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HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Roban Ec 135 Conversion
12-24-2019 08:27 PM  16 months ago
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Roban Ec 135 Conversion
Hello Guys,

I bought a Roban Ec 135 that was a very nice kit until I got the mechanics powered up. I found that the Fenestron required a insane amount of force to operate the pitch control. So much force was needed that you couldn’t budge the bell crank by hand. I snapped the ball off of the bell crank from the force. I am using a 320oz servo for rudder control. Going with a bigger servo would require upgrades to the linkages and pushrod and I wasn’t certain that would do it. Motion swears a 67oz servo will do it. So that got the gears turning, and I was looking for a challenge. So I decided if I lock the fenny full open and vary the speed of the fan, that in theory it should work the same.

Here’s the mechanics with the transmission.

Tail drive gutted

Amazon coupling 8mm to 6mm.

Scorpion 4025 730kv

Trex 550 motor mount. This required some grinding and alignment with a caliper. I would recommend trying another mount. But if your in a pinch it will work.

Fitting the Motor.

Motor in between the frame.

Now the hardest part. I wanted the tail motor to shut off when throttle hold is tripped. And I didn’t want to arm the esc by deflecting my transmitter stick and I didn’t want the motor to shut off if I gave it to much stick. I wired a spdt relay to pick up the signal of a spare channel that’s set to lowest end point to arm the esc. When I flip the switch the relay contacts send the esc signal to the rudder channel of the FBL system. So when the ikon senses yaw it speeds up or slows down the fenny. And the fennys neutral stick speed is 6000rpm.

I flown 4 packs through her so far. The heli performs just like my Vario Ec 135. It flys smooth and has plenty of tail authority. The fenny runs at 7500rpm in a hover and is capable of 17000rpm if needed. She’s running 2 6s 5000 batteries. I got it set to 15500 for now. There’s a guy on scalerchelis that’s getting 5 minutes on his stock roban and it can’t do forward flight turns that good. With the energy savings of the variable speed I’m getting around 7:30 of run time, very efficient. I’ll take it out to the field in the spring to test the forward flight capability’s. I wish I new how to post on youtube? Also this requires a lot of programming to get it right.

12-26-2019 03:00 AM  16 months ago


Hong Kong

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Thank you for sharing. My friend's Roban EC135 has the same situation. What we did was to fabricate a mount to put 2 powerful tail servos in series(push/pull) configuration. It can hover and do some forward flight but both tail servos come down hot.
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HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Roban Ec 135 Conversion

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