way up, I still have full rudder travel. It's not a gyro problem because I disconnected the gyro and the same thing happens.
So, since the problem seemed to be caused by rotor rpm, I thought it could be one of two things. Either the servo does not have enough power to move the blades against the rpm load (it is the digital servo that came with the gyro, so it should be able to) or it is an electronic problem, perhaps related to interference caused by the rpm signal of the governor speed sensor. I ruled out an electronic problem because I disconnected the tail rotor linkage, spooled the rotor up to max rpm, and observed full travel of the servo. So it must be a mechanical problem.
Could it be a problem with the servo? It is a brand new servo that came with the Futaba gyro, and I don't think it should have a problem.

Any ideas?

Thanks,
A.C.