1967brutus

Continuation of the discussion about electronically solving carburation issues when converting glow engines to gasoline over on :censored:
Any and all questions can be placed here, and links to the files will be posted here within a few days.
We hope we can continue the discussion here without the interference we experienced over in :censored:

For now although the Github Wiki is still down, at least a preliminary link to the data and base information
GitHub - raleighcopter/my-mixture-controller: RC engine Fuel Mixture Controller
in :censored

Cat 1

My Feedback: (1)

So glad you have found a solution to keep this going. I felt lost this morning not having this “outlet”.

I get us started again with a bit of progress. This is a prototype to confirm measurements and design. Will be fairly easy to make when I sort it all out.

cmulder

Good to see it continue at a forum i want to reply to.

Raleighcopter

welcome, everyone. i will get the github wiki up in time. i've posted the source code and all the files that were on the github but the wiki is being more difficult and i'll probably need to rewrite the wiki pages. it'll probably take some time but i'll eventually get it back up. let's hope the trolls don't show up here.

Glowgeek

Thank God, I was having withdrawals.

Lonnie

Glowgeek

Chris, the regulator housing looks very nice. Will you be making them available to others?

Also, where will it be located In the fuel line? If the regulator is located before the solenoid I suspect that it will not sense fuel demand exactly as designed; If placed after the solenoid it seems it would then damp the solenoid pulses, losing the increased vaporization inherent to pulsed fuel delivery. Just my thoughts, and not very well educated ones at that.

Raleighcopter

In the Stihl carb, which has a pump, the pump is before the solenoid.

cmulder

On that regulator mount a tiny magnet on the lever and then measure its movements with a hall sensor.
Then you can open the solenoid synchronized with the fuel demand of the engine.

Would that work and help?

Cat 1

My Feedback: (1)

And the regulator is “pre solenoid” too.

If it works out I probably can supply these as they are fairly straightforward and with a little specialized tooling can be produced quite easily.

Glowgeek

My thoughts as well. In an M-tronics carb the pump and the regulator precede the solenoid. The solenoid replaces the HS and LS needles and the solenoid and regulator are as close as can be to one another. In the case of a glow carb there's no way to get the two that cloise together. Partly what prompted my question.

1967brutus

The regulator is as well: the solenoid is where the needles are in a conventional Walbro-type.

So I'd expect the regulator to not disturb things when placed in line before the solenoid. Whether it will work properly, IDK, but I have the feeling, Chris is going to surprise us with a "muffler pressure biased" regulator...

Guys, happy to see y'all here.

EDIT: dang, you guys are fast: I answered to Dave's reglator remark when I saw it and meanwhile three of you said the same. Not used to that over here... Normally it takes three weeks to get three additional responses here

1967brutus

I don't think you can "sync" the solenoid with the regulator movement, because when the solenoid is closed, the regulator won't move.

But it MIGHT be usable (provided accuracy of the hall sensor allows it) to derive some sort of flow measurement out of that signal which either could be used for R&D, or possibly as a cascade control for fuel feed. I'd have to think about that.
But as it is, I'd say that cascade control simply is way too complicated.for our purpose.

cmulder

So its not that the regulator is opened and closed by the crankcase pressue.
And then if the regulator is open it passes the fuel while solenoid is closed, the solenoid will "see" the fuel tank pressure and block that so no fuel is passed to the carburator.
Close or do i overlook something?

Raleighcopter

Or that fuel tank level telemetry you've been wanting.

1967brutus

That is the YS regulator system... what Chris is building and what Walbro and Stihl use, works differently. Those regultors do not sense crankcase pressure but basically atmospheric pressure, and they keep thepressure in the fuel line at a fixed offset from atmospheric. As soon as the engine starts consuming, the regulator opens to maintain that set pressure.

1967brutus

Oh dang, now why did I never think of that....

Going to be a fair bit of fabricating, but absolutely possible...

cmulder

This is supposed to measure what went out of a tank
https://www.jetimodel.com/katalog/mflow2-gas-800-1.htm

And this might be able to measure the tank pressure
https://www.jetimodel.com/katalog/mb...scription-info

likely vrry expensive though..

Raleighcopter

Those aren't useful at the flowrates of our engines. They're for turbine engines.

cmulder

frsky has this gas telemtry hub
https://www.frsky-rc.com/product/gas-suite/
https://www.t9hobbysport.com/frsky-g...rt-port-sensor £76 and shipping, import ect..

Raleighcopter

Same problem. There just aren't inexpensive sensors that measure flows that low.

1967brutus

Yup... a clubmate of mine had one, it did not even SEE the fuel consumption of a DLE 35 cc 2-stroke.... At full throttle it appeared to measure "something" but at anyother throttle setting the figures just jumped up and down.

As Dave said, it is for turbines or really large engines...It only works if minimum fuel consumption is above 20 ml/min. That means, at idle the engine should consume that in order to produce usable readout. My largest engine ( the 65 cc radial) barely manages that at full throttle...

cmulder

This is the buton (norvell) style glow plug adaptor but it does look promising.
The controll unit / and cdi / battery will be way to heavy to fly but be among the smallest ignition engines "out there"

anyway back to the original subject

1967brutus

That really is not too far fetched... I am working on a 1/2A project on gas, using an OS FP 10. Ignition weighs 40 grammes (Runtronic) and the single battery set-up will consist of a 2S 400 mAh LiPo. Won't provide much operational time, but I expect somewhere in the neighbourhood of 30 minutes.


Now for that Cox engine, I am not really sure if the ball and socket would hold out on my standard 10:1 fuel/oil mix, but other than that, I am 100% positive that with a Runtronic ignition I can build something flyable, RC, with that engine. Not even really going to be a challenge. Won't be an exiting hotrodder, just a nice sport plane, but still, 100% sure it WILL fly as long as the engine doesn't wear out
But it will need something different than just a Norvel style glow plug adapter because the spark plug will really mess up the shape of the combustion chamber big time and that will kill a lot of power. Would not be surprised if that would need a custom made sparkplug,

The FP10 however, as you can see, runs fairly well, and that is still without the solenoid.

cmulder

Am using 20% castor in my glow fuel would 20% castor also work wit petrol?
Standard compression of a cox is fairly high so a bigger space above the piston might not be such a huge disadvantage, assuming petrol needs a lower compression. 30 min flying time on that wing would be greath

Glowgeek

Any engine that can run 30% nitro without detonation problems, eg cox engines, are suitable for CDI/Gas conversion imo. Most cox engines have a CR of less than 8:1, some as high as 9:1.

Yes, castor oil can be mixed with gas. Back in the day that's primarily what 2 stroke oil was.