Hinge gap
 

On my LT-40, I had an elevator CA hinge break on me. I decided to cut out the remaining CA hinges and got some plastic hinges, cut new slots and reinstalled. Works great now. However, I notice in flight there is a slightly strange noise that is new. I am thinking that the gap between the rear of the horizontal stab and the elevator is a bit wider now due to the hinge pins, etc and air might be slipping through that slot and causing a bit of flutter. I was advised that a good repair would be to get some ultracote and fairly loosely iron a thin piece along the top and bottom of that hinge gap to keep the air from slipping through it. Is that sound advice? Is there a better way to handle this?

RE: Hinge gap
 

I would use clear packing tape. KISS rules rule.

RE: Hinge gap
 

One of the guys bought a roll of clear Ultra just for that reason, it works grreat for sealing the gaps.

RE: Hinge gap
 

And you only need to do one side (usually the bottom just to hide it)

RE: Hinge gap
 

Yup - what GB and MinnFlyer said. I've tried hinge tape with a glow engine - didn't last long. Where I've had more than one color of film across the hinge line I use clear Ultracote. If it is one color then I just use matching color film.

If glow powered and the exhaust exits on top of the wing - cover the top to protect the backside of the seam from glow fuel. If it exits below the wing - then do the bottom.

RE: Hinge gap
 

I don't need to use it very often the way I cover but when I need some I always have someone to borrow it from. Bottom only is needed but if you do the top too it helps the end of day clean up.

RE: Hinge gap
 

The relative stiffness of CA hinges is probably a vibe dampening effect to some degree. A seal line is generally a good thing though. Abbott and Dohenhoff ( a classic reference on subsonic aerodynamics) published data showing ~20% efficiency gain for hinged surfaces that were sealed.