Author Topic: FAI fuel question (Read 5734 times)

Ted Fancher · « **on:** September 12, 2019, 10:23:12 AM »

I've got a "unique" fuel consumption problem with a "senior age" stunt ship from the mid 1980s I'm wanting to fly again. Not enough room aft of the engine for the use of conventional nitrated fuels...even 5% makes it impossible to complete patterns.

The last time I did fly it I was able to obtain FAI fuel at the LHS but that is no longer an option. My understanding is that FAI fuel is a combiation of methanol and castor oil but I'm uncertain of the percentage of each when mixing.

Any of you got the goods on that? Or, for that matter, whether any of my assumptions re methanol/castor are incorrect.

Thanks in advance.

Ted "Too Old for the Show" Fancher

Brett Buck · « **Reply #1 on:** September 12, 2019, 10:54:10 AM »

Quote from: Ted Fancher on September 12, 2019, 10:23:12 AM

I've got a "unique" fuel consumption problem with a "senior age" stunt ship from the mid 1980s I'm wanting to fly again. Not enough room aft of the engine for the use of conventional nitrated fuels...even 5% makes it impossible to complete patterns.

The last time I did fly it I was able to obtain FAI fuel at the LHS but that is no longer an option. My understanding is that FAI fuel is a combiation of methanol and castor oil but I'm uncertain of the percentage of each when mixing.

It's 80/20 methanol/castor. But I think we should be able to come up with a less radical solution to this issue, like a bigger tank in the same space, even if we have to modify the tank compartment. You have about as much as you can fit a relatively simple tank shape, but we have done some pretty crazy things to fit in more power.

Brett

Howard Rush · « **Reply #2 on:** September 12, 2019, 11:52:06 AM »

D. Fitzgerald has the technology to make carbon fiber tanks of any shape.

Tim Wescott · « **Reply #3 on:** September 12, 2019, 11:58:25 AM »

If it has almost enough space, add Coleman lantern fuel to your Nitro fuel. No more than 2 ounces/gallon. It'll bump up the fuel efficiency, and make it easier to start on cold days.

I flew that overweight Somebodyized (who was that guy??) Twister for years on a 4 ounce tank and a 46LA. On straight GMA 10% fuel it'd poop out in the middle of the clover. With Coleman fuel it'd last 6-10 laps past (very reliably, too).

Jack Pitcher · « **Reply #4 on:** September 12, 2019, 12:07:30 PM »

No less an authority than Bob Emmett put me on to adding Coleman lantern fuel. His rule was 4 oz per gallon. It made a significant difference.

Jack

Peter in Fairfax, VA · « **Reply #5 on:** September 12, 2019, 12:31:24 PM »

Well venturi size and prop can influence economy, too. I run an LA .46 on a 12-5 Rev-Up cut to 11-1/2" and get the full pattern on 3-1/4 oz on roughly 10% nitro. If I go to 3 oz, it cuts in the clover. What's your engine?

Randy Powell · « **Reply #6 on:** September 12, 2019, 12:58:28 PM »

Hey, Ted back flying. I'm excited.

Trostle · « **Reply #7 on:** September 12, 2019, 12:59:21 PM »

Another solution would be to put a "thimble" type cap on the tank where you have the room to do so. Size can vary to suit. Cut a hole on the top (bottom?) of the tank the size of the "thimble diameter so that the fuel in the thimble can dump into the main part of the tank. This is assuming you have a wedge tank with a "normal" configuration.

I have not done it but have been told by an experienced flier that I rely on for this kind of information that it works. Does not seem to change the way the engine sees fuel coming from the tank. Probably be best to use muffler pressure.

Keith

Perry Rose · « **Reply #8 on:** September 12, 2019, 01:09:24 PM »

Your engine will determine how much and what kind of oil to use in the fuel.

Tim Wescott · « **Reply #9 on:** September 12, 2019, 01:17:47 PM »

Tip tanks?

Ted Fancher · « **Reply #10 on:** September 12, 2019, 01:22:55 PM »

Thanks for the replies, guys. This is likely a one time operation to get my old 1986 Nats winner in the air one last time for the Meat and Meet and, maybe, Golden state. It's not critical enough to modify the airplane or make a new tank (this plane was originally made for a four stroke and had the nose shortened appropriately. that plus the header and pipe make the space all but impossible to squeeze anything bigger into it).

I like the idea of the Coleman lantern fuel as the run is only about 30-45 seconds short of enough for the .46 VF. Might be worth a shot as the simplest in time for flying Sunday.

Randy, don't get all excited (yeah, right), this is hardly a rebirth. More a desire to see the guys and participate at Jimby's contest. I've got so many hitches in my get-a-longs nowadays (and no convenient place to fly) that I'm unlikely to rejoin the parade on a regular basis.

Ted

p.s. thanx to all for your suggestions

Alan Resinger · « **Reply #11 on:** September 12, 2019, 01:55:44 PM »

Ted,
We could try mid air refueling.😁😁😁

Bob Whitely · « **Reply #12 on:** September 12, 2019, 02:14:48 PM »

Ted, I have run into this problem a couple of times and there is a very easy immediate fix. Get 10 to 18 inches of fuel tubing,
put it in the tank compartment however it fits and done. Just make sure it goes from filler or pressure tube to the tank. Works
every time, no muss, no fuss! Easy, Bob

Peter in Fairfax, VA · « **Reply #13 on:** September 12, 2019, 02:42:36 PM »

The FAI fuel is not a bad idea, if you actually have any. As far as oil, maybe half castor, half synthetic instead of all castor. 20% total oil is a good starting point.

Yet another idea is to effectively change the venturi slightly by adding an air filter.

Ted Fancher · « **Reply #14 on:** September 12, 2019, 04:45:15 PM »

Quote from: Trostle on September 12, 2019, 12:59:21 PM

Another solution would be to put a "thimble" type cap on the tank where you have the room to do so. Size can vary to suit. Cut a hole on the top (bottom?) of the tank the size of the "thimble diameter so that the fuel in the thimble can dump into the main part of the tank. This is assuming you have a wedge tank with a "normal" configuration.

I have not done it but have been told by an experienced flier that I rely on for this kind of information that it works. Does not seem to change the way the engine sees fuel coming from the tank. Probably be best to use muffler pressure.

Keith

HI Keith!!

Been there and done that. problem was the cap on the bottom would suck up all the fuel during the first loop of the clover and the engine would quit with fuel still in the added "reservoir". That tank went bad anyway and between Brett and I got a new one built without the extra reservoir and it's just not cutting it. Uncle Jimby brow beat me into flying at his contest weekend after next so now I'm trying to make the resulting sow's ear into a silk purse but refuse to try to make another very complex...especially even a more complex-er one!

Its 46VF powered so the five ounces that fits in the space needs some help. I figure the Coleman Lantern fuel suggestion is as far as I'm willing to go since I've no smaller venturies. If that doesn't cut it I'll just fly the old Ruffy in "Expert (yeah, right)" as well as Classic and say I did so on purpose so I (probably) wouldn't beat all the hot shots with their "modern" fleet.

Ted

Ted Fancher · « **Reply #15 on:** September 12, 2019, 04:50:43 PM »

Quote from: Peter in Fairfax, VA on September 12, 2019, 02:42:36 PM

The FAI fuel is not a bad idea, if you actually have any. As far as oil, maybe half castor, half synthetic instead of all castor. 20% total oil is a good starting point.

Yet another idea is to effectively change the venturi slightly by adding an air filter.

Thanx, Peter. Alas, I'd have to blend my own FAI stuff and a brief search locally didn't turn up any small quantity source of methanol.

I'd been running two layers of nylon stocking filters back when I was last trying to fly it (a year+ ago) and I've found some of much smaller mesh that I've installed since trying to get it in the air again. Hoping that and the Coleman additive will give me the last thirty second I need. Too old and too lazy to fret over it any more than that. Will just fly my Classic ship with the "Big Boys".

Ted

Ted Fancher · « **Reply #16 on:** September 12, 2019, 04:53:37 PM »

Quote from: Alan Resinger on September 12, 2019, 01:55:44 PM

Ted,
We could try mid air refueling.😁😁😁

Alan,

SOLVED!!!!. You bring your tanker and we'll pull it off between the horizontal eights and the squares just to be sure it's topped off in a a timely fashion.

Ted

RandySmith · « **Reply #17 on:** September 12, 2019, 05:21:07 PM »

Quote from: Ted Fancher on September 12, 2019, 04:45:15 PM

HI Keith!!

Been there and done that. problem was the cap on the bottom would suck up all the fuel during the first loop of the clover and the engine would quit with fuel still in the added "reservoir". That tank went bad anyway and between Brett and I got a new one built without the extra reservoir and it's just not cutting it. Uncle Jimby brow beat me into flying at his contest weekend after next so now I'm trying to make the resulting sow's ear into a silk purse but refuse to try to make another very complex...especially even a more complex-er one!

Its 46VF powered so the five ounces that fits in the space needs some help. I figure the Coleman Lantern fuel suggestion is as far as I'm willing to go since I've no smaller venturies. If that doesn't cut it I'll just fly the old Ruffy in "Expert (yeah, right)" as well as Classic and say I did so on purpose so I (probably) wouldn't beat all the hot shots with their "modern" fleet.

Ted

Hi Ted

The 46 VF should do a whole [pattern on 6 ounces, maybe less.
I do remember building several of these for you, Many in AAC configurations, and I remember you wanting to use the silver Nickle plated OS SF Needle assemblies, These were small diameter, and Most everyone else used the ST ot PA size ones, these are maybe 20 to 25 thou larger.
The small OS NVAs cause you to use more fuel, and good bit more, If this is the case you could swap to a PA or st NVA, Using White gas, Coleman fuel, Acetone ( this is what i use acetone ) will help, That engine runs well on a 265 to 290 venturi, Most used a 281, So check what you have in that 46
I seem, to remember you running these at a couple 1000 RPMs higher than others, I was sure it was the small spray bar that lead you that direction.
and as alway if I can help you with this I will do what I can

Remember you could also run an 8 or 6 ounce plastic tanl plumbed uni, They work well with the VF too
Randy

Ted Fancher · « **Reply #18 on:** September 12, 2019, 05:50:58 PM »

Quote from: Bob Whitely on September 12, 2019, 02:14:48 PM

Ted, I have run into this problem a couple of times and there is a very easy immediate fix. Get 10 to 18 inches of fuel tubing,
put it in the tank compartment however it fits and done. Just make sure it goes from filler or pressure tube to the tank. Works
every time, no muss, no fuss! Easy, Bob

Wow, Whitley!

I've heard other guys call you a genius but just sort of scoffed at 'em after you dorked that ship at your feet in the middle of the overheads at that airshow down at Edwards AFB a "few" years back. But now...an 18" long tank reservoir! Who'd-a guessed! As a matter of fact, I think the ship now in question is the same one I flew for the gathered multitude in your unfortunate absence come show time!

Trouble is it's that airplane I built for a four stroke with the inch or more shorter nose due to the extra weight of the planned motor. I sorta doubt there's room what with the tank, the header and the pipe sharing the available space. I will definitely check it out however...maybe run it aft into the pipe tunnel and then back or something.

Ted

Ted Fancher · « **Reply #19 on:** September 12, 2019, 06:18:29 PM »

Quote from: Brett Buck on September 12, 2019, 10:54:10 AM

It's 80/20 methanol/castor. But I think we should be able to come up with a less radical solution to this issue, like a bigger tank in the same space, even if we have to modify the tank compartment. You have about as much as you can fit a relatively simple tank shape, but we have done some pretty crazy things to fit in more power.

Brett

Hi Brett,

Thanks for the willingness, my friend, but I'm unwilling to go that far for a one shot deal at the M & M. I'll either find some of that Coleman stuff to try or just fly the Ruffy. I've got other stuff on my plate now and the airplane stuff has already become too time consuming...to say nothing of frustrating. For some reason I can't even find Coleman Lantern fuel any where on the Peninsula. Weird.

Ted

Whitley's long skinny tank sounds of interest, however. Don't know how to insulate it from the header heat though.

Balsa Butcher · « **Reply #20 on:** September 12, 2019, 06:37:19 PM »

Ted: I can bring some FAI fuel to the M & M if you want to give it a try. I use it in my MVVS engines.

bob whitney · « **Reply #21 on:** September 12, 2019, 07:05:32 PM »

once had an os 40 ship that was a little heavy tank was built in I installed a S/T 46 and the tank wasn't big enough ,mixed the fuel with 1/3 ISO propel alcohol and 2/3 methanol to get 68 % with 22%oil and 10% nitro had no problem getting my laps

Jerry Eichten · « **Reply #22 on:** September 12, 2019, 08:38:39 PM »

You could signal from the center of the circle and have someone else start your motor. Launching earlier saves the small amount of time normally spent getting out to the handle.

RandySmith · « **Reply #23 on:** September 12, 2019, 10:38:52 PM »

Quote from: Ted Fancher on September 12, 2019, 06:18:29 PM

Hi Brett,

Thanks for the willingness, my friend, but I'm unwilling to go that far for a one shot deal at the M & M. I'll either find some of that Coleman stuff to try or just fly the Ruffy. I've got other stuff on my plate now and the airplane stuff has already become too time consuming...to say nothing of frustrating. For some reason I can't even find Coleman Lantern fuel any where on the Peninsula. Weird.

Ted

Whitley's long skinny tank sounds of interest, however. Don't know how to insulate it from the header heat though.

Ted
you do not have to use Coleman fuel Acetone works every bit as well, and its easy to find hardware store and Big Box building supply stores all have it

Randy

Trostle · « **Reply #24 on:** September 12, 2019, 11:40:37 PM »

Quote from: Ted Fancher on September 12, 2019, 05:50:58 PM

Wow, Whitley!

I've heard other guys call you a genius but just sort of scoffed at 'em after you dorked that ship at your feet in the middle of the overheads at that airshow down at Edwards AFB a "few" years back.

(Clip)

Ted

Ted,

That is not fair to Whitely. The air that morning was dead calm. That airplane turned in on on the outside turn overhead because of torque. It happened so fast that all Bob could do was scamble really fast to get out of the way. It was one of the finest examples of a model completely destroying itself that I have ever seen.

I can still remember that the ground crew for the Thunderbirds later that day were really concerned that your airplane might run into one of their parked birds.

Keith

Brett Buck · « **Reply #25 on:** September 12, 2019, 11:57:54 PM »

Quote from: RandySmith on September 12, 2019, 10:38:52 PM

Ted
you do not have to use Coleman fuel Acetone works every bit as well, and its easy to find hardware store and Big Box building supply stores all have it

So far. We can't get mineral spirits and probably not Stoddard Solvent any more, VOCs you know.... I would imagine REI might still have Coleman fuel (white gas) but as you note, there are lots of perfectly acceptable liquids that burn. Gasoline, kerosene (Ted has a kerosene heater, or did), acetone, lacquer thinner. Almost everything has a higher specific power than methanol.

I think we are homing in on a better solution off-line - slightly smaller venturi and Whitely's rubber hose should get him back in business. It's an AAC 46VF, power is not an issue. Push comes to shove, I actually have Ted's first-ever tuned pipe engine (a Precision Aero 40VF) that would do about two patterns on a 6 ounce tank.

Brett

Alan Resinger · « **Reply #26 on:** September 13, 2019, 07:29:02 AM »

I still am in favor of midair refueling. Impression points would be through the roof. Ted, do you want to refuel flying inverted or should I rig the tanker to supply fuel while inverted? Boy you talk about impressing the judges. Oh yes, wear white pants, colorful shirt and a new pair of white runners.

Ted Fancher · « **Reply #27 on:** September 13, 2019, 05:21:48 PM »

Quote from: Trostle on September 12, 2019, 11:40:37 PM

Ted,

That is not fair to Whitely. The air that morning was dead calm. That airplane turned in on on the outside turn overhead because of torque. It happened so fast that all Bob could do was scamble really fast to get out of the way. It was one of the finest examples of a model completely destroying itself that I have ever seen.

I can still remember that the ground crew for the Thunderbirds later that day were really concerned that your airplane might run into one of their parked birds.

Keith

Keith,

After reading that part of the post after the fact I realize it doesn't necessarily come off the way I intended it. I meant only to needle Bob over the incident--about which we kidded each other regularly over ensuing years. Your description of the air that warm morning was exactly correct and the way it happened just as you described.

For the benefit of others reading this: Keith had invited Bob Whitely and I to come down (actually, "up" in Bob's case) to Edwards AFB where he (Keith) was the comptroller and fly demo patterns during a "HUGE" full scale Air Force airshow. The demise of Bob's ship was exactly as Keith described...although my description was equally accurate...but insensitive.Ultimately there were thousands of spectators oohing and awing over really fancy machinery...and politely watching the intrepid Earth bound CLPA demo flyers....um, er...flyer!

I've enjoyed telling the story about that, alas, solo, demo flight where--according to me--"I had the assembled masses in the palm of my hand until, upon my entry into the dreaded overhead eights, a full scale aircraft passed behind my daring display and into the view of those assembled masses at low altitude...a B-52 in near knife edge flight!!!. Interest in my thrilling aerobatic routine faded away more or less like interest in the musical accompaniment for Janet Jackson at the 2004 Super Bowl halftime show when the infamous wardrobe malfunction took center stage.

My public apologies to Whitley if my rambling was insensitive.

Ted Fancher · « **Reply #28 on:** September 13, 2019, 06:58:40 PM »

Quote from: Balsa Butcher on September 12, 2019, 06:37:19 PM

Ted: I can bring some FAI fuel to the M & M if you want to give it a try. I use it in my MVVS engines.

Hi Pete,

A quart or so of that would possibly be a great help. Going to work on some of these other ideas in the meantime on Sunday in Napa. Last year I had been running FAI to which I added some 5% each time I gassed it up. Quit starting or climbing into the four leaf both officials. Probably Straight FAI would do the trick. I've got enough of last years jug of FAI left for a couple of flights at Napa and if that gets the job done I'd love you forever if you had the quart or so for the weekend! I wasn't planning to bring it to Napa without having enough left for the contest but your offer opens up the possibility of the simplest solution...straight FAI for the weekend.

Thanks for the offer, my friend.

Ted

Ted

Ted Fancher · « **Reply #29 on:** September 13, 2019, 07:03:29 PM »

Quote from: Alan Resinger on September 13, 2019, 07:29:02 AM

I still am in favor of midair refueling. Impression points would be through the roof. Ted, do you want to refuel flying inverted or should I rig the tanker to supply fuel while inverted? Boy you talk about impressing the judges. Oh yes, wear white pants, colorful shirt and a new pair of white runners.

Nah, Alan. I'll just pull the leadouts out of the other wing for the weekend and we can do the refueling with one upright and one inverted. That would set the stage for my usual 40 point clover. The crowd will go nuts!!!!!!

Ted

Ted Fancher · « **Reply #30 on:** September 13, 2019, 07:09:50 PM »

Quote from: Brett Buck on September 12, 2019, 11:57:54 PM

So far. We can't get mineral spirits and probably not Stoddard Solvent any more, VOCs you know.... I would imagine REI might still have Coleman fuel (white gas) but as you note, there are lots of perfectly acceptable liquids that burn. Gasoline, kerosene (Ted has a kerosene heater, or did), acetone, lacquer thinner. Almost everything has a higher specific power than methanol.

I think we are homing in on a better solution off-line - slightly smaller venturi and Whitely's rubber hose should get him back in business. It's an AAC 46VF, power is not an issue. Push comes to shove, I actually have Ted's first-ever tuned pipe engine (a Precision Aero 40VF) that would do about two patterns on a 6 ounce tank.

Brett

Brett,

I got a gallon of 5% at J&M and a clean quart of acetone. Pete Cunha made an offer to bring some FAI fuel to the contest so I'm going to bring what little I have left from last year to Napa to see if straight FAI will do the job. Got enough for two, maybe three, flights. Good thing I've got a van in which to haul all this um, er paraphernalia.

Ted

Air Ministry . · « **Reply #31 on:** September 13, 2019, 09:55:07 PM »

Obviously you can use the correct Oil % for your engine . ( would it be VOLUME of oil ! .)

Didnt Bob Giese use when neccessary White Spirit to stretch the duration .
Some state 1 % acetone as a ignitor .
Ive tried this but not recalling effects .

Was a range extender brew for B team race , used in equal proportion to the nitro . Said to require engine in rag to retain warmup heat for first race start . Dunnoif thatd makeit stall out / conk .
Was maybe toxic too .

The Comp fuel . Speed & FAI power was once 3 : 1 or the option of 4 : 1 ( 80 % M. & 20 % oil ). as the POWER was a figure in the result .

Cumene maybe it was . Will check . Heres a bit of glow fuel historic drama http://www.control-line.org.au/content/dkd/clmodels/glowfuel.html

Istvan Travnik · « **Reply #32 on:** September 14, 2019, 01:46:12 PM »

Dear Ted,
If you want the simplest solution, get a bottle of iso-propylic alcohol, and you can significantly reduce the fuel consumption.
In metric measures, by a 150 ccm tank if you add 2 (two) ccm IPA, you get 1-2 laps more... (11 seconds more)
Istvan

Air Ministry . · « **Reply #33 on:** September 14, 2019, 08:50:31 PM »

Look at P 152 Here , He is talking about a 94 / 6 methanol / acetone blend . And the TOXICITY of methanol & its Vapor !!!!!!!!!!!!

https://books.google.com.au/books?id=1PoIKeAV9u0C&pg=PA140&lpg=PA140&dq=steve+lancefield+.+norton+tuner.+patents&source=bl&ots=9IabqirQtJ&sig=ACfU3U1DeNaU86rZS4aC7ho9qFfkvklt1A&hl=en&sa=X&ved=2ahUKEwiPuJ-159HkAhVkguYKHfKtD38Q6AEwAHoECAkQAQ#v=onepage&q&f=false

PAGE ONE FIFTY TWO .

944_Jim · « **Reply #34 on:** September 14, 2019, 09:27:04 PM »

Gentlemen,
As a new guy around here I try to read the meat and potatoes of a given thread, while leaving the desert of inside jokes and personal storylines alone.
So while entertained by these stories, I still try to absorb the points and details.

I'm missing the point of acetone in the fuel.
Is it to improve burn?
Is it a replacement for nitro?

And the book referenced didn't clearly indicate the purpose of acetone either (or I missed it trying to read it on my phone).
I just don't get it, especially in the small quantity this thread is indicating.

So what is it for?
Thanks in advance.

Brett Buck · « **Reply #35 on:** September 14, 2019, 09:49:47 PM »

Quote from: 944_Jim on September 14, 2019, 09:27:04 PM

Gentlemen,
As a new guy around here I try to read the meat and potatoes of a given thread, while leaving the desert of inside jokes and personal storylines alone.
So while entertained by these stories, I still try to absorb the points and details.

I'm missing the point of acetone in the fuel.
Is it to improve burn?
Is it a replacement for nitro?

And the book referenced didn't clearly indicate the purpose of acetone either (or I missed it trying to read it on my phone).
I just don't get it, especially in the small quantity this thread is indicating.

It has a higher energy density than methanol, so replacing some methanol with some acetone gives you more energy per unit volume. So, for the same power level, 6 ounces of modified fuel runs longer. Same with Coleman Fuel (white gas), pump gas, kerosene, etc.

It's far from a miracle, it will only extend the run a little bit, but as I recall, thats all he needs.

Brett

944_Jim · « **Reply #36 on:** September 15, 2019, 03:25:40 AM »

So what is the downside? Harder on glowplugs? Harder on dope finishes?

If I understand Nitro correctly, it has extra oxygen, so more fuel is needed (richer mixture by weight, or open the needle).
Does the acetone with the extra energy mean less fuel (leaner mixture by weight (close the needle)?

Thanks

Gordon Tarbell · « **Reply #37 on:** September 15, 2019, 07:03:43 AM »

Acetone used to be used in Alcohol fueled race cars as a power booster (cheating) before better fuel testers where common at the race tracks. It does boost power but not nearly as much as CH3NO2 (nitro) . Does not have the smell either,making it more dificult to detect. I normally have around 50gal of M1 grade methanol on hand and all the other ingredients that you would use in model airplane fuel. Including acetone (not for cheating) . If you would like I can bring a gallon of what ever to Meet and Meat for you. Several choices of syn oil ( klotz original techniplate, and a lighter viscosity version ( not heli ),Benoil brand castor, and Nitro same brand supplied at NHRA sanctioned events. I have no desire to go into business of mixing fuel but to get you through a tight spot what I have is offered to you. Just let me know. If you are concerned with purity I can bring my calibrated Hydrometers to verify specific gravity.

Brett Buck · « **Reply #38 on:** September 15, 2019, 08:11:00 AM »

Quote from: 944_Jim on September 15, 2019, 03:25:40 AM

So what is the downside? Harder on glowplugs? Harder on dope finishes?

If I understand Nitro correctly, it has extra oxygen, so more fuel is needed (richer mixture by weight, or open the needle).
Does the acetone with the extra energy mean less fuel (leaner mixture by weight (close the needle)?

The air/fuel ratio for acetone is lower, as a consequence of the higher energy density. So it's like you put a *very slightly smaller* venturi on it - all different ways of saying the same thing.

I think the settled on methanol because it has the necessary catalytic action with platinum, and it goes well with nitromethane, since it's ionically bonded. Hard to mix oil (covalent) and water (ionic). That's why conventional motor oil floats on top of methanol. Check out what is in gasoline sometime - every paint shop component you can think of (MEK, ketone, acetone, on and on) is in there. Gasoline in small amounts works exactly the same way, Coleman Fuel is white gas.

Brett

Air Ministry . · « **Reply #39 on:** September 15, 2019, 11:05:58 PM »

HooKay ,

Remembered I used the acetone as was the lower half of the methanol , and the damp season .
It was said to absorb any moisture from the methanol . ( which can be absorbed from atmosphere )
And also somewhere it said acetone was a ' ignitor ' when used in fuels .

Just dragged this outta R C groups Via googlesearch on acetone / glow fuel . Which reminded me why I cautiouslt tried a drop .

" Adding 3% acetone for 2 strokes can help with starting and idle (although I've never had a problem with straight methanol). A fellow club member who does a lot of experimenting with 4 strokes found that 5% acetone gave much easier starts and eliminated kicking back, no more thrown props. Acetone is added to Shell A Racing fuel (3%) but in that case I believe it's done because acetone reduces the hygroscopic ability of methanol. As a fuel, acetone is only about .6 as good as methanol but in the very small percentages needed the advantages outweigh this. "

" Acetone isn't used as a power booster the way nitro is used. In 2 strokes it's recommended to only use about 3% as an aid to faster starting and somewhat lower idle speed compared to a zero nitro fuel where it's equivalent to using about 5% nitro in the fuel. For 4 strokes (with zero nitro) about 5% acetone has been found to work very well at stopping kick backs (thrown props) when starting. One minor plus with acetone is that it reduces the hygroscopic ability of methanol which could explain why Shell A racing fuel has 3% acetone added in their drums. "

This is from somebody going by the handle of " Downunder " . So may be a neigbour, statewise anyway , here .

Think what I mayve read related to the flashpoint & burn rate when combined / used in methanol .
It was the ' keep it alight ' which I thought could be usefull . Dunno if THAT was when I was getting it stopping at half tank thou !

Could well be . Maybe try only 1/2 a litre , to test . The WHITE GAS seems to be the tried & proven formular .

Ted Fancher · « **Reply #40 on:** September 16, 2019, 11:55:15 AM »

Well, this is embarrassing and my only excuse is I can't explain it.

Took the Citation V out to Napa to fly with David, Brett and Uncle Jimby armed with multiple different "solutions" to the underrun problem. As a baseline I flew the first flight with straight FAI fuel and the danged thing ran over seven minutes...this is on ~5.25 oz of fuel capacity. Subsequent flights on different mixes proved the duration was no "one of a kind" event.

I've "NO" explanation for why a tank identical to the one that ran out of FAI fuel + 1/2 oz of five percent every flight almost exactly a year prior did this. The new tank is as close to identical to the old one as I could make it...cause pretty much nothing else would fit in the shortened nose.
The old tank was deteriorating inside and plugging the fuel filter after a couple of flights which would seem to explain some of this but the engine runs were dandy right up to flame out' i.e. no leaning out and quitting and the tank was, in fact, empty. this internal deterioration of the 34 year old tank was the reason, by the way, for building the new tank.

Mysterious to me

Ted

p.s. thanks to all for your input. As of now I've no idea what to do other than short tank the flights or jump into the nitro bottle and start all over. For sure my search for FAI fuel and or lantern oil was 180 degrees out of sync.

Tim Wescott · « **Reply #41 on:** September 16, 2019, 01:10:42 PM »

Quote from: Ted Fancher on September 16, 2019, 11:55:15 AM

Well, this is embarrassing and my only excuse is I can't explain it.

Brett snuck into your house and soldered that wart he was advising onto the tank?

Robert Zambelli · « **Reply #42 on:** September 16, 2019, 01:49:24 PM »

Hi, Ted.
Dumb question (?) but why not use the four stroke engine?

Which one did you use by the way?

Bob Z.

Peter in Fairfax, VA · « **Reply #43 on:** September 16, 2019, 02:32:11 PM »

Glad you got things worked out for a good engine run. The discussion was interesting, especially the parts about tank design and why white gas or acetone might be added.

Peter

Brett Buck · « **Reply #44 on:** September 16, 2019, 05:37:57 PM »

Quote from: Ted Fancher on September 16, 2019, 11:55:15 AM

Well, this is embarrassing and my only excuse is I can't explain it.

Took the Citation V out to Napa to fly with David, Brett and Uncle Jimby armed with multiple different "solutions" to the underrun problem. As a baseline I flew the first flight with straight FAI fuel and the danged thing ran over seven minutes...this is on ~5.25 oz of fuel capacity. Subsequent flights on different mixes proved the duration was no "one of a kind" event.

I've "NO" explanation for why a tank identical to the one that ran out of FAI fuel + 1/2 oz of five percent every flight almost exactly a year prior did this. The new tank is as close to identical to the old one as I could make it...cause pretty much nothing else would fit in the shortened nose.
The old tank was deteriorating inside and plugging the fuel filter after a couple of flights which would seem to explain some of this but the engine runs were dandy right up to flame out' i.e. no leaning out and quitting and the tank was, in fact, empty. this internal deterioration of the 34 year old tank was the reason, by the way, for building the new tank.

I was present for both events and can confirm the observations, it's not something obvious. Maybe, the old tank didn't full completely before it started spewing out the overflow, but, your methodology (the not-recommended-but-too-late-to-fix-now "put in X amount" rather than "pull out X amount") would generally make that obvious. It *was* perfectly satisfactory to get through patterns before whatever happened, now it is again, to the aberration is why it was running short last year more than why it is running longer this year.

Note also this was 72 degrees or so, when it's 90+, you will end up sucking some out. The engine runs fine either way - Randy 46VF AAC - and has plenty of power, even on FAI fuel. But now you have options.

For the elucidation of the group, the old tank was about as bad as I have ever seen one as far as internal corrosion goes. There were numerous pinhole leaks right through the steel, not at a joint, but straight through the metal. We tried to fixed them, and fix one, and another two develop. It was essentially hopeless. I am sure this is a combination of StaBrite flux and then the *33 years* of whatever acidic byproduct was left behind and whatever forms from old nitromethane fumes.

Brett

Brian Hampton · « **Reply #45 on:** September 16, 2019, 08:22:31 PM »

Quote from: Matt Spencer on September 15, 2019, 11:05:58 PM

Just dragged this outta R C groups Via googlesearch on acetone / glow fuel . Which reminded me why I cautiously tried a drop .
" Adding 3% acetone for 2 strokes can help with....... "
This is from somebody going by the handle of " Downunder " . So may be a neigbour, statewise anyway , here .

<--------downunder Adelaide

That info was a summation from an original article written by a club member for the club's newsletter maybe 20 years ago. The original article can be found at https://holdfastmac.asn.au/technical-articles/all-about-fuels/ where the tech specs of most fuels can be seen. Because I did the online version of the newsletter I slightly altered the original article to show a comparison between latent heat of evaporation compared to methanol and the potential power each type of fuel could give compared to methanol with a link to each to explain the reasoning.

Peter in Fairfax, VA · « **Reply #46 on:** September 17, 2019, 01:10:37 PM »

Kind of surprised that no one suggested adding propylene oxide.

http://fhsoils.com/product/hp-booster-prope/

Balsa Butcher · « **Reply #47 on:** September 17, 2019, 01:44:31 PM »

So Ted, does this mean you are going to go back to 5 or 10% nitro for this weekend's contest? No matter, I'll bring the FAI fuel anyway...just in case. Glad this issue had a happy ending.

Brett Buck · « **Reply #48 on:** September 17, 2019, 07:26:35 PM »

Quote from: Peter in Fairfax, VA on September 17, 2019, 01:10:37 PM

Kind of surprised that no one suggested adding propylene oxide.

http://fhsoils.com/product/hp-booster-prope/

That's not going to make it run longer - plus, you can't easily get it at local supply houses.

Brett

Peter in Fairfax, VA · « **Reply #49 on:** September 17, 2019, 09:00:28 PM »

Hmm.

1) The link shows that having a quart of prope delivered via UPS from Red Max Fuels is a simple matter.

2) While prope is primarily used in model fuels both to ease starting and to keep the engine lit, it does have the same property as the gasoline, acetone and benzole (whatever that is) of producing more BTUs than either methanol or nitromethane. That's my reading of the various links.

Brett Buck · « **Reply #50 on:** September 17, 2019, 09:42:22 PM »

Quote from: Peter in Fairfax, VA on September 17, 2019, 09:00:28 PM

Hmm.

1) The link shows that having a quart of prope delivered via UPS from Red Max Fuels is a simple matter.

2) While prope is primarily used in model fuels both to ease starting and to keep the engine lit, it does have the same property as the gasoline, acetone and benzole (whatever that is) of producing more BTUs than either methanol or nitromethane. That's my reading of the various links.

I think propylene oxide is primarily an oxygen contributor when used as a model fuel, so you would want to add some fuel, not use less. It would probably decompose spontaneously from catalytic action of the platinum of the concentration was high enough, but not in the amount you could plausibly use in a glow engine.

Brett

Peter in Fairfax, VA · « **Reply #51 on:** September 18, 2019, 05:58:49 AM »

Again referring to the chart linked above, prope requires a leaner mixture than methanol or nitro, more akin to the acetone / gas.

RandySmith · « **Reply #52 on:** September 18, 2019, 08:37:06 AM »

Quote from: Peter in Fairfax, VA on September 17, 2019, 01:10:37 PM

Kind of surprised that no one suggested adding propylene oxide.

http://fhsoils.com/product/hp-booster-prope/

Hi Peter
Some fuel makers have quit using this chemical because it is a carcinogen, I stopped using it because it is so hard to keep, You need to keep it in a glass bottle, as plastic ones keep blowing up, the jug get very fat, gets a lot of pressure on it , and every time you open it is blows air out of the jug . it evaporates extremely fast plus warning is below :

Potential Acute Health Effects:

Eyes: Very Hazardous in case of eye contact, vapors and liquid may cause severe eye irritation with redness, tearing, burning, swelling of the conjunctiva and corneal burns. Damage may be permanent.

Skin: Hazardous in case of skin contact (irritant/permeator). Contact may cause severe irritation with redness, pain and severe burns or blisters. Propylene oxide may be absorbed through the skin in harmful amounts causing systemic effects similar to those listed under ingestion and inhalation. Propylene oxide is a skin sensitizer and may cause an allergic skin reaction. Dilute solutions may be more irritating than undiluted materials.

Ingestion: Swallowing may cause severe burns to the mouth, throat and stomach with nausea, vomiting and diarrhea. May cause central nervous system depression with headache, dizziness, drowsiness, drunkenness and collapse. May be fatal due to respiratory failure. Aspiration may occur during swallowing or vomiting resulting in lung damage.

Inhalation: Inhalation of vapors or mists may cause mucous membrane or upper respiratory tract irritation with central nervous system depression. Symptoms include headaches, dizziness, coughing, narcosis, drunkenness, incoordination, nausea, vomiting, and collapse. High vapor concentrations may cause unconsciousness, coma or death.

Potential Chronic Health Effects:

General Effects: Very hazardous in case of eye contact (irritant), of ingestion, of inhalation. Hazardous in case of skin contact (irritant permeator), Skin: Prolonged or repeated exposure may cause delayed secondary burns, ulcers or superficial scarring. Inhalation: Studies with animals have shown chronic effects such as growth depression, lung and slight liver injury. Ingestion: Studies with animals have shown chronic effects such as loss of body weight, gastric irritation and slight liver injury.

CARCINOGENIC EFFECTS: Classified 2 (Reasonably anticipated.) by NTP.

MUTAGENIC EFFECTS: Not available.

TERATOGENIC EFFECTS: Not available.

DEVELOPMENTAL TOXICITY: Not available. The substance is toxic to lungs, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage.
CARCINOGENICITY: Propylene oxide appears to induce cancers at the site of exposure in experimental animals. Sarcomas occurred at injection sites, and nasal and GI cancers occurred with chronic exposure.

MUTAGENICITY: Propylene oxide has been found to be mutagenic in experimental animals including salmonella typhimurium, escherichia coli, drosophila spermatozoa and spermatids, and neurospora crassa assays.

NEUROTOXICITY: In high concentrations propylene oxide has caused CNS effects, including CNS depression, headache, motor weakness, incoordination, ataxia, coma, and neuropathy in experimental animal studies. Peripheral neuropathy has been reported in chronic studies with experimental animals.

TERATOLOGY: Inhalation development toxicity studies with rats exposed to propylene oxide vapor at concentrations of 500 ppm showed fetotoxicity and developmental abnormalities.

Abi · « **Reply #53 on:** September 18, 2019, 02:48:41 PM »

FAI fuel is 17% oil, 50/50 castor/synthetic.

P.S. Our common friend, Steven Yampolsky, is sending his regards and suggests calling S&W Fuels: their FAI mix is just 5% castor.

Reptoid · « **Reply #54 on:** September 18, 2019, 09:59:32 PM »

Quote from: Abi on September 18, 2019, 02:48:41 PM

FAI fuel is 17% oil, 50/50 castor/synthetic.

P.S. Our common friend, Steven Yampolsky, is sending his regards and suggests calling S&W Fuels: their FAI mix is just 5% castor.

Depends on "Which" FAI fuel you're talking about
Legal FAI fuel was always 20 % Oil and 80% Methanol and still is for free flight, speed events, and Tether cars Worldwide and is normally supplied by contest management and mandatory to use. F2D combat fuel was 20% castor, 10% Nitro for many years until 2019. New F2D rules require 15 % oil (any) and 5% nitro (stupid rule change IMHO) You can get it from Ritches Brew (5% castor, 10% syn, 5% Nitro) or???

Ted Fancher · « **Reply #55 on:** September 19, 2019, 11:41:02 AM »

Quote from: Balsa Butcher on September 17, 2019, 01:44:31 PM

So Ted, does this mean you are going to go back to 5 or 10% nitro for this weekend's contest? No matter, I'll bring the FAI fuel anyway...just in case. Glad this issue had a happy ending.

Your question answers itself.... I expect I'll use straight 5% but don't want to abandon the other (your) resource as I'm more perplexed than convinced as I sort of preferred the run on the FAI brew. Ergo I appreciate that you have room for it in your vehicle!

Right now, however, my M&M presence is no longer a sure thing as Shareen's knee transplant has turned out to be the lesser of her ambulatory problems in the last week or two. Pain from a bone spur in her opposite ankle has increased significantly in the last month...likely due to more reliance on that leg due to the new knee status...and her second visit to the podiatrist this morning has her looking into an ASAP MRI appointment and a likely near term surgery to address that issue.

Oi vey, growing old versus the alternative.

Ted

Jim Kraft · « **Reply #56 on:** September 22, 2019, 01:12:09 PM »

I use to use Coleman stove fuel in all my spark ignition engines. Now I run Crown stove fuel, (white gas) as it is somewhat cheaper. Both available at Walmart. I also use Walmart Super Tech standard 2 stroke oil. Runs cool and clean.