Eagler's Nest

Airframes => Single Seaters => XL => Topic started by: Shay King on May 12, 2024, 08:37:09 AM

Title: Spar web scarf joint
Post by: Shay King on May 12, 2024, 08:37:09 AM
On Leonard’s plans, with the spar web butt joint, he reinforces it with an extra piece of 3/4 X 1/2 spruce.
Of those of you who’ve scarf jointed your spar webs, has anyone bothered to reinforce the joint?
Title: Re: Spar web scarf joint
Post by: jrbirdman47 on May 12, 2024, 10:57:48 AM
Not me. The scarf joint is an inch and a half long, (12:1) and more than sufficiently strong on its own.
Title: Re: Spar web scarf joint
Post by: Kamcoman77 on May 12, 2024, 12:18:09 PM
Not me, either. Like jrbirdman47 says, the scarf is about 1-1/2" long.
Title: Re: Spar web scarf joint
Post by: Shay King on May 12, 2024, 01:21:52 PM
Thanks for the replies guys.
I’ve just realised while looking at your scarfs that all the 1/8” ply that came in my ’kit’ from the US has only 3 plys. It’s stamped Aircraft Plywood, Spec-Mil-6070,Birch face. Do you think this is ok? I’ve scarfed it, but haven’t glued it onto the spar yet.
Title: Re: Spar web scarf joint
Post by: Kamcoman77 on May 12, 2024, 01:38:38 PM
Lots of 1/8" aircraft plywood is 3-ply. Since it has fewer glue joints than mine, you have more wood. Might be stronger than mine. I certainly would not be afraid to use it.
Title: Re: Spar web scarf joint
Post by: Shay King on May 12, 2024, 01:52:12 PM
Phew! Thanks again.
Title: Re: Spar web scarf joint
Post by: Chuck in Indiana on May 12, 2024, 02:06:27 PM
Mine was 3 ply, too. Not to worry..
(https://static.imgzeit.com/reduced/39d78444e170e0f0/IMG_20200715_164044337.jpg)
I thought I had a picture of the router jig I made to do it, but can't find it. (scratching head) I already gave away all the tooling I made, so you'll have to use your imagination.  :)
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