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Transmitter not sending full throttle

Old 06-12-2007, 12:19 AM
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Default Transmitter not sending full throttle

I was wondering if anyone was familiar with the situation where the transmitter's full throttle setting is not full throttle for the motor. For example, I push the throttle stick all the way up, but the motor only spins at 80% of full speed.

The reason I am posting is that my new brushless motor is giving about half the thrust it should, so I'm thinking maybe the transmitter is not sending true full throttle to the ESC/motor.

Is it guaranteed that if you listen to the motor at full throttle with trim all the way down, and then increase the trim, and you don't hear a difference in motor RPMs, it means your transmitters full throttle is motor full throttle? In other words, if changing trim at full throttle does not change motor RPM, does that mean the transmitter is definitely sending full throttle?

On my new brushless motor (2408-21T), I hear no difference between trim down and trim up full throttle, but on an old brushed 380, I do hear a difference. In fact, the stock transmitter that came with the RTF kit with the 380 (SDM Cub) causes the motor to give higher RPMs than my other transmitter (E-Sky Lama), even though they give the same max RPMs for the aforementioned brushless motor.

Do some ESCs come with a programming option to set true full throttle? Why would the brushed ESC give difference performances between transmitters but the brushless ESC exhibit no difference? Any help would be greatly appreciated.
Old 06-14-2007, 01:16 PM
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Default RE: Transmitter not sending full throttle

This most likely has to do with the ESC. The ESC might be set to auto calibrationg. This means that it will sense the high and low after powering up. You have to first arm it at low than give it full htrottle to establish high. You may have to do this each time.
If you think it is not getting full power, then move throttle to full power and increase the throttle trim. If you hear an increase in RPM then you will need to increase the overall throw of the throttle channle done in the transmitter.
These are only general guidelines, it would be helpful to know what the ESC is and what they suggest for programming
Old 06-14-2007, 02:29 PM
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Default RE: Transmitter not sending full throttle

Thanks for the advice. It's a TowerPro Mag 8 18A brushless ESC ( http://www.oz********.com/2007/04/to...ogramming.html ). I can set timing mode, low voltage cutoff, braking, and battery type. I've messed with timing and braking but they don't seem to change the max throttle. The RPMs do not increase when I increase the trim at full throttle.

I'm not sure what you mean when you say to increase the throttle to full after arming, because that's what I am doing currently. I connect the battery, the motor is armed, and I immediately check out full throttle. Do you mean go from zero to full throttle before the motor is armed?

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