powerchute50

Hi. In going over the plans for a Lancaster I was not impressed with the wing. This is a 100 inch model. The designer specifies 3 straight foam panels glued together on each side with no other support. Considering that 2 heavy gas engines have to hang from this foam and the landing gear just sits in a balsa box in the foam, I am less than impressed. I would prefer a spar, at least for the engine panels. Does anyone have any design hints on a spar for a solid foam wing? Light ply would work I guess, and cut the wing panel to match. I would want some ply ribs at the engines as well, and the gear. It would also be good to have a spar carry through in the fuselage, instead of just straight foam. I have no experience with spars in foam wings. Any info or plans come to mind to help with this?

Thanks

Don
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You don't learn anything if nothing goes wrong

Gremlin Castle

My Feedback: (14)

The wing skin and the attendant splicing materials are the real question rather than the foam. A 100" foam wing with large engines is quite within the design capabilities of foam balsa and fiberglass. Even engine nacelles attached only to wing skins are more than capable of safely holding 50cc engines in place.
The other side of the coin is whether the original builder had an adequate design and whether the modeler has the materials and skills to properly carry out the intent of the designer.
As for structure buried in foam it is done a lot but for optimum performance it needs to either be in intimate contact with the outer skins which are the true load carriers. If that is not practical them the structure needs s large amount of surface area to widely distribute the load into the foam which ultimately takes it back to the skin structure.
If the plans have enough info to make rib patterns then a built up center section with foam outer panels might be something to consider.