u7 helicopter -A question

[mp1p]

Hey, I have a u7 helicopter i was flying outside in the summer last years, unfortunately it got stuck at the top of a tree and it was stuck there untill a recent wind storm.

 

I found it on the ground covered deep in snow, I brought it inside let it dry out i charged up the battery and it held! Now the lights turn on the unit, but it wont turn the rotors - iam sure the engines are pooped out -

 

So my question is, is there anything else iam missing here or is there a way to bench test them to check to see if they turn on - and or it could be the motherboard. Only paid $60.00 so not look a spending to much on it

 

I got my electrical tester out and was able to see voltage was ok at the battery -

 

My remote seems to sync as it flashes untill i go up and down on the throttle and it goes solid - Any constructive suggestions would be appreciated !

 

thank you

[SBuzzkill]

Hey dude! Just so you're tracking, this is a full sized manned helicopter forum. You will have much better luck finding the answer you're looking for over at RCgroups.com, which is my favorite forum for all things RC. Good luck and happy flying!

Edited March 20, 2017 by SBuzzkill

[iChris]

So my question is, is there anything else iam missing here or is there a way to bench test them to check to see if they turn on - and or it could be the motherboard. Only paid $60.00 so not look a spending to much on it

 

I got my electrical tester out and was able to see voltage was ok at the battery -

 

My remote seems to sync as it flashes untill i go up and down on the throttle and it goes solid - Any constructive suggestions would be appreciated !

 

thank you

 

This is generally not an RC Forum, as stated above. However, try these basics. RC helicopters incorporate the following components:

 

-Battery

-Motor

-ESC (electronic speed control)

-Radio receiver

-Servos

 

The battery supplies the required power for each component. The ESC is connected to the servo channel on the radio receiver and rather than controlling the position of the servos alone, the radio receiver through the ESC, also controls the speed and torque of the electric motor by electronically selecting between the three sets of windings in the motor.

 

After drying it out, the next thing to look for, before ever connecting the battery, is corrosion. Check for corrosion around all electrical components, wiring, connectors, and especially the motor. Depending on the level of corrosion, if found, you may be able to save some of your components. Try some CorrosionX products.

 

More than likely your battery was completely drained well before corrosion set in, which would’ve precluded any electrical shorting; therefore, most of your sealed electronics are still good, i.e. your ESC.

 

Try a known good battery. The most likely culprit is your battery. The batteries used in most RC helicopters are multi cell batteries. These batteries do not like to be completely discharged and left in that state for long periods. Even though you may have charged the battery and it appears good and shows the correct voltage, one or more cells are likely bad and that battery is unusable under the full load of your RC.

 

 

 

The motor can be checked, depending on type, Brushed motor (two-wire) or Brushless motor (three-wire). For the two wire motors, just connect the two-wires of the motor to a good battery using test clips. If it’s good, it should turn freely.

 

For or a three-wire motor, you could use your multi-meter to check for open windings between phases, using the ohm setting. However, most failures are due to shorted windings caused by corrosion or overheating, your multi-meter won’t help much, due to the inherent low resistance. What you need is an inductance/capacitance meter (LC meter) to identify a bad phase in the motor.

 

Since you don’t have an LC meter, what you can do is, use your cordless drill or DREMEL tool to drive the shaft of the motor, turning it into a generator. Then connect your multi-meter, set on the AC mV range, across all three phases (wires) of the motor (i.e., Red-Grn, Red-Blk, Blk-Grn). If the motor is good, all three phases should generate approximately the same AC voltage.

Edited March 23, 2017 by iChris