Helicopter Testing

[WCarneyJX]

I've uploaded a low res copy of the plan and will link to it after it's approved.

[WCarneyJX]

3293|68/SO_Helicopter_Plan_Low_Res.jpg

Not sure why the thumbnail doesn't show up but clicking the "X" icon above brings up he Helicopetr plan.

[chia]

Baw... I just tried testing my new helicopter, which has both rotors free, and it started going every which way, crashed into a wall, and the top prop hook came off. Thankfully the rotors themselves stayed intact (rotors are so much sturdier than they look!). I'm just not sure why the top hook wasn't strong enough; I glued it the exact same way I've glued them before.
Also, do you find it sort of awkward to launch a helicopter with both rotors free? When one is fixed you just hold onto the motor stick with one hand and the top rotor with the other, but with this kind you need to keep both rotors from spinning...

[WCarneyJX]

Chia,

The big question is the flight pattern. Assuming the rotors are constructed correctly with one clockwise and one counter clockwise, the only other explanation I can think of is massive motor stick bending.

As for launching the Heli with both rotors free it just takes a bit of practice. My kids sort of hold both rotors and then release the top, transfer that hand to the middle of the motor stick, then allow the bottom rotor to spin up a bit and let her fly.

What sort of prop hooks are you using?

[chia]

I don't think the motor stick was bending that much. I may have just released it at an angle. I think it could have straightened itself out if I had been testing it in an actual gym instead of my cramped foyer...
Using aluminum hooks btw

[WCarneyJX]

Do you mean aluminum tubing with wire hooks? If so, you can wrap the tubing with some thread and glue but you have to consider the weight of doing so. also consider it probably wouldn't have come loose except for the crash...

[chia]

Nope, it's a bent aluminum metal hanger (not the best method, but what I have available at the moment). Either way, I reinforced it with thread, like you mentioned (it was underweight anyway).

[jander14indoor]

Where's the balance on this new copter? You want the center of gravity to be low to help stabilize it. To high and you'll get wandering like that.

Jeff Anderson
Livonia, MI

[kjhsscioly]

I don't have the copter with me, but it should be low, we added clay at the bottom

[thewinner]

And for stability, the top rotor needs to generate more lift than the lower. Try fiddling with the pitches of the rotors and see what works best.