Remembering my caveat, anything I say is my opinion, yada, yada... And I'll ask, do you have a copy of the rules? Because if not, GET THEM! Can't emphasize it enough, to be successful in SO, you MUST read the rules for yourself!!
OK, off soapbox, sort of.
SFCMS wrote:<SNIP>If you make your own propeller, can you buy a thrust bearing from a store and use it, or do you have to make your own? <SNIP>
The rules para 2.e says: "Competitors must construct the rotors themselves. Commercially available rotors or propellers must not be used in whole or part. Rotor thrust bearings may be commercially available items." Seems pretty clear, you HAVE to make your rotor/propeller, (the word 'must' is used) you have a CHOICE about the bearing make it or buy it (word 'may' is used) up to you.
SFCMS wrote:<SNIP>This is especially to jander14indoor, since you seem very good at this- <SNIP>
I wish... more like capable, good is a whole 'nother level, just been mentoring Wright Stuff a while and have SOME knowledge of aeronautics. I actually DON'T know what the nationals winning design will look like. I have a guess, but only minimal experience and minimal theory to justify it. So I'm keeping my mind open. There are some absolutes I know, beyond that, there's a WHOLE lot of room for surprises.
<SNIP>Would the helicopter still be able to fly if both rotors were fixed (I don't know if I'm using the correct term, but I'm talking about the prop attached to a motor...), instead of having one "free" and one "fixed"? In other words, there would be two seperate motors, each half the length of the entire helicopter, and one motor would go with one prop... I hope that makes sense...
PLEASE HELP ME!
Kind of makes sense, pictures or drawing would help.
Anyway, the rules seem to allow for multiple motors (para 2.f) and don't say how you use them. I'd phrase what you are trying to say differently. I'd say you have two 'free' rotors, each individually powered.
Some approaches would work, some wouldn't. What are you going to anchor the other end of the rubber band to? How are the rotors spinning? With two, you almost HAVE to have them counter-rotating, or the thing will spin funny, not creating power/lift.
If you just have one motor stick with rotors top and bottom and the ends anchored to the stick, and counter-rotating, you really have the same dual rotor design we've been talking about, think about it or a while and you'll see.
I did see one last year at nationals that had two rotors with half motors each. Each pointed up, and had its own motor stick. They were side by side and had a frame in-between. Think a Chinook copter like this: http://en.wikipedia.org/wiki/File:CH-47_2.jpg
Not very successful because it weighed too much for all that connecting structure. Stability was questionable for what little flight time it had, could probably resolve that.
Hope that helps