Anybody flying diesel?

Hello!

Back in the 60s I had a Super Tigre .15 diesel for CL racing. In fact still have it. We ran 7x6 props and they stung pretty good when the kicked back. We couldn't stay with the glow guys but we could complet the entire 100 laps with no pit stops. It was a blast.

Well I was recently given an OS .45 FSR with a Davis Diesel head an although I have the head to convert back to glow I'm contemplatin running it as a diesel. Why? Who knows? It's a challenge I guess. have a couple of questions:

1. What is the formula for diesel fuel?

1. Where/what is the best source for the ingrediants?

2. Specifically, what do I ask for at the John Deer tractor store?

Also, my son works at a truck repair service. could they help wit securing the right stuff?

Thank

-- flyboyanderso

----------------------------------------------------------------------- flyboyanderson's Profile:

this thread:

View this thread:

Diesel fuel mixture depends on the type of bearings you have. It is approximately equal parts castor, kerosene, and ether, with approximately

2-3 % Amyl Nitrate added for smoothness. With twin ball bearings you can lower the oil content to 22% and add kerosene. Your best bet is to buy it ready mixed from FHS Supply, inc., (if you want a 4 gallon price break), or from Eric Clutton (Try calling PAW Diesels - (931) 455-2256 - Ask for Eric Clutton) if you want it one gallon at a time. Diesel fuel runs 2 to 3 times as long as glow in the same size engine.

IIRC, which seldom happens these days, I was under the impression that he was using a Davis conversion head. Will converted engines run well on a standard diesel mix? Too much oil and not enough ether, I would think...

Ed Cregger

think...

--------------------------------------------------------------- You are right Ed, he was talking about a Davis conversion head. I owned one at one time and bought the Davis fuel in concentrated form. It came in a gallon can and you added a gallon of kerosene or lamp oil to make two gallons. That proves that there was at least 50% kerosene in the final mix. The oil/ether ratio I wouldn't know. I had trouble with the narrow range of compression that the engine was comfortable running at. So, I added a servo and a gadget to adjust the compression while in the air as the engine temperature changed with speed and load. The conversion was just good enough to make me want a diesel that was designed to be just that. I have two now, and they are very forgiving of my preflight setup. I buy my fuel ready mixed from FHS Supply, Inc.or from Eric Clutton.

think...

I was aware that he was running a Davis conversion, but have no experience of these - I have always been able to get "proper" diesels.

However, I can't see any reason why the conversions wouldn't run on standard fuel.

Ether provides the means of ignition and does little towards the power output. The kerosene is the major power source - that's why I preferred the

2:2:1 mix rather than the 1:1:1 even though both will work. The oil aids cooling and piston seal and thus the compression needed to generate ignition. Many years ago, there was a C/L team race "expert" who used as little as 7% oil in his fuel and made up the difference with kerosene for the extra power and duration. His engines might not have lasted more than a season of competition but he often won races.

I believe that Davis conversions have a diaphragm rather than a contra piston. Does that give them a lower compression range than engines designed as diesels with contra pistons? In both, I undestand that adjustment is via a compression screw or vernier as it is sometimes termed.

Malcolm

"Malcolm Fisher" wrote

I only have a few proper Diesels. They got hard to get for a while in the US. Plus there was always a super premium price for the diesels. For someone just wanting to experiment with a diesel, the DDD conversions were the cheapest way to go.

They very well might. I've never tried it. I was just repeating what I have "heard" over the years. No empirical data to back up my suggestion.

I would think that the Davis conversions provide less compression. That would seem logical. But I have never attempted to measure the compression.

I wasn't shooting down your suggestion. In fact, it was nice of you to mention it. I forgot the formula for basic diesel fuel, otherwise I would have posted it myself.

Ed Cregger

I always was interested in trying one but the problem from my standpoint was how to get ether, the critical fuel component. They always looked like fun. -Paul

What about using starting fluid for cars and trucks to obtain the ether?

Ed Cregger

Snip> >>

That would be a possible source, but there is the problem of extracting the ether from the aerosol can without losing most of it by evaporation - if you use the "spray button" on the can, most will disappear into the "ether" :-)))

Perhaps the can could be cooled in a freezer for some time then let out the propellant by making a small puncture - yes I know that all aerosols warn aginst puncturing them.

The best source would be a pharmacist or laboratory chemical supplier - when I worked in a metallurgical laboratory, we used gallons of the stuff for drying out standard volume glass flasks to avoid compromising the standard volume by using a heat source, and yes, I did help myself to a little from time to time when I had to wait for a fresh supply from my local pharmacy.

Malcolm

----------------------------------------------------- In Eric Clutton's diesel book he says you turn the auto starter fluid can upside down and release all of the propellant, then punch two holes in the base, opposite each other and pour off the ether. It will be in a chilled state.

Eric says that a

----------------------------------------------------- In Eric Clutton's diesel book he says you turn the auto starter fluid can upside down and release all of the propellant, then punch two holes in the base, opposite each other and pour off the ether. It will be in a chilled state.

Eric says that about 2/3 of the contents of the auto starter fluid can is ether. It has been said that the John Deere brand starter fluid cans are about 80% ether.

On the topic of Davis Diesel's heads, they have a piston in the head that is screwed in and out by a socket (allen) head screw that protrudes from the top of the head. The travel is limited. I think you should use his fuel to assure the right compression range is obtained.

Brian

Why didn't I think of that...

I'm sure you're right - as said earlier, I have no experience of conversions.

Malcolm