Elevator tips too narrow, widen?

[JDBoston]

Me again.. so I did a rough fit of my elevator tips on the RV14 and will admit these parts have been stored for a long time.

Both of them are undersized but a lot (maybe 3/8 inch on each side). This may be basic but I assume the solution is to heat them and try and get them to expand? One photo to illustrate the issue is below. Thanks.

 

[JonJay]

3/8” is a lot. Check the elevator counterbalance against the plans and measure the width of the tips. Perhaps someone has what the tip width should be.
I would want to know why this is before I executed a fix.

 

[Kyle Boatright]

Me again.. so I did a rough fit of my elevator tips on the RV14 and will admit these parts have been stored for a long time.

Both of them are undersized but a lot (maybe 3/8 inch on each side). This may be basic but I assume the solution is to heat them and try and get them to expand? One photo to illustrate the issue is below. Thanks.

Are they too long as well? That pretty much means they collapsed during storage. Squeeze 'em from the ends and they will expand in the middle. If that works, you'll probably need a helper to squeeze 'em from the ends while you drill 'em in place.

 

[DanH]

What Kyle said. I'd skip the heat.

 

[JDBoston]

Are they too long as well? That pretty much means they collapsed during storage. Squeeze 'em from the ends and they will expand in the middle. If that works, you'll probably need a helper to squeeze 'em from the ends while you drill 'em in place.

Believe it or not they are perfect length.

 

[JDBoston]

What Kyle said. I'd skip the heat.

Thanks Dan. I actually got the heat idea from a kitplanes article a while back (I think our very own @wirejock wrote that)

 

[rockyfatcat]

Heat works well to reshape fiberglass. The real question is how are you going to jig it up to hold it in the correct position while it is HOT and while it is cooling down?

Clecko’s?

 

[JDBoston]

Heat works well to reshape fiberglass. The real question is how are you going to jig it up to hold it in the correct position while it is HOT and while it is cooling down?

Clecko’s?

I’m actually writing this post to make sure there’s nothing fundamentally wrong before I start to do this, but the article suggested actually that you expand it so that the fiberglass sits on the outside of that aluminum, which is of course bigger than it needs to be as it cools then I think the theory is, you can sort of push it inward to fit and it will be a tight fit.

Check out “Fit the Tips” from this article. Not sure if it applies here …

Tip Tips - KITPLANES

How to finish control surface tips.

www.kitplanes.com

 

[wirejock]

I’m actually writing this post to make sure there’s nothing fundamentally wrong before I start to do this, but the article suggested actually that you expand it so that the fiberglass sits on the outside of that aluminum, which is of course bigger than it needs to be as it cools then I think the theory is, you can sort of push it inward to fit and it will be a tight fit.

Check out “Fit the Tips” from this article. Not sure if it applies here …

Tip Tips - KITPLANES

How to finish control surface tips.

www.kitplanes.com

I don't know the fundamentals. Experts here would know.
I know it worked. They didn't take the shape of the outside. They just expanded so they fit snug inside without clekoes.
Not much heat. Use a thermometer. I wouldn't go over 150.

 

[fl-mike]

Shove a piece of Ethafoam in them to bulge them out, install, drill, remove, remove the foam and do whatever you need. Install.
If necessary, drill a hole near the middle of the length and install a Cleco to pull on during the final installation. Fill the cleco hole.

 

[RV7CardenMike]

One thing you may want to check - there can be a tendency for the aluminum skins to "flare" out at the extreme ends of the elevators and rudder too. Try laying a straightedge along the aluminum skins, perpendicular to the fiberglass tips, and see if the skins are "opening up" where the tip goes in. I've seen this happen before. If so, you may want to/ can correct with a seaming pliers to get the shape back. I'd check this first.....
And yes -long time listener, first time caller.....

 

[JonJay]

One thing you may want to check - there can be a tendency for the aluminum skins to "flare" out at the extreme ends of the elevators and rudder too. Try laying a straightedge along the aluminum skins, perpendicular to the fiberglass tips, and see if the skins are "opening up" where the tip goes in. I've seen this happen before. If so, you may want to/ can correct with a seaming pliers to get the shape back. I'd check this first.....
And yes -long time listener, first time caller.....

This is what I was trying to communicate, poorly, in my first post. Much better explanation here…..

 

[JonJay]

By the way, the flange on the tips can have an inconsistent, or larger than needs to be, radius where the flange mates to the main body of the tip.
This can cause a poor fit. A few minutes with a sanding block can fix this and make that join line look much cleaner.
So, while your at it…..

 

[rockyfatcat]

Before going buck wild, why don’t you stuff something inside it and let it sit outside in the sun for an afternoon. Use the metal tip as a mold and cut some styrofoam and fit it inside.

If it doesn’t work you can always go for the heat gun and clecko’s.

 

[Norman CYYJ]

Are they too long as well? That pretty much means they collapsed during storage. Squeeze 'em from the ends and they will expand in the middle. If that works, you'll probably need a helper to squeeze 'em from the ends while you drill 'em in place.

Tie down straps work great for pulling the ends together, makes it a one man job for mounting and drilling.

 

[PhatRV]

The open end of the fiberglass tip has no structural integrity. It is flexible because the end isn't closed before it is attached to the elevator. Drill and cleco for fitting. The fiberglass tip will conform to the aluminum strap.

 

[Reflex]

I remember having the same thought. Solution below (scrap balsa stiffeners removed after drilling and clecoing):

Before:


After

 

[JDBoston]

Thanks all. I did take @rockyfatcat and @Reflex ideas and put some foam inside which allowed it to expand enough to fill the gap. I posted because it surprised me how much it needed to expand but I’m starting to get more fiberglass experience now so am starting to get it.