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RimFire VPP setup for a JR 9303

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Old 05-19-2006, 07:59 AM
  #1
Mike Parsons
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Default RimFire VPP setup for a JR 9303

Hey Spec,
I am using a JR 9303. Lets start this in a new thread. Keep in mind that as of the time of this post it hasnt been tested in flight yet.

I can post the screen shots I am using in the article and a snippet from the text. Let me know if this helps and we can go from there.

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I started off by selecting a Model in my JR 9303 and choosing the Heli mode. This enabled the mixing charts you see above. In the JR Radio, they are Pitch Curve and Throttle Curve. All other mixes are turned off. I setup my mixes as the above chart references for Gov Mode. Everything seemed to be working correctly, but at the extremes of throttle on both normal and Idle, the system was getting hot and I had nearly no thrust. I began scratching my head as all of my mixes were set up exactly as the above charts depicted. I took my Wattmeter and took readings. I was pulling 23 amps at full throttle range. Something was definately wrong.

I then read between the lines. This is just a starting point and the mixing will need to be fine tuned. My throttle seemed to be perfect, but it was the pitch that was out of line. Basically I had max pitch mixed in so they blades were becoming paddles giving more than 50% pitch. I really only needed about 30% pitch. So I started by decreasing my pitch until the amps came into line. I found that I went from -100% and +100% to more like -25% and +60%. This kept the pitch to a postive or negative 30% at the high end and low end of the throttle. Amps came into line at about 11.5-12 amps at either range and gave an input of about 113 watts. This is right around what I had with a standard Fixed Pitch system.

Normal and Idle up are programmed to a Switch. I have mine on my Flight Mode Switch. Flight Mode Norm or zero contains my Normal flight mixing. This simulates a fixed pitch system. Flipping the switch down to Flight Mode 2 enables the VPP mixing. Center stick has no pitch, up has positive pitch (forward flight) and down has negative pitch (backwards flight). Something to get used to is transitioning from normal flight to VPP flight. If you are in normal flight and down on the throttle and flip to Flight Mode 2, guess what is going to happen? Yep..negative pitch and your going backwards. It is best to transition from Normal Flight to VPP while at about 3/4 throttle from what I have found. In fine tuning the mixing, right around 3/4 throttle seems to be pretty even matched in Normal mode and VPP mode. This makes for a smooth transition.
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Old 05-19-2006, 08:00 AM
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Default RE: RimFire VPP setup for a JR 9303

Throttle Pitch Norm as you can see spans the full range from 0% to 100%. This is a linear throttle that is the same as a Fixed Pitch setup. The Pitch Curve Norm is set at 60% and is a flat line. This gives about 30% total prop pitch and is constant no matter where the throttle is.
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Old 05-19-2006, 08:01 AM
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Default RE: RimFire VPP setup for a JR 9303

Throttle Curve Flight Mode 1 gives a different view however. It looks like a large V. As the stick is at the bottom, it is turning the motor at 100% throttle. As the stick moves toward center, the throttle is cut to 10% and as it moves towards the top end, it goes back to 100% again. The motor never stops turning although it is changing RPM from center stick to either full up or full down.

Pitch Curve FM 1 shows that the pitch has been toned down a bit from the chart above. The max pitch on positive throttle is the same as our Norm setting which is 60%. On negative throttle I have about 25.5% to keep the blades from over pitching. Both ends produce about 12 amps and 113 watts.

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Old 05-19-2006, 09:11 AM
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Default RE: RimFire VPP setup for a JR 9303

thanks i will read all when i get off work and will get back with you Im sure you have posted most of what i need to get me in the ballpark thanks so much its been hard on my mind so for ... spec
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