alderblee

I'm wondering what the best technique is for joining fuselage halfs for larger planes that use formers, such as a 2M pattern plane. I've seen threads about smaller planes like pylon racers and didn't notice formers being added at least during molding.

- When joining the sides in a mold, do you join them with tape, then add formers later? (seems hard to get to the glue joints)
- Or do you add the formers as you're putting the mold halfs together? If so, how do you deal with the extra thickness of the tape/cloth on the joint for the former?

Are there other ways to do this? Thanks for any information.

speedracerntrixie

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A picture is worth 1,000 words. This is my Divergent 2M pattern airplane just prior to joining the fuse halves. You can see that all the formers in place however those formers in most locations do not fully come to the center of the fuselage allowing clearance for the 1” fiberglass tape.




Ready to join.

Finished product

alderblee

Interesting, I hadn't thought about formers that don't go all the way around. I presume then that it's strong enough, and you don't have cross pieces? It looks like those may be Divinycell sandwich or some other foam. After this post I saw the F3A build help thread on RCG from a year or two ago, and it sounds like some may do a flange onto the flange of the mold, then tape the inside before trimming the flange.

For those that make full formers, generally 1 piece, do you know the order they would do the tape and formers? I've seen some kits that look like they come as a shell and you have to install the formers yourself. Seems like it would be tricky to get a clean glue joint on those.

I appreciate the advice.

speedracerntrixie

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There is a single cross brace in the middle if the fuselage. The layup is very light being only two layers of 1.4oz cloth for a outer skin, 1/32 balsa core and the inside skin a layer of 3.2 crows foot weave. Trying to install formers after removing from the molds would just distort the fuselage shape and be a major pain. My process to bond the formers in place is to tack them in place with CA and then do a fillet of laminating epoxy with a little milled fiber and micro balloons.

alderblee

I see, interesting. Thank you for information and pictures.