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HelicopterAntiques or Out of Business › Cricket dudes! I need a little help here.
08-05-2011 03:26 PM  6 years agoPost 1
MADGUNS

rrApprentice

Kadena AB Japan (Okinawa)

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OK so I've converted this Cricket to electric. I was struggling with some bad vibrations. I finally discovered my head pivot?/block was out of round.

With that sorted and a brand new set of blades with everything balanced it was running smooth. I junked my E-flite power 25 motor for a TREX 500 motor. I remembered reading how a .25 glow motor screams on these so something with a higher KV rating was more appropriate.

Got her all back together and revved it up. I use the stock clutch so it sounds sweet spooling up. Once I got it into a hover I would somtimes get a jerk in the tail ( clutch slip ). I sorted the clutch out by roughing up the shoe which was polished to a high sheen. Now the clutch was engaging and that cured the slip. Then as more power was applied I would lose tail rotor authority and you could hear the belt slip off the pulley.

To cure this I installed a belt tensioner. It really didn't put the belt under any stretch it simply positioned the belt closer to the power side of the pulley. This was necessary primarily because of the motor set up. I couldn't tighten the motor/clutch pulley as this would put allot of stress on the forward bearing of the motor.

I think the answer is a different motor mount. I would need one that supports the outrunner motor from the front and the back, but still have the capability of being adjustable on the frame for proper belt tension. What do you guys think?

Or are just my pulleys and belt so worn out that they were bound to slip from the start. Once I get this sorted this heli will fly awesome.

Has anyone used a gear on gear drive with a stock cricket?

TREX 500 motor
Stock Clutch
Hobby King OPTP 40 amp ESC
Castle Creations BEC
Turnigy NANO tech 4S 3000 MaH Lipo

Happiness is a belt fed weapon

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08-06-2011 03:42 AM  6 years agoPost 2
gorhambirds

rrApprentice

Hickory Hills Illinois, usa

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From what I can see from the photo of your motor installation, the belt does look too slack. The original thought behind using a toothed belt was the fact that the belt should run somewhat slack. When the belt is squeezed together between the pulleys, it should be about 3/4 of an inch apart. I've run the same belt/pulley combination literally for years on a single helicopter and never wore them out. Also, keep in mind that the torque curve of a powerful electric motor can be much more aggressive than that of a glow engine resulting in a worn pulley should the belt be run too slack. As far as the clutch, once at the necessary rpm to engage, it shouldn't really be slipping regardless if the shoes are polished or not. We used to take the shine off of the shoes used on r/c cars, but those shoes were composite, not steel, and would develop a "glaze" which would allow them to slip. The GMP clutch, like all clutches I've seen, are machined with smooth surfaced shoes and should grip regardless. Anyhow, as long as it works. Looks good.

Steve Z

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08-06-2011 06:08 AM  6 years agoPost 3
MADGUNS

rrApprentice

Kadena AB Japan (Okinawa)

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You're right about the clutch. I would slip a little until the RPM went up some more then it would catch again.

I need to build a different mount. One that supports the outrunner on both ends so I can tighten the belt an not worry about smoking the forward bearing of the motor.

Happiness is a belt fed weapon

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