motor/propeller question (trying to build UAV)

[icy]

I'm trying to build a small autonomous hovering copter. I ordered replacement main drive motors and propellers for a micro RC Helicopter to use on my own project. The motor is rated for 3.7 V. I applied a 3.7 V, 2000 mAh battery to the two motor leads. It spun very fast but once I put the propeller on, it moved very slowly. I don't understand why there isn't enough torque because it is meant to be used with a propeller. If anyone could offer any insight into this issue, I would appreciate it!   

[icy]

It is a coreless motor, and because it only has two wires it can't be brushless...

[waltr]

Have a link to the motor and propeller?

[jkerns]

How big a propeller compared to what the motor was designed for? How does the pitch of the propeller compare? Too much pitch will load the motor down.

If the motor and rotor are from the same helicopter kit - are you missing a gear reduction that is often between the rotor and the motor?

[TaoBaiBai]

Hi,
I seldom see a 3.7 V motor,please check carefully the ratings ,normally 12v is used for this project,and what is the motor nominal current ,the length of your propeller and what is the discharge rate of your battery?

Btw,does anyone know what is the relationship between thrust,rpm,number and length of impeller blade?

[waltr]

Google 'Propeller thrust' for a number of calculators and other info regarding these combinations.