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-   -   Spark Ignition 2 stroke with glow fuel (http://www.rcuniverse.com/forum/glow-engines-114/8117070-spark-ignition-2-stroke-glow-fuel.html)

hornet dave 11-05-2008 06:43 AM

Spark Ignition 2 stroke with glow fuel
 
I've read another thread or two talking about the merits of spark ignition conversions on 4 stroke motors still using glow fuels. Some of the benefits claimed include easier handling, lower fuel use, a large savings on your car insurance, and I think it promotes world peace, too. I know there have been people using spark ignition on larger two stroke motors and still using glow fuels, I just want to hear about your experiences.

Ram Jet 11-05-2008 08:43 AM

RE: Spark Ignition 2 stroke with glow fuel
 
I don't have any experience with spark ignition on model engines but I think the ability to precisely control ingintion timing would be a benefit, (with added mechanical compication). Now if someone devises a self contained magneto ignition for my engines I wouldn't be able resist the temptation.

Bill

Campgems 11-05-2008 12:57 PM

RE: Spark Ignition 2 stroke with glow fuel
 
We have a guy at the field with a O.s 300FT that has a mechanical advance spark system using glow fuel. When it's running right, it is a good performing engine. However, the mechanical advance seems to need attention on a real regular basis. I would think that one of the electronic advance ignitions would be a better bet.

As for your converting a two stroke to ignition, if it is at least a 60 size, it whould work. Smaller than that, there is to much added weight to be effective.

I've been following an intersting thread about converting two stroke gassers to glow. Turns out to be a simple matter of putting in a glow plug adaptor replacing the spark plug and then mixing a blend of glow and gassoline. They say the mix is critical to it working right, but they claim all of the benefits you stated. It also solves the problem of raido interference from the ignition system. One kicker is that the carb has to be able to stand up to the nitro and alcohol as well as the gassoline.

Don

Patxipt 11-05-2008 02:47 PM

RE: Spark Ignition 2 stroke with glow fuel
 
I have converted two engines to run on spark burning regular glow fuel.
Smells nicer, the mixture doesn't need to be set as rich, don't kickback and start in two flips or so when primed.
There is some discussion regarding this subject on the Conversions forum.

DarZeelon 11-05-2008 03:56 PM

RE: Spark Ignition 2 stroke with glow fuel
 
The single most prominent reason to convert to spark ignition, is the cost of fuel...

Compared even to low-nitro fuel, gasoline is 1/7th of the cost per flight... With high nitro it can be as low as 1/10.


Using glow fuel after having converted an engine to spark ignition, is what I would put in the dictionary definition of 'sheer waste'...


I wouldn't even consider it...


gkamysz 11-05-2008 04:16 PM

RE: Spark Ignition 2 stroke with glow fuel
 
Gasoline was not significantly cheaper than methanol this summer when I checked. The consumption rate of gasoline is less than half that of methanol.

Reliability with spark ignition is enhanced. If you can source methanol locally, running oil and methanol is cheap. Methanol should be available at under 4USD per gallon, maybe even less now that gasoline is cheaper. The other alternative is E85 from
the gas station. I have run it in my glow to spark conversions. E85 is down to 2.35 local or less here.

This is an FS-52 I converted recently. www.dieselrc.com/project1.html


Strat2003 11-05-2008 05:07 PM

RE: Spark Ignition 2 stroke with glow fuel
 
As far as I know, all the SAM old timer ignition flyers run glow fuel in their engines although they were originally run on gasoline. They're limited to FAI type fuel (no nitro) but still believe they get more power from methanol.
Of course, they're using maybe 2 or 3 ounces per flight, compared to much more in a large sport flying sparker, so fuel cost isn't a big factor.

Campgems 11-05-2008 06:39 PM

RE: Spark Ignition 2 stroke with glow fuel
 
Dar, the cost of fuel aside, the low end of the glow engines don't take kindly to the gasoline mixes. Almost all gassers have needle bearings on the rod which lets them handle the lean oil mix. The glow engines with the bronze bushed rods really like the 5 to 1 to 6 to 1 ratio of fuel/oil Gassers like the 45-1 or leaner on the oill after break in. This is a good reason to stick with glow fuel. That and it gives better performance.

Don

hornet dave 11-06-2008 08:05 AM

RE: Spark Ignition 2 stroke with glow fuel
 
What I was thinking, among other things, is that when using a spark ignition, we are no longer subject to the whole interaction of glow plugs, compression ratios, nitro content, and port timing to determine the best ignition point. So, perhaps with spark ignition, we can run a higher compression ratio? Perhaps power can be a little higher, or lower nitro fuel used to make the same power?

Even if power remains unchanged, I would be willing to try an EI if it would help with flip-starting. Sometimes my OS 160 FX is a bit tricky to flip start, if the engine started in a more reliable fashion, I think I would enjoy the airplane more.

With the cost of an ignition unit now on par with about a season's worth of glow plugs, about the only downside to the experiment would be the additional weight of the ignition unit. Fuel cost isn't an issue for me, I don't fly glow airplanes much, maybe a case of fuel a year, so it's pretty insignificant. Compared to my helis, its really a drop in the bucket.

LouW 11-06-2008 02:24 PM

RE: Spark Ignition 2 stroke with glow fuel
 
1 Attachment(s)
When I bought my first model airplane engine (1948) they were all spark ignition since the glow plug had not been invented yet. We ran them mostly on gasoline mixed with 70 weight oil. There were some racing fuels available that were methanol based with castor oil. Some of these had a little nitro but it wasn’t necessary. When the Arden glow plug became available, the conversion consisted of taking out the spark plug, removing the ignition stuff from the plane and flying. Of course the alcohol ruined many nitrate dope paint jobs, but “fuel proofing” products appeared to fix that.

Many of the engines designed for spark ignition begun to break or quickly wear out using the glow plug ignition as it puts more load on engine parts. When engines designed for glow ignition appeared, they were significantly stronger (and heavier).

The spark ignition engines were gentler to start since the spark is retarded for starting. After starting, the timing was adjusted to conditions. This permitted the engine to turn a wider range of propeller sizes than most glow engines can handle. The down side was the added weight of the ignition stuff, and the fact that just as in automobiles, the old breaker point type ignition required constant maintenance and adjustment to function reliably.

The photo is that first engine, a Fleetwind 60.

Campgems 11-07-2008 12:15 AM

RE: Spark Ignition 2 stroke with glow fuel
 
When I was a kid, some how, I became the owner of an Olson & Rice 60. All I had was the engine and one day, the milk man saw me fumbling with it and told me he had an ignition coil and capacitor for it. He came over to the house one night and we made an awful stink in the house. We had it mounted on a 2x4 that we clamped to the kitchen table. We never got it running, but we sure smoked up the house. Later, I found a glow plug that would fit it and I got it running several times, outside now as I was banished from the house. Many split fingernails from the back fires. I don't know what ever happened to that engine, but three years back, when I got back into the hobby after about 40 years, I saw a new O&R on ebay. I'm looking at it on my desk now.

I can't believe my mom let us try to start that engine in the house. My wife and me included would have killed my son if he had tried that, and I know he would kill his son. Times have changed.

Don

bogbeagle 11-07-2008 12:35 PM

RE: Spark Ignition 2 stroke with glow fuel
 
Some of you may find what I am going to say to be controversial, but here goes.

I recently converted an Enya .60 Four Stroke to spark ignition, using methanol as the main fuel constituent.

When I compared its performance to that of the same engine/prop running as a glow engine, the spark ignition setup was considerably more reliable.

But, when I added an on-board glow driver, the story changed. In fact, I could support a 300rpm lower tickover when using the glow driver. Now, over the course of about 4 hours running (so, not a great deal, really) I could find no clear distinction between spark ignition and augmented glow ignition. This surprised me and definitely challenged my presumptions. In any case, I won't be trying to convert any more of my 4-stroke glow engines to spark ignition.

Of course, it may be a different story when petrol is used; I don't know. My Enya would not run satisfactorily on petrol as a stock engine. I think that it needed some adjustment to the compression ratio, or maybe to the carb.

captinjohn 11-08-2008 08:37 AM

RE: Spark Ignition 2 stroke with glow fuel
 

Quote:

ORIGINAL: Patxipt

I have converted two engines to run on spark burning regular glow fuel.
Smells nicer, the mixture doesn't need to be set as rich, don't kickback and start in two flips or so when primed.
There is some discussion regarding this subject on the Conversions forum.
Patxipt, I thing I am going to buy a SuperTiger 2300 and run glow fuel and CD ignition. I read somewhere it really works nice. Is there many RC flyer,s in Portugal? Best Regards Capt,n

captinjohn 11-08-2008 08:40 AM

RE: Spark Ignition 2 stroke with glow fuel
 

Quote:

ORIGINAL: DarZeelon

The single most prominent reason to convert to spark ignition, is the cost of fuel...

Compared even to low-nitro fuel, gasoline is 1/7th of the cost per flight... With high nitro it can be as low as 1/10.


Using glow fuel after having converted an engine to spark ignition, is what I would put in the dictionary definition of 'sheer waste'...


I wouldn't even consider it...


If you read more about using ignition on BIG glow engines like a SuperTiger...you may change your mind! Best Regards capt,n;)

Patxipt 11-08-2008 08:50 AM

RE: Spark Ignition 2 stroke with glow fuel
 
Captin, there are quite rc flyers in Portugal, but not many places to fly in. In our Capital, Lisbon, there are only 3 or 4 sites nearby, 2 of them in military airbases.
I don't fly for over a year, as I now mainly collect engines and run them once in a while. That's enough fun for me :D

captinjohn 11-08-2008 09:20 AM

RE: Spark Ignition 2 stroke with glow fuel
 
Francisco, I have many engines also. I sure would like to see a photo of the engines you collect over there. If you would, take a photo of them, and post or email them. Thanks John west Michigan, USA

Patxipt 11-08-2008 03:34 PM

RE: Spark Ignition 2 stroke with glow fuel
 
Will do [8D]

captinjohn 11-18-2008 10:52 AM

RE: Spark Ignition 2 stroke with glow fuel
 
I bet he forgot....I do he same thing....it si a sighn of getting older! Man, that is hard to admit! Capt,n

Patxipt 11-18-2008 11:53 AM

RE: Spark Ignition 2 stroke with glow fuel
 
Talking about the photos? I sent a PM to you over a week ago...[sm=50_50.gif]

Lou Crane 11-21-2008 07:53 PM

RE: Spark Ignition 2 stroke with glow fuel
 
I'll try again: timed out the other night...

The advantages of using glow fuel in 2-cycle spark engines?

More oil - the methanol-based fuels get less time/fl oz, and have a similar oil% fraction. More fuel through in the same time, more oil available to the engine.

Cooling - methanol chills nicely on vaporization, which helps keep at least the bottom end cooler.

Mixture settings - methanol can burn in a wider range of fuel/air ratios than gasoline, or for diesels, kerosene. This allows us to run richer, needing a more open needle setting. That makes the needle less sensitive and less fussy. I fly CL Precision Aerobatics, and the air loads in high-g maneuvers require a "richness reserve" to survive the accelerations and decelerations. Sparkers on gasoline-based fuels often starve to silence in these high-g events. As long as the prop turns, the sparks keep coming, so they -usually- resume noise when fuel can get back inside the engine as loads unload.

Castor is a great oil, and the abundance flushing through a sparker on glow fuel can only be a good thing. We are limited to authentic or valid replica engines from the height of the spark era. The precision fits that go with ABC-type engines are irrelevant. No modern conversions in Old Time Stunt (Spark).

Disadvantages of glow fuel for sparkers?

I miss that magical smell of petroleum oil and gasoline exhaust fumes.

And, Dar, I'll stand by this - I've seen it work to advantage. In principle, I mostly agree with you. For this specific use, I think it makes a lot of sense to burn low nitro glow fuel in a spark 2-cycle

The bigger consumption means we have to shoehorn a larger tank into a model designed about 60 years ago for a more economical gasoline-base sparker.


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