After I saw in a ChillPhatCat's post a pack of balsawood ribs for a wing I have been thinking a while of the possibility to use cheaper materials for this components. Actually in Italy Balsawood is expensive and for sure it is possible to save something at least for rectangular (untapered) wings.
First alternative material is depron, which is also very easy to work : cut as many rectangular pieces as required ribs just a little bigger than the ribs themselves; make 2 ribs in playwood or aluminum as per cutting a foam wing; pack everything together with 2 threaded bars (2 or 3 or 4 mm depending on the rib size); finally cut the ribs with the hot wire. You can foresee also the slots for the spars (make them a little smaller as the wire will "eat" some material and the spar must be tight) and also eventual lightening holes. Off course the depron could be 3 or 6 or other mm size depending on ribs and wings size.
The second alternative is to use foam, but not the normal white foam, the more compressed one (see photo) that could be found yellow, blue, green, pink and maybe more colours : you just cut a piece of wing with the playwood ribs previously described and then slice it on the thickness you need.
It should be simple and easy.

I decided to publish all the plans posted up to now (9) in my blog in the tiled version for all those that could be interested but do not know how to get the image and print it....Continue Reading