Goggles

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I have an old F-15 that I would like to make as light as possible. There are quite a few 1/4" plywood formers and I was wondering what could be a strong composite or sandwich replacement and if any one had any good ideas?

Would 2 laminated pieces of 1/8" light ply covered with CF fabric be lighter and stronger?

Thanks

Mike James

That's hard for any of us to predict, because... "It depends". (which formers, what stress you put on them, etc.)

But...
There are lots of composite solutions, and one that's even lighter than what you mentioned is end-grain balsa, sandwiched with carbon. You might find that 1/8" birch ply by itself would be sufficient in most areas, which would cut the weight approximately in half. Most compositie suppliers sell this stuff, although it's a little pricey.

Since you mentioned that it's an "old kit"...
Years ago, everybody built with crashing, rather than flying, in mind, and 1/4" ply was the norm, especially for firewalls and landing gear mounts. I've done quite a few models over the last 10 years or so where I used 1/8" ply for these parts, (including, for example, the firewall for a YS .91 4-stroke, on a 3D plane) and had no failures.

Some photos of your kit, or a little more info might help some of us give a little better advice, but I think it's true that almost every airplane can be built lighter, with some careful thought, and the better your flying skills are (especially landing) the better your chances of success.