Thorp Air Command - T18.net

Hi All,

Looking for (Hopefully) a quick bit of help. My Thorp is in for an inspection before the start of the Air Race in a months time and I want to get all the rigging etc adjusted as the aileron trim does not appear to be working correctly. I'm assuming the system it uses is the original style with the knob on the flap lever that will lower one flap when screwed in. I have been told that the flaps might be adjusted too tightly so that when you screw the knob in it doesn't allow just the one flap to lower slightly. I've looked through the plans and through a bunch of the news letters but I can't find a reference to how this system should be rigged.

Can someone direct me towards the correct way of setting this system up? It would definitely be a huge help to have a working trim system.

Thanks

I'm a lurker on this one, inquiring mind wants to know. I have the same system on N8786 and it works perfectly. Left flap knob. I do need some rigging adjustment on both flaps as they both seem to be a bit in trail.

Rap

_________________
Base: KALX
N8786
SN 929

I have read this post several times. I'm not sure what, exactly, you have going wrong. Does the Aileron trim (flap) not deploy? Do they deploy together? Can you just not turn the wheel?
Cubes

It has been a while since I installed the flaps on my S-18 and I don't recall any rigging specs . Flaps full up with no slack in the cable . As far as the trim knob goes it should only deploy the left flap . If you have both flaps deflecting with the "Trim Knob" something else is going on . You may need to pull of the flap handle cover and see whats going on in there ! I never used the trim knob as I put in electric aileron trim and replaced the trim knob with a S/S round head bolt .

Not sure what adjusted too tightly means ? Deploy both flaps ? When you screw in the trim knob in on the deck what do the flap/flaps do ? Don't tell me the "Hokie Pokie !! "

RB

Thanks for all the replies.

To try and clear it up a bit, when the fellow Thorp owner flew my aircraft he mentioned that the flap cables appeared to be too tight so when the knob was turned both flaps moved instead of only the one flap. I've tried looking through the plans for something that could be adjusted to effect this but I'm not sure what I'm looking for.

I am not overly familiar with the system but, just looking at mine, I think you have something either siezed or not connected IAW the drawings. My left flap is independant of the right at the handle pivot and a push pad is used to lower the left flap when the handle is raised. The trim adjustment essentially changes the location of push point.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Ah. This will be an easy fix. Look at the 742 drawing. In your cockpit, the bolt that goes through the flap handle is too tight or is binding. Look at the pivot bolt and loosen it 1/4 turn. Might try some lube as well. That should free things up.
Incidentally, deploying the flap produces more drag than a simple Aileron trim tab.
Cubes

Thanks Cubes, that's exactly the information I was hoping for. Now I know what to pass onto the maintenance organisation.

I've been wanting to install an aileron trim tab, I just have to find someone in Australia that will do it for me without charging an arm & a leg since I can't legally do most of the work myself. It's on a (long) list of upgrades/work that I'm looking to get done on my Thorp. Sadly with the Charity Air Race coming up next month funds are a bit lacking atm. Oh well, we'll eventually get there.

Cheers for everyone's help