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DX8 throttle rpm adjusting help?????

Old 07-24-2013, 07:46 PM
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DoubleDD
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Default DX8 throttle rpm adjusting help?????

Have a DX8 setup controlling an 85cc Yak. My question is that the throttle travel adjustment is set up correctly but I would like to be able to adjust my rpm to be consistant with throttle stick position. My full throttle rpm now is at approx 6400 static but at half throttle on stick tachs at about 5000rpm. I thought sub trim would help me change this to get my half throttle stick position to about 3500-4000rpm but I can't seem to do this without sacrificing bottom end idle. Is it possible to adjust this setting radio wise instead of mechanically?
Old 07-24-2013, 07:59 PM
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BuschBarber
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Default RE: DX8 throttle rpm adjusting help?????


ORIGINAL: DoubleDD

Have a DX8 setup controlling an 85cc Yak. My question is that the throttle travel adjustment is set up correctly but I would like to be able to adjust my rpm to be consistant with throttle stick position. My full throttle rpm now is at approx 6400 static but at half throttle on stick tachs at about 5000rpm. I thought sub trim would help me change this to get my half throttle stick position to about 3500-4000rpm but I can't seem to do this without sacrificing bottom end idle. Is it possible to adjust this setting radio wise instead of mechanically?
What about Throttle Curve in the Mixing Menu?
Old 07-24-2013, 08:12 PM
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DoubleDD
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Default RE: DX8 throttle rpm adjusting help?????

I tried that by adjusting the 25%, 50% and 75% points but as soon as I changed one I would lose the high end. Confused me. The 100% setting I didn't change but yet the WOT dropped from 6400rpm to 5400rpm. 

Old 07-24-2013, 11:02 PM
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chuckk2
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Default RE: DX8 throttle rpm adjusting help?????

What I would do is figure out how to mark the actual engine throttle position for full throttle RPM, and the other desired RPM positions.
Then with the engine shut down, find out what servo position is needed.
Since I have a servo tester and digital readout, I'd check the actual servo control pulse and record it for each of the desired positions.
Then, using a bound receiver and the servo control pulse readout, Adjust the travel, centering, curve, and finally the positions needed for the desired RPM.
It's also possible to play with linearity between the servo and the throttle. This has to do with the position of the servo arm and the throttle arm.
Back in the before computerized transmitters days. linkage was a primary tool to try to obtain better behavior.

Propeller size can also play a part.
Old 07-25-2013, 04:24 AM
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AndyKunz
 
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Default RE: DX8 throttle rpm adjusting help?????

I'm pretty sure that we put RPM telemetry data on the throttle curve screen in heli mode, if that suggests anything to you.

Andy

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