Inflight adjustable needle valve ("the perfect needle")

Electronic projects that are either related to the firmwares for the 9x, or simply great for radio control applications.
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gsjames
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Inflight adjustable needle valve ("the perfect needle")

Post by gsjames » Fri Jan 05, 2018 4:21 pm

There is a need in fuel powered, RC pylon racing (events 424, 426, 422) for an in-flight automatically adjusting needle valve. Such a device would most likely read RPM (probably with a Hall effect sensor) and EGT (a thermistor?) and make MINOR adjustments to the mixture to achieve max RPM, without going over lean by using a servo to drive a needle valve like the OS 71703009 or this combo unit: http://www.worldchampionproducts.com/en/93-vs99002.html.

The racing rules prohibit the use of an in-flight adjustable needle IF the adjustment is made from the ground, BUT if an Arduino Nano or similar were to be in the airplane, and do the measurements, calculations and drive the servo, it would be legal.

Has anyone attempted this project? If not, is there anyone out there that might be interested? I don't have the coding skill to be able to do it.

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jhsa
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Re: Inflight adjustable needle valve ("the perfect needle")

Post by jhsa » Fri Jan 05, 2018 4:42 pm

I would like one I could adjust from the ground :) Not for racing obviously..
If automatic it would have to adjust on all throttle range, not only at full RPM..
Did you try searching online for such a project? Perhaps we could ask nicely if this could be implemented on the oXs (OpenXsensor). :)
You can search for it here on this forum.

João
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Kilrah
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Re: Inflight adjustable needle valve ("the perfect needle")

Post by Kilrah » Fri Jan 05, 2018 7:06 pm

jhsa wrote:
Fri Jan 05, 2018 4:42 pm
If automatic it would have to adjust on all throttle range, not only at full RPM..
I think these guys know nothing but full throttle ;)
gsjames wrote:
Fri Jan 05, 2018 4:21 pm
The racing rules prohibit the use of an in-flight adjustable needle IF the adjustment is made from the ground, BUT if an Arduino Nano or similar were to be in the airplane, and do the measurements, calculations and drive the servo, it would be legal.
This rule sounds too weird not to think it was written at a time where nobody would even have thought autonomous adjustment onboard would be possible at all, but once it is it would be revised stat to exclude that too...

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jhsa
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Re: Inflight adjustable needle valve ("the perfect needle")

Post by jhsa » Fri Jan 05, 2018 7:35 pm

Yeah, the reason I would like this would be for normal glow model flying, not competition.
The problem is that as the tank gets emptier, the needle valve setting moves away from the optimum point. The engine tends to lean. with on board adjustment we could adjust it and make sure that the engine doesn't stop, and also lasts longer..

João
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