More food for thought from the January 1986 Aeromodeller magazine (and no, I don't who Lou is)

Diesel Fuel Without Ether

... from an article in the Jan 86 Aeromodeller magazine titled :
“ETHER...OR”

Sub-Headline: Robert Dulake poses some very interesting questions on what
should go in our fuel tanks...

-----------------------------------------------------

Necessity can be the mother of invention. So can bad planning, to wit
the evening when I was caught ready to fly with no [diesel] fuel, save
only a few drops left from the previous Sunday. My ether ration,on order
from the model shop,so far hadn't arrived,so I tried the local chemist
He had a sense of humor, ether at 8.00 Pounds per litre...[$12 per
quart].. no chance, I'm afraid, of making a sale. So what to do? Thinking
back I recalled some bench-bound experiments of the previous winter when,
priming with ordinary fuel, I had managed to make a variety of diesels
pick up and run from cold on a paraffin/oil blend. No startingly new idea,
this, but one implanted in my memory long ago while reading Model
Aircraft (Bowden) under the desk in school, and now was the time to see
how such a fuel would behave in the air.

Garage, kitchen and brain were ransacked until a blend of cooking oil,
Castrol 545 [detergent?], paraffin and isopropyl nitrate emerged which
didn't distress the PAW 19 [England's Fox .35?] too much, so off I went to
the park with my last remaining drops of respectable fuel for priming.
Four flights, one rich cut and three recognizable stunt schedules were
enough to prove the point. Ether IS NOT necessary to fly a diesel.

At this stage, however, the PAW wasn't entirely happy and would labor
if over leaned as only an unhappy PAW can. [dieselers can imagine!]
Cheering it up was the next task and it soon became clear that the
lubricant held the key. Logical, this, as paraffin evaporates very slowly
and stays around to dilute the oil at the bearings giving an effect not
unlike a metallic equivalent of arthritis.

After discarding several mineral oils, and then finding mediocre
results with Shell 2TX [for cars?], I returned to cooking oil, which is a
beautiful natural vegetable oil, a fair lubricant, and above all, cheap.
This time I boiled in small amounts of dish detergent and glycerine giving
a fine, fairly stable suspension of dehydrated and non-paraffin soluble
lubricant to coat the bearings. This seemed to have the desired effect, so
I ran some RPM checks comparing fuel to the following formulation with
MODEL TECHNICS D2000 [a commercial UK diesel fuel]:

I.P.N.... 1%, Paraffin.... 66%, Modified cooking oil.... 33%

I tested three engines, a very down at the heels ME 'Snipe', a well
run-in but still excellent PAW 19 R/C and a newish E.D. 'Viking'. They
gave similar figures, prop for prop, on both fuels, and similar throttle
performance too- where appropriate. Handling was different, of course.
The ether free fuel needed a very rich needle to pick up from cold and a
little compression chasing to nurse it through the first few seconds of
running. [Ahh, diesels...] It was also more sensitive to adjustment when
hot and needed a little more compression advancement. Accepting this, once
fuel was at the spraybar, a prime of ether containing fuel was all that
was needed for a cold start. Hot restarting only needed a heav[y]ish prime
or choke.

As a basis of experimentation the fuel formulation given earlier was as
good as any. Nitrate level might be varied to suit individual motor/prop
combinations and can be increased to improve cold pick up.

The overwhelming advantage gained in omitting ether is economy. The
price of fuel works out at less than 1 Pound [$1.50] per litre and on a
cost/weight /performance basis this must make the diesel a formidable
rival for the four stroke glow motor. Against this is a little extra time
in establishing settings while the motor warms up and an extra tin of fuel
for priming. Power and throttling appear unaffected.

Ether free fuels seem well worth considering for sports C/L and R/C
work where long engine runs are called for [vs. FF] and they offer a
challenge to anyone who just enjoys experimenting with diesels.

As for the diesels themselves,I have never heard them express an
opinion on diet or anything else for that matter but it is quite possible
that replacing all that anaesthetic with calorific value might make them
livelier than usual.


"Why Cooking Oil?"

Vegetable oils come from many sources. Chemically they are very
similar, ie. they are triglycerides of C18 fatty acids. Differences,
except for one very special case, are confined to the degree of
unsaturation. Those with higher saturation, eg, sunflower and linseed are
in demand for their drying properties by the paint industry and are
relatively expensive. Some less expensive types, eg, soya, rape,
groundnut [peanut?] etc. tend to be less unsaturated and find their
way onto the supermarket shelves under the guise of branded cooking oils.

The special case mentioned earlier is that of castor which has little
unsaturation and does not dry but is hydroxylated which makes it thicker
than the other oils, unsoluble in paraffin and important for glowmotors -
soluble in lower alcohols. The other oils dissolve readily in paraffin but
not in alcohols.

In diesel fuel, castor is undoubtedly superior to other vegetable oils,
but needs ether to keep it in solution. Without ether, one is left with a
choice of mineral oil, some synthetic oils, or ordinary vegetable oil. The
mineral and synthetic oils are not at their best in high paraffin fuels
where dilution effects come into play and here they have little, if
anything to offer over the cheapest vegetable oil.

However, when it comes to modifying an oil (it is probable some
chemical change specific to vegetable oil take place as well as physical
dispersion) as in the accompanying article, a simple chemical substance of
known non-toxic properties is much safer to play with than a commercial
2-stroke oil which may contain unknown hazardous ingredients. Add to this
the consideration of cost (some more expensive cooking oil contains
thinning additives and should be avoided) and the question becomes not WHY
cooking oil but WHY NOT cooking oil.

"MODIFIED COOKING OIL LUBRICANT”

1) MIX :-

Water 15 cc

Glycerine 5 cc

Washing up liquid 20 cc ('Fairy' brand cited - I used 'Joy')

2) STIR INTO :-

Cooking oil 1/2 litre [500 cc](Cheapest, thickest brand)

3) WARM IN SAUCEPAN until frothing stops,then simmer very slowly until
all froth disappears.

Stir well all the time (important)

4) COOL AND DECANT

5) DISCARD INSOLUBLE RESIDUE

**TREAT HOT OIL WITH RESPECT. WEAR GLASSES IN CASE OF SPLASHING**


LOU’S COMMENTS after the article:

About 1/2 hour to boil up a liter. Residue settles for a day or more
after boiling. I've run this on DDD's and as-built diesels. With 10% truck
starting ether, starts need no ether prime; but settings must still be
chased. Without nitrate, starts are reasonable hot/cold; need LESS
compression than run setting, (wet prime?). Sooty exhaust- may be the
unscented kerosene.(Exhaust smells like the grille at Joe's Diner!) Flies
like commercial mix, when set correctly. REMEMBER: The recipe is for the
oil ONLY- The FUEL is 20/10/3 parts kerosene/oil/ether (or the 2/1
kerosene/oil + 1% IPN as above).

Lou,