Helicopters B

[jander14indoor]

"1nxtmonster" That gives us something more to work on, yes.
Weight at 3.2 gm should come down 0.2 gm, but you should be able to beat 50 seconds at that weight. Won't win nationals, but can be better.
Sounds like you are winding hard, good.
3/32 with lots of winds left. That says go shorter, but that loop is pretty short now. I suspect you need a fatter motor, more like 0.125, and longer to get more torque (power) into the system.
Rubber brand, in reality there is only ONE maker of competition quality rubber, that's FAI Model Supply. They make two quality levels, Tan Sport and Tan Super Sport. You want the Tan Super Sport for competition flying. Stores more energy per gram which works out to more turns.
Almost everyone else just buys and resells FAI's rubber. Problem is, when they relabel without saying TAN Sport or Super Sport and you don't know how it's been stored, so you are kind of buying a pig in a poke. (for you youngsters who may not be familiar with that phrase, that buying a pig in a bag(poke) without looking at it, who knows what you're getting) And what is "good enough" in your case. Plan to win nationals, not likely. Win regionals, possible. State, depends on the state.

Bazinga+ Can't hurt to try the 3/32, but as I said above, probably on the thin side for these rules.

Jeff Anderson
Livonia, MI

[1nxtmonster]

"1nxtmonster" That gives us something more to work on, yes.
Weight at 3.2 gm should come down 0.2 gm, but you should be able to beat 50 seconds at that weight. Won't win nationals, but can be better.
Sounds like you are winding hard, good.
3/32 with lots of winds left. That says go shorter, but that loop is pretty short now. I suspect you need a fatter motor, more like 0.125, and longer to get more torque (power) into the system.
Rubber brand, in reality there is only ONE maker of competition quality rubber, that's FAI Model Supply. They make two quality levels, Tan Sport and Tan Super Sport. You want the Tan Super Sport for competition flying. Stores more energy per gram which works out to more turns.
Almost everyone else just buys and resells FAI's rubber. Problem is, when they relabel without saying TAN Sport or Super Sport and you don't know how it's been stored, so you are kind of buying a pig in a poke. (for you youngsters who may not be familiar with that phrase, that buying a pig in a bag(poke) without looking at it, who knows what you're getting) And what is "good enough" in your case. Plan to win nationals, not likely. Win regionals, possible. State, depends on the state.

Bazinga+ Can't hurt to try the 3/32, but as I said above, probably on the thin side for these rules.

Jeff Anderson
Livonia, MI

It's not that I'm lacking torque (helicopter shoots rapidly towards ceiling and gets stuck in high gym) off the beginning, but at the end of flight. Do you think that I could potentially use thinner rubber and more winds? Like 1/16 rubber x 1500 winds?

[ThatRoboGuy]

I've been told that the best possible helicopter rotor angle was 15 degrees, half what we are using now. It seems ridiculously small to generate the same/more lift.

[Bazinga+]

As you can see the optimal angle is 15 degrees. This is the angle were the drag messes less with the lift. Also 1nxtmonster, try using a longer rubber band. Usually people use rubber 1.5 to 2 times the length of their helicopter. That way not only will you get more winds and the helicopter wont shoot up as fast, but the rotor will spin at a more constant speed. Ideally, if rubber had no weight, one would use rubber of infinite length, that way the rotors would literally spin forever at a speed enabling it to stay in the air. But rubber has a mass

[chalker7]

Where did you get that graph?

[ThatRoboGuy]

Researched the origin of the graph. Has nothing to do with balsa helicopters. It was found through a google search, likely, and can be easily traced to: http://upload.wikimedia.org/wikipedia/c ... ve.svg.png

Currently trying to find where the graph is used in wikipedia.

[Bazinga+]

http://en.wikipedia.org/wiki/Angle_of_attack

[ThatRoboGuy]

angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft

wing of a fixed-wing aircraft

wing

We're talking balsa wood super-light rubber band powered mylar winged helicopters. Not heavy duty planes without a limit to their power. Talked this over with my coach. Now, sure, if we had the power to keep it flying, fifteen degrees would be great. You mentioned drag. At the low speeds we fly drag is minimal and can easily be looked over and ignored. Planes, on the other hand, fly very fast and are large, making drag an issue, and thus validating the idea of a fifteen degree "angle of attack".

[Bazinga+]

The basic idea is the same for both planes and helicopters. You want the largest lift force and smallest expense of drag.

[gmui]

My son's team didn't make States this year so just for reference, he got first at regionals with times of 1:57 and 2:07 for his flights.

I think 2nd place was half that at maybe a minute.