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Electronic solutions to modifying glow engines of all sizes to gasoline

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Electronic solutions to modifying glow engines of all sizes to gasoline

Old 10-13-2022, 05:01 AM
  #1051  
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Originally Posted by BarracudaHockey
interesting. I always found the shaft on heli engines too short to get everything you need on there to mount a prop as they are made for screwing on a fan and prop bolt.
We will get a chance to see first hand.. The seller and I have agreed on a price and this one will be in the collection. I will compare to a "standard" .40 when it arrives.

Think I might try it first "as is" to see if one can make a "simple" gasser. Maybe will try with an "e-pump" also.. to see how that works stand alone.
Old 10-13-2022, 07:55 AM
  #1052  
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Originally Posted by 1967brutus
It still surprises me, because AA5BY over on RCGroups reported a Sig LT25 to fly very well with a Saito 30 on gas...

But it might also simply be me, having a different definition of "underpowered". As long as a trainer can take off from a lawn-quality grass runway, maintain a climb at a 20 degree angle or do a loop from level flight, I consider it adequately powered.

with the fs40 on gas, it did not have enough power to climb at more than about 5 degrees and if i tried to turn at more than about 10 degree bank it would lose altitude. it was way underpowered so i don't understand how aa5by could fly the same plane with a similar sized or smaller engine. i do recall he never actually posted video of his engines running on gas....

Last edited by Raleighcopter; 10-13-2022 at 08:00 AM.
Old 10-13-2022, 12:25 PM
  #1053  
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Originally Posted by Raleighcopter
with the fs40 on gas, it did not have enough power to climb at more than about 5 degrees and if i tried to turn at more than about 10 degree bank it would lose altitude. it was way underpowered so i don't understand how aa5by could fly the same plane with a similar sized or smaller engine. i do recall he never actually posted video of his engines running on gas....
I have no reason not to believe him. My Charter is actually fairly close in specs to the LT25, and flies pretty good with an ASP 30 (which I estimate to be less powerful than the Saito).
Personally, I am amazed that it was THAT bad (losing altitude at more than 10 degrees bank angle).
My Charter easily holds a 60 degree bank and I have no issue testing/demonstrating that at 5 ft altitude.
What propsize were you using?
Old 10-13-2022, 02:52 PM
  #1054  
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A member here and on RCG flies a Saito 30 powered LT25, on methanol and seems happy with it. He does like to fly on the wing however.

I've never had an OS 40 4S but have run the Saito 40 and can say, for its displacement, it's a dog engine. The Saito 30 is a little powerhouse and will come within a couple hundred rpm of the Saito 40 using the same props. The Saito 40 fell out of popularity rather quickly, of course.
Old 10-13-2022, 02:59 PM
  #1055  
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Originally Posted by BarracudaHockey
interesting. I always found the shaft on heli engines too short to get everything you need on there to mount a prop as they are made for screwing on a fan and prop bolt.
I remember for the ASP .36HR it was totally no problem: Propdriver fitted without issues and the threaded part of the shaft was long enough. Not overly long (I probably would not want to fit a spinner) but other than that zero problems. Not the nut hanging on on only a few turns or anything, easily full engagement.

Never tried the OS 37 though.
Old 10-18-2022, 05:13 AM
  #1056  
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Been a little quiet Here .... I have been busy and shop time is at a premium but I do have a good hardware and software solution figured for the E-pressure controller now I think - Just waiting for a few parts from digikey to show up to make a "production version".

Here is a video of a little test... the serial readout on the computer is the RPM reading from the ignition box and a reference number from my control loop - this test has a linear progression but curve progressions are included as an expo function.


Edit: I did tune the needle valve a bit into the test to get the pressure to +50 - that's why there is a variance a few seconds in...
Old 10-18-2022, 05:18 AM
  #1057  
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Neato. Share some drawings and code so we can see exactly what you're doing.

I've got some time off as I change employers so I can probably start working on code and a design to add to the xiao controller.
Old 10-18-2022, 08:13 AM
  #1058  
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Originally Posted by Cat 1
Been a little quiet Here ....
No worries! I have been busy, but not with engines, but with a transportation method for engines:

Click image for larger version

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But since that is wood and aliphatic, it's not for this thread...
Old 10-18-2022, 08:57 AM
  #1059  
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Yep, that's a bachelor's pad alright!

Ducted fan project? Something for your Wankel?
Old 10-18-2022, 09:07 AM
  #1060  
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Originally Posted by Glowgeek
Yep, that's a bachelor's pad alright!
It wasn't me... Some terrorist made a dirty bomb laced with balsa dust...

Originally Posted by Glowgeek
Ducted fan project? Something for your Wankel?
For the Wankel. It is based on the Graupner X1200 of the '70's and '80's, that was specifically designed for the Wankel.
Old 10-18-2022, 09:20 AM
  #1061  
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I see, the Wankel pusher prop config you mentioned earlier. Cool plane.




Last edited by Glowgeek; 10-18-2022 at 09:25 AM.
Old 10-18-2022, 07:55 PM
  #1062  
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Originally Posted by Raleighcopter
Neato. Share some drawings and code so we can see exactly what you're doing.

I've got some time off as I change employers so I can probably start working on code and a design to add to the xiao controller.
As soon as I have a few moments to spare to gather up the latest version I will do that Dave - Im sure this could use your Code and electronic skills - I only know enough to be "Moderately Dangerous"...

I did come up with a neat PCB making trick - Probably done a thousand times but I didn't see this online - just kind of thought it up... I have used cut vinyl masks for making small boards but cutting this vinyl with small traces is frustrating - This time I tried the laser and found it worked great. Etching the board right now in the kitchen sink ..(to keep it warm) don't tell my wife - Not a bachelor pad and if I get caught there will be S#*T to pay!!!





Old 10-18-2022, 08:03 PM
  #1063  
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Done and I didn't get caught!!!! a little clean up and should be usable...



Old 10-19-2022, 04:19 AM
  #1064  
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Originally Posted by Cat 1
don't tell my wife - Not a bachelor pad and if I get caught there will be S#*T to pay!!!
I just KNEW there HAD to be at least SOME positives about staying single...
Old 10-19-2022, 06:00 AM
  #1065  
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That's pretty slick, Chris. Now I need a laser head for my printer. Could have picked one up last week for $50 too. Maybe next trip to Baltimore.

Here's a hint for maximum stealth: don't use the good silverware to stir your copper sulfate etching solution or you will be found out. Don't ask how I know.

Post or email your pump code. I'm intrigued.
Old 10-20-2022, 05:08 AM
  #1066  
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Originally Posted by Raleighcopter
That's pretty slick, Chris. Now I need a laser head for my printer. Could have picked one up last week for $50 too. Maybe next trip to Baltimore.

Here's a hint for maximum stealth: don't use the good silverware to stir your copper sulfate etching solution or you will be found out. Don't ask how I know.

Post or email your pump code. I'm intrigued.

Thanks for the tip Dave!!! I have had a few non-stealth incidents in my past that have caused issues!!! .

Im not avoiding you on getting you the code its just i'm very bad at revision control and have to get out to the ship and sort through the laptop there to get the latest version - I have tons if little clips of code to test certain things but got to piece them all into the good file.. This weekend I should have time - my digikey parts showed up so I will hopeful be able to share a draft version of the board too if it works as planned.

Old 10-20-2022, 05:31 AM
  #1067  
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Excellent!
Old 10-23-2022, 02:04 PM
  #1068  
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So ... after a crazy week at work got a bit of shop time this weekend to finish up the Controller for the e-pressure setup that maps the ignition speed. I lack Dave's electronic skills so this is a bit of a triumph for me .

the controller is a simple Arduino mini with a PCB shield with the motor control Mosfet and a Optocoupler to allow for different Ignition and board voltages. Its powered by a single plug into the receiver that also brings in a spare channel for a prime function - This connection also powers the pump which runs on 5-6 volts and only draws about 100-150ma. another servo plug gets connected to the ignition tach output to sense the speed of the engine - The program has an expo function that curves the output to mimic exhaust pressure. Its adjustable as in the "predicted" max speed at which the pump output speed will be max.

Below is a demo of the system and a "live fire" run with a very quick 2 minute tune. My "jet size" is too big again - the opposite issue I was fighting before when had to restrict the exhaust to get enough pressure to help fuel feed - I have a 11mm proper (very fine) thread tap and die set now and will probably work on a less restrictive exhaust system now to allow better breathing.

The system works well up to 1.5 psi but I could only run 0.6 or I was too rich. as a test I switched from a 18-6 APC to a classic 16-8 MA and picked up about 7-800 rpm and it didn't need a mixture reset. I tried the leaf blower trick and could only get a few hundred RPM more but it seemed to handle it well... Now we have to "air test" it but I'm afraid our flying season is quickly ending up here.. It was cold today and trying to snow...

Dave has the "code" now and i'm thinking he might be able to cook up some better code and hardware.. and maybe integrate it into the mixture board.

https://www.youtube.com/watch?v=e_1L...ature=youtu.be

https://www.youtube.com/watch?v=vXyz...ature=youtu.be
Old 10-23-2022, 03:30 PM
  #1069  
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Looks good!
Old 10-23-2022, 04:40 PM
  #1070  
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Chris, what if the pump were programmable with a curve, like the solenoid, while tracking rpm? I wonder how it would run, without the fueling solenoid.

Last edited by Glowgeek; 10-23-2022 at 05:06 PM.
Old 10-23-2022, 05:01 PM
  #1071  
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My engines run good enough to fly most of my planes but there is some compromising wrt throttle stick speed. When I speed up the fuel channel I can advance the throttle quickly with good transition but when I advance the throttle more slowly the engine leans at the dip in the curve. Vice versa if I slow down the fuel channel. There seems to be no happy medium wrt to fuel channel speed unless I slow the throttle over 1.5 sec.

That's all well and good for my high wings and warbirds but is not quite good enough for my 3D birds where throttling must be quick and predictable.

Bert, have you found any advantage in running behaviour using the solenoid in tandem with a reground throttle barrel? Wouldn't mechanically eliminating most of the dip in the curve solve the issue?

Last edited by Glowgeek; 10-23-2022 at 05:08 PM.
Old 10-23-2022, 06:27 PM
  #1072  
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Originally Posted by Glowgeek
Chris, what if the pump were programmable with a curve, like the solenoid, while tracking rpm? I wonder how it would run, without the fueling solenoid.
Lonnie, first impressions of this system are that its very "powerful" in regards to changing the mixture of the engine - I think it might be effective at "curving" a mechanically adjusted (two needle) carb to allow for gas burning without the solenoid but this will have to be tested - one would probably have to "push" a little harder at idle and use the needle to lean it back out so as to have some headroom for leaning the midrange. I did get that OS 37 heli engine and I might try that on gas with no solenoid and no carb mod and simply play with tank pressure modulation. I didn't think it would work prior to today but todays testing showed just how adjustable the system is. now I have the hardware working it would be easy to re-code the control to just read a receiver signal and curve it like the solenoid.

Control on the pressure is very good albeit a bit slow - but with electronic control and mixing we can slow the throttle to wait for the pressure change. I think it might just be another element usable in certain systems. The engine does seem to run smoother using this pressure - I'm assuming its because the pressure is constant and not reliant on what the engine is doing.

I think we can really call it fuel injection now also as when you use the Prime function, Its capable of pushing lots of fuel in. My next plan is to jet back down and let the pump push more pressure to see how that works.
Old 10-23-2022, 11:39 PM
  #1073  
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Originally Posted by Glowgeek

Bert, have you found any advantage in running behaviour using the solenoid in tandem with a reground throttle barrel? Wouldn't mechanically eliminating most of the dip in the curve solve the issue?
Yes, there is that advantage. Simply because it is easier to finetune a fuel delivery that allready by itself is not too far off.. This is a piped ASP with ground throttle barrel.


I made this 2nd vid on request of a 3D flyer, I am not flying 3D, but the guy commented that it would be usable for that purpose.
Old 10-27-2022, 04:23 AM
  #1074  
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Default could this be usefull?

Found this while sorting trough things.
It once came with a batch of used items and always assumed it was related to the retracts system and never opened it.
Turns out its a fuel pressure regulator / return valve.

Would a system like this be usefull to regulate the pressure before the solenoid?

Construction appears to be a (silicone?) tube that moves to open the return path on a set pressure has exeeded.a pressure value.






Robart Auto mix instructions

Robart Auto mix side

Robart Auto mix top
Old 10-27-2022, 04:27 AM
  #1075  
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I finally loaded a spool of black ASA into my printer and had a go at it. Prints well but not as easy to print as PLA....




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