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HelicopterGasser Model RC HelicoptersOther › GV1, Stator Gator, Wierd throttle curve
10-24-2004 01:11 AM  13 years agoPost 1
DaveThomasPilot

rrNovice

Apex, NC

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My GV1 isn't working on my XCell gasser. I'm using a Stator Gator.

The GV1 worked fine on my Fury (using the Hall Effect sensor). I have a switch to turn it on/off. I can confirm the switch works in the StSw menu. I can also see the SwPt toggle from off to on when the throttle moves up.

I'm thinking the problem is my throttle curve. I have the arm geometry set up so that when the throttle servo arm is at a 90 degree angle (to the linkage), the angle between the carburetor arm and the linkage is also 90 degrees.

But I had to bring my throttle curve WAY down to avoid overspeeding. The SwPt does not toggle from off to on until I get around 3/4 stick throttle. That corresponds to 38% throttle (I thought it was supposed to kick in around 25%).

Pitch is +/-10 degrees with 0 pitch at mid stick.

Hovering RPM is around 1700 even though I've set the GV1 to 1400 so I could verify if it was regulating the RPM.

So I have a three questions:

1) Is there a way to set the throttle threshold at which the governor engages to a lower value (via a "hidden" menu or something like that)?

2) Is it normal to be at such low throttle at hover? Do I need to set up something non-linear for the throttle, so it takes a lot of servo travel to move the carburetor arm at little bit at the low throttle range?

3) Is there an easy way to test the Stator Gator
Thanks,

Dave Thomas

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10-24-2004 01:07 PM  13 years agoPost 2
DaveThomasPilot

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Apex, NC

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OK, Tom. I understand.

I'll try setting up mechanically for less throw so it requires over 100% TTA on the radio for full mechanical linkage travel. That way 25% of (max - min) pulse width will correspond to a lower throttle opening.

I was able to get closer to 25% by being more careful on the LMT setup. So this alone should help the problem somewhat.

Using less mechanical throw will slow the linkage movement. (Poor man's way to get a faster servo is to go farther out on the arm). But I'm using a cheap servo for my throttle--I don't think the delay in throttle servo movement will be signficant compared to the delay in spooling up/down the engine. So I'll give it a try.

Apparently some disagree--I see TJ now supports a high frame rate output.

I think I could get the SwPt threshold lower by using lower TTA during LMT setup. If the GV1 really uses 25% (max-min), a lower (max-min) during LMT should result in a lower SwPt. But maybe the GV1 also uses the pulse width range associated with min to max throttle to calculate a gain factor to achieve an optimum control loop. Lying to it about max and min pulse width settings might result in it using higher gain and could result in overshoot or hunting.

It would be nice to be able to set a lower SwPt threshold. Still interested in the details of the "Hidden Menu" options.


Thanks,

Dave Thomas

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10-24-2004 03:55 PM  13 years agoPost 3
llamatrails

rrApprentice

Gainesville GA - USA

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hidden menu information:

http://www.natew.com/rcheli/frames....ml.FutabaSecret

Use at your own risk, seek advise from your attorney, discuss with your financial advisor and tax counselor.

Rick

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10-24-2004 08:37 PM  13 years agoPost 4
DaveThomasPilot

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Apex, NC

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Thanks for the replies guys.

Fixed the governor problem by "lying" to GV1 during LMT set-up. I played with the transmitter's TTA to get the GV1 to kick in at the servo position that corresponded to 1/4 stick with the "real" TTA I wanted to use. After setting up the LMT, I went back to original throttle curve and travel adjust settting and everything worked fine.


I'm going to try the hidden menu thing too.

Dave Thomas

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10-25-2004 02:36 AM  13 years agoPost 5
DaveThomasPilot

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Apex, NC

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Tom,

The Stator Gator works fine. The only problem was the "hockey stick" throttle curve that I had setup for governor backup resulted in the governor requiring more throttle stick position than I prefer. I was able to lower the stick position at which the governor engaged by messing with throttle TTA during LMT setup.

Thanks,

Dave Thomas

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