funfly58

could someone tell me about foam core wings? why foam instead of balsa? does it hold retracts well? stronger or weaker than balsa? basically the pros and cons. thanks

kdheath

Foam for speed/ease of construction and straightness. Retracts are no big problem. Mount them on a plywood plate supported by two lite-ply ribs. Cut-outs in the foam can be made by shaping some copper wire into the shape you want and putting it in a soldering iron for hot cutting the foam. Foam wings tend to be stiffer than all-balsa and usually a bit heavier. The key factors are the weight of the wood you skin the cores with and how much glue you use. Carefully select contest balsa for the skins and learn how to use the least possible amount of glue. Foam wings built right are very strong, light, and equal to or better than a built-up wing.

birdnest

Sheeted foam wings look great, the finished surface is smooth. You need a really large, flat, solid table that can support a lot of weight while sheeting them. I suppose many builders may not have this, and this is the reason most kits come with built up balsa wings. For a pattern airplane wing, you really need a band saw to cut out the ailerons. You will also need to shape the leading edge.

Balsa is lighter. Little screw-ups can probably be fixed easier. Most people probably have enough tools and an adequate table to build a balsa wing. You an use CA hinges (CA eats foam)

Peter

rmh

kits use all wood parts because it is easier to package and typically wood kits can be done by anyone who can read and follow instructions.
Foam and wood done right -- is is very hard to beat for strength/weight
I don't use a heavy straight table either -- just a big clamp which I adjust to PSI for desired bond
Parts are straight as an arrow.
Which is better?
Not a good question as "which to use for a specific application ", makes the most sense.
I use both -depends on th desired results.

funfly58

thanks for all the info.. the kit i was looking at was an a-26 invader w/foam core wings. i won't let foam be a factor in kit selection again! thanks