eric208

Hi All,

I just got this FEDA Mini Dragonfly a few days ago. After flying (crashing) it for the last few days, the rudder stop spinning after a small crash this morning. Can anyone offer any troubleshooting direction? I¡¦m a newbie to electric RC helicopter.
Some more information about the problem:
1.) The main rotor will spin and lift the helicopter up when moving the throttle up. Since the rudder stop spinning, the helicopter will spin like crazy while moving up.
2.) The GWS Gyro LED stay green after connected the battery. If I move the helicopter left or right, the green LED flash red then go back to green. Normal?
3.) The Mixer and Speed Controller flashing Green and Red before turn on the Radio unit. After the Radio is on, the LED stays in green. Normal?
4.) There is no physical damage on the helicopter.

Thank you in advance for all the help.

Eric

Popcyclical

Hi Eric -- Welcome to the Hair Pulling Club....

Re:

1.) The main rotor will spin and lift the helicopter up when moving the throttle up. Since the rudder stop spinning, the helicopter will spin like crazy while moving up.

**This is normal because you have no tail rotor running to counteract Main Rotor's torque.

2.) The GWS Gyro LED stay green after connected the battery. If I move the helicopter left or right, the green LED flash red then go back to green. Normal?

** I don't have the GWS Gyro (I use the Century Gyro that came with the HB) but you can troubleshoot to find out if it's working:

A) Unplug the Main Motor's connector from the 'Throttle' connector on your ESC and:

B) Plug the 'Rudder' connector (the connector attached to the wires going to your Tail Motor) into where you unplugged the 'Throttle' connector on your ESC.

C) Turn-On your transmitter, connect your flight battery and slowly increase throttle on the Tx. If the Tail Motor runs and your Tail Rotor Blades are running (Clockwise as viewed from the left side of the HB), then your Gyro may not be passing the receiver's 'Rudder' command to the ESC. If the TR is running CCW instead of CW, the Rudder connector should be turned around at the ESC.

If the Tail Rotor Motor does not run, then the following failures are possible: either as mentioned above, the Gyro is not passing the Receiver's 'Rudder' command through the Gyro to the ESC, or the receiver is not sending a 'Rudder' command to the Gyro or the Tail Motor has failed, or the wiring from the Rudder connector to the tail motor is damaged and bad. A continuity check with an 'Ohmmeter' can be used to verify that the red and black wires from the rudder connector to the solder joint(s) at the tail motor have not been damaged resulting in not sending TR voltage and TR (ground) return voltages to the tail motor. Although I've got over 200 flights on my Tail Motor and it's still good, I read that lots of people are having failed Tail Motor brushes.

3.) The Mixer and Speed Controller flashing Green and Red before turn on the Radio unit. After the Radio is on, the LED stays in green. Normal?

**Yes, this sounds normal, HOWEVER, you should develop the habit of ALWAYS turning-on your transmitter before you connect the flight battery. This could save you some trouble if the throttle is not all the way off or the transmitter falls over turning the throttle all the way on, etc, etc.

4.) There is no physical damage on the helicopter.

**Good -- 'Tough little bird isn't it

'Hope this helps you get humming (or FEDA'ing) again....
Good Luck

avance_x

Normal operation for the GWS gyro would show both green and the red light on (i.e. simulataneously). A solid green or a solid red would tell that the set-up is not correct.

eric208

Thanks for all the respond guys.

Hi Popcyclical,

Thanks for the great troubleshooting tips. After tested Plug the 'Rudder' connector to 'Throttle' connector on the ESC. It is still not spinning. I checked the continuity follow your suggestions. It seems likely that the motor is broken¡K..

1.) Anyone know where I can buy a cheap replacement motor in the US? I bought this Dragonfly mail order from Hong Kong.

2.) I found a shop locally carry the century hummingbird. Will the tail motor from the hummingbird interchangeable with the Dragonfly? They look almost the same.

3.) After fixing the motor, I think my next step is to check the GWS Gyro. Any suggestions on how to do it?

Thanks again for all the help.

Popcyclical

Hi Again Eric...
Re:

1.) Anyone know where I can buy a cheap replacement motor in the US? I bought this Dragonfly mail order from Hong Kong.

I bought a pack of 2 tail motors for 10.99 + sales tax + 3.00 shipping from Hobby People.com. You can find them on the web or possible they have a store near you in the bay area? Note that although the bypass capacitor is already soldered across the motors, they do not have pinnion gears installeld so you would need to pull the pinnion of the old/bad motor and install it on the new motor. This would require a MICRO GEAR PULLER such as the GWS micro puller. The motor shaft size is around 1 mm diameter-- I think these were packaged for use with tiny propellors in a twin-engine micro flyer of some sort or possibly a boat because they are wired in parallel, together. You can just cut one of the 2 off the existing harness and wire it into your heli. Except for no pinnions installed, they appear to be identical the the tail motor on the Hummingbird. You can either splice the wires to your existing tail motor wires or unsolder the bad motor, install one of these (with gear) and solder the existing wires to the new motor. The part number is as below:

128470 Sub Micro Motor 2Pcs/Pack 10.99

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2.) I found a shop locally carry the century hummingbird. Will the tail motor from the hummingbird interchangeable with the Dragonfly? They look almost the same.

Although I've never seen a dragonfly, I've heard that they're really the same as the Hummingbird.

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3.) After fixing the motor, I think my next step is to check the GWS Gyro. Any suggestions on how to do it?

Someone using a GWS Gyro should brobably advise you on proper detailed testing of that Gyro. If it were me, I'd do a 'quick & dirty' test of simply plugging the 'Throttle' connector (the one going to the Rotor-Drive Motor) into the 'Rudder' connector on the ESC and only apply a very small amount of Rudder command. Before doing this I would set the Rudder Trim slider all the way to the left and hold the rudder stick on the TX all the way to the left which should be a 'no-signal' condition. Then, slowly moving the rudder stick to the right (with flight pack battery connected) should start to turn the main rotor. That would be evidence that the Gyro is at least sending the rudder signal from the RX through the Gyro to tell the ESC to start driving whatever motor is attached to the 'Rudder' connector on the ESC. If you have a spare motor laying-around you could use it instead of driving the main rotor's dirve motor. That would eleminate any risk of 'out-of-control' rotor blades attacking you.....

Fun Stuff, HuH? :spinnyeye:

eric208

Thanks again Popcyclical. I ordered the motors from hobbypeople.net. Hopefully with the new motor, I can get the HB working again soon. I guess fixing and flying are part of the fun things flying the helicopter.

Cheers

Eric

sachin998

I have the hummingbird for two days now, And I was also baffled why my tail motor stopped running. I later found out that my gear mesh was wwway too tight.

The tail rotor functioned much better when the tail motor gear had very little contact with the main tail gear. The moment I tried to get a slightly closer mesh between the gears, it would stop running.

This motor does not have the torque to counter a tight gear mesh , so I suggest moving the motor down slightly and as far away from that big tail gear as possible.

I havent read all the posts to your problem, but this is just my opinion as to your problem and something that I experienced as well.

This was the only thing that worked for me.

sachin998

By the way

I ensured that the gear mesh was fine before running the bird. It worked fine, and the mesh actually got tightened in flight.

I flew it about another five or so times thereafter and it got tight again and the tail motor stopped. I later put a drop of cyano and I'm sure this would solve the problem.

Other than that, it flies great.

eric208

Thanks for tips sachin998, my problem actually turn out to be a bad motor. I have replaced it since then and it's working again.