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-   -   How to bond wood H-Tail to CF tail booms? (https://www.rcuniverse.com/forum/composites-fabrication-repair-97/11705323-how-bond-wood-h-tail-cf-tail-booms.html)

dougiewho 02-20-2023 03:47 PM

How to bond wood H-Tail to CF tail booms?
 
Hi everyone.
I started building a 2.2m H-tail pusher today. The plane came with no instructions.
Everything else was relative self-explanatory but the H-tail. I cannot figure out how the vertical surfaces are supposed to attached to the CF rods.
There only cut-outs for servo wiring on the CF tods, no holes for bolts or mounting hardware.
I assume they are meant to be glue together? But I find it hard to believe someone designing a 86 inch plane, weighing almost 20lbs, with a glue-on tail?
What kind of epoxy or CA should I use? Or is there a better way to assemble the tail?
Thanks in advance!!!!!

RCFlyerDan 02-20-2023 05:25 PM

I’m not familiar with the plane that you are building. I do build jets with composites, CF, fiberglass and plywood. Hysol 9462 is excellent, but I don’t think it’s made anymore. BVM Jets carries similar and might be the exact thing.

Adhesives


dougiewho 02-21-2023 06:41 AM

Thanks for the link! Any special prep needed for CF? I've never worked with CF before. This is my first non-foam plane.

RCFlyerDan 02-21-2023 06:50 AM


Originally Posted by dougiewho (Post 12762945)
Thanks for the link! Any special prep needed for CF? I've never worked with CF before. This is my first non-foam plane.

If it is fabric, use laminating epoxy resin 4:1. Just as you would with fiberglass. If it is cured and hard, just scuff it with sand paper. And use the BVM stuff. Clamp or tape in place while curing.

Vettster 03-07-2023 12:47 PM


Originally Posted by dougiewho (Post 12762902)
Hi everyone.

What kind of epoxy or CA should I use? Or is there a better way to assemble the tail?
Thanks in advance!!!!!

A picture is worth a thousand words. But as Dan said.. Use Hysol Do NOT use cheap epoxy, it will fail.

dougiewho 03-07-2023 02:18 PM

I purchased Aeropoxy from BVM Jets, as Dan recommended, and I also got some milled fiber. It got delivered a couple of days ago. I plan to mix some milled fiber in the epoxy to fill some air gaps.
But looking at the parts, the curvature on the bottom of the stabilizers may not be a perfect match as the tubes, leaving much space in between for a proper bond.
Ugh... that's what you get for buying bargain deals. I appreciate any ideas.
To clarify, it's a twin-boom H tail.

I tried to post pics... But I'm a brand new member and need to make 10 posts first. :(

RCFlyerDan 03-08-2023 03:07 AM

Gap
 
You can use the some milled fiberglass, but I would use more of Microballoon and make a fillet. You want it the consistency of thick toothpaste or icing. Use blue masking tape to hold in place and not run or sag.
If you want to email some pictures to me, I can see what you are up against. My email is the same s/n: rcflyerdan at gmail.
Dan

RCFlyerDan 03-08-2023 03:23 AM

Here is an F-16 that I bought to rehab just to show what can be accomplished. This jet I bought was on fire after a flame out.

https://cimg2.ibsrv.net/gimg/www.rcu...a447e551f.jpeg
This is after cleaning up the fire damage
https://cimg7.ibsrv.net/gimg/www.rcu...b48d0c51a.jpeg
I used what center section I had from it.
https://cimg3.ibsrv.net/gimg/www.rcu...e275f3e6a.jpeg
I lined the interior with fiberglass sheeting to make a backing
https://cimg4.ibsrv.net/gimg/www.rcu...2e78f03a4.jpeg
Filling with fiberglass cloth between layers of laminating epoxy. And of course a lot of sanding
https://cimg5.ibsrv.net/gimg/www.rcu...096297c77.jpeg
Here the bottom is finished. So gaps and joints can be filled. Consider installing fiberglass sheeting or plywood to help fill the gap and then use the epoxy and Microballoon to fill the gap. Microballoons will create a strong, but lightweight filler surface. And can be sanded to meet the contours. Microballoons also creates more surface area for the epoxy to adhere.
https://cimg6.ibsrv.net/gimg/www.rcu...1907a282f.jpeg
Finished paint job.


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