Conference vmszoo::rc

    Does anyone in the notes file have any information on what is used
    to color model airplane fuel?  I only want proven methods, as I
    am not about to experiment with a $150 engine on methods that would
    color the fuel but might ruin the engine.  The reason is for being
    able to tell when I am running out in my chopper, when not using
    a special helicopter fuel.
    
    Ken
    
    

	Back from my course now, so watch out world.... There are
	about 1 million systems in Highfields connected to the outside
	world, ie ENET by a ONE 14k serial link, most of the time it's real
	bad news.....

	Anyway, colouring (or coloring for you folks who can't spell)	    
	fuel has received a few mentions in the Helicopter coloumn
	of RCM&E recently. It's seems too be a controversial sort of
	subject. They mentioned several flyers who colour their fuel,
	and they mentioned several flyers who are known to eat engines.
	you guessed it, same names.....

	I mixed some synthetic and castor based fuels together, it turned
	a strange sort of black colour. Something to do with the Nitro I'm
	told. Easy to see, but not sure wether it was doing the engine any 
	good. 

                                

		bob

    I have a generic recommendation for fuels:  Do not use only synthetic
    lubricants.  If you do, and you have one lean run, you WILL damaage
    your engine.  Synthetic fuels vaporize and fail to lubricate at
    a lower temprature than Castor Oil.  In most engines, the upper
    end of the connecting rod will suffer first.  I had this experience
    with my OS 40FSR last summer.  I had to replace the piston due to
    excessive wear at the wrist pin holes.  I have since switched to
    a Castor based fuel.  My next batch of fuel will be a mix of synthetic
    and castor.

    Interesting!!  The fuel I run is 12.5% nitro and 20% oil. The oil
    is 2% caster and the remaining 18% synthethic.
    
    
    						Tom

Q1? How do you color (for Bob don't no how to spell; COLOUR) fuel.

Easy really. You go to your wife's, or Mother's kitchen and get some of the
food coloring they use to hide the indiscretions of their latest culinary
achievement food dye (it's ok my wife does not work for DEC and cant read the
notes file). You add a couple of drops and Wham! Tartan fuel; well not quite
but colored anyway. 

Q2? Synthetic oil should not be used. 

Suggest you read my note #289.0. This statement is totally incorrect. I have
used Synthetics down to 2% and up to 20% by volume, some are better than
others, some are worse than acceptable. The trend as reported in some of the
Mag's to use Turbine (Mobile Jet Oil 2 etc) oil I don't personally like,
however I do know of people who have used it successfully, it does smell funny
and I think it contributes to unreliable engine performance but I have no
evidence to say don't use it. 

In F3D Pylon I use the FAI standard 20% castor 80% methanol as required by the
rules, in all my other engines 2 stroke and 4 stroke I use a 10% Synthetic FX10
oil, 5-10% Nitro, and the remainder methanol. The synthetic I use is ok down to
2% but it makes the engine touchy to needle margin. I have experimented with
Klotz KL200 down to 12% and if you are careful its ok, for safety 15% is
probably the minimum. For the Poms (sorry Brits) I have tried the ModelTec (I
think thats how you spell it) Car Oil. That's good but a little expensive.
others I have tried include Bel Ray was poor, and Delta which was good but
again expensive and difficult to mix as it is very thick. 

As said in -.1 don't run the engines lean as synthetics vaporize completely,
castor just gums up the engine. You will find you get an increase of
performance with synthetics over castor fuel, like wise the reduced oil content
give a further increase in performance due to the greater amount of combustible
material (ie Methanol and nitro). 

(IN THIS SPACE PLEASE READ THE STANDARD DISCLAIMER) 

Go Synthetic and leave the castor for curing constipation. 

John.

    In my recommendation, I was not saying that synthetics are not good
    lubricants, but that you have to be extremely careful not to run
    too hot with them.  If you need the performance (ie racing) then
    you can do better with the minimum amount of oil that your particular
    type of engine requires and synthetics will do a better job at lower
    percentage mix.  If you are a sport flyer like me, you are more
    concerned with reliability and engine life than with maximum
    performance every flignt.  The insurance of some caster in your
    fuel will help prevent disaster during a lean run.
    
    Here are some causes of lean runs that I have experienced:
    
    1.  The pressure tube falls off of the tank (or I neglect to install
    it after refueling).  As fuel burns off, the mixture will lean out
    more than normal.
    
    2.  The clunk is forward in the tank.  A hard landing or noseover
    can cause the clunk to flip forward and get caught in the front
    of the tank.  If this happens, the engine runs fine on the ground
    with a full tank, but in the air, any vertical manuvers will cause
    the engine to fuel starve.  Eventually, you will run out of fuel
    prematurely, but during the flight, you will lean out every time
    you pull up into a loop.
    

Re.7

While not meaning to be cynical but all those reasons for a lean run are the 
fault of the operator for not doing a preflight. I agree with your statement 
that castor is insurance but its like holding your pants up with belt and 
braces, overkill. The only time I recommend Castor oil fuel is in VERY HOT 
engines, ie. some of the rotating valve 4 strokes and engines that through 
necessitate of bad installation have inadequate cooling.

I don't use Synthetic oil for the improved performance, I use it because of the 
problems associated with castor oil. These are briefly:-

	. The oil forms a carbon build-up in the engine when it burns and causes
	  a varnish to form on the bore that has to periodically be removed.
	. Any dismantling of an engine for cleaning reduces the life of the 
	  engine and increases the possibility for incorrect reassemble.
	  (just read through this notes file and see the number of problems 
	  emanating from engine disassembly; I prove my point?)
	. It sticks to the model like the proverbial shit to a blanket, it's a 
	  pain to clean the model after the flight.

Synthetics however:-

	. Reduced/eliminate carbon build-up in the engine and pipe. (no engine 
	  disassembly for cleaning)
	. No Varnishing in the bore.
	. Easy cleaning of the model.
	. Reduced oil content means less nitro for the same power.
	. Less of a problem if it gets into the model. Easier to clean out.

Really if you are a sport flier "GOOD" synthetics are the way to go, in the US 
you have so many good synthetics you are crazy not to use them.

One I did not mention previously was Morgan Hobbies in Alabama. They have a 
good synthetic which I have used. The only problem for us in OZ is the price to 
get is here.

If you really want to extend the life of your engines, follow a few simple
rules and take care of your investment. I have never worn out an engine
completely. I have replaced bearings many times, but never junked an engine. 

	1. Always use an after run oil or light machine oil after each days 
	   flying.
	2. Cover the engine in the workshop to keep out all dust. The dust from 
	   sanding a model particularly a glass model is very abrasive.
	3. Don't run an engine for more than is necessary on the ground. The 
	   dust level on the ground very high. Idling on the ground waiting 
	   for takeoff causes the engine to ingest high levels of grit which 
	   ruin your engine.
	4. Always use good quality clean fuel with a final filter in your fuel 
	   can. It is not necessary to have a filter in the model if the fuel 
	   is clean going into the tank.

Don't put yourself down by saying you are only a sport flier, there is more of
you than competition fliers, many of you have a greater level of skill than a
comp flier but lack only the desire to compete. 

Give synthetics a go.

John

RE: -.8

AMEN!!  Synthetic lubricants have to be one of the best things to come down
the pike since pop-top beer cans......I ALWAYS loathed the after-effects of
castor-based fuels!

John, you've already addressed the negative internal effects of burning
castor, but how about the external effects?  I remember all too well the
castor burning onto the engine exterior, going from a golden-brown to BBQ'd-
BLACK if the engine wasn't cleaned regularly.  Engines in this condition were 
referred to by us as "Pot-Roast Specials" and it shouldn't require too vivid
an imagination to picture what one of these looked like...YUUUUUCKKK!

The negative aspects of this condition were more than cosmetic too as the en-
gine's cooling efficiency was drastically reduced, contributing further to its
premature demise.  We tried everything from carburetor "boil-out" to household
iron sole-plate cleaner to Easy-Off(?) oven cleaner but NEVER found the ideal
solvent and most of these attacked the cast aluminum if not used judiciously!

No, I could NOT be sold on going back to castor oil...why take a giant step
backward??  Castor was great when that's all there was but consider this: we
used to talk about engines having a life-span of less than 100-hours, back in
the castor-days...nowadays, the subject of life-span is never even mentioned.
Must be a message in there, somewhere!

As you said, pay a little attention to proper/adequate cooling, don't try to
tweak the very last RPM out ot an engine on each run and it should last, vir-
tually, forever.  Synthetics are the answer to one of "this"  Desert Rat's
prayers...I LOVE `EM!!!

Adios,	Al

    Too bad synthetics are pretty odorless. Like the smell of good
    pipe tobacco, the smell of castor-laden exhaust brings back
    memories of the good old days.
    
    But, I don't smoke a pipe - tastes horrible, I let others do that
    and I just enjoy the nice smell (assuming they're smoking one of
    the milder brands). And, I burn synthetic, because I get plenty
    of opportunities to smell the sweet smell of castor that other
    guys are using (like when Charlie blows his prop wash my way!).
    
    Dave

    Dave, You are a smart ass.  I'll keep my opinions to myself.
    I especially like the smell of castor on my favorite flying jacket!
    

    I've got a question, I recently bought an OS 40 fp. About two weeks
    prior, I bought 4 gallons of 5% tower hobbies fuel. I was led to
    belive 5% was,is, suitable for this type of engine and that nitro
    was only there to improve idle. Did I just throw away 30+ dollars
    on useless fuel or will I be O.K with this combo? One other question
    comes to mind, it is said that you should run all remaining fuel
    out of your engine at the end of each session. Does the momentary
    lean run serve to slowly wear down your engine or is it to brief
    to cause damage? Thanks for any help.
                                                          Jim

    Jim,
    
    5% should work just fine in the O.S. .40.  Try it before making
    any decision...as you've been told, the nitro is mainly there to
    provide a better, more reliable idle.  Unless it were some ultra
    high performance racing type mill, I can think of NO reason to ever
    run more that 10% nitro and the difference from 5% would probably
    be unnoticeable.  
    
    When you pinch off (or remove) the fuel line to run all the fuel
    out of the engine, it will not go lean enough, long enough to do
    the engine any harm. Bear in mind that the fuel you're burning out 
    was "still" metered into the engine by the needle-valve so only a 
    very slight increase in RPM will be realized before the engine quits
    ...just the same as if you simply ran it out of fuel.  Besides, you
    don't have to do this at full throttle (which might even be dangerous),
    do it at about half throttle.                          
    
    Adios,	Al
    

    Anyone having problems with fuel recently? I have a strong feeling
    that the recent heat/humidity have affected my fuel. Last weekend
    I filled the copter's tank with its usual K&B 500H dosage and flew
    for a while. No problems. Fuel normally looks a clean tinted red
    color. For some reason I don't recollect I didn't pump out the fuel
    remaining in the tank after the flight(s). About 1/4 tank was left.
    
    I fired it up last night, but noticed that the fuel had darkened,
    and seemed "thicker". _Power_was_way_down_. I drained the tank and
    re-filled from my "pump tank" on the flight box. Even this fuel
    looked darker than normal, though not as bad as the fuel in the
    copter tank. By contrast, a gallon of SIG 10RC (several weeks old)
    in a *sealed* plastic bottle was still its original color.
    
    OK -- what is happening to the fuel? Is something evaporating (the
    nitro/alky?) and leaving a higher ratio of oil?? Should I throw
    the discolored fuel away? Should I be storing the "flight box" fuel
    tank somewhere cool (it's a vented tank, not totally sealed)? Any
    other wisdom or similar experiences?? [ I have looked through notes
    156, 243 and 309... ]
    
 ------+------
    (Z[]>=====X  Jimi.
  `--'-`---
    

    Jimi,
    
    	It's my understanding that fuel onced mixed will not seperate.
    What does happen is that opened/unsealed containers of fuel can
    soak up moisture. I run S&W 12.5% and have no issue at any time
    of the year. We run this fuel in our pattern, sport and choppers
    and change nothing. One thing I do know is the S&W used new nitro
    instead of reclaimed nitro as some other manufacturers do.
    I guess that it could also be he type of oil used?
    
    						Tom

Jimi.

You don't mention what type of tank you are using but prolonged exposure (like 
12 months+) to opened tin plate cans  causes an oxidization that turn's the 
fuel a brownish color. The fuel is still usable but I suspect it is 
substandard.

If you are using a clear plastic container high intensity sunlight can also 
cause a long term degrading of the fuels performance. 

Your fuel may have some additives that are affected by high temperature,
humidity or light exposure, I cannot tell. In brief what you describe is 
unusual but not unbelievable. I suggest if the fuel if proven to be a problem, 
write to the manufacturer and ask them for a recommendation.

John

    Good article on fuels in this month's RCM...
    
    Jimi.

I've got about a half gallon of 10% fuel left which, since my son is off to 
college, will probably stand around collecting (whatever). Is there a problem 
with shelf life? How well will the fuel keep and how can I prolong it's life?

    /\
^/\/  \/\^
   Dave

    Dave,
    
    Model fuel doesn't store all that well.  The alcohol tends to attract/
    absorb moisture and the nitro evaporates, either of which situation
    (or both) renders it, if not useless, certainly sub-standard and
    problems with running, idling, needle adjustments can be experienced.
    Also, though I can't support this, I've read that this loss of nitro-
    content and moisture absorption can occur right _through_ the nylon
    jugs commonly used as fuel containers.
    
    To begin with, especially for such a small quantity, I wouldn't
    even consider storing fuel for any period over a month or so.  If
    you choose to do so, however, I'd transfer the fuel to a metal can
    which can be sealed _airtight_! and store it in as cool and dry
    a place as possible.  Personally, I'd use the 1/2 gallon in question
    for weed-killer and start fresh when yer' son returns.  Yer' likely
    to save _lotsa_ aggravation when the time comes to fire up the engine
    again.     

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    
    I second that!  I've seen enough engine problems that were caused
    by old fuel that I'll never try to use stuff that has sat over the
    winter - unless the bottle was never opened.
    
    Bill
    
    P.S. I don't second Al's weed-killer recommendation - we have enough
    	 chemicals polluting the ground as it is!

re Note 771.119 by Charlie Watt,     "NEVER leave fuel in your tank."  
    
>>  Methanol absorbs H2O like a sponge.
    
    That I understand;  I use it for dry-gas in my autos.  In microscope
    work there are times when you need alcohol with *NO* water content;
    it cannot come from a partially used container.
    
>>  NEVER leave fuel in your tank.
    
    As a wet-behind-the-ears beginner, I had and have no preconceptions
    or earlier habits here.  I ask, I observe, I think, and I probably
    do the wrong thing after all that.
    
    I observe:
    
    1)	The leave-it-in-the-flight-tank people
    
    	They attain a reasonably closed up tight system by looping one
    	of the lines from tank fitting back to the other tank fitting,
    	so the fuel cannot leak out and air (and moisture) cannot get in.
    	
    	Moisture already in the tank will be absorbed, and if much of
    	the fuel had been used, that moisture can be considerable ---
    	considerable because the exhaust system had been pumping air
    	and gunk in there to replace the fuel being used, and the
    	combustion process produced moisture.
    
    2)	The pump-it-back-into-the-fuel-can people
    
    	They don't worry about the moisture in the tank except for
    	condensation during weather changes.  (Northerners don't leave
    	vehicle gas tanks near empty during the winter.)  Evidently
    	they don't worry either about the exhaust by-products 
    	contaminating the virgin fuel still in the can.
    
    I have yet to observe
    
    3)	Any discard-the-stuff-and-start-fresh-next-time people.
    -----------------------------------------------------------------
    
    P.S.  Charlie, the problems were with the virgin fuelings, albeit there
    was some [diluted] old fuel in every tank.  This leave-it-in has been
    my practice since day one, but I am considering dumping the daily
    excess.  Now you might still be on the track, because this unopened
    fuel was purchased last year. 

        Re:< Note 309.23 by GUSHER::RYDER >

                Your symptoms  are also typical of two other problems, so
        if you continue to have them check for the following:
        
                Pinched fuel tank  vent  line.    At high RPM the pinched
        line created a vacuum in the tank and the engine leans out.  This
        is a particularly nasty problem because it takes quite a while to
        build up the vacuum, so adjusting  and  testing the engine on the
        gound often doesn't reveal the problem.   But  a  bit  into  your
        flight, whammo!  Try to blow through the  fuel delivery line into
        the tank and then notice whether you get your  mouth full of fuel
        when you stop blowing.  The nimble of mouth may see a jet of fuel
        come out of the delivery line after quickly removing it from  the
        mouth.  You may also see some fuel coming out of the  line  after
        filling the tank.
        
                Dirt in the high speed  needle  valve,  or a pinched fuel
        delivery line.  This can be  detected on the ground.  Symtoms are
        engine too rich at indermediate throttle and  too  lean  at  high
        throttle.  Disassemble and clean the carburettor, also  install a
        fuel filter.
        
                      _ 
                     / |
        |  _====____/==|
        |-/____________|
        |    |        o \
             O           \ 
                          O
         Hang in there! o_|_
                          |
             Anker      \_|_/

    My observations...
    
    The best way to describe this is that it is just like the engine
    had a cut off switch when it stops.   The engine is running and
    then it is not.  
    
    Then engine does not sound like it is leaning out or loading up
    before it quits.
    
    We have changed the glow plug, but I suppose it is possible that
    we installed a defective one.
    
    The fuel line from tank to carb is always full.  Occasionally, there
    has been a very small air bubble or two.
    
    If the radio had failsafe, I would say that the failsafe was shutting
    the engine down.
    
    The throttle *appears* to be under my control at landing.  However,
    I am not convinced we do not have some kind of interference/radio
    problem that is causing the throttle servo to close the throttle.
    The radio was factory serviced about 20 flights ago... 
    
    To add to my theory that it is a radio problem, the same engine
    outage happened a couple of weeks ago... I switched the trainer
    switch and the engine went dead.  There have also been a couple
    of times where Al did not feel that he was in control.
    
    Range checks and battery checks are all fine, batteries have been
    cycled...
    
    One other possibly related problem...  Sunday after landing and
    retrieval of the plane (it was deadstick again, so I couldn't taxi
    it back!) I noticed that the ailerons were fully deflected...  I
    don't know for sure that Al did not move them when he picked it
    up, but it sure seemed like a radio problem...
    
    =====
    
    Now, on a totally different tact, the one other difference in the
    setup this weekend was that Al was using his new fuel storage system,
    a 1/2 gallon container that did contain "FORMBY'S (?)".  He thoroughly
    cleaned it out though...  Still a variable that needs to be
    considered..
    
    Comments on the validity of the above statements welcome..
    
    thanks,
    jeff
    

    I gather that the switch from 15% to 10%, in itself, is a red herring.
    
    The switch from an open gallon of fuel to an unopened but older gallon
    of fuel may be a factor.
    
    The switch from an old, air-contaminated field can to a new field
    can is very suspect, especially inasmuch as the new fueling subsystem
    may have chemical and mechanical contaminants despite my care.
    
    External radio interference is *NOT* a factor.  The first flights
    of the day were in a populated town; the rest were 20 miles away
    in a very rural area (maybe 20 houses within a mile and no known
    radio sources).  The engine symptoms were the same --- surprising
    considering that the servo tray mounting structure had been cracked
    (maybe the previous week) and repaired mid-day between outings.
    
    A hard landing the week before may have damaged the airborne controls
    and/or the fuel system.
    
        The previous weekend's flying was terminated when the main
        landing gear was ripped from the Kadet's belly by a log that
        the nose gear had cleared; the plane then finished the landing
        rather smoothly and right-side-up, etc. The repair was made
        without disturbing the RC subsystem, so it is not known if the
        servo structure or fuel tank had any damage at that time and
        therefore during Sunday's first flight. *IF* the first flight
        Sunday was indeed terminated by the same gremlin (I had
        thought not.), then the gremlin may not be fuel at all; that
        is consistent with Jeff's feeling that it is radio, not fuel. 
    
    I will:
    
    	check out the airborne fuel system for leaks, clogs, etc.
    
    	switch back to Jeff's brand of fuel and fueling equipment.
    
    But how do I check for servo glitches?  Turn it on and wait?

    Empty your plane's fuel tank completely.

    Then borrow a tank of fuel from somebody else who isn't having
    any engine trouble.

    That's the quickest and easiest way to tell if you have contaminated
    fuel. I've had the "old, tired" fuel problem a few times and if
    I borrow a tank from somebody and the engine runs fine, then I
    know for sure it's my fuel, and if it still acts up I can be
    pretty sure it isn't the fuel.

    Dave

    Al,
    	The sudden cutoff symptom you describe is exactly what happens
    with bad fuel.  I've seen it many times.  It usually goes from full
    power to dead with no warning often on takeoff when you least can
    afford it.  Try some fresh fuel, I'll bet it will cure the problem.
    	The other possiblilty is that your clunk got stuck on a hard
    landing.  It can flip forward and stay there, causing you to run
    out of fuel soon after taking off.  Always check for this if you
    have a hard landing or noseover.  It happens often under those
    conditions.  This usually results in a dead stick during a pull
    up manuver like a loop after some of the fuel is used.  However,
    since it is running out of fuel, it leans out first.  That's why
    I would bet on bad fuel from your description of abrupt cut out.
    
    Charlie
    

I agree with Charley - it is the klunk.

Before you perform surgery here is how you check it.

   In a quiet place simply tip the plane from side to side and listen for the
klunk to slide in the tank.  If you always DE-FUEL your ship after every
day it is obvious - when it should be nearly full you can't get any fuel 
pumped out!

Here is how you fix it.

You have to hold the plane in a strategic place and impose some G forces
on the tank in the opposite direction of the crash.  In other words bang
on that sucker with your fist - sounds bad but I've seen several experienced
flyers whack their plane until that clunk slides back.

That same problem...the engine cutting out suddenly, was what
drove me nuts while I was trying to get some instructor
time.  He'd get the plane up and trimmed, then as soon as he
handed me the box, it'd cut out.  That went on from late May to
late August.

Every time, the local wags would gather around and pontificate on
the fact that I had a .25 and everyone knows that a small engine
doesn't run up here, or that I wasn't putting enough pressure in
the tank, or that my tank was too low in the plane... None of
which had anything to do with anything. 

I changed the fuel lines, I raised the tank so its half-line was
ABOVE the carb (made for a very ugly Eaglet).  Nothing worked.
Finally, I put in a new tank and it was fixed.  Why? I don't
know.  I thought I'd do a post-mortem on the old tank, but every
time I look at it I get so mad I just throw it back into the
drawer. 

Actually, I don't think the new tank had anything to do with it
either. 

>>    I will: 
>>    	check out the airborne fuel system for leaks, clogs, etc. 
>>    	switch back to Jeff's brand of fuel and fueling equipment. 
>>    But how do I check for servo glitches?  Turn it on and wait? 

    I put a vacuum testing pump on the line from tank to engine.  The fuel
    drained from the tank completely at a vacuum much less than 1 psi; the
    remaining fuel in the tank was about 1 cc, so we can rule out a bent or
    clogged pick-up line or a [still] stuck clunk.  (Beside, the engine
    never leaned out, just died.)  The condition of the fuel in the test
    jar was inconclusive; a hint of cloudiness was consistent with a
    possible drop of gunk from the exhaust-to-tank pressure line; a hint of
    lint fiber could have come from searching for a test jar while wearing
    a flannel shirt. 

    I pulled the needle valve and found a bit of debris in the aperture to
    the supply line, but not enough to stop up the flow. 

    I refilled the tank and pumped it out with pressure instead of vacuum;
    it flowed easily.  I folded the output line and applied an unmeasured
    pressure; there was no sound of leaking air or fuel from the plane, and
    when I released the line, fuel squirted across the garage floor.  So
    there seem to be no air leaks or other problems with the tank.  This
    second quantity of fuel had no trace of cloudiness, so the fueling
    system seems to be innocent of colloidal contamination. 

    I turned on the radio pair and let them sit a few hours; I have no
    evidence that the throttle servo ever moved unrequested. 

    The next step is as others have suggested:  switch back to Jeff's fuel
    [and fueling system]. 

    Al,
    	If you found any junk in the needle valve, you may have found
    the problem.  I'd still bet on watered fuel.  It happened to me
    a couple of years ago and trying a tank of someone else's cured
    it.  I dumped the remaining fuel and opened a new bottle - problem
    cured.  I never even had to take anything apart.  I think that the
    water separates and stalls the engine by fuel starving it.
    
    Charlie
    

Re: < Note 309.33 by LEDS::WATT >

>                           -< Water's still my bet >-

Be a little careful; water is not the problem it is made out to be. As is
already stated methanol is hydroscopic (sp), it readily mixes with water. I
have at my club field demonstrated to disbelieving members the following test.

	1. I poured about 20oz of 20% Klotz, 80% methanol fuel into a bottle.

	2. Added to the fuel 1oz of water.

	3. Mixed  to dissipate the water.(the fuel turned a milky color)

	4. Fuelled and started the engine which ran for a complete tank.

Some adjustment to the needle was required and performance was down; but it
still ran a full tank.

John

    One of the reasons that methanol makes a lousy motor fuel for cars
    is the water problem.  It is true that you can add water to the
    fuel and it will go into solution.  It is also true that under the
    right conditions it can separate!  This does not happen if you add
    some methanol to water but if the solution is mainly methanol it
    does happen.  Believe me, I have seen several examples of abrupt
    engine failure from bad fuel, usually on takeoff where you require
    full power.  I did this three times in a row once and the damn thing
    ran fine on the ground, but when I throttled up to take off, it
    got about 10 feet up and signed off without warning.  (It wasn't
    lean either)  I borrowed a tank of fuel and things were fine.
    
    Charlie
    

    Re .35.... I too have had the same exact circumstances happen to
    me. Ran fine on ground in all positions, take off down the runway
    get 10 feet in the air, engine quits instantly. I solved the problem
    by buying new fuel.
    
    
    						Dave
    

        Re:< Note 309.36 by TARKIN::HARTWELL "Dave Hartwell" >

                I also  have lots of experience with the "running fine on
        the ground but  quits  in the air" syndrome.  I DISAGREE strongly
        that the primary cause of this can be bad fuel.  I have seen that
        the problem can be COMPUNDED by a fuel change, not necessarily to
        bad fuel, just different fuel.
        
                My  most  recent experience is with  my  Super  Sportster
        Saito  .80  engine.    I  had exactly  this  problem  when  using
        perfectly good 4 stroke fuel, buch much less of a problem with my
        regular  2  stroke  fuel.  Also, the problem got  worse  in  cold
        weather.  I had resigned myself to just using 2  stroke  fuel  in
        cold  weather when the engine decided to get real cranky and  not
        care  what fuel it was using.  I finally took the engine  out  of
        the  plane, diassembled and  cleaned  the  carbutettor  and  that
        eliminated the problem totally.
        
                I also have an explanation  for the syndrome.  It sim ply
        has to do with the nose  up  attitude  on  takeoff!   I am pretty
        certain the problem we are discussing at the moment was caused by
        the gunk in the carburettor.  Gunk in  the  main needle valve has
        the interesting property that at low and medium throttle settings
        you  can  often  compensate for it by adjusting the needle valve,
        but  invariably  it will cause problems at full throttle and nose
        high attitudes.
        
                      _ 
                     / |
        |  _====____/==|
        |-/____________|
        |    |        o \
             O           \ 
                          O
         Hang in there! o_|_
                          |
             Anker      \_|_/

    Gunk in the carb will give you fits.  If you find something in there
    that shouldn't be, that's probably the problem.

    However, I would like to put in a statement that I have had bad fuel
    many times with the same symptoms you have described (I learn slow
    :-) - it runs fine on the ground and dies as soon as you get it in
    the air.  I've experienced this with a .40, a .25 and a Cox .049
    (which doesn't have a carb - just needle and reed valves).  

    Once, with the .049, I fought with it for 8 to 10 tries then gave up
    and went home to clean out the needle and reed valves.  The next day
    I went back to the field and had the same problem.  The VERY FIRST
    time I put new fuel in it, it ran the full tank of fuel with full
    power.  As a test, I put a tank of the old fuel in it.  As expected,
    the engine died as soon as it got in the air.  
        New fuel: runs great.     Old fuel: dies unexpectedly.

    My conclusion is this: 

    Fuel that has been opened (exposed to air) for too long DOESN'T WORK.

    I don't know if it's because water gets in or the nitro goes out or
    both or maybe even something completely different.  All I know is
    that when I get this problem now, the first thing I try is to
    COMPLETELY EMPTY my tank and then borrow a tank of known good fuel
    from someone else.  90% of the time it's the fuel.  (At least for
    me...)  I suppose guys like John Chadd never have this problem
    because they use up their new gallon of fuel in a couple of days
    (before it has a chance to go bad).  :-)  :-)

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    Has anyone had any positive or negative experience running anything
    other than COX fuel in various .049's?  I have an .049 Tee Dee that
    I have been running a lot of fuel through and was thinkin of purchasing
    a gallon of something for me and a friend to share in our engines.
    
    Thanks for any input
    John

Re: .58

I used to run a TeeDee powerpod on a glider I had and I ran Fox Missle Mist 
through it ('cuz that's what I flew my power planes with) I believe it was 25%
Nitro? Never ran into any problems and the engine wasn't any more sensitive 
for the needlevalve settings.

The TDs need high nitro, at least 15% and 25% is better.  I
learned this when I tried to run my TD on 5%; the plane barely
flew.  A kind soul loaned me some TD fuel and the thing went like
a shot (with my usual result).

I wonder if running a higher nitro in my .20 will help...I now
run 5%, perhaps 10% would be better.  I have noticed that my
engines seem to run hotter than the others, and attributed it to
the old engine jinx.  Everyone at the club runs 10%, I even have
to request the 5% special from Phylin' Phil because he does not
stock it.

John Chadd: From this discussion I gather that the pylon engines
running 0% FAI (I assume that's what you run???) have a serious
heating problem that I suppose you have to modify the engines to
handle.   

I've had a problem with old fuel and I thought I'd enter a note
here to comment on it and to ask a question.

I've had some problems with my K&B .20 deadsticking (OK, so I'm
prone to understatement!).  This has gotten worse over the last
few months, and Saturday it got bad enough that I took the engine
out and prepared to send it back to the factory.  It would take
maybe 15 to 20 seconds to wind up when you give it full throttle,
for one thing: I think this a problem with their carb, the engine
loads up terribly, but if you set the idle leaner it gets hot and
dies in the air.

This one isn't so bad, its the good old Dying Just After Takeoff
probem that's been especially frustrating.  Anyway, I thought I
had the goods on the Evil K&B this time -- Inspector Colombo
caught it messing up without an alibi, and I got it ready for
shipment.

Then a funny thing happened Sunday.  I took the Thunder Tiger .15
out and had a devil of a time getting it going.  It would start
fine and idle well, but when you pulled the glow and wound it up
it would die after 10 seconds or so.  If you left the glow on it
worked great.  I changed the plug several times, since that was
the obvious.  Then I removed the carb and blew it out; still no
luck.  Of course, the local wisdom was that it was a small engine
which don't run too good up here, and I had better go to 15% fuel
because they need it...the usual stuff, bless their hearts.

Randy Oswald came over and offered me a tank of his Tower 10%, lo
and behold my wonderful TT .15 was back!  So I've got bum fuel.

Now, this is a gallon of Magnum 10%, purchased early last summer
from Phlyin' Phil, of course.  I've kept it tightly closed in my
shop which is in the basement and is heated, so I know it can't
be due to condensation.  There ain't even enough moisture in the
air up here to kick CYA, least of all mess up a jug of fuel.  And
anyway, I've kept a close watch on the jug for just that reason
and I know for fact its been dry.

But there's the evidence; the fuel must have gone bad in the 8
months or so since I bought it.  I can't possibly use a gallon of
fuel in that time since I usually crash long before I use up the
pint of fuel I take to the field.  Its now about half gone -- any
comment on this?  I know John Chadd has entered some notes on old
fuel and I've read them -- is there any other wisdom?  I need to
buy my fuel in smaller quantities from now on, at least until I
learn to fly!

Worse than all of this though, now the K&B has again copped out
on a bad fuel alibi, so  I've got to give the blasted thing
another chance.  Curses, foiled again!

    Re: .39
    
    Sounds very familiar. If you'll look back in the "engine wizards"
    note from this past summer, you can see that I was having the exact
    same problem with an OS46SF. Keep the glow warmer on and it would
    rev like crazy. Take it off and it would die right out. Use someone
    else's fuel and it ran fine. Go back to my fuel, and it would run
    ok. Take off, and it would die. Use someone else's fuel and it would
    run and fly fine.
    
    Turns out it wasn't the fuel. The carb simply wasn't adjusted properly.
    Once evil Eric put his mind to working and put the touch on the
    carb, it ran fine from then on. I found with that engine that I
    had to lean it out to max rpm's before takeoff, and then back it
    off three clicks. Then go fly.
    
    I'd get your local engine wizard working on the carb.
    
    Steve

I used to be a partner in a company that manufactured over 1/2 of the
commercial fuel produced in Australia. I know the product produced and the
containers were of the highest quality. I also know that many shops had the
product on the shelf for in excess of 12 months yet it still performed well for
the user. 

I have seen many examples of bad fuel, what generally is common to all of them
is a change of color and smell. Moisture is not the problem a lot of the old
timers make out, agreed in castor or mineral oil based fuel it can create a
carburettor blockage, however with synthetic oil a considerable amount of water
can be added to the fuel and it mixes. Remember methanol is hydroscopic and
therefore wants to absorb water, a small amount does little harm. 

What I have noticed is that many of you use plastic containers for fuel storage
which I believe contributes to the rapid deterioration of the product over
time. A steel can with a good seal will give better service and keep the fuel
better and safer. 

John

OK.  I recall a few notes ago there was a comment that the
storage can should not have a plated lining.  Can we assume that
a can made for gasoline would be suitable?  Otherwise, its pretty
hard to get a can without a plated liner nowadays.

This sour fuel problem has followed me through several gallons of
fuel now, I'm getting tired of it!
__________________________________________________________
A SLIGHT FROWN CREASES HIS BROW AS A TINY GLIMMER OF THOUGHT
MAKES ITS WAY THROUGH THE DRUG-FOGGED BRAIN THAT BARELY SURVIVED
THE 60's...

Say, I don't have to take a metal can to the field, all I need to
do is store the fuel in a metal can...then I can transfer it to
the plastic container I take to the field on my normal bi-weekly
basis!

    I borrowed a COX .09, and the owner suggested I get some COX fuel for
    it.  Tom's Hobby Korner didn't have it in stock; Tom suggested some of
    his 35% fuel instead.  I asked what if I were to use lower nitro fuel,
    and Tom said I would get less power.  Now this .09 is going on an old
    glider; power is not a concern; I elected to use the fuel I have.

    But I'm a bit uneasy.  Is that really the only difference?  I believe
    COX fuel sells for about $125 a gallon; is that only because it comes
    in tiny cans?   Would there be an important difference in lubricants?

    When I wrote the previous note, the RC11.A file was being created. 
    Upon checking later, I found [and moved] the following entries.

    But instead of deleting my question, I'll let it stand; I'm still
    uneasy.

    Alton, a man with a borrowed engine.

Just to reinforce the last comment: you need high nitro in the very small
engines like the TD. I too was loaned some 30% fuel, and an engine which had
virtually refused to run went up like a rocket. 

Fritz Bien explained that the very small carburetor made the needle setting
extremely critical, and that using a high nitro fuel reduced the sensitivity
to the setting. Something about the nitro carrying with it the oxygen needed
for combustion???

Re: Note 309.47 by 29497::TAVARES "John -- Stay low, keep moving" >>>

> John Chadd: From this discussion I gather that the pylon engines
> running 0% FAI (I assume that's what you run???) have a serious
> heating problem that I suppose you have to modify the engines to
> handle.   

John,

The heat problem we have with the FAI is due to extracting 3 BHP and above from 
a 40 at 25,000 - 28,000 RPM. Agreed Nitro would run the engine cooler but at 
that sort of performance it is bound to get hot.

Re the TD's: We used to run them in a �A event. I still have a couple at home 
which percolate quite nicely on 50-70% Nitro. We had overheating problems with 
them untill we started lapping the liner with Tooth Paste as a piece of tapered 
brass turned just smaller than the bore.

For sport use can I suggest you:-

	1. Try to obtain a modified needle assembly, I think made by COX or it
	   could have been Dubro with a very fine taper. The standard needle is
	   too course and therefore touchy to adjust.

	2. Get a ball joint swage. It is a tool that allows you to tighten the 
	   ball joint on the bottom end, improving performance and engine life.

	3. Don't over prop them, let them run fast. Too much prop increases the 
	   heat.

I used the GlowBee heads no the Cox, it may not be any help but it's worth 
trying one.

Hope this helps

John.

    
    I have a question that has probably been aske before but I can't find
    it. Some of the members in my club told me that if you ran your engine
    with 15% nitro fuel, you can not go back to 5% after on the same
    engine, that it will not run good. Is this thru and why?
    
    THanks
    

Up to 15% nitro is low nitro fuel and it has little if any effect on the 
engine. The nitro engines do run looser and cooler all things being equal, but 
at the sort of performance delivered by a sport engine it is of no concern. If 
you run 25%+ in something like a Ducted Fan engine you "could" experience some 
problem after prolonged operation.

I will ask the question; "why run 15% nitro", the performance improvement will 
be minimal if any and the reliability will be no better than achieved with 5%. 
In most cases Nitro above 5% is a waste of money.

John

    At the higher altitudes above 7200', it does help to compensate for the
    lack of oxygen.  I get just about 1000 extra r's.  Still it's not that
    great a difference to warrant $2 to $3 extra per gallon.  I, too, have
    heard to story of not going from 5% to 15% then back again.  The story
    holds about a much water as going from one brand of car oil to another.
    It has no effect.
    
    John

Boy, you should hear the local wags talk about 15% nitro...need
it up here to keep the engine lit, them small engines like to
have high nitro, gotta have the nitro to get the power.

I run 10% now because when I used to run 5% and had an engine
problem they'd say first off -- how much nitro you running?  I'd
say 5% and they'd say nope not enough nitro up here, need 10% at
least and 15% is about right.  Then they'd walk away saying get
some 15% next week, and that's the extent of the help I'd get.

Ivan Munninghoff, our local pattern whiz and ducted fan jockey
uses 5% Tower in everything, even the ducted fan engines.  He's
been doing it for years and has had no problem with the engines
(though the DF performance is a tad weak).  But then he doesn't
need help from anyone.

     
    To be a little bit more precise, this is what the guys told me. Feel
    free to set me staight on this because it makes sense but it might be
    dead wrong to.
    
    When you run your engine at a higher nitro % the engine heat's more and
    the parts expand and wear to that temperature expansion. When you go
    back to a lower nitro % the engine does not heat as much and you do
    not get the compresion you should because the piston does not expand
    to the same amount leaving more space between him and the sleeve.
    
    Is this last statment thru or false?
    Is there a nitro % difference not to brake before you can't come back?
    [ for example:(15%-5%)=10% difference]
    
    Thanks
    
            Jacques
    
    
    
    

    Hopefully John Chadd will pop in here soon. I believe it was he that
    stated that high nitro fuels burn cooler. John should have some input
    since he's run everything up to straight nitro with a pinch of oil
    (from the sounds of it 8^)

    
    
             Perhaps I'm wrong or have misunderstood.. But I recall
       that the higher the nitro the cooler the engine runs due to 
       the fact that nitro "burns" quicker thus causing more power
       but less time for the metal of the engine to absorb the heat.
    
            I  just asked an quicky 500 pilot and he believes the same.
       Kevin

    
    Well what if it is cooler. Does the principle of running at a
    different temperature wear the parts differently, preventing me from
    running my engine at 5% nitro after it has run with 15% or 25%?.
    Will I still have a good running engine?.
    
    Thanks
    
    Jacques  

Now that you mention it, I do believe that both Clarence Lee and
Stu Richmond have mentioned in thier respective columns that
after an engine is run with high nitro fuel (above 15%) that it
will not run well with low nitro fuel.  I do not recall them
saying exactly why, though the previous explaination seems
reasonable.

The following is an extract from a fuel article I put in our newsletter, it may
be of interest. 

As to Nitro fuels running cooler than no nitro fuels, it is true "but"; only to
a point. If you heap in the nitro you will get more power; power is energy
which in turn produces heat. 

I had a length discussion with Stu Richmond on this subject when he visited
Australia in 1987. From that discussion I believe our thoughts match which is
it does not matter within normal usage. 

John













				Methanol Fuel 

Fuel technology is a modest and not very highly publicised branch of our sport
with the result that the average modeller, including most pylon flyers who are
always after more horse power knows very little about the fuel he or she uses
than about any other aspect of their craft. 

This is to the competitors regret as engine performance, engine life depend not
only on engine design and workmanship, but also on the characteristics of the
fuels used in them. Methanol is such a great base fuel it must have been
designed for model aircraft engines and more specifically for pylon engines. 

People who are suffering from narrow needle margins should again look at their
engine set ups, because methanol has very wide explosive limit - between 6% and
21% mixture strength. I've seen so many piston liners destroyed due to lean and
undercompressed and over loaded engine runs which in turn lead to other
failures. Methanol also has a very low calorific value (5330) petrol has 10,000
calories. A calorie is energy or heat energy available in combustion. Methanol
also has a very high octane rating or SIT (Spontaneous Ignition Temperature). 

Methanol SIT is much higher than petrol, methanol (475c), petrol (280c), and
the other most fascinating thing and which keeps our little power houses cool
is the latent heat of vaporisation i.e. the amount of heat energy required to
convert methanol from a liquid to a gas. This is very important because our
motors are so small in head and surface area to conduct heat away into the
atmosphere - methanol due to its latent heat requirement and low calorific
value requires nearly 3 times the fuel flow into the engine so that the mixture
is within its correct explosive limits absorbs an enormous amount of heat
energy back from the motor, and in turn this heat also vaporises the methanol
ready for combustion and therefore cooling the engine. We can compress methanol
much higher than petrol be cause of the octane rating, or SIT. This is where
methanol motors in compression to petrol motors put out more horse power and
also run cooler. 

    
    	Last night I got a call from two of my fellow modelers asking if we
    were going to be putting a fuel order together.  In order to get around
    the $ 5.00 per case hazzardous materials charge from UPS we try and get
    a group of guys together to buy 10 cases at a time.  This was we have
    the fuel shipped common carrier and delivered to a fellor modelers
    automotive business.  Anyways, seems they'd been pricing fuel in the
    area stores to the CT. valley and prices ranged from 8.95 for Cool
    Power 10% to 24.00 for Red Max 15% per gallon.  The prices rise is
    supposed to be driven from the Nitro shortage.  I called and spoke to
    the guy we buy our fuel from and he informed me that he'd been
    contacted wednesday night.  They were offering him 100.00 a gallon for
    his nitro.  He presently has 68 gallons of it with three 55 gallon
    drums scheduled for reciept in week one July.  OK so as prices go we're
    still getting our fuel for 34.00 a case for 12.5% shipped by common
    carrier. But when his present 68 gallons runs out the new fuel will
    cost an additional 8.00 a case or 42.00.  I'm wondering what others are
    seeing?
    
    
    Tom

Nitro shortage...any idea why; don't tell me Saddam Hussein has
got his fingers in that pie too!

A month or so ago I noticed an increase in my favorite Byron's
and mused about how as soon as I discover something the price
goes up.  We've had a general increase of about $1 a gallon
around here.

    I put it in the DECRCM file but didn't copy it over to here.
    
    The major supplier in Texas burnt. WR Grace stated that they'll only be
    able to supply about 30% of the demand. Tom's Hobby Korner in
    Chelmsford MA used to make fuel (up until last year) and he's was
    contacted by Tower to supply them (he's out of the business to stay, he
    said) This info is from talking to him.

    What is the effect of running my OS 46 ABC, used to a steady diet
    of 10~12% nitro the 100+ hours it has run, on FAI fuel (i.e.
    75/25 Methanol/Castor nitroless fuel?)
    
    This will happen when I take a Gremlin along to fly in the
    sub-continent, when I go visit my wife to see if she still remembers me
    - sometime end August...
    
    Of course, I use 50/50 castor/synthetic mix, so pure castor might mean
    things get gummed up, but am I gonna be hoiting it, or not?
    
    Remember that the entire world, outside of the US, is lives below the
    nitro-poverty line, unlike you yanks, and n'er seen a drop of nitro in
    their lives!
    
    ajai

    Question ! What have the prices been like for fuel over there in the
    US ? I just bought a box of 15% 'pink gin' and it cost (at $1.40 to the
    Irish pound) $19.60 a gallon. Fuel is Sort of hurts ! Fuel comes from
    the US. Will put the name/manufacturer of it in on Tuesday.
    
    And whats worse is that it is a US gallon which is not the same (read
    smaller) than the European gallon. 
    
    Of course the Yen is all over the place with OS stuff jumping. And the
    shops seem to always forward the increase but not the decrease !
    
    
    Eric.

    I just bought pattern fuel and I paid $11 per gal for 10% nitro
    including shipping.  We now get hit with a $1.50/gal extra charge to
    have fuel shipped UPS.  $19.60 a gal sounds pretty high but you pay
    twice what we do for gasoline also. :-(
    
    Charlie
    

Article: 11271 of rec.models.rc
Xref: undergrad.math.uwaterloo.ca rec.models.rc:11271
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undergrad.math.uwaterloo.ca!watmath!watserv2.uwaterloo.ca!torn!spool.mu.edu!uwm.
edu!cs.utexas.edu!swrinde!dptspd!TAMUTS.TAMU.EDU!zeus.tamu.edu!tskloss
From: [email protected] (SKLOSS, TIMOTHY WILLIAM)
Newsgroups: rec.models.rc
Subject: Water in FUEL, a solution!
Date: 24 Aug 1993 11:23 CDT
Organization: Texas A&M University, Academic Computing Services
Lines: 55
Distribution: world
Message-ID: <[email protected]>
NNTP-Posting-Host: zeus.tamu.edu
News-Software: VAX/VMS VNEWS 1.41    

This just dawned on me.  If you have a problem with water in your fuel, there
is a way to simply reduce it to below part-per-thousands level.

In my lab, I am using molecular sieves, a type of porous crystal that lets
molecules of certain sizes inside.  Once inside, the polar nature of the 
crystal structure binds to other polar molecules (e.g. water) and won't let
it out without lots of heat.  They hold approx. 20% of their own volume in 
water and can be rejuvinated by simple heating in an oven for a few hours
above 300 degrees F (or above 120 deg. C but not over 370 deg. C, 700 deg. F).
While still hot, transfer to a glass bottle (wide-mouth is good, pickle jar)
and cap tightly after a minute.

Source:  I get mine from our stock room, but I believe that they should not be
hard to find in the real world since they are cheap.  Reagent grade sieves
that I use are about $7.00 for a pint and a half (1/8" dia beads), so normal
quality should be less.

Important:  Molecular Sieves (also called zeolites) come in different pore
sizes and the one we want is size 3A.  3A stands for 3 angstroms, the size that
lets water in, but not methanol or anything else larger (nitromethane, oil).
Size 4A will adsorb (not absorb, difference here) methanol as well, and thats
bad for us.

Also important!:  The sieves may make dust by rubbing together, so a final 
filtering into a clean container is best before heading out to the field.  the
fuel should be clear, not cloudy; otherwise you may have accerated engine wear.

This will help those who demand high performance from their fuel for their
high performance engines--helicopter, ducted fans, competition.  Why go out
with questionable fuel?  Rejuvinate that old fuel thats been laying around open
for a few years...:-)   3A molecular sieves are used in the ind. drying of 
nitromethane, and can be used for just nitro if you can find a cheap source
of it wet (wet stuff is less attractive, but now we can get around it).

e-mail me if you need more info.  I am sorry for the lack of sources, but if
there is enough response, I could poke around here at work and try to find
local, or mail-order sources.  This stuff has been used extensively in the 
chemical industry since it's synthesis in 1957, so there is an awful lot of
it around; you just have to know where to look.

BTW- the molecular sieves are non-toxic (don't put them in your mouth since
they give off a LOT of heat when they adsorb water.  Basically, they are a
form of glass and sand...

/------------------------------------------------------------------\
|* *(* (**)(* *)* *)*|                 Tim Skloss                  |
|*  *   \/  \/  *   *|  Texas A&M University, Dept. of Chemistry   |
|*    /=========\   *|       College Station, TX 77843-3255        |
|*    | OXFORD  |    |    LABORATORY FOR MAGNETIC RESONANCE AND    |
|     |  mags.  |   *|             MOLECULAR SCIENCE               |
|*    |  RULE!  |    |           voice: (409) 845-4459             |
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|      ==     ==     |  My opinions do not reflect those of TAMU   |
\------------------------------------------------------------------/