Baudis Diana 2 - how to secure the wings to the fuse

[Hoot]

I've flown F3J planes for 15 years and we secure the wings to the fuse using electrical tape. What is the best way to secure the wings to the fuse on a Baudis Diana 2 ?
Thanks !

[Parallax]

At the wing's LE root, I drilled a 1/4" hole in the fuselage root, ensuring it was centered between the upper / lower surface. After plugging the wings in, I marked that hole onto the wing panel roots.

I then drilled out the wing panel to accept a HEX 1/4" x 20 bolt shank (~1" long). I then roughed up the shank and glued it into the wing roots. I then enlarged slightly the fuselage hole slightly to make it easier for a 1/4" x 20 NYLON HEX head bolt to engage the shank.

I used 1/4" x 20 x 1" long NYLON bolts with similarly sized regular grommets (2) with a custom cup of similar size that ensured when I tightened them down, the grommet would not work its way over top of the (round) HEX head. I snugged them down such that both grommets were compressed enough to prevent any movement during high speed / high roll roll rates.

This system works really well. I With two grommets, it allows for a very large rate of compression in case of unplanned amneuvering that results when a wing tip decelerates quicker than the yaw angle of the fuselage can keep up with :^)

If you GOOP two NYLON 1/4" nuts onto the inside of the fuselage - near the mounting points, when you remove the bolts it offers a convenient means of storing the bolt / grommet / cup assembies until next set-up.

[Hoot]

I'm not completely understanding your instructions.

Is the 1/4 20 shank an insert that is glued into the wing panel that allow a 1/4 20 nylon hex head bolt to be screwed from the inside of the fuse into the shank ?



This is my first large scale plane and I appreciate your help and patience with my questions.

[Parallax]

Exactly. The pic of the unit your posted will function just fine. Use a 1/4" bolt with a nut, then screw the shank onto the end. Then hand-tighten the nut up against the shank to hold it in place. After drilling the hole in the wing root just large enough to thread the shank in so it is flush with the wing root (test-fit), take it out and mix some slow-setting epoxy and cotton flox to be just barely flowable.

Put a little vaseline on the end of the shank / bolt end (but not the thread structure). You want to hold the wing level with LE down; use the corner of a plastic bag filled with the epoxy / flox slurry (say 1/2 - 2/3 the volume of a AA battery by volume) to squeeze the slurry into the hole. It should be thin enough to slowly flow towards the LE inside the wing. Now apply epoxy to the threaded structure of the shank, screw it into the the wing root so the shank so it is flush with the wing root, stand the wing vertically so the epozy inside the wing flows back around the shank and let cure.

Once cured, unscrew the bolt and you should be good to go.

In the pics below you see the fuselage root hole and the 1/4" x 20 x 1" NYLON HEX, two grommets and the backing cup stored in the 1/4" nut glued to the inner wall with Goop.

p.s. if you ever have an incident and the NYLON fractures inside the shank, its easy to remove with a small straight bladed screw driver. Simply heat the blade tip hot enough so it melts the NYLON, push into the bolt face a ways, leave it, let it cool and turn it out...

[Hoot]

Parallax,
Thanks for your help and the photos !