Chapter 12 - Section 3

Fitting Elevators & Torque Tube


  Fitting Alignment Pins    Aligning the Canard   Fitting Elevators & Torque Tube to Fuselage 


Trimming Elevator Ends

I trimmed the inboard ends of the elevators till I got 1/8" clearance when the elevators are in the full trailing down position. Since the gap is tight against the fuselage, I have to move the canard off and on the fuselage between sanding - total about 10 times and it is getting heavier every time.









Securing the Offset Control Arm Nut

It has been reported that the offset control arm nut tends to get loose occasionally. This is especially inconvenient after the inboard ends of the elevator are sealed off. In addition, there are times this nut needs to be removed for fine adjustment later on. Besides, I need to plug up the access hole before glassing the inboard end of the elevators. Note the bolt and regular nut.








Approach #1

To seal off the access hole, I shaped a small cover with Clark foam. However, I need access to the nut behind the cover later. So I made a crude wrench out of 1/16" aluminum and drilled out a couple small slots on the foam cover.









I figure, if I need to get to the nut after the inboard of the elevator is glassed in, all I need to do is to drill out those two little slots, stick the wrench in, tighten the bolt, then seal those little holes back with just about anything (like 5-min epoxy, hot glue etc.) and nobody can see... so far so good.


Then I got to thinking, what if I need to remove the bolt totally out of the tube, separating the elevator and the control arm - the nut is going to fall off somewhere inside, I will have no way of getting to the nut with my home made wrench...!@#$.





Approach #2

I posted the question to Wayne Hicks and he suggested a nut plate. Ahhh... that made sense, but how do I rivet the nut plate onto the tube at this point? 


Here's what I did - I cut up a small 1/16" aluminum tab and mounted a nut plate on it with rivets as always. Then I carefully replaced the existing nut with the new nut plate. I also shaped a new Clark foam cover with a slot cutout to accommodate the aluminum tab.





Once I tightened the bolt to the new nut plate, I floxed the aluminum tab in place (inside the access hole). 










I fitted the foam cover in place and added more flox to the tab ends (of the foam) and around the foam cover. Then I glassed the whole inboard end of the elevator.









Inboard elevator ends are glassed in and sanded off. It turned out nice. I like this approach better then the first, but I'll find out how well it'll work the next time I have to mess with that bolt.










Installing BID over Fuselage Sides

After all the alignment on the canard was completed, I have a very small gap between the fuselage edges and the bottom of the canard. I can probably slide 2 maybe 3 sheets of paper between them. In addition, the gap is not uniform throughout. So if I follow the plan and install 1 ply of glass, I may still end up with a gap somewhere. I decided to use flox as a filler. It worked out nicely - no gap and no seam. Don't forget to lay down packing tape onto the bottom of the canard or it will give you a really, really bad day when you have to remove the canard!