Q500 wing with no SPAR ??
 

I am building my first q500 and its a sheeted foam core wing that has no spar what soever. The wing panels are simply butt jointed with "5 min epoxy". The center section is to be glassed, but how is that enough to hold the wing together at 100mph + ?

Depends in part on the weight of the glass used. A chunk of 6 ounce would prevent things from coming apart quite well.

There are many models out there with sparless foam wings. In your case the sheeting takes on much of the job of the spar. Another trick is to run a strip of fiberglass re-enforced packing tape down the length of the bottom of the wing where a spar would normally be. One continuous run tip to tip then sheet the bottom.

And I'd use 30 min epoxy for the joint and the glass.

I put a vertical sheer of carbon on mine and the wings are good for the fastest classes.

http://www.rcuniverse.com/forum/q-50...q500-wing.html

Just including this reply for those searching similar glassing tasks in the future:

As I have learned from a mentor, fiber orientation can help in some instances too.

Bi-directional cloth applied to the center section with fibers running 0-90 will have only those running span-wise providing strength across the butt-joint. Those fibers running chord-wise - which comprise half the material - are not providing strength across the joint. [++++++l++++++]
You may achieve better results with uni-directional material where all the fibers are running 90 degrees to the joint. [--------l--------]

If you have enough bi-directional material to do the job and the cloth is applied on the bias (45/45), then all the fibers will be working to strengthen the joint like the uni- but with the added benefit of torsional rigidity. [XXXXXXlXXXXXX]

From personal experience, I was reprimanded for taking too long to cut some cloth for a project. Boss sez: "What took you so long? - I was getting ready to send out a search party." Me: "Oh, I was cleaning up the area after cutting materials, putting some things away, and then I was talking with someone in the hallway." Boss: "Geez, I didn't ask you to weave cloth, did I? We don't have all day! This task should have taken minutes, not hours! Please don't tell me you're cutting one piece of cloth at a time." Fact of the matter is, I spent an enormous amount of time deliberating how to keep fiber orientation while cutting cloth off the roll. After much head scratching, I had to draw some arrows on both sides of the pattern and turn it over several times to help me see what happens here.

1) Stacking two pieces of plain weave cloth while using care to maintain orientation coming off the roll and cutting both with a pattern at the same time gives identical pieces - two rights or two lefts and both pieces will have warp and fill fibers running exactly alike. For this example, slashes can represent the fibers running the length of the roll. [//>] [//>] 2) Using care to turn only one of the pieces over now gives a left and a right with fiber orientation in a mirrored or balanced manner. [//>] [<\\] 3) Overlapping a portion of the two pieces gives two layers in the center and one layer outboard. [<\X/>]

Also from experience, early AMA 428 class Q-500s were shown to be having wing failures in compression, not tension - so strength was commonly achieved by concentrating on reinforcement to the top of the wing, not the bottom. Glass coverage on the top of the wing usually extended out further than the bottom to avoid stress concentration - especially at the LE. In other words, not simply a single wrap of narrow, constant-width cloth around the wing panel joint which may have been fine for 424.

great Job from Scott

mine here only run up to 100mph or 110, I made my wing with some 12k unidirectional fiberglass ( now I don't remember how much which makes me wonder ), epoxy. I use polyurethane glue for the skin. Then join the two halves with 2 layers of what I believed as 200gsm fiberglass cloth.