Cooked Motors

Hi All.

I have the Eco 8 using 8 2ah cells and find that the motors are cooking with the heli not even getting off the ground. I am using a carbon fibre training undercarage.

I have tried a 16 turn triple wound car type motor and a Kyosho K Speed heli motor. The Kyosho motor actually melted the solder and plastic brush housing.

Any ideas? BTW: I can't afford a brushless setup!

Regards Steven.

Hi Barf,

I have been using a car type motor LRP GT 1 23x2 (modified for reverse turn), 10 t pinion, 8x 1,700 mAh with no problem.

Two points to consider:
gear ratio - are you using 10 t pinion
timing of the motor - is this correct

Now I have GM racing AIR 2000 (=Ikarus Performance) and 9*1,700 mAh - seems to be very good combo for a HELi beginer.


My Eco 8 pages (now in Czech only) http://www.multiweb.cz/elektrolety/eco.htm



[This message has been edited by mila (edited 08-07-2000).]

Hi,

I also think that 20-23turn RC-car motor is suitable for your ECO8. The pinion gear will be 10-12T.

Less teeth gear is low power (= kind for the motor), and vice versa. In addition, if you don't want more power, you may use 7cells for the motor with 10-14T.The life time of the motor becomes longer than the case of 8cells.

Note that in many of cheap motors, the motor timing cannot be changed. Since ECO8's gear unit requires the rev. direction opposite to normal RC-cars, the motor timing may have to be adjustable.

Hi,

Just to note LRP GT 1 is a stock motor, i.e. the timing may not simply be changed. I had to modify the motor (open the motor - change timing -close it and drill two holes for screws M2 - 20 minutes). I had big problems with bushing on LRP GT1 - I had to replace them with ball bearings.

Thanks for the replies guys.

The problem is sorted out. I am using a 25 turn motor with around 16 degrees advanced timing. At last it gets into the air, that battery is lightly warm and the motor is only warm!

The problem I had tonight was that when I got the heli in the air it was moving like a top. It wasn't spinning (the tail rotor is doing it's job) but each leg was dropping in turn. If you can understand what I mean!

I wouldn't have thought the training gear would be very far out of balance.

Regards,
Steven.

Steven

The gyrations you describe "spinning like a top" are most likely due to too low a head speed. Increase your head speed either by changing gear ratio (use a pinion with more teeth) or perhaps you have too much pitch on before the motor is running fast enougth.

Either will result in low head speed and the sort of behaviour you are experiencing

Eric

Thanks Eric!

I bought a JR 652 radio and am using the pitch/throttle mixing and that has helped alot. It isn't completely gone but at least the heli is controlable now :-)

I have ordered a couple of pinions as my motor and battery are only lightly warm.

Thanks,
Steven.

Hi,
Try to buy in towerhobbies, this motor Kyosho Magnetic Mayhem Reverse (22turns-single), is very cheap (about $30) and Eco fly very well, also this motor work good with low temperature (13T pinion). I use with Ikarus Heli 4000 Speed Control. I will replace bushing in this motor with ball bearings to improve performance...

Now, I fly my Eco with X-250-6 Brushless, but from time to time (to rest brushless motor), I replace with my Kyosho MM and hover is good. One advantage of my brushless over Kysoho MM is the flight time (about 15 min with brushless X-250-6 and only 6min with Kyosho MM)

Bye.

I've been using the Magnetic Mayhem Reverse motor on the 10 tooth pinion for a few months now, and everything is working 100 percent. I have got a 13t pinion, but have not tried it yet - if it ain't broke then why bother fixing it??

Batteries are Sanyo 3000's (10 of them) and give flight times of up to 13.38 minutes.

Just for inspiration:

The propeller is from "Air Freshener" which is used in cars. http://www.heliservis.cz/images/chlazeni.JPG
Please note that the fan blows up - the author says, it is Ok and moreover the dust from bushes is not in the motor !

I am using a similar fan, but built from balsa and plastic for opposite rotation.