View Full Version : Help! Probs with phonix & Neu combo f5b

05-17-2006, 02:50 AM
I recently got a Twister III from NE- Sail Plane. As Sal recommended I installed a 1509/1Y 6.7-1 Neu Motor, Phoenix 80 Speed control, ThunderPower 3S 4P 5300 Mah Li-poly battery pack, 17 x 13 Aeronaut CF prop. On my maiden flight all was great until about 5 min or so into flight and Wham....no throttle control and it's running at full power. I have all other controls just no throttle. After almost 5 min of scary loops to keep it in sight as it was late and a very gray day. Finely the motor starts to cut in and out. Then it stops....thank goodness I think..... unfortunately at this point I also start to get intermittent control of every thing else.(I figure it's a realy low Batt.) By some miracle I get it back to tera firma in one pc. and breath a sigh of relief. A few mins later all is working fine. Hummmmm
First I check the battery and it's got about 40% left in it, not what I expected. So I start thinking about the set up and I realize that I have the 4 Micros in the wing and the high torque on the elevator all running from the BEC on the speed controller. Do I need a separate BEC? If I overloaded the speed controllers BEC would it exhibit a full power on condition like I experienced? I think this is a heat related problem. I also realized that the speed controller was mounted directly next to the battery and I will move it elseware. The speed controller heat shrink was melted a bit but then running at almost 1000w non stop would do this.
Any help or suggestions would be greatly appreciated. This is my first high power, high end motor set up.

05-17-2006, 06:34 AM
Hi Frank

As a rule, which I stick to no matter what, I never use the BEC if my setup is going to draw more than 10 amps. I think you'll find that your servo's are drawing more than you think and it's affecting the effective supply to the Rx.

05-17-2006, 06:37 AM
Your experience is why Ive always flown with a seperate reciever battery, the extra weight helps you dive faster anyways and is way safer. My reciever is wrapped in alluminum foil also but the back part is open where the antennae comes out.

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Jason T
05-17-2006, 12:04 PM
In high performance models I use receiver packs. I also use a separate BEC in my 3D plane. I suggest the receiver pack especially if you are pulling more than 80 amps out of the CC80. It says it can handle 120 amps in bursts but I would not use its onboard BEC at that point.

BTW, that is great motor. I have the same one in my Zoom Race that I use on 16x17 RFM prop with a 16 cell pack of GP2200's.

05-17-2006, 11:02 PM
Thanks for the replys. I will run a seperate rc batt and hope this cures it, fingers crossed....................

Joe Ford
07-22-2006, 09:04 AM
Any news Frank? FWIW...you were definitely pushing the BEC, but that was not the cause I assure you. If the BEC were overloaded it would shut down in 1/20th of a second increments and appear identical to a radio glitch. You would lose all controls not just the throttle during that time. If the BEC were in a state of constant overload (usually from a stalled/stripped/failed servo) you would have met terra firma soon afterwards. Some things to check...make sure the esc is at least 3-4" away from the receiver, model passes range check w/motor on & antenna down @ around 25-30 paces, temperature of the motor/esc/battery pack are measured after a flight, and the antenna is not routed near any carbon fiber or metal. What receiver are you using by the way?