Prop rigging

[HispanicMechanic]

I cant get rigging down. My engine rigging checks out good. But when I get up to the input lever part I cant get reverse to line up. Only flight idle and take-off will pin. (alpha shaft pins in F.I. too) Reverse is always about half a hole off. (short of hole) I have tried everything; adjusting my 6 1/2 in. rod, clevis(spread), and input lever micro adjusting ring. Oh by the way this is on a new prop. I don't think it is my VH either. I'm out of ideas now. Does anyone got any ideas?

[Heimie]

Something you can try, I don't think this is the proper way to do things, but if you are out of ideas you can play around with it. Just be careful with this, because it could throw everything else off. The nice part of rigging is you can disconnect things and line up holes. You can disconnect the 36" rod from the intermediate bellcrank, rotate the input lever to reverse, and with the coordinator at 0 degrees, find out what isn't lined up. Just be careful, you adjust one thing to get reverse to line up and it might throw other things off, but it might give you some insight.

Also, make sure it pins in feather. If the 36" and 24" rod aren't adjusted properly, they won't give you the entire spread needed to reach both holes, as the 36" and 24" rods push and pull the bellcrank which rotates the input lever through the 6 1/2" rod.

Just an idea, just make sure you rig from the rear forward, otherwise you will chase the problem back into the engine. Rigging is definately one of those things that you just have to play with, but it is how I would go about this problem based on what you have done already. Good luck!

[pjvr99]

Given engine rigging is good, check the backlash screw in the VH cover is tight, and

take a look at repositioning the input shaft micro adjustment.

[Lkuest]

When I do rigging, I always make sure the Gearbox Clevis has about 4 1/2 to 5 1/2 threads showing. If you adjust it in or out by alot, it will throw you off. Also, obviousy, since you turned to a forum for maintenance advice, I'm assuming the problem is taking you a large amount of time to resolve, so I'd advise you to go ahead and disconnect the gimbal from the doghouse at the firewall. This will enable you to go through the entire range of throttle motion without having someone in the flight deck or running up and down stands every five minutes to get below the filght idle gate. As it has already been alluded to, it is the coordinator/fuel control rigging that has the internal stops for reverse and takeoff. With the gimbal disconnected, you can check everything quickly, except ground idle, which is in the throttle quadrant. Also, while you are adjusting the rigging, tighten down all the hardware before you check to see if everything pins. Sometimes the rigging changes after you tighten stuff down.

In an unrelated matter, Gimbal cables won't affect Reverse/Takeoff at the ValveHousing, but if you do adjust the throttle gimbal cables, run the throttle up and down a few times and re-check adjustment before you install gimbal clips. Sometimes it moves a little on you after adjustment.

[ddhix]

Given engine rigging is good, check the backlash screw in the VH cover is tight, and

take a look at repositioning the input shaft micro adjustment.

I second this.

[keepemflying130]

somebody has pounded on an input bellcrank on the FC with the blind spline a tooth off. The rest of the rig is off because of that. Pull them off and recheck.

[galgany2009]

IF YOUR ENGINE IS RIGGED PROBERLY AS PER MM,DRY RIGGING IN PROP.WITH PIN ALIGNED IN TAKEOFF. FLT IDLE. REVERSE.CHECK FEATHER ANGLE 92.5 BACK LASH IS ADJUSTED.VALVE COVER IS INSTALLED CORRECTLY.THEN U WILL NOT FACE ANY PROPLEM.