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PAW .60 mix

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Old 09-15-2015, 02:45 PM
  #1  
dkwflight
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Default PAW .60 mix

Hi
Just a comment
I started mixing my own fue. 10% ether, 33% Klotz castor 2% amsoil, The remainder Kero.

It seemed to me the starting was fine, I used an electric flipper :<)
The exhaust was pretty black & oily and it seemed to be making more power than the stock Davis Dieael fuel

I have had this engine sitting on the shelf for some time, years and I decided to revive it..

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Old 09-17-2015, 07:07 AM
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Hi DK: you could use much more ether and a third less Castor. My recommendation:

Castor-20%, Ether-35%, Amyl Nitrate-1.5%, the remainder is Kerosene. This is a reliable

general purpose mixture that also generates very good power.
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Old 09-17-2015, 07:49 AM
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Hi
As my first mix I used less ether because of the cost of it.
It did seem to spit out a lot of castor.
I may try less castor next time.

I forgot to mention I was spinning a 15X4. paw says up to a 18" prop. That seemed to me to be too big. I'll try an 18" some time.

Thanks for your response
Dennis
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Old 09-17-2015, 10:45 PM
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Dennis,

I agree - too much castor, too little ether...

If your engine is new, more than usual castor is not a bad idea, but 33% is way more than needed, imho.

Yes, ether is scarce and expensive, but is available. Any farm or tractor supplier in your area who handles John Deere products? JD starting ether is "moderately" priced - at least compared to pharmacy or other direct suppliers.

Understanding JD's labeling is a learned art. Label says it is 80% technical ether. Previous discussions of this product, here, mentioned that the label spec is no way precise, but we can assume that they list it by weight. Di-ethyl ether has a specific gravity around 65% of that of water. Example: If a can of JD has 7 ounces total weight, 80% of the weight is the ether. Fluid ounces are volume measures, not weight measures.

That's 5.6 ounces (weight), So, the volume of ether is 1/.65, or 1.54 times as much- which works out to a bit above 8 fl oz by volume.

We usually mix by volume not by weight, so you can consider that a can of JD has about 8 fluid ounces of di-ethyl ether. The rest of what is in the can includes the propellant. (Did I mention the JD is packed in a spray can?) ...and maybe a very small % of rust preventive.

So one can of JD could yield 8 fl oz for your fuel if you "capture" all of it. That's a BIG IF!

That 8 fl oz would be 25% ether content in a quart - much easier starting, and usually easier to adjust settings. The oily and black exhaust suggests too much oil and too little ether - requiring higher than ideal compression settings. The black oil could also suggest a lower quality kerosene (paraffin in other countries.) I've been using #2 auto diesel, which runs cleaner, without problems for sport and everyday uses. And, again, is of reasonable price compared to other "high quality, low sulfur" kerosenes.

"Capturing" ether from a spray can is a problem because ether is very volatile - evaporates very quickly. I use a two-jar method. Jars? - like Planters' Peanuts sell in, large enough to hold 8 to 10 fl oz liquid. Empty and clean, of course... For one jar, puncture the lid just large enough to pass one of those spray straws, as used on WD-40 spray cans. (Those fit the spray tip on the JD cans I've used, can't guarantee others...)

The other jar itself isn't needed, but its intact cap is.

Change nozzles- the "WD-40" type for the JD can's original nozzle. Pass the straw through the punched hole into the jar and spray away. When spray weakens, pull the straw out and shake the can. It will spray more. Do this until the pressure in the JD can seems exhausted. Switch caps to seal the captured ether. This is a safe and sensible method. Most of the pressure vented out is propellant, very flammable if you spray it at large - this method keeps that near the vent in the cap and allows it to dissipate harmlessly.

The straw aims the liquid ether against the cool sides of the glass jar, reducing loss by evaporation. You could - should - mark the "catch jar" at the volume of ether you'll need for your fuel. It may - usually does - take more than one JD can t make up 30% for a quart. A small part of the contents of a second can completes your "milking" from JD cans. Simply stop "milking" then. The JD can keeps the unused portion, of what was in it, sealed safely, and ready to use the next time you 'capture' ether for your fuel.

BTW, AFTER you've drawn all the pressure from a JD spray can, there is still a small amount of liquid ether in it. IF no pressure remains, it is safe - if you are careful - to punch two or three holes through the JD can's rim and pour those drops into your 'catch jar.' Seal the jar well with the intact cap until you mix the fuel, and don't waste much time before mixing up your batch.

Storing mixed fuel - I much prefer storing diesel fuel in a metal can. Plastics may allow ether to seep through caps, or pass through the plastic. A quart can (946cc) has enough expansion volume to hold a liter of fuel safely. The metal cap allows a good method of preserving your mix. I use a lab graduate in cc (or ml?) to simplify the % of the fuel fractions, usually oil, then kerosene, then finally ether and "amsoil.'

Drill or punch the cap so you can solder two 1/8" tubes through it. The tubes - one extended - say with a length of Tygon - to the can bottom and the other as merely a vent, allow you to draw fuel without much evaporative loss. A loop of neoprene or Tygon tube across the outer ends of the soldered tubes seals the can. (Mark which is the vent and which is extended to the bottom! If you don't open the vent first, residual pressure will squirt a surprising amount of fuel out the other tube!)

Seal the metal can's metal cap threads with - at least - two turns around of plumbers' Teflon seal tape. Make sure it does not go into the can in a way that allows shredding into the fuel!

Keep the sealed can at a low a temperature - say, around "room temperature?" A lot of pressure can build up if the fuel is heated in the sun...

(I've written this up several times. but not recently. Some among us may not have seen it, so here it is again...)
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Old 09-18-2015, 02:13 AM
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Hi

I did the John Deere ether can thing to re-activate a gallon can of Davis fuel I kept on the shelf for a number of years. You can with a very sharp needle type punch make a very small hole in the top of the spray can after refrigeration/ cooling the pressure in the can should be at its lowest. After the pressure is released, then the hole can be enlarged and an additional hole can be made on the opposite side. Then the liquid could be poured off.
Part of the contents of the cans is I believe propane. This then is part of the contents. The propane also helps common diesel engines to start.

I googled "ether sale" and found a company that seemed reasonable.
I bought 4 liters ether. It came in a brown glass with a very good cap. No leakage. My nose picks up the ether smell well.
I also recently bought Davis diesel fuel which came in a metal can with a plastic neck and cap. When I opened the box that davis sent the mix in I immediately smelled ether. I told Davis about the smell. Their comment was don't worry about it. The can was good enough. I don't think so.

I had saved a quart/ liter can that had a metal neck and top. This can does not leak ether with hand tightening. I also have a pint can, 500ML with the same type of metal cap.
I looked around for cans that would serve as well. I believe the "Camping fuel" cans might do as well to keep the ether in the mix. I have yet to spend the $19-25 to buy a camping fuel can.

In comparison local supplies of Kero seemed expensive, $25 for 2.5 gallons. Florid, Ace hardware
I bought Amsoil cetane improver instead of Amyl nitrate.

I intend to test my engine further. I have read of other people running model diesels on normal diesel fuel/ no. 2 alone after pre heating. This would be very hard on model diesel I believe, but doable depending on the quality of the engine.
I used to live in NY and #1 kero was sold as heating fuel. We used the #1 to mix with #2 to lower the gel point of the #2 ( the temp when the waxes start making crystals and would stop the flow of the diesel through filters ETC)
THe cost of the #1 was close to #2 in price.
Fuel meant for lamps is more pure, less smell, I think
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Old 09-20-2015, 12:32 PM
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You would be very hard pressed to get better results than Davis' fuel, the only fuel I ever found that is it's equal is Red Max.

I have been playing today with two Irvine .40's, one Diesel and one Bumpy Port. For those that may not know it, the Diesel has the Irvine .46 crankshaft and a .030" smaller bore than the glow .40.
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Old 09-20-2015, 12:38 PM
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I mixed my own fuel first time out of the gate and other than getting the carb settings in the ballpark, the engine fired off good yesterday. 31% John Deere ether, 20% castor oil, 50% kerosene, 2% Amsoil cetane boost. Yep, it's more than 100%... Plenty of room in the can. Less than $8 a quart. Now that's hard to beat.

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Old 09-20-2015, 12:55 PM
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Hi
The only real difference with 10% ether is it takes more compression to fire off.
Once the engine is running I can back off the compression nearly to the area I run with 30% ether.
Peak power does take more compression.
An RC engine like my 49 PAW needs more compression to keep the fires lit at idle and then pick up smoothly to full open.

My .060 MP Jet ran fine on the 10% ether mix today
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Old 09-20-2015, 01:51 PM
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I'm a hardcore traditionalist. I'd rather use the extra ether and not have to worry about my engine being super picky or needing to run way overcompressed to keep the fire lit. I'm a cheapskate, but the ether is $4.40 a can which is the most expensive part of the fuel.. Ill stick with what's "usual" for ease.. I'm new to diesels anyway.
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Old 09-20-2015, 02:29 PM
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For those who are interested in such things:

The crankshaft in the Irvine .40 diesel is not only the Irvine .46 item, to be absolutely accurate it's the Irvine .46 'heli' spec. crankshaft.

A little off topic - my apologies.
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Old 09-20-2015, 02:50 PM
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It's Diesely enough.
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Old 09-20-2015, 03:17 PM
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Hi

I really only wanted to try the lower ether content to see how it works out.
Since the increased kero is burned, I figured more power if the engine took it
I haven't used the 500ml I mixed yet so I haven't seen any changes in the PAW 49
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Old 09-20-2015, 04:39 PM
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Originally Posted by dkwflight View Post
Hi
The only real difference with 10% ether is it takes more compression to fire off.
Once the engine is running I can back off the compression nearly to the area I run with 30% ether.
Peak power does take more compression.
An RC engine like my 49 PAW needs more compression to keep the fires lit at idle and then pick up smoothly to full open.

My .060 MP Jet ran fine on the 10% ether mix today
Hi DK, I hope I'm wrong; but I see total destruction of a nice 1cc MP Jet in your future.

Tony
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Old 09-20-2015, 11:56 PM
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dkw,

As mentioned, I've been blending using #2 auto diesel for the kerosene portion. Does burn cleaner and has less exhaust smell. Ether odor still abundant on unburnt fuel, tho. Current pump price here for #2 auto is about 20 cents more per gallon than unleaded gasoline - less than $2.50.

I don't see paying way over $10 for a gallon of hardware store "low sulfur" kerosene, or $3 to $5 a gallon from a camping supplies vendor (camp heaters and such) when both smell strongly of kerosene. Auto gas station #2 diesel has very low odor, here at least. Exhaust smells more like steam than like an old coastal rust-bucket trading vessel in 3rd world small ports.

I prefer milking the JD as described, straw into catch jar. Had tried spraying into jar open vented - too much lost ether!

Tried chilling the can before spraying - little if any gain In capture...

AFTER all pressure was blown away, using GREAT care, I punched the rim once with an awl - leaving the awl in place as a bung so I could tease the point out gradually. There was ALWAYS residual pressure venting when I did. After that two more holes to vent the can and pour out the remainder. Messy, too, and no simple, dependable way to store unused ether. Pouring it into another jar made a storage problem, too, and over a week or so it tended to find its way out. (Didn't have plumbers' Teflon tape back then)

With my method I usually capture over 9 fl oz from one JD can...

Kerosene was very cheap in the late 1950's, when I started blending my own diesel fuel. Baker's AA Castor was reasonable, too.

The ether wasn't a problem then. No druggies were trying to cook up their 'recreational use' substances using it. I walked into a chemical bulk goods vendor on old Canal Street, NYC, 17 yrs old or so, DA hair, attitude, etc. Clerk asked how much I wanted. A fork-lift "flat"? Coupla 5 gallon barrels? I had to ask what was the smallest amount he could sell me. Turned out to be a gallon. ...$2.00... So, I hopped on the subway and rode home to Brooklyn, with a gallon can 'conspicuously labeled' with "Highly Flammable" and 'skull & crossbones poison' warnings. People may have noticed that can, but it didn't faze them. ...or scare them. A different world back then...

It made great fuel, too, even without any "ignition improver."
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Old 09-21-2015, 01:00 AM
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dkwflight
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Hi
I haven't gotten around to trying #2 fuel. Not much of a problem, I drive a diesel truck. I see you are in AZ. Plenty warm so starting should be go with any mix.

I bought 4 liters ether on line. No issue about the purchase. They took my credit card OK.
I don't have an issue with JD. It is convenient and they are tight until opened.

I bought a couple of small engines from Sharma in India.
Good quality. They start good.
I bought an .09 control line and a 3.2cc RC engine.. I bought some of their Props. Quality not as good. They seemed excessively out of balance.
I can recommend dealing with Hangars
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Old 10-02-2015, 04:21 AM
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Hi
I did a fuel mix yesterday.
30% ether, 20% Klotz castor, 3% ams oil cetane booster, remainder kero.
This ran the 49 PAW diesel fine. Easy starting.
With a Sharma 12x6 prop it seemd to spin up fine.
With what I know was a low compression setting I got a honey color from the exhaust liquid. I have a 12" tube carrying the exhaust away so the color was easy to check.
A little more compression and got coffee color and more RPM, throttle response good.
More compression and got a inky black color, throttle response best so far. The 12x6 prop idled at a pretty fast speed.
The needle seemed a bit touchy, going too lean with little adjustment. Also the engine seemed to have a lot of vibration at full throttle.

I use a 500ml beaker to mix in.
The castor in first was difficult to mix. This last time I put in 200ml kero first. This seemed to help the mixing. the remainder kero in last. Then tipping with my hand over the top.
Dennis
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Old 10-02-2015, 05:37 AM
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You can mix fuel with almost zero waste
of any ingredients like this:

For capturing the ether from a spray can,
don't even try to spray it out. Put it in the
refrigerator or freezer until it is really cold.
This helps keep the ether from evaporating
while you are mixing the fuel. Turn the can
upside down and spray off the propellant.
At first a small amount of ether will puff out
then nothing but propellant until the
propellant is gone.

Then with an awl, punch a small hole just
below the shoulder of the can where the
metal is thin, and another on the opposite
side (one for ether to exit, and one for air
to go in). Do the punching immediately
after spraying off the propellant, if you let
the can sit around while you go looking for
the awl, pressure will build up again.

Pour the ether directly into your measuring
cup. You should have no trouble getting it
all out at once. It will continue to bubble while
some dissolved propellant evaporates. It is
usually not enough to make a difference.
It will probably all evaporate while you figure
out how much kerosene and oil to use with
the measured amount of ether.

Pour the ether into your storage can. Measure
enough oil to correspond to the amount of ether
and add it to the can. Measure the corresponding
kerosene in the same measuring cup and stir it
to get the remaining oil into the mix.

Add the cetane booster to the kerosene. Swish
the kerosene in whatever you are using to measure
the booster to get it all into the mix. Add the kerosene
to the can and shake it gently. If some pressure
builds up release it before it is enough to pop the
can. Shake it again harder a couple of times,
releasing pressure as needed. You're done.

Jenny

PS I use 33% JD ether
12.5% Klotz synthetic oil
12.5% Sig castor oil
2% cetane booster
40% kerosene
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Old 10-02-2015, 05:58 AM
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I tend to run more at high throttle, so I set
the compression a bit lower and sacrifice
throttle response for engine life. (I tend to
put smaller engines in bigger planes.)

On a plane with plenty of engine, where
full throttle only happens for short periods,
a little higher compression setting is fine,
just high enough to smooth out the idle,
and give smooth acceleration. Crisp and
immediate acceleration is ok if you don't
mind accelerated wear.

Running slightly rich keeps the engine
cooler so the compression is more
consistent from idle up through full
throttle. Running on the lean side
makes the engine hotter at full throttle
which make the compression get too
high as heat builds up.

Jenny
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Old 10-02-2015, 06:13 AM
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dkwflight
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Hi Jennifer
I used the JD spray can stuffa couple of years ago. I took the plunge and bout 4 liters ether here http://www.rightpricechemicals.com/b...grade-acs.html 4 liters should last a good while, the bottle they shipped is a good brown chemical type with a very good screw cap.
I looked at Sig castor and Klotz benol , If I remember right they are about the same price.

The 12x6 prop seemed too light for the engine. I will make another run with a 12x8 Zinger I had on the shelf.
When I am satisfied I will install it on a plane that last had a Saito 65 running it.
I think the 49 PAW should be a good match.
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Old 10-02-2015, 07:04 AM
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Jennifer Curtis
 
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That's a nice price on 4 liters of ether.
Thanks for the tip.

I'm guessing the plane came from
someone who kept the saito 65 that
was on it. I can't imagine taking that
engine off unless it was worn out (and
that engine never wears out).

The PAW 49 should fly it nicely,
without ever throwing the prop.

Jenny
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Old 10-02-2015, 07:12 AM
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John Deere ether costs about $4 (around here anyway) per 7oz by weight can which I believe is actually about 8oz by volume. I used a small canning jar marked with how much ether volume I needed and put a lid and ring on the jar and poked two holes in it. I then used a straw on the ether can (I modified a different tip to use a straw) and squirt the ether into the jar through one hole. I put the ether cans in the freezer beforehand. This way I won't have a punctured partial can to contain. I measured out the kerosene, castor, and Amsoil cetane booster and put it in the can first and added the ether last. A good shake and it was all mixed. I used a metal acetone can which is a bit over a quart and used 31% ether, 20% castor, 2% Amsoil, and 50% kerosene. So far this has worked well for me.
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Old 10-02-2015, 12:29 PM
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https://www.youtube.com/watch?v=dmvm...ature=youtu.be

A vid showing the paw
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Old 10-06-2015, 05:27 PM
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Originally Posted by dkwflight View Post
Hi
Just a comment
I started mixing my own fue. 10% ether, 33% Klotz castor 2% amsoil, The remainder Kero.

It seemed to me the starting was fine, I used an electric flipper :<)
The exhaust was pretty black & oily and it seemed to be making more power than the stock Davis Dieael fuel

I have had this engine sitting on the shelf for some time, years and I decided to revive it..
You probably have more 'power' because the above brew has 55% kerosene whereas a typical Davis fuel has 40%.
And since it is the kerosene that has the highest calorific value its percentage makes the most difference.

And lowering the ether content takes away some of the cooling (evaporation) ability of the fuel.

I would expect that the engine will run hotter as a result.
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Old 10-07-2015, 08:44 AM
  #24  
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Hi
I agree although I don't currently have a tach to check.
The engine definitely runs hotter.

The old thing about diesels running cool is correct only when the mix is rich and the compression is low.
I don't think diesels are more powerful than glow either. Diesels will run with very large props for a given size but a real comparison will show
the real power is comparable with normal glow engines running no nitro.

Dennis
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Old 10-07-2015, 12:36 PM
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Dennis and Chris... Hi.

Some thoughts about power differences between glow and diesel engines -

Power is the rate of delivering force. For there to be power, work must be done - there must be motion resulting from a force.


The force our engines deliver is the torque applied to the propeller.
Horsepower is a defined rate of power delivered - as I recall, in 'traditional units' 33,000 ft lbs per minute. (corrections welcome if memory goofed.)

Which Is more powerful? - a big tractor for a long-haul semi or a street-racer tuned small import? They might each be rated at, say, 200 HP. The semi's engine seldom sees 2,000 RPM; the street-racer's engine can wind much, much higher than that.

The result of force and the number of times per minute (or second) it is applied multiplies out to the same number (unless the claimed HP for the street-racers came from the advertisers, not the engine developers.)

I guess, theoretically, if you could gear a small, high-RPM engine down far enough you might get applied power similar to the big truck's slow thumper... How practical would that be?

Relate this to our model engines - Diesels make excellent torque at - usually - lower RPM. Glow engines make excellent power at usually higher RPM. Comparing 'ordinary' engines of their types...

Glow (methanol -based) fuels burn effectively over a great range of fuel-air mixture conditions. Our diesel (kerosene-based) fuels are much fussier about the range of fuel-air ratios they can work with.

All our engines are basically air pumps bringing volumes of air in, then manipulating that air to release heat energy. (Mixing a flammable fuel into it, compressing and heating it to burn the fuel-air mix. The ignition and combustion expand the compressed charge, creating the great pressure to push the piston down and rotate the output shaft.)

-That is our useful work.

Correctly burned gasoline and kerosene can yield about twice the heat per unit weight as the alcohols (commonly methanol or ethanol.) We can't simply increase the amount of kerosene in our diesel fuel to get more power, because the engine is limited in how much air it can pack in. If we get out of the useful range of kerosene/air, we lose optimum conditions.- too much will not mix well with the air going into the engine to burn well, and with the compression ratios we use we have little or no space in the combustion chamber for unburned, liquid fuel. And to lean simply can't produce as much power as at the optimum.

Glow engines gain from the evaporative cooling of the alcohol in the fuel, and operate well at much lower compression ratios than diesels - there is room forunburned fuel and oil, within limits of course. More RPM passes more air through the engine in a given length of time and nitromethane in effect provides its own oxygen as it burns. This is why we can run glows productively at higher RPM - combustions may go less efficient beyond ideal conditions, but we can add enough more of them to continue to gain power.

I think the torque vs RPM chart relates to volumetric efficiency - to how well the flow passages admit the air into our 'air pumps.' The passages inside don't change, so at the torque peak RPM, volumetric efficiency is likely to be very close to optimal. We don't see as many charts of horsepower and torque by RPM anymore; they used to be in every published engine test! Generally, the torque maximum RPM is seldom as high as 2/3 of HP peak RPM. E. g. , - example: engine peak HP RPM 15,000: torque peak around 10,000 RPM.

It seems to me, then, that our ordinary diesels do very well around torque peak RPM. (There are exotic, extreme diesels for special contest events that rev far beyond our simpler, less expensive and more user-friendly diesels,)

Like the big semi-tractor, we have more usable torque at a very usable RPM range for our models. The 'bigger props for diesel' idea is, to an extent, correct. The 'greater fuel economy', again, is 'true' because of the character of our fuel's kerosene.

The early, mostly European, diesels that 'ran cool to the touch' often used a fuel of 1/2 ether 1/2 kerosene (or motor oil - I disremember. In any event, the full force of ether chilling had effect.)

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