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Empennage Fiberglass Part Deux?

Duhg

Well Known Member
I purchased my kit from another builder who had done the fiberglass work on the tail before receiving the fuselage. I had some concerns using the horizontal stab/elevators as is, but mounting the rudder today I think it will be unusable at least with the suggested rod end lengths. Having not done these steps myself I’m unsure if its feasible to remove and reinstall the existing parts or if it would be better to place a new order with Vans and start fresh. Suggestions on removing the existing glass without damaging the aluminum?
 

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The easy thing to do is just carve out what you don't like and re-do it. For instance, it sounds like you may be uncomfortable with the clearances. So "all" you need to do is trim away what you don't want - say 1/4" on the aft edge of the vertical stabilizer tip. Then add it back using techniques you'll see in the fiberglass tips and tricks section of the website.

Here: https://vansairforce.net/community/forumdisplay.php?f=106

Alternately, if you don't like the contours of your current tips, you can reshape them using techniques in the same section of the website. Looks like you might have a 1/8" misalignment on one tip. Building up the low area isn't difficult. Plenty of "how-to" in the fiberglass section.
 
Fix fiberglass

Easy fix but read up as mentioned.
When you get close, use a piece of lexan or glass the thickness of the desired gap. Apply some wax so it doesn't stick. Apply some micro. Stick the spacer in place. Secure it in the gap. Let it cure. Perfect gap.
 
Perfect, thank you. I know I can massage the gaps, I was more worried about the outside shape and if I'm able to sand below the outer fiberglass "shell".
 
Fiberglass

Perfect, thank you. I know I can massage the gaps, I was more worried about the outside shape and if I'm able to sand below the outer fiberglass "shell".

Whoa! That's different. If you bust through and make a hole, that needs to be fixed to retain structural integrity. There's ways to repair without removing the tip. If you blow a hole, ask first.
Edit...
Thinking about it more, I like Kyle's fix. Cut the aft cap off the HS. Then remove what you want. Repair the cap with fresh glass working through the open end then replace the flat cap. I remember mine didn't fit right.
 
Last edited:
Perfect, thank you. I know I can massage the gaps, I was more worried about the outside shape and if I'm able to sand below the outer fiberglass "shell".

What, in particular, are you considering doing?

The reality is you can't screw up fiberglass to the point it is unfixable.
 
What, in particular, are you considering doing?

The reality is you can't screw up fiberglass to the point it is unfixable.

I simply want the tip to be shaped as close as possible to the airfoil of the rest of the flying surface and the 2 surfaces flow evenly into each other. In picture 3 the counter balance is at least 1/4" fatter than the VS and the VS isn't symmetrical. I'm guessing the gap is pretty simple to fill or shave since it's the open end of the fiberglass.

If you were trying to get these things lined up would it be easier and more feasible to start over again with fresh parts or manipulate (or mutilate) the current pieces?
 
I would use micro balloons/epoxy to change the shape of the undersized shape to match the fatter shape, assuming the fatter shape is appropriate.

I wouldn't undo everything and start over. But that would be one way to do it.

Truth is, these pieces are often warped and don't match perfectly. Plenty of builders can live with that and plenty will spend hours getting it exactly right. Both way fly just the same.
 
The white gel coat could be thick or thin. It provides little strength. Feel free to sand it down the glass if needed. I had to cut slits to expand some parts and shrink others. These white parts look like my 2004-ish -7 parts. If too fat, slit the length, and/or fill (shim with epoxy) the aluminum contact area offset.

Basically, do what you need to get it to near net shape then add filler and sand for the proper contour. To make the gaps "right" I took bent (curve) some thin plexiglass to the desired radius and laid a couple of layers of glass, then patched them to the ends as needed. The gap was even during rotation, parts thinner and reinforced/patched on the inside.

Hopefully, someone with current vintage 7 or 8 parts can report on the shape accuracy. The white pieces are not very good IMO.
 
Cut the tip in half lengthways then cleco the two halves to the tip. Now you can bond some strips of glass to the tip, making it align properly with the aft rudder tip. If it is the wrong as well, then the cut it in half and make it fit the front part

This method will allow you to match parts without the excessive use of micro balloons

It is a process that takes a few minutes a day for two or three days to get perfectly aligned parts. After that lay a bonding strip on the interior of the parts as was done initially at the factory
 
First photo appears to be a VS-rudder. Before working the tips, be sure the rod end hinges are adjusted so the rudder skins just barely clear the fuselage skins at full deflection, down near the lower hinge. The adjustment affects the horizontal gap at the counterweight.

As Bill said, you can cut down a high area in the gel coat without any change to the strength of the underlying part. Definitely remove the gel coat for any sort of structural bonding. I remove it even prior to adding epoxy/micro filler, but that's me.

Some empennage tip posts on this page: https://vansairforce.net/community/showthread.php?t=22931&page=3
 
Fiberglass

I simply want the tip to be shaped as close as possible to the airfoil of the rest of the flying surface and the 2 surfaces flow evenly into each other. In picture 3 the counter balance is at least 1/4" fatter than the VS and the VS isn't symmetrical. I'm guessing the gap is pretty simple to fill or shave since it's the open end of the fiberglass.

If you were trying to get these things lined up would it be easier and more feasible to start over again with fresh parts or manipulate (or mutilate) the current pieces?

I missed the gap issue. Like Dan said, make sure all the surfaces are adjusted to spec or you'll be doing this again. If the parts are not bonded, consider drilling out rivets and removing them. Much easier to work on them and less possibility of damaging an expensive control surface. Might even order some newer gray gell coat parts. They fit better. I had to split some of mine to get the fit I wanted.
 
I missed the gap issue. Like Dan said, make sure all the surfaces are adjusted to spec or you'll be doing this again. If the parts are not bonded, consider drilling out rivets and removing them. Much easier to work on them and less possibility of damaging an expensive control surface. Might even order some newer gray gell coat parts. They fit better. I had to split some of mine to get the fit I wanted.

Thanks Larry,

I believe these were originally grey. The emp kit is from 2011 The white is primer sprayed over his glass work. Everything is definitely bonded and finished to what he felt was final sanding.
 
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