Prop Oscillates

[sglynn]

My constant speed prop oscillates a little on take off? Why and how to fix?

I put in new engine, rebuilt the prop governor, and when it was all back together and flying I notice my prop speed fluctuates a little on take off. Once I pull it back a little it stops fluctuating. What I mean by fluctuates or oscillates is it speeds up and slows down a little. A little is 50 to 100 RPM. Not a lot. It didn't do this before engine change.

So anybody know about this? I'm thinking I didn't get the prop cable tight enough and the prop may be at top speed on take off and the governor is kicking in to slow it down, or a loose cable is letting the prop change itself.

Any other ideas?

thanks

[airguy]

Originally Posted by sglynn

My constant speed prop oscillates a little on take off? Why and how to fix?

I put in new engine, rebuilt the prop governor, and when it was all back together and flying I notice my prop speed fluctuates a little on take off. Once I pull it back a little it stops fluctuating. What I mean by fluctuates or oscillates is it speeds up and slows down a little. A little is 50 to 100 RPM. Not a lot. It didn't do this before engine change.

So anybody know about this? I'm thinking I didn't get the prop cable tight enough and the prop may be at top speed on take off and the governor is kicking in to slow it down, or a loose cable is letting the prop change itself.

Any other ideas?

thanks

What prop/governor/engine combination?

[bcondrey]

This was a symptom of an issue with older version MT governors - prior to rev F as I recall. Their facility in FL can update yours if that's the problem.

Bob

[sglynn]

The engine is O-540 with McCauley prop. I think I have convinced myself it is merely slack in the cable. I flew it a bunch this weekend and experimented with taking up the slack in the cable and it works fine. It only oscillates when the prop control is full forward. Plus I visited McCauley's website and they list this loose cable as a potential source for this issue.

thanks

[HSANTIBANEZ]

Originally Posted by sglynn

The engine is O-540 with McCauley prop. I think I have convinced myself it is merely slack in the cable. I flew it a bunch this weekend and experimented with taking up the slack in the cable and it works fine. It only oscillates when the prop control is full forward. Plus I visited McCauley's website and they list this loose cable as a potential source for this issue.

thanks

There is a regulation in the hub to the max static rpm, in my 7 we restricted to 2650, so when i push wot the rpm goes there but then goes to 2700 may be these is your issue