Author Topic: Converting Glow Engines to Gas  (Read 3987 times)

Craig

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Converting Glow Engines to Gas
« on: December 13, 2011, 01:20:37 PM »
Have any of you ever converted a glow engine to gas? Besides the obvious need for an ignition system, and maybe a different carburetor, what else is needed? I have an OS 90 four stroke that I would like to convert to gas if it is possible and a viable alternative.

WildManWillie

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Re: Converting Glow Engines to Gas
« Reply #1 on: December 13, 2011, 03:43:47 PM »
Running on Gas could cause overheating problems or at least higher running temps than Methanol but will need only 1/2 size fuel tank!
Note the shallow cooling fins on glow compared to gas weed eater type engines.
Flying C/L Rat race in the 70s we did not cool the engines with air we cooled them with fuel at the rate of about 6oz of fuel in 2 or so minutes.

Some where in the past I read about using just enough Methanol in gas/oil mix to keep a Glow plug lit. Sounded like a good idea if it worked out. Never did find out.

This would allow economy of gas at the weight of a glow.

If anyone knows anything on the Gas/Meth mix please post!
This is the hold up on getting the G.B. R-2 in the air at a reasonable wing loading.
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Craig

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Re: Converting Glow Engines to Gas
« Reply #2 on: December 13, 2011, 07:50:52 PM »
Thanks for the input, guys. I have read about the shortcomings you mentioned, both the connecting rod and additional engine temperatures. It seems some have reported good results while others have experienced less than favorable results. One thing that seems abundantly clear: If it were as simple as converting from glow to gas, O.S. would have already done that instead of going through the growing pains they are right now trying to engineer and produce a viable gas engine. Again, on reports via the web; since the guys testing these various conversions are not in a controlled environment where gas to oil ratios, air temperatures and other factors can be kept consistent, there is no way of knowing who or what to believe exactly. Unless the oil viscosity or oil mix ratios were out of spec, not really sure why a bushed connecting rod should be a big factor. After all, that's exactly (almost) what's in any automobile engine and certainly not needle bearings, so it's not clear to me why needle bearings would be a must. In the long run, it would probably be more reasonable to buy a known, reliable gas engine rather than convert. I guess it's the 'tinkerer' in me that makes think about things like this more than it is being 'reasonable'.

Craig

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Re: Converting Glow Engines to Gas
« Reply #3 on: December 13, 2011, 07:56:17 PM »
Oh yeah, the 'stink' is not a factor at all to me as I have a separate three car garage where I keep and work on all my gadgets. I have a tractor, lawn mowers, weed eaters and everything else in there, so the smell of a little gas model engine doesn't amount to a hill of beans. Also, am building a covered trailer right now to haul my models to the field, so that's not a factor, either.

WildManWillie

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Re: Converting Glow Engines to Gas
« Reply #4 on: December 13, 2011, 08:46:35 PM »
As temp rises Castor oil becomes.....Aw, read this..good info.
http://www.go-cl.se/castor.html

WMW  
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Craig

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Re: Converting Glow Engines to Gas
« Reply #5 on: December 13, 2011, 09:07:33 PM »
WMW

That was a good article. I remember when guys mixed castor oil with gas (or was it alcohol?) for powering the racing go-carts. Read the same thing you did, where some guy claims he mixes 1/2 methanol with 1/2 Coleman fuel along with his lubricant and runs on glow rather than spark. Getting the correct lubricant in the correct mix ratio is key to survival of any 2 stroke engine as far as I know. A guy would probably need to be real careful not to run the gas engines too lean or they would burn up for sure.

Chophop

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Re: Converting Glow Engines to Gas
« Reply #6 on: December 29, 2011, 05:01:39 PM »
There is a thread at RCG in which some people show their SUCESSFUL conversion of I think a .90 glow to gasoline in a .90 heli. And it does medium 3D. The key must be the CDI ignition. In the old days a big old magneto just wasn't practical on such a small engine.
Still sounds about the same but no smoke. I think it ruins the fun of flying heli's but the stream is sort of cool on a plane. And remember that sticky mess is a real hassle in the intricate structure of helicopters.
« Last Edit: December 29, 2011, 05:03:14 PM by Chophop »

Chophop

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Re: Converting Glow Engines to Gas
« Reply #7 on: December 29, 2011, 05:22:08 PM »
To anyone not yet banned, here's the thread :

http://www.rcgroups.com/forums/showthread.php?t=1476259&page=2

Craig

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Re: Converting Glow Engines to Gas
« Reply #8 on: December 29, 2011, 05:29:48 PM »
Cool...thanks for that. Have bookmarked the page for late night reading material.

When a user gets banned from RCG, the links to searched pages no longer come up? Didn't realize that.
The only forum I have been banned from (so far) is the Hobby King forum. They don't like criticism at all and will instantly ban someone who does so. No big loss there, as I don't plan to buy anything from them in the future anyway.

WildManWillie

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Re: Converting Glow Engines to Gas
« Reply #9 on: December 29, 2011, 06:38:10 PM »
Thanks Chop!
And yes the new ignition systems are lighter and should have built in and adjustable advance and retard.
The advance/retard makes big difference in operation.
>timing retarded for start/idle/ low RPM then advancing as RPM increases.
Reason is the mixture burns at the same rate/speed so needs to be lit sooner at higher RPM so that maximum cylinder pressure is achieved at the proper crank angle.

In our 2 stroke engines as RPM increases the supercharging effect of the bottom end to top end mixture transfer can raise compression(increase in VE) and that will tend to advance the ignition timing on glow engines.
Seems that Loop charge(By Pass/Deflector) would have more crashing flame fronts leading to detonation/pre ignition(not) Than Schnurle engines as these(Schnurle) should have less problem with contaminated and erratic mixtures in the chamber. This should allow Schnurle to run more compression and or ignition advance than non Schnurle engines.

Would like to find out more on the Gas/Meth mix using glow plug.
I think TreeHog did some work on this.?
WMW  
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crypto666

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Re: Converting Glow Engines to Gas
« Reply #10 on: December 29, 2011, 08:13:55 PM »
I was just talking about this today with a coworker, because we live in the middle of no where and glow fuel is expensive (shipping).

He mentioned the Davidson(?) Diesel conversions.  I vaguely remember seeing these, anyone remember?
I like the idea of diesel; no glow or spark, plentiful, more stable.  I want to be able to fly after 2012.

I have been running Speed Scents in my chainsaws just to see how they smell.  It isn't quite cinnamon smelling, but does smells nice.


Craig

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Re: Converting Glow Engines to Gas
« Reply #11 on: December 29, 2011, 08:18:58 PM »
I was just talking about this today with a coworker, because we live in the middle of no where and glow fuel is expensive (shipping).

He mentioned the Davidson(?) Diesel conversions.  I vaguely remember seeing these, anyone remember?
I like the idea of diesel; no glow or spark, plentiful, more stable.  I want to be able to fly after 2012.

I have been running Speed Scents in my chainsaws just to see how they smell.  It isn't quite cinnamon smelling, but does smells nice.

Doesn't the model diesel fuel require ether? These days, that may be harder to acquire than glow fuel.

crypto666

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Re: Converting Glow Engines to Gas
« Reply #12 on: December 30, 2011, 08:29:41 AM »
I don't know about the ether or what other additives might be needed, I have never messed with the diesels, but have always been interested in them.

But if the ether is just to get it started, starting fluid is pretty cheap. 

Craig

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Re: Converting Glow Engines to Gas
« Reply #13 on: December 30, 2011, 08:44:03 AM »
Here is a quote from "Fuel for Model Diesels - the Inside Story"
http://www3.bc.sympatico.ca/dieselcombat/diesel_fuel.htm

"Briefly, a model diesel fuel has four major ingredients:

1. Kerosene, which is the base fuel and is the major power-producing ingredient
(equivalent to the gasoline in your weed whacker);

2. Oil, which performs the lubrication and sealing functions;

3. Ether, which has the function of reducing the temperature necessary in the cylinder for ignition to occur and also acts as a solvent to keep all the components in solution; and

4. an ignition improver, which further lowers the ignition temperature requirements and also reduces lag time for ignition to commence when the right temperature is reached."

crypto666

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Re: Converting Glow Engines to Gas
« Reply #14 on: December 30, 2011, 09:57:01 AM »
Here is a quote from "Fuel for Model Diesels - the Inside Story"
http://www3.bc.sympatico.ca/dieselcombat/diesel_fuel.htm


Dang, that just destroyed my fantasy.  I had this image of refueling my plane by opening the filter drains on the one of the tractors.
It doesn't sound like diesel is a good option, and now I know why they aren't more popular.

Ok, back to converting to gas.