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FREE Smoke Tips
Smoke TIPS provided by TME
Tejera Microsystems Engineering, Inc.
This information is believed to be as true and accurate as humanly
possible , feel free to copy and distribute. Don't forget to
check out our massive collection of Smoke Oil
Recipes.
How to maximize smoke?
- A high volume smoke system happens only when two
needs are met. 1. The muffler provides the most
amount of heat transferred to the oil. 2. The
right amount of oil for a given amount of
heat.
The muffler cavity where the oil is heated is a very important part
of the smoke equation. If heat energy is not transferred efficiently,
then the oil cannot completely vaporize to create the smoke effect
we desire. There are many commercially available smoke mufflers out
there made by Slimline and others that provide baffles, coils and
other tricks for this efficient transfer of heat. TME's
Smoke Secret tips booklet included with all our Simple
Smoke Pump products show you how to easily convert any model engine
muffler into an efficient smoke muffler.
The right amount of oil is another important
consideration. Too much oil causes the muffler to cool
down and in turn provide less heat for the oil. The net
effect is that too much oil produces LESS SMOKE and MORE
OIL on you plane. You can tell if you have too much oil
by flying your plane around for a few minutes without
smoke and letting the muffler get real hot. Turn the
smoke on and watch your plane closely. If you get a big
burst of smoke when first turned on that rapidly dies
down to very poor smoke and you have a big mess to clean
up on your plane when you land, YOU have too much oil!
Too little oil simply results in less smoke without a
mess. Therefore maximum smoke occurs only when things are
in balance, just the right amount of oil for a given
amount of heat.
How should I set my oil rate?
- Here is a rough rule of thumb for calculating oil rate and recommended
tank size. REMEMBER these are rough starting approximations. The
efficiency of you muffler and the type of smoke oil will determine
the actual rate you need. Experiment with your settings once your
smoke system is working. The size tank depends on the available
heat and oil consumption rate and available space. This all ties
into engine displacement. To approximate just multiply the
engine size times 8 and this will give you the size of a 4 minute
tank. Divide that number by 4 to get the oz. per minute you must
adjust the oil rate to.
Example: For a 1.2 cubic inch engine multiply 1.2 X 8 = 9.6
oz tank then divide 9.6 by 4 = 2.4 oz per minute.
If you have room for a larger tank in your plane, go for it.
Sometimes a 2 or 3 minute tank is all that is possible. Remember,
turn the pump on only to accent a maneuver and you can stretch
2 minutes of smoke into a whole 15 minute airshow.
- Fine tuning the oil rate: While flying, let the
engine heat up for about one minute before turning on your smoke
pump. If when you turn it on, you see a big burst of smoke followed
by less impressive steady smoke. Your oil rate is too high, back
off on the amount of oil. ( Your oil rate is so hi it is cooling
off the muffler temperature ) If the amount of smoke stays the same
but you feel it is not putting out as much smoke as you expect,
you may try increasing the oil amout in 1/2 oz per minute increments
and retest.
-
Studying the observations above we can conclude that more heat
(bigger engines) will allow you to provide more oil and in turn
get more smoke. Real big engines demand the high volume of oil
that the Simple Smoke Pump
can produce.
Special tips for GIANT SCALE (greater than 4.2 cu
in.) engines!
- As engines used in GIANT SCALE planes get bigger and bigger we
learn more and more about making these planes smoke their best.
With huge airplanes like 1/3 scale Stearmans and 44% EXTRA 300S's
special precautions need to be taken with the check valve used to
prevent loss of prime of the Simple Smoke Pump. Due to inherent
limitations in the Perry Varsane check valve, high volume applications
require two check valves in parallel. (The TME
high volume check valve does not have this limitation and you
can use only one. )
The reason for
this is that this check valve, while being the
best suited to insure a positive shutoff in this
application, was never really designed to handle
such a large volume of oil flow. When forced to
pass more than about 6 or 8 oz per minute the
check valve seems to choke and restrict flow
almost to the point of shutting off the flow. In
this mode the valve seems to remain stuck until
all pressure is removed (pump turned off).
Since most large engines tend to be twins the
solution is very simple to implement. Run a tee
from the pump output to go to each muffler or
header pipe. Just before you go into the
muffler/pipe put a check valve in the tubing.
Don't forget that the last few inches of tubing
should be black neoprene to withstand the heat.
Now each check valve shares half the flow rate so
you can pump up to about 16 oz per minute for
those big 8 + cu inch engines. This is the setup
used by Mike McConville in his 42% Giles G-202
and others at the TOC using the Simple
Smoke Pump.
If you need more help in getting the Simple
Smoke Pump to work properly check out our Tech
TALK page.
10 Steps to Safe Smoke.
Please read carefully
- DO NOT USE ELECTRIC PUMPS TO PUMP GASOLINE. UNDER
NO CIRCUMSTANCES SHOULD YOU OPERATE AN ELECTRIC
PUMP IN THE PRESENCE OF GASOLINE VAPORS. THE
MOTOR BRUSHES MAY CAUSE GASOLINE VAPORS TO
IGNITE. PLEASE BE SAFE, IT'S JUST A HOBBY, ENJOY
IT SAFELY!
- Flammable liquids and battery shorts This danger
is present with or without a smoke system. Please
look out for frayed battery, pump, or servo
wires. Always inspect everything closely after a
crash, no matter how minor the external damage
is.
- Range test your radio system with any electric
pump before flying your model. Any
electric motor (even servo motors) placed near
the receiver can reduce the available range no
matter how well it's filtered.
- Make sure your system is off when inspecting or
installing the tubing, otherwise it may splash
liquid into your eyes or model. Secure all tubing
with plastic ties or wire.
- Wait until the system is cool before refilling
with smoke fluid.
- Do not ground test except for very short
intervals. Otherwise Smoke fuel may accumulate
and catch fire.
- Make sure your smoke system is off while starting
or whenever your engine is running at idle. Smoke
fluid that accumulates in the muffler may catch
fire.
- Angle your muffler exhaust downward and away from
the airplane so that no excess smoke fluid can
accumulate in the muffler.
- Although not necessarily a safety consideration.
Be cautioned that some film coverings and paints,
especially the low temperature films, are not
compatible with the smoke fluids commonly used.
Run your own compatibility test and divert heat
and oil away from your plane as much as possible.
Read the film manufacturers' instructions or call
them if in doubt.
- Clean your model frequently when using your smoke
system. Inspect for seepage near control surface
hinges frequently. Smoke oils may eventually
loosen the hinges causing you to lose control of
the model.
BE SAFE & ENJOY...
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