Forward mounted governor control problem

[Bill Wightman]

This one's got me stumped:

I have a Lyc 360 with a front mounted prop governor - its in front of the #2 cylinder. Years ago, I bought an MT 420-3 governor, which was the recommended governor at the time.

The poorly written MT operation/installation manual denotes the model 420 governor as "pressure to increase pitch. CW facing engine mounting pad" so I naturally assumed they were talking about "CW" being the direction the control arm would move to increase pitch. Wrong: the reference is to the direction of rotation of the output shaft on the engine drive pad. (FYI for you new builders) The control arm on the governor will decrease pitch with CW rotation (governor arm & cockpit lever both moving aft as shown), which makes my prop control backwards in the cockpit.



Have any of you dealt with this specific problem before: the forward governor location resulting in backward lever operation? I'm aware that I can rotate the cap on the governor body to any angle I like, so could rotate the control arm to the bottom, but that means I'd have a weird "S" bend in the prop control rod which I really don't like. Would the VAF Brain Trust have a better way to reverse the rigging on the prop control?

The other option would be to ditch the MT 420-3 in favor of a different governor: one that would work with my rigging. Perhaps a version of the PCU-5000? Or do they all work the same way with CW rotation of the control arm giving less pitch/more RPM on the prop?

Any help MUCH appreciated!!

[dpansier]

I used a bell crank to change the direction and to add more cockpit control movement, the attached photo should answer your questions.

[DanH]

Originally Posted by Bill Wightman

Have any of you dealt with this specific problem before: the forward governor location resulting in backward lever operation?...........The other option would be to ditch the MT 420-3 in favor of a different governor: one that would work with my rigging. Perhaps a version of the PCU-5000? Or do they all work the same way with CW rotation of the control arm giving less pitch/more RPM on the prop?

Bill, I had the same problem with a PCU5000, as I originally intended to bring the cable up from below the engine, in front of the governor. Well, the PCU5000 is made in both CW and CCW versions. The fine folks at American Propeller arranged a swap for me, and my setup now looks like yours, cable straight over the top of 2-4.

[Bill Wightman]

Dan, I think the PCU5000 is the answer then. Somebody's gonna get a nice discount on a brand new MT420-3.

[rocketbob]

Don't throw the baby out with the bathwater...should be just a matter of moving some internal pipe plugs and reversing the spring on the governor. I believe the PCU5000 and the MT governors are all made by Jihostroj in the Czech repuplic.

[Bill Wightman]

Bob, that's a good thought. I spoke with Juergen at MT-USA and he tells me the 420 model cannot have its control action reversed. They're all built one way and work one way. Different models are made to accommodate CW or CCW drive pads. Perhaps their new 800-series units can be reversed - ?

A call to American Propeller confirmed that *some* components between the MT and PCU governors are made by Jihostroj but not all.

I'm going with the PCU5000X, which American will configure to match my control rigging.

[yakdriver]

I used the stock Vans bracket and came up underneath the governor and it works great.