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More than you wanted to know about nitromethane. Sorry, I would attach the .pdf if I could.

Lohring Miller

Nitro-methane…..everybody knows it's there, but few, it
seems, really know much about it.
(The following is the third in a series of articles exploring all facets of model
engine fuel. The writer is Don Nix, President of GBG Industries, Inc.)
Nitro-methane…everybody knows it's there, but few, it seems, really know
much about it. Although most seem to know, at least vaguely, that's its primary
purpose is to add power, we still get an occasional call or letter asking, "Why do
you use it in model fuel?" At best, there is much misinformation regarding this
somewhat exotic ingredient. Let's see what we can do to clear some of it up.
Nitro-methane is just one of a family of chemicals called "nitroparaffins."
Others are nitro-ethane and 1-nitro-propane and 2-nitro-propane. Nitro-ethane
can be used successfully in small quantities. (Top fuel drag racers, which
generally run on straight nitro-methane, sometimes add a little in hot, humid
weather to prevent detonation.) At one time, nitro ethane was only about half as
expensive as nitro-methane, but its cost now is so nearly the same, using it to
lower cost is hardly worth the trouble. Neither of the nitro-propanes will work
in model engine fuel. Incidentally, nitro-methane is made of propane, in case
you didn't know (and I'll bet you didn't).
Yes, NITRO = POWER!But.there are conditions and contingencies.
First of all, it doesn't add power because it's such a "hot" chemical. Not at
all. This may come as a surprise to most readers, but the methanol (methyl
alcohol) in the fuel is by far the most flammable ingredient….nearly twice as
flammable as nitro-methane. As a matter of fact, if nitro were only 4 degrees
less flammable, it wouldn't even have to carry the red diamond "flammable"
label!In actuality, nitro-methane must be heated to 96 degrees F. before it will
begin to emit enough vapors that they can be ignited by some sort of spark or
flame!(I demonstrated this not long ago to a friend by repeatedly putting a
flaming match out in a lidful of nitro. I might add that he insisted on standing
about 20 feet away during the demonstration.)
So….how does it add power? We all know (I think) that although we think
of the liquid part substance we put in fuel tanks (in our automobiles or model
airplanes) as the fuel, in truth, there is another "fuel," without which the liquid
part would be useless. Remember what it is? Right….just plain old air (in
reality, the oxygen in the air). Every internal combustion engine mixes air and
another fuel of some sort….in our case, a liquid…glow fuel. The purpose of the
carburetor is to meter those two ingredients in just the right proportions, and
every individual engine has a requirement for a specific proportion of liquid fuel
and air. Try to push in too much liquid without enough air, and the engine
won't run at all. That's the purpose of the turbocharger on full-size engines….to
cram in a lot more air than a simple carburetor or fuel injection system can
handle. Now…..suppose we were to find a way to run more liquid through our
model engines without increasing the air supply? That would add power,
wouldn't it? Well, guess what….we can!An internal combustion engine can
burn more than 2 ½ times as much nitro-methane to a given volume of air than
it can methanol. Voila!More Power!That's how it works, and it ain't all that
complicated. Nor do we have to spend a lot of time thinking about it in the
course of a normal day's sport flying. However, there are some factors we do
need to consider. As a practical matter, virtually all our everyday sport flying
can be done on model fuel containing from 5% to 15% nitro-methane. If you're
flying something like a trainer or a Cub or similar model, there's probably no
reason why 5% won't work perfectly well. Need a little more power? Move up to
10% or 15%. In most of our sport engines today, I really wouldn't recommend
going any higher than that. It probably won't hurt anything, but it won't do you
much good, either. We sell more 15% fuel than any other single blend, and for
good reason. Most of the popular engines on the market today are built to run
on something very near that blend. Typically, European engines will
successfully run on lower nitro blends, because they are built to do so. Why? In
Europe, nitro can cost between $150 to $200 a gallon!Reason enough?
Nitro does more than just add power. It also helps achieve a lower, more
reliable idle. One good rule of thumb for checking to see if a particular engine
needs a higher nitro blend is to start the engine, let it warm up for a few
seconds, set throttle to full idle and remove the glow driver. If it drops rpm,
move up to a 5% higher nitro blend. If there is no discernible drop, you should
be fine right where you are. One of the most popular misconceptions is that by
adding substantial nitro, the user will immediately achieve a huge power jump.
Just ain't so. Most will be surprised to learn that in the 5% - 25% nitro range,
you will probably only see an rpm increase of about 100 rpm static (sitting on
the ground or on a test stand) for each 5% nitro increase. In the air, it will
unload and achieve a greater increase, and it will probably idle better, too. My
pet rule is this: If you have a model that's doing well, but just isn't quite "there"
powerwise, go up 5% in nitro. If that doesn't do it, you need a bigger engine, not
more nitro!Most of our popular sport engines in use today aren't set up to run
on much more than 15% or 20% nitro. Increasing the nitro has the effect of
increasing the compression ratio, and each specific engine has an optimum
compression level. Exceed it and performance will probably suffer, not gain,
and the engine will become much less "user friendly."
High performance racing engines, for example, are tuned entirely
differently….compression ratio, intake and exhaust timing etc….and are
usually intended to run on much higher nitro blends. One exception, of course,
are racing engines used in certain international and world competition (FAI). By
the rules, these engines are not allowed to use any nitro at all, and they go just
as fast as those that run on 60 or 65%!The first question that comes to mind,
then, is, "Why aren't all engines designed to run on no nitro, so we can all save
a lot of money?" Ask any of the world-class competitors. Those engines are a
serious ***** to tune and run, and are definitely not user-friendly!In fact, they
are well beyond the skill levels of most average flyers. There's a price to
everything. Another statement we read or hear frequently is that nitro-methane
is acidic and causes corrosion in engines. It isn't acidic, and the manufacturers
say it doesn't happen…..can't happen. However, at least one noted engine
expert and magazine writer insists that it does. Flip a coin. (I once asked Dave
Shadel, 3-time World Pylon Champion, and a fellow who works on more high
performance engines than anyone I know, how frequently he encounters rust in
engines that have been using high nitro blends. His answer? "Never.") Why does
nitro cost so much? While I have no clue as to the cost of manufacturing, other
than it takes a multi-million dollar investment in a large refinery to produce it,
there is one pretty good reason: There is only one manufacturer of
nitromethane in the Western Hemisphere. Figure it out for yourself. Also (and
this will come as a big surprise), our hobby industry only consumes about 5%
of all the nitro-methane produced; and full-size auto racing about another 5%
or so. This means we have no "clout" whatever, and simply must pay the asking
price. Where does the rest of it go? Industry. It's used for a variety of things - a
solvent for certain plastics, insecticides, explosives (yes, it was an ingredient in
the Oklahoma City bombing) and I'm told it's an ingredient in Tagamet, a wellknown
prescription ulcer medication (no wonder that stuff is so expensive!).
Please note that while nitro-methane is an ingredient in making some
explosives, under normal use, it in itself, is not explosive. (Remember….the guy
used fertilizer, too.) Hardly a month passes that someone doesn't call to ask, "I
hear more nitro will make my engine run cooler. Is that true?" Nope. The higher
the nitro content, the higher the operating temperature. Fortunately, in most of
our sport engines, the difference in operating temps between 5% and 10% is
negligible, and there are lot of other factors (proper lubrication, etc.), that are
much more important.
Finally, remember in the beginning of this, we said that nitro adds power
because we can burn more of it than we can methanol, for a given volume of
air? This also means that the higher the nitro content of the fuel, the less
"mileage" (or flying time) we will get. In a typical .40 size engine using 15%
nitro, we can usually get a minute to a minute and a half flying time for every
ounce of fuel. The Formula 1 guys are lucky to get 2 minutes out of an 8 oz.
tank!What's the practical side of this? If you go to a higher nitro blend, be sure
to open your needle valve a few clicks and reset before you go flying. Otherwise,
you'll be too lean, and could hurt your engine. Conversely, if you drop to a
lower nitro blend, you'll have to crank 'er in a little.
This may not be everything you ever wanted to know about nitro but
its a great start.
Nitro-methane is one of a group of chemicals known as nitro-alkanes,
which consist of an alkane molecule, such as methane, ethane, or propane, in
which one of the hydrogen atoms has been replaced by a nitro group (-NO2).
Nitromethane is used in a number of products, including fuels, explosives,
solvents, preservatives, and pharmaceuticals. Angus's nitromethane production
process results in the joint production of four nitro-alkanes, of which nitromethane
has the highest value.
Standard Nitro-methane (CH3NO2) becomes Di-Nitromethane when
exposed to UV (Ultra Violet rays as from the sun or "other means") and is more
entertaining to run. All commercially available Nitro-methane is never available
at 100%. Some agreement with the ICC. It is typically cut (reduced in
concentration) by approximately 2% or so with Benzene or "other" agents.
Besides, 100% won't light very well without being cut with something. Back in
the old days, some few folks were indeed getting hold of REAL 100% (from other
than normal suppliers) and cut the load by 2% with spectrophotometric
benzene (not your normal get it anywhere Benzene).
Comments about purple nitro: Potassium Permanganate (KMnO4) can be
mixed and although a slurry, can be burned with either methanol or nitromethane,
or nitro-propane. Also one can add methyl purple (no gain, just fun
coloring), methyl orange, or methyl blue. You can even add oil of wintergreen if
you wish.
Like an atomic device, the separate components of a fission-fusion device
are relatively benign, but when a special set of artificial conditions is created it
will produce a dramatic result. Nitro-methane is the atomic equivalent of
uranium 238. Getting it to burn is a major problem, it needs lots of heat. But
once the correct temperature is achieved, it will give more energy than most
people can use.
A match will not light nitro-methane. Dropped into a pool of nitro spillage
floor, the match will sizzle and extinguish just as if it had fallen in a pool of tap
water. But take a hammer and hit the pool - it will explode. The small amount
of fuel caught between the hammer face and the concrete floor will become
unstable and cause a spontaneous fire which occurs quickly enough to be
labeled an explosion. The tiny bit of lit fuel is hot enough to set off the rest. And
bigger the pool, the bigger the explosion. Enough nitro and the result will be a
good-sized crater in the cement floor.
Joe Fette, a former vice president and general manager of Angus Chemical,
worked intimately with the nitro-methane departments, and remembers when
the discovery was made. "The condition first came about by accident," says
Fette. "Luckily, it was an accident where nobody was killed. But nitro-methane
used to be shipped in tank cars before this condition was known. Two separate
accidents within a year of each other stopped that. The tank cars exploded,
leaving holes 800ft wide and 300ft deep. Luckily, these were out in unpopulated
areas. What happened is that the fuel was compressed when it slammed into
the other car (as the train crashed). There were also rumors of power lines
being around, although that was never proven."
Regardless of an external spark, the impact had sufficient force to begin
the reaction that would ignite the explosive. The liquid, trapped inside the
detonated by itself - at least in the corner of the container that suffered the
largest degree of compression. With the initial explosion, extreme heat - the
second factor that contributes to nitro-methane's instability - was already
building up. With nowhere to go the heat spread through the compressed fuel
in the tanker, setting the entire railroad car on fire before the structure had
been punctured. The result was an explosion that changed the land's
geography".
The Chinese nitro is still being made in China at a specially constructed
plant. It is imported to the US by Wego Chemical Company in NY. It is made by
a different process than the Angus (now Dow Chemical as of 2 or 3 years ago)
nitro. A test was done on the three nitro products that were available in 1996
and they found the Chinese nitro to be more pure than the Angus nitro, and
much more pure than the product that VP was selling at the time. Those
results may not hold up now, but they were accurate at the time the products
were tested.
The nitro that Chuck Bryant (C.L. Bryant Inc. in Modesto) sells is the
Chinese nitro and is used by a number of the NHRA nitro racers. It is available
in both the 90% version and the uncut version which is 99+% pure nitro. Phone
number is 800-399-4176.
Steve LeSueur (formerly with World Wide Racing Fuels) is the person
selling the Chinese nitro at the NHRA National Events. Steve lives in Virginia
and can be reached at 804-842-1838 or by cell phone at 973-454-0663.
Alcohol and Nitromethane
Gasoline is for washing parts, alcohol is for drinking and nitro is for
racing. I saw that on the back of a fan’s shirt at New England Dragway. It
seems some folks just don’t appreciate gasoline. What is so special about
Alcohol and Nitro-methane anyway? Well…..people don’t race funny cars; they
race ALKY funnies or NITRO funnies. Gasoline has no real pizzazz in the racing
world. Sure it powers Pro stock cars, trucks and bikes, but it just doesn’t have
the same powerful intonation as Alcohol or Nitro. So where does this notoriety
come from and why would someone want to use either of these fuels? Alcohol
is usually used in the form of Methyl alcohol or methanol for short. CH3OH is
the chemical formula. Methanol when compared pound for pound to gasoline
yields about half of the heat energy potential. Where alcohol offers 9000
BTU/lb. Gasoline offer 18000 BTU/lb. Basically methanol is a far less powerful
fuel on a pound per pound basis. Gasoline however burns at a stoichiometric
(scientifically correct) ratio of 14.7:1, and makes best power running slightly
richer at 12.0 to 12.5:1, while methanol burns at 5.0 to 6.0:1. When the
mixture is run in this fashion the result is a 5-11% increase in power. The
best part is, the above is not the only benefit. Methanol allows for much higher
mechanical compression ratios far in excess of what even the best racing
gasolines offer. Just a few years ago Pro stock (gasoline) bikes ran a max of
13:1 to 15:1 compression ratio, but alky bikes of the time could run 16 to 17:1.
The extra compression allowed alcohol engines to gain a 15% advantage in
power while normally aspirated. Now figure in the fact that methanol has a
higher latent heat of evaporation (it absorbs or uses more heat in the
evaporation process), and we have a fuel that can cool the intake charge better
than gasoline. Can you think of a good use for this? How about supercharging
or turbo charging? Compressing air makes it get hot. Superchargers and
turbochargers are not 100% efficient for several reasons, not the least of which
is through lack of mechanical efficiency and compression of the intake charge
itself the intake temp rises. Hot air is not good. 10 psi of hot air contains less
oxygen for burning fuel than 10 psi of cold air. Think of it this way. If you blow
up a child’s balloon and let it sit nothing happens. Put it in the freezer for 5
minutes and what does it look like? It comes out all shriveled up. Put it next to
a warm bright light and not only does it return to its original size, it blows up
even bigger as the air is heated. Now if we take that same hot compressed
intake air and dump a little methanol into it, you guessed it, the temperature
drops as the alcohol is evaporated. Alcohol is atomized and the mixture gets
denser allowing for a whole lot of mixture to be shoved into the engine, much
more so anyway than that of the turbo/gasoline mixture. It is not unusual for
supercharged alcohol motors to realize a 20% improvement over their gasoline
brethren. Nitro-methane works in a similar way. It is clear and very hard to
light with a match. If you are somehow successful at lighting it, you’ll see it
burn with a lazy blue flame. Smack a puddle of Nitro-methane with a hammer
however and the head of the hammer will be come a projectile as the nitro
explodes in a violent blast. Like methanol, Nitro-methane does not have a lot
going for it in sheer power per pound. ·
Gasoline : 18,400 BTU/lb. ·
Benzol ; 17,500 BTU/lb. ·
TNT (trinitrotulene) : 6,500 BTU/lb. ·
Ethyl Alcohol : 11,500 BTU/lb. ·
Methanol : 9,500 BTU/lb. ·
Nitromethane : 5000 BTU/lb.
Nitro-methane does contain a lot of oxygen, which makes it nearly a monopropellant.
Meaning, it requires almost no additional air (oxygen) for burning.
Therefore it burns best when run at a very rich ratio of 2:1 to 1:1!Thus even
though pound for pound nitro is less powerful than gasoline, nitro can make
almost double the power of a gasoline engine of the same configuration.
Air Fuel ratio vs. Resulting Max BTU released ·
Nitromethane: o 1.3:1 46,000 BTU ·
Methanol: o 5:1 23,000 BTU ·
Gasoline: o 12:1 18,400 BTU
 

John Beardslee

Well-Known Member
Joined
Apr 20, 2011
Messages
1,823
Good info Lohring,

Our contact many years ago at Angus said that the cosmetic (make up) industry used a lot of nitro paraffin also.

Thanks, John
 

XtremeRcBoats

Well-Known Member
Joined
Jan 31, 2002
Messages
1,139
great article Lohring. If you want, send me the pdf and i'll put it online on our website and put the link here. My email is Paul AT Xtremercboats dot com.
 

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