Return spring on the MT/Jihostroj prop governor?

RV8Squaz · #1 05-10-2009, 06:20 PM

Hello Guys and Gals,
My Jihistoj governor has a return spring that returns the prop control to high rpm/low pitch in the event of a prop cable failure. However this feature is quite annoying. While flyiing formation or doing aerobatics (basically anytime I'm moving the throttle in other than normal cruise) I like to keep the quadrant friction quite low or even off. When I do this the prop lever moves forward and increases rpm due to the spring. I am tempted to take the spring off. Anyone, have any other suggestions before I remove this obvious safety feature. Do other governors incorporate a returm spring? Thanks!

Jerry

JDAviator · #2 05-10-2009, 07:55 PM

I wouldn't remove the spring. If the prop control would become disconnected, you're really going to want the prop at low pitch. Perhaps you can rig some sort of a permanent friction device for just the prop control? Maybe where the cable attaches to the governor?

pierre smith · #3 05-11-2009, 05:05 AM

....drill a small hole through both the quadrant and the prop control, while it's where you want it (mark the position in flight with a light colored marker) and insert a pin/cotter key, when you loosen the friction.

Sometimes my Air Tractor prop RPM gauge takes a fritz and I know where to pull it to, in relation to the condition lever.

Regards,

RV8Squaz · #4 05-15-2009, 07:27 PM

Jerry and Pierre, thanks for your replies. I did experiment today and temporarily removed the spring. I prompty re-installed the spring after a short flight. I found the spring is a necessary part of the governor, not just for safety in the event of a cable failure. As it turns out, without the spring, there is some kind of internal force (oil pressure?) driving the governor control arm toward coarse pitch/low rpm. The tendancy to drive the control arm toward coarse was more vigorous when power was increased. I even noticed it a bit during the run up. As I increased power, the prop lever moved aft. So in a nutshell, I believe the spring is there to overcome this internal force and is necessary. I just wish the spring wasn't so strong as to drive the prop toward fine pitch/high rpm when I loosen the quadrant friction. Anyway, I think what I'm going to do is drill a small hole in the prop lever below the top surface of the quadrant and attach a small spring between the lever and somewhere else to balance the force of the spring.

Anyone else have problems with the prop lever moving forward when the quadrant friction is loosened? I have the DJM deluxe three lever quadrant.

Thanks for your help guys.

Jerry
RV-8 N84JE