Which wing structure can be made stronger - sheeted foam, balsa spars+ribs?
Having a hard to find rc wing structure construction techniques...internet or books! Any help?!

cant wait for responses to this one

On an average, foam is stronger, built up is lighter.

It all depends on materials and methods used. If you use super soft wood without any reinforcement, such as spar doublers, etc., in either case, the strength will suffer. I've seen both types of wings fail in very minor mishaps. OTOH, I've also seen both types of wings slice stout fiberglass fuses in half during a mid air and land with nary a scratch.

John

flypaper is right.

Foam wings = Flying Surfboards. Strong and heavy. Be a man and build your wings from wood.

Uhh huh, yeah. Someone needs to teach you how to build a foam wing for a pattern plane. They are anything but heavy, yet strong enough to pull full throttle square loops all day long.

John

Just to add another dimension to this discussion :stupid:

White Foam, Pink Foam & Blue Foam

All different, I like Blue for wings

I like hallow foam cores with just 3 or 4 foam rib structures to keep them from collapsing.
For me it's easier to control the airfoil with hallow core foam but easier to keep the weight inboard with built up.

Touchy, touchy. Don't take it personally. I can build anything but because I actually enjoy building, I like wood. I've seen some light foam wings, but usually not. It just depends on how much time someone is willing to spend cutting a lattice-work from it.

I've yanked on my planes pretty hard to include terminal velocity power dives ended by cranking back the elevator. I fluttered off a couple elevators back in my early R/C days, but I've never folded a wing ever.

Not touchy at all. You just made the comment about foam wings being surf boards. So, I replied accordingly

I build both types of wings, and have never had one fail.

As far which is stronger, take a look at what the sailplane guys are doing to make both built up and foam wings incredibly strong while remaining light.

John

John - I agree that foam wings are stronger - they have to be due to their added mass/greater inertia. As far as I know the guys using foam wings are doing so because the average builder can make a foam wing more accurately and faster than a good wood wing.

I've heard the legend of the "light" foam wing for years, but I've never seen one that wouldn't be lighter if it were built of wood. In fact, I've never picked one up that didn't feel like a brick. I'm sure there is a light foamie out there someplace. One day I'll happen upon it.

As far as which is stronger, it's a moot point if both types are strong enough. Personally, I think foam wings are fine for those who want them, but I can build the same wing from wood and it will be lighter.

This is the kind of thing that can go back and forth for the entire thread and since neither of us can substantiate our claims, then make your counter remarks and let's get back to our building.

PS. As long as you're building, it's all cool no matter what it's made of.

Doesn't it depend on the application?
For example, the airplanes for the SAE competion will never fly faster than 50mph. Still their wings will need to withstand some 25~30lbs, plus gusts, 60 degree bank turns, etc. X 1.5 safety factor! All that at one or two attach points!!!
How do I handle that?
Books, magazines or sites suggestions with pictures, figures, graphs and the available methods / options are welcome!
Thanks again.

Again, I point you to the sailplane crowd. They perform extremely rigorous zoom launches on winches which visibly bow the wings. They would be the best source, AFAIK, for the type of information you are looking for.

John