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Old Dec 09, 2012, 04:16 PM
FPV Noob KD0VMK
United States, MO, Platte City
Joined Jun 2012
438 Posts
Question
No power increase above 80%?

During a rebuild of my HK450 rotor head (well, the whole helicopter really), I spun up the motor with only the mainshaft in place (no rotor head, swash, blades, flybar, anything else...just the mast and the tail rotor).

I noticed that I hit max RPM (as determined by my ear), at around 80% stick. Increasing the throttle further produced no increase in power. For the sake of this experiment, the throttle curve was completely linear....0%-50%-100%.

Motor is a Turnigy 2223 3500kv, HK 50-65A ESC, Nanotech 25C 2200 battery. I think I have plenty of power to turn the motor, especially with an unloaded rotor head.

Is there anything that would cause the motor to top out early? ESC timing? PWM setting? Maybe it's hitting a governor somehow that I don't know about?

Even at 80% throttle, it still has plenty of power...but I could always use more!
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Old Dec 09, 2012, 05:36 PM
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Joined Dec 2007
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Quote:
Originally Posted by Chubbs View Post
During a rebuild of my HK450 rotor head (well, the whole helicopter really), I spun up the motor with only the mainshaft in place (no rotor head, swash, blades, flybar, anything else...just the mast and the tail rotor).

I noticed that I hit max RPM (as determined by my ear), at around 80% stick. Increasing the throttle further produced no increase in power. For the sake of this experiment, the throttle curve was completely linear....0%-50%-100%.

Motor is a Turnigy 2223 3500kv, HK 50-65A ESC, Nanotech 25C 2200 battery. I think I have plenty of power to turn the motor, especially with an unloaded rotor head.

Is there anything that would cause the motor to top out early? ESC timing? PWM setting? Maybe it's hitting a governor somehow that I don't know about?

Even at 80% throttle, it still has plenty of power...but I could always use more!
It sounds like you have not calibrated your ESC to your TXs low and high throttle positions, or you calibrated with your throttle trim at full low and the scaling isn't accurate.
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Old Dec 09, 2012, 07:14 PM
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Also check that your throttle endpoints are at 100% in both directions if you have a non calibrating esc.
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Old Dec 09, 2012, 10:12 PM
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United States, VA, Fluvanna
Joined Jan 2011
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Originally Posted by Xrayted View Post
It sounds like you have not calibrated your ESC to your TXs low and high throttle positions, or you calibrated with your throttle trim at full low and the scaling isn't accurate.
+1
Recalibrate and you should hear the difference.
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Old Dec 10, 2012, 06:31 AM
FPV Noob KD0VMK
United States, MO, Platte City
Joined Jun 2012
438 Posts
The ESC allows for 2 throttle ranges: "auto", and 1.1ms to 1.8ms. The default is auto. I guess I should try the other one, even though I don't know what it does.

What's the general procedure for setting the auto range? Nothing is mentioned in the manual. programming mode is entered by going to full throttle before turning the ESC on, and the mode is exited by going to minimum throttle. I guess I thought that's what did it.
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Old Dec 10, 2012, 08:49 AM
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Quote:
Originally Posted by Chubbs View Post
The ESC allows for 2 throttle ranges: "auto", and 1.1ms to 1.8ms. The default is auto. I guess I should try the other one, even though I don't know what it does.

What's the general procedure for setting the auto range? Nothing is mentioned in the manual. programming mode is entered by going to full throttle before turning the ESC on, and the mode is exited by going to minimum throttle. I guess I thought that's what did it.
Check your throttle curve and make sure its set linear 0,25,50,75,100. Make sure you have the same one for any switch position you are in. It's easy to forget that throttle hold has its own TC and many times we make adjustments with TH on not realizing we are using its values and not the flight mode values we think we are. Make sure your throttle end points are all set to 100% both directions.

Make sure your throttle trim is at center and not full low, as this will have an effect on your curve and what the ESC sees as 0-100%. Make sure you don't have any of the "hover throttle" or similar switches for nitro setup activated, or these can also jack up your curve.

Verify that you are getting full 0-100% by using the "monitor" function on your TX so you can physically see what is happening with stick movement. You might be surprised to see that your throttle isn't going to 100% on the monitor even though the stick is at high. This indicates something going on with the curve settings in the TX listed above and not your ESC.

If all checks out, then follow the instructions for calibrating your particular ESC. Typically this is done by powering up with the throttle at full high and then following the prompts to set high and low stick positions, but this depends on your particular ESC.
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Old Dec 10, 2012, 01:14 PM
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I'd also check the transmitter stuff like subtrim and endpoints.
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Old Dec 10, 2012, 02:33 PM
just gotta mess with it!
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North West Louisiana
Joined Nov 2009
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Deadband

Some Align ESC's reach 100% at 90% throttle - in effect, the last 10% is "deadband". It's possible that other ESC's have a similar feature, but you need to make sure to calibrate the throttle anyway. There are phone apps you can use to check the motor rpm, if you don't have a tacho.
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