Cardboard Construction

Take a look here

KH

That was an interesting site, Wes. Thanks for passing it along.

Harlan

What about using foam for ribs, construction paper in place of thin balsa and tissue paper in place of monocoat? You could use water based polyurethane in place of resin, saving weight and having everything be fairly fuel proof. While this might be heavier than either all foam or traditional balsa construction, it would be less expensive. Interesting. I might have to play with this on a 1/2 A control line model for my nephew....

Randy

I agree, what a great site, makes my own look rather pathetic

Thanks for pasing it on

Trefor

"Vervain Speller" wrote

First, you have to be real careful with weight, and the thickness of corrugated you use. The regular stuff boxes are made of gets real heavy, real quick. All corrugated cardboard is NOT created equal!

The lighter stuff is usually painted and printed on, on one side. It may be wax impregnated, which will make gluing a problem.

You can solve that by using a lighter, and lightly burning the wax away, but move quickly, and of course be careful with the fire safety.

If you want some magnets for building, and need real strong ones to make downforce clamps, consider some of the smaller size welding magnets. This is just one site where you can find them.

"BCRandy" wrote

The problem is trying to get construction paper tight. It has no strength in compression. All in all, not very good to work with.

As long as you are looking at alternative construction materials look at foam core board. It is available at some dollar stores. Paper on both sides with about 1/4" of foam between. Also if you have never cut a foam wing they can be really inexpensive and more than strong enough when sheeted with paper applied with thinned white glue. Bob

wrote

It is kinda heavy, for most uses, but really strong. Good to use, but only in places where it needs to be strong, or you will have a heavy airplane.

Yep, I HAVE done that one.

I used the type of very rigid blue foam that boat docks sometimes float on. Heavy, but very strong. I used brown kraft paper, like grocery bags are made of. I used very thinned glue, and put it on the paper and the foam. After I applied the paper, I kept smoothing the paper with my hand until it was mostly dry. Until then, it was kinda wrinkled. As it dried, it smoothed out, and shrunk a little bit.

I would add that it helps to let the glue soak in for a while, so the paper streatches out some. That will help it shrink as it dries, as I remember. It has been a few years back.

I'd check out the forums on on RCGroups.com and RCUNiverse.com that talk about SPAD (Simple Plastic Aircraft Designs) and also see if there's anything on cardboard as well.

Currogated cardboard has given way for coroplast (plastic sign "cardboard") and some of thedesigns are amazingly strong.

I do all my foam cutting with the very light white beaded foam. It has very little strengh itself but the paper covering creates a strong shell (kinda like the aluminum skin of a full size plane). I used white "banner" paper that weighed about half of what the kraft paper weighs. To keep the glue from adding too much weight I cut it to fit the wing, pre-sprayed it with water to let the paper relax and streach. Then I brushed on thinned white glue (thin it to a good brushing consistancy and add a couple drops of food coloring so you can see the glue). The damp (not soaking wet) paper smoothed out almost completely as it dired and with the glue diluted with water it added very little weight. Make sure the "grain" of the paper runs the same direction on the top and bottom of the wing and cover the whole thing at one time to avoid building in a warp as the paper dries. I fly CL combat with the Fox 36 combat special (about the power of most 40's) and with paper covering and 1/4x3/8 balsa spars I have never folded a wing doing almost 100mph and pulling tight 6 foot turns. I overlap the paper for the middle 1/3 of the wing using an oval pattern to spread out the load. Bob