Brinesharks

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I think I know the answer but is there any one who has run a small motor on true distillate (diesel) fuel? I know it's poor quality fuel and likely to ruin a model engine but I have a professional curiosity.

bogbeagle

I've tried running a mix of automotive diesel and model' diesel. I can't recall the proportions, now, unfortunately.

My engine did run, but poorly and with great clouds of smoke. in fact, it was so smoky that I very soon quit that experiment. However, that engine was of fixed compression; and fairly modest compression, at that.

I see that the auto-ignition point of ether is 170C, and that of paraffin is 210C.

Model diesel fuel comprises paraffin, oil and ether, in essence. You would need a higher CR to run without ether.

You've got me thinking.

Diesel Fan

I don't think that you can run a compression ignition engine on real diesel principles, the distillate is too heavy to fire without the properatomizationprovided by fuel injection and (as stated) the compression ratio would need to be around 22:1.

Its here that the ether content will emulsify the fuel oil mixture, provide a lower flash point (-40C) and an auto ignition point probably lower than 170C but I am of the impression that even theSaviourprovided by an ether content will not make heavy distillate a good fuel for our use. Distillate is too dirty a fuel if you just substitute the kerosene content, and by the way kero is just a refined distillate in its own right.

Cheers.

Brinesharks

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Thanks for the responses. I know distillate is not a good fuel - I was thinking of a non-modelling application where distillate is the only available fuel. There are a lot of issues with such a small diesel engine, but I thought I would see if anyone had had any success. Modellers are a pretty inventive lot!

qazimoto

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Australian auto pump diesel will run ok as a replacement for the kerocene in model diesel fuel. A friend and I tried it. You do need to drop the percentage of ignition improver a bit. It's a slightly down on power compared with higer quality kero but it's completely safe. Should be ok for sports flying where good kero's hard to get.

Motorboy

I has used diesel instead kerosene in diesel fuel, works well as standard diesel fuel for model engine. There are little to compare between diesel and kerosene, they are near each other in destilate, the kerosene are lighter destilated than diesel. The difference are the smell of diesel exhaust.

In theoretical the engine can run with pure diesel and oil as lube, but not tried. Here are the engine running without ether, the engine are running with pure kerosene, oil and MEKP:

[youtube]http://www.youtube.com/watch?v=wmH6WUMUEJg[/youtube]

earlwb

The problem with a model diesel engine and using a non-ether model diesel fuel is in being able to get it to start. As a model diesel engine gets smaller and smaller it is more and more difficult to get them to start with out ether in the fuel.

Now I was reading where several guys have started a model diesel engine on regular model diesel fuel with ether in it, and then they switched over to straight diesel and oil fuel after getting the engine heated up. But they tended to be more smoky and there was a noticeable power loss difference. But they would run though.

The big diesel engines commonly have a special glow plug used to help start them when cold.
Unfortunately we don't have that on the model diesel engines. Ether tends to be pretty handy in this respect. Heck all the Truck stops sell starting fluid with "ether" inside to help truckers start their big truck diesel engines too.

Kerosene wound up being popular to use with model diesel fuel as it has a slightly lower flash point than diesel fuel has. So along with ether it helped to make it easier to get the model diesel engines to start and run.

Now here is someone who used Vegetable oil mixed with some napha fuel (maybe Coleman fuel) in a Norvel .15 engine.
[youtube]http://www.youtube.com/watch?v=3g0ri5kiRkM[/youtube]

Mr Cox

That looks like AndyW, what he hasn't tried on engines is probably not worth trying...

Lou Crane

I have had success, on the bench only, so far, with automotive pump diesel as the kerosene fraction of the fuel blend. In the USA, I believe this is called #2 Diesel.

Don't know the situation in Oz, but for the ether fraction I've been using John Deere starting ether. Deere is a farm equipment outfit, at least around here. The ether in this product has been discussed in this forum several times, and the liquid in the spray can is almost 100% di-ethyl ether. The can also contains propane or butane dissolved into the ether, and possibly a trace of anti-rust and some inert propellant.

For oil, I use AA Castor. USA model manufacturer SIG sells this directly or through hobby shops. Again, no idea of the relevance to conditions in Australia. I've heard that there are still Castrol products of equal composition...

AMSOIL, another USA fuel products mfr, sells a Cetane booster that works very well.

The #2 diesel fuels I've blended start at least as easily as blends I've made from other materials, and comparable to commercially available diesel fuels. The exhaust is cleaner than with blends from other kerosene sources. Control adjustments seem at least as sure. I haven't tached "kerosene" and #2 fuels side-by-side on the same day and prop, but RPM on the #2 based fuels was quite respectable.

NOTE: Most truck starting ether spray products (in the USA, anyway) consist mostly of a less suitable liquid, such as n-Heptane. Fuels blended with these products generally require higher comp settings, are more difficult to start, do not adjust as surely, and run both hotter and rougher. Settings seem to drift worse over the course of a several minute flight, too.

NOTE 2: Extracting the ether from a John Deere-type spray can seems easiest if you substitute the original tip with a spray tip with a thin straw extension, as with WD-40 spray cans (again, a USA exclusive?). A "catch-jar" - glass, with a metal screw-on lid, large enough to hold the ether from more than one can of JD, is used this way:

-Punch a hole in the lid, slightly larger than the straw.

Pass the straw through the hole, to the interior of the jar.

Spray the contents into the jar. The dissolved butane or propane gasses off, venting around the straw. The liquid ether is captured. When there is apparently no more liquid to spray out, change lids on the jar for one that is NOT punched through. (If you punch a few holes around the top of the JD spray can, you can pour the remaining few cc of ether into the catch jar.)

This is much neater, simpler and safer than many other methods that have been used, and appears to "catch" a greater amount of the ether, as well. Not my original idea, and I thank the guy who posted it here! Of course, work outdoors, away from flame and direct sunlight (ether will evaporate rapidly, given any opportunity.) Mix the fuel soon after gathering the liquid ether and seal the (preferably metal) fuel can well as soon as possible.

Most of this is not news to many in this topic, but may help others who haven't 'been-there-done-that' yet.

Brinesharks

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Thanks for all the information - greatly appreciated! The application I'm thinking of is for agricultural use and the end users are insisting it run on diesel at it's readily available. We have tried an electronic injection controller and have tried spark, glow and compression ignition. I think the glow has been the most successful. Making the start less manual is a real challenge!

qazimoto

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What about electric with a cheap IC powered charging system?