Thorp Air Command - T18.net

well, that sounds like it should slap right together then!

If I remember right , it took me about 2 weeks to make and fit all the paper templates . After seeing some other trim strips on other AC I am glad I took the extra time and trouble to get the smooth exact fit . Bing, Bang , Boom !

RB

Drawing 519 says the stick should move forward and aft 15 degrees from vertical. I can not understand drawing 521 to determine how many degrees the stabilator tab should travel based on the max stick fore/aft deflection. I have attached a screen shot of the stabilator tab deflection drawing (#521). Can anyone tell me if my below interpretation is correct?

Here is what I think the drawing is says:
1) when the stick is moved from the vertical position to 15 degrees forward, the stab tab should travel 25 degrees down
2) when the stick is moved from the vertical position to 15 degrees aft, the stab tab should travel 35 degrees up

Ryan,
My take is the stabilator moves 15 deg up and 5 deg down with the neutral point being 5 deg up. The trim tab moves +- 20 deg from the chord of the stabilator. With the stabilator in line with WL 44.0 the trim tab should be 10 deg down.

_________________
Bruce Finney
N18JF T-18C #262
Yelm, WA USA

Bruce, that helps a lot. I was not seeing that one of the arcs was for the chord of the stab. thank you. Also, after sleeping on it, I will not concern myself with the position of the stick while checking the stabilator movement, as I have already determined I have the 15 degrees of fore/aft stick movement as called out in DWG 519.

Remember, the stops are set at the stick end. I had to grind some off the bolt heads at the sticks to get enough down travel. Up travel is limited by the stop plate.

_________________
Bob Highley
N711SH
SN 835
KLAL

Bruce is right. Plus 15 and minus 5 from level. The tab moves through plus or minus 20 from those positions ONLY if you include cockpit trim. Set up follows. Level the plane via WL42. Put an incidence meter on the the horizontal and set it 5 degrees leading edge down. The trim should turn 5.5 turns stop to stop. Set the trim in the middle of its range. With the above horizontal position, the tabs should be exactly faired even with the aft edge of the horizontal.
Make sense?
Cubes

Cubes, that's great info. Thank you all. Even the info about the bolt, because it looks like I might have a very slight bolt interference issue like Bob that was causing me major concern.

I got the push pull tube installed and the tail group connected to it. Also reinstalled the trim shaft and reconnected the wiring. I got the controls connected to the other end of the push/pull tube after a consultation with Cubes. I got the correct amount of travel on the tail and anti-servo tab. Also installed the trim strip on the front windscreen. Rich, you were right, I took that thing on and off more times than I can count, but I'm pleased with the final product. Once I get my tail wheel group installed, I think I will be finished with everything on the back end of the airplane. Also got the rounded center tunnel cleco'ed in place. Im liking that already. Might have to do that to my flying Thorp.

I still need to install the stop plates at the control stick end....I am kinda typing that to help me remember to do it! It sure is one bite at a time, but I am enjoying it.

Excellent! Keep at it. Addicting isn't it?
Cubes

Good looking canopy trim strips will tell folks a lot about you as a builder and your attention to detail . It is time well spent . I've seen some that looked like they were done at nite with all the lights out !

RB

Should I buy the 493 rudder spring or the 493-2(Long) rudder spring for my rudder pedals? I cant seem to locate the 493-2 in my plans. I am building a standard T18.

Bob and I use the standard spring and drill the firewall and use eye bolts to adjust tension

Thank you....and for the tip on the tension. I likely would not have thought of that.

I installed a Ray Allen position sensor on my elevator trim jack screw and connected that to a Ray Allen trim position indicator on my panel. Problem is that the jack screw only moves such a short distance fore and aft that the position indicator only moves one bar up and down. I called Ray Allen and they said the only thing I could do was to install the position sensor in such a way that the jack screw caused the position sensor to use the full length of its travel, and that would give me full length of the light bars on the indicator.

Does anyone have the Ray Allen system attached to the elevator trim, and if you do, can you post photos of how you attached your position sensor? Thanks for the help.

PS I dont have this stuff on my flying T18, so I dont have to have it on the project, but I figure I would do it if I can get position sensor geometry figured out.