Patrol elevator trim throw

[Pbruce]

Hello flyers of the Patrol. I’m wondering how much throw is required for the elevator trim tabs, specifically “nose up” trim. With the elevator neutral, I have maximum available throw of 14.5 degrees or 1.25” at the trailing edge. I can get more by ordering a longer clevis fork, but if I have enough (plus a margin), then I’ll move on. Picture shows how the length clevis fork length limits upward throw. Thanks.

 

[DBeaulieu]

Pbruce, This probably doesn't answer your question...but here is what I did. When I set mine up I had elevator neutral, servo trim tabs neutral and set the overhead handle in the cabin midrange of effective rotation or movement of the cable attach points on the handle, then clamped it in position. Then I made my cables with shackles at the rear on the horn held on by clevis pins and my cable length with one turnbuckle up front in the cabin. Had good servo tab movement along with elevator deflection and/or with trim handle movement. Seemed like plenty, though I can't quantify the amount for you. I have since disassembled the tail feathers, etc. after fitment. Just another data point for you...HTH!

Dave

 

[jaredyates]

I have only flown one Patrol and I think I might have only touched the trim wheel a time or two. I didn't get a chance to really load it up for comparison. On our 360 Bearhawk I used a quarter turn of the trim wheel. On the 540 it's more like 3/4 of a turn. Hopefully this will get you in the ballpark.

 

[Pbruce]

Ok thanks guys. I did pretty much exactly what DBeaulieu did. After some tweaking I now have 1-3/8” tab deflection in the nose-up direction (trim tab deflected down) and 1-1/8” nose down (trim tab deflected up). Mark G advises I will never need that much down trim, which makes sense. So I biased for as much nose up as I could get. This was accomplished by screwing the rod ends almost all the way in, thus shortening the trim pushrods as much as possible. It sounds like I’ve got all I need.