ORIGINAL: branded
ORIGINAL: Rcpilet
I think foam is always going to be heavier than built up.
Whats all that space between the ribs in a built up wing? Air
Whats air weigh? Nothing
Whats foam weigh? Solid foam wing?
Even using 1 pound density foam--compared to 8 pound balsa. I still think balsa built up is lighter than foam. There is very little of that balsa in a built up wing.
Thats my totally biased opinion because I prefer a built up wing over foam sheeted. IMO--sheeting foam wings is a pain in the butt. I can frame up a wing pretty quick.
Uh, air has weight to it just as any other fluid. What's in a built up wing is alot of stuff not found in a foam core wing: ribs, spars, shear webs, etc.
This brings the weight of the two types of wings very close to each other, particularly when speaking of larger sized airplanes.
I find foam core wings much quicker to build up but they do require some aquired experience, particularly when cutting out control surfaces, planning for retracts, etc......
I disagree about air having weight to it. Thats an argument over symantecs and pointless in this discussion.
I kow how to build a foam wing. Done a few dozen of them. I just don't like it.
You still have spars in some foam wings. You still have a leading edge piece of balsa on the wing. You still have a trailing edge piece on the wing AND another leading edge piece on the control surface. You still have caps on the root and tip. Just like a balsa plane.
A balsa wing isn't always sheeted on the whole wing--so there is weight savings over a foam wing. A balsa wing has a lot of air in it and air weighs less than foam--I don't care what planet you live on. Foam is heavier than air--thats the point.
Look how much more glue it takes to install a phenolic tube in a foam wing as opposed to a built up wing. On a foam wing, you really should be coating the entire socket with glue and making sure you get glue on every part of the tube when its in the socket.
In a built up wing, your only going to put glue where the phenolic touches the ribs. If your a good builder, you wipe off runs and keep the glue neat.
Glue weighs something. There's a lot more glue in a foam wing than a built up wing. I certainly think there is.
Okay, your turn ....
Maybe we should do an experiment? I'm fixin to build an 80" wing with about 980 sq.in this summer. It will be a traditional balsa wing. Maybe I should weigh it as I build and you should start that kit you've been eyeballing for the last 2yrs. You know, the one with the foam wings?
