Bad Fuel

Just a warning- we found what appears to be a bad batch of fuel today. It was Powermaster GMA 10/22, and I will post the batch number when I get it. Its Paul Ferrell's.

Had all the hallmark signs - engine was running perfectly, and Paul switched to a new gallon (decanted from a can to a plastic bottle for some reason). Immediately, there was much reduced "power" for the first two flights, and it ran "funny". Then it started simply quitting on the ground like you had flipped a switch. We went through the entire engine/tank and fixed a few things, but for the most part it was OK. Tried again, and it quit pretty reliably after about 10 seconds of ground running and any time you touched the needle or revved it up with your finger over the vent. Fiddled some more, and on the second attempted ground run it wouldn't even start - it would fire right up but as it got to full speed, it would quit, almost like it had run out a prime - even though a fuel mist was obvious at the venturi.

We switched to my fuel (Powermaster 10/18 R/C fuel) and fired it back up. After a few false starts, it ran for a while, then quit. On the second start, it ran out the tank, getting better as it went. Paul flew it, carefully, a few times, and it worked fine again.

Note that this is very much like what we were getting in the 1995-96 time frame starting at the 1995 "SIG Fuel Disaster Nats". The symptoms were very similar - it was like some substance was plating itself to the engine and making it run bad, and it took some running with good fuel before it worked correctly again. I don't think it has anything to do with 10/22 GMA as a fuel type - it worked fine on a different can of GMA earlier in the week. But the problems started as soon as they started on a new gallon. Although there were a few other engine issues today, I don't think it was related to the air. The air quality was *very very* bad today from smoke.

Brett

I suggest you change the plug as well because I have heard that bad fuel will "mess the plug up" even though it may still look ok.

This happened to one of our top flyers in Sydney recently. He had the same symptoms as you and he the changed fuel. This improved the run, but when he changed the plug as well, everything was ok again.
(He had changed the plug first off, but that did not fix the problem.)

I had some fuel "go off" lately as well and I believe it is the nitro that does this.

Maybe it's the alternate source of Nitro that's messing up the works?
Be careful when running new Jugs of Sig fuel at the Nats! I don't know what other fuel companies have latched onto the alternate Nitro source, but be very careful with new containers of fuel....


Jim Pollock

As far as I understand, and Sig fuel, at this time, is from old sources.

>As far as I understand, and Sig fuel, at this time, is from
>old sources.

Sig just about ran out of fuel around the time of the Sig contest. They got a new nitro supplier a couple of weeks ago. So if the fuel has been at the hobby shop for a while, it is the old nitro. Most fuel being shipped by Sig now, should be the new supplier.

>I suggest you change the plug as well because I have heard
>that bad fuel will "mess the plug up" even though it
>may still look ok.
>
>This happened to one of our top flyers in Sydney recently. He
>had the same symptoms as you and he the changed fuel. This
>improved the run, but when he changed the plug as well,
>everything was ok again.
>(He had changed the plug first off, but that did not fix the
>problem.)
>
>I had some fuel "go off" lately as well and I
>believe it is the nitro that does this.

Hi Bandelero,

For the record a plug change the first step taken. It gave all the appearances of an ignition problem and doing so seemed the logical first step. Didn't help, however.

It was an interesting day in that several others were having some less consequential but still aggravating run problems, notably Uncle Jimby (RoJett .61, but this had been going on for a couple of weeks), Paul Pomposo, ultra lite .40, Dave Shirly older cast case RoJett .61. I still think there was some issue with the atmopherics but none of us had the capability of checking density, humidity, "smoke trash", etc.

Brett (RJ .61)and David's (PA .75)engines seemed to run pretty much perfect, as did PTG's VF .40. I'm usually pretty reluctant to point a finger but this jug of fuel definitely seemed to "glow" with potential guilt. The one thing that concerns me a bit is the fact that it had been poured out of the original container into a plastic jug. One would assume it was a jug whose only previous resident was good clean glow fuel but I've no way of verifying that.

Nobody wanted to try it after such a long day but I would like to have seen a tank put in another engine as a step in trouble shooting.

Ted

> The one
>thing that concerns me a bit is the fact that it had been
>poured out of the original container into a plastic jug. One
>would assume it was a jug whose only previous resident was
>good clean glow fuel but I've no way of verifying that.


That was a sub-optimal plan. It's my considered opinion that *anything* we do to the fuel other than suck it out of the original container (including decanting it to filter it) is a big mistake and can only hurt. If there was some bad contaminant I would sure be interested in what it was, because it really didn't work.

One nice thing about Powermaster is that they do have batch numbers and can be traced. We would love to have had that back in 1995. To confirm it one way or another all we would need to do is find another gallon from the same batch and see if it works.

>Nobody wanted to try it after such a long day but I would like
>to have seen a tank put in another engine as a step in trouble
>shooting.

I don't think anyone is going to jump on that bandwagon the week before the NATs! Particularly since it seemed to persist even after you switched, for a while.

Brett

Brett,

Let us know the batch numbers. I just got a case of Powermaster 10/22 GMA that's unopened. Be nice to check.

I had trouble with a gallon of Sig Champion 5% nitro/20% castor. My earlier engines would not stay lit even with a new Thunderbolt plug. Switch to some home brew and all was well. The Sig would run fine in my OS LA 40's, but they run on anything.

Sorry to hear this Brett!

And I am sorry that it did not happened here in Sweden. I have access to most chemistry equipment at my job in a pharmaceutical research lab for organic synthesis.
Just a drop of the old fuel and a drop of the new fuel is enough to make a very quick NMR analysis.
This showes directly the differencies between the fuels. It also shows water content.
To determine the percentages is however something that requires knowledge in organic chemistry - and I am electronics engineer (keeping equipment up and running).

Further on I am not very familiar with the american map, but if you happen to live in the bay area there must be some modellers employed at Varians facilities on Hansen way in Palo Alto that happily will help you to definately give evidence "black on white".


As a parenthesis I can mention that the thinner for common dope in Sweden is about 3 times more expensive than the complete dope ( ! sic ! ) and the ingredients were stated on the bottle, we just checked the internal integrals för the various solvents, and since several years back I can mix my own dope thinner.


Good luck in your hunt for the cause! // Ingvar, city of Boraas in Sweden

Hi Ted,
That must've been another incident as this particular Sydney (Australia) flyer was over here in Adelaide (at our South Australian State Champs) when he had the problem.

>Hi Ted,
>That must've been another incident as this particular Sydney
>(Australia) flyer was over here in Adelaide (at our South
>Australian State Champs) when he had the problem.
>

Hi Bandolero,

Sorry, I didn't make that note very clear. I was there as an observer when the problem Brett was discussing was occurring. My comments were specifically about that event and the unusually high rate of engine problems for what is a pretty sound and well tuned group of stunt flyers.

It was a very frustrating way to spend a couple of hours of a planned Nats and WC tuneup for most of the guys there. Young Paul Ferrell whose RoJett .61 powered airplane is the subject of the discussion is the Junior member of the US's F2B Team. His new airplane (an amalgam of a Trivial Pursuit and an Imitation) was just starting to get dialed in when the engine (which had performed flawlessly ever since the first flight on the new airplane) just flat quit running. Lots of high powered help came to his rescue (David Fitz, Brett, Uncle Jimby, PTG,etc) and it still took the better part of the morning to get it back in the air.

Ted

>
>It was a very frustrating way to spend a couple of hours of a
>planned Nats and WC tuneup for most of the guys there. Young
>Paul Ferrell whose RoJett .61 powered airplane is the subject
>of the discussion is the Junior member of the US's F2B Team.
>His new airplane (an amalgam of a Trivial Pursuit and an
>Imitation) was just starting to get dialed in when the engine
>(which had performed flawlessly ever since the first flight on
>the new airplane) just flat quit running. Lots of high
>powered help came to his rescue (David Fitz, Brett, Uncle
>Jimby, PTG,etc) and it still took the better part of the
>morning to get it back in the air.

It was alarming to say the least, and they were getting VERY frustrated. I think we found a few other relevant issues but it sure took a while to work through it all. Let's say I have some idea how frustrating it is - I lost the better part of a year and a pretty good airplane trying to track it down back in 1995/96. It was certainly the last thing Paul needed.

Some of the other issues were more explainable. I talked to Dave Shirley this morning and it looked like his pipe was abnormally long for the RPM, which fits pretty well with having to run screeching lean and then overheating. Jim's engine didn't work much different from before - there's something about the airplane and I don't think the new engine is "right" but the old one ran about how it had before. Dave's engine actually healed itself after it wouldn't run right at the Team Trials.

I would be surprised if this has anything to do with it, but the air this weekend was world-class, Peking-quality, bad. Maybe all that suspended ash and smoke has something to do with it, but Paul's engine ran fine after we switched fuel.

We probably ought to test the fuel in another (known sensitive) engine but I don't think anyone was up for it until after the NATs/WC

Brett

>>It was certainly the last thing Paul needed. <<

He has a more consistent fuel supply now.

The batch number is #4795. I called Powermaster this morning and they are checking. The Plastic jug we poured the fuel into previously held the same fuel( Powermaster 10% nitro 22% oil GMA) from a different batch and everything worked just great on that can. No reason to suspect any contamination. However, we'll not decant going forward. All fuel was bought at Sheldon's and no reason not to think the fuel is fresh as they do high volume.

Many thanks to Brett who put in a lot of time and thereby gave up some practice flights to help us figure out the problem and otherwise improve our set up.

Kevin and Paul Ferrell

>The batch number is #4795. I called Powermaster this morning
>and they are checking. The Plastic jug we poured the fuel into
>previously held the same fuel( Powermaster 10% nitro 22% oil
>GMA) from a different batch and everything worked just great
>on that can. No reason to suspect any contamination. However,
>we'll not decant going forward. All fuel was bought at
>Sheldon's and no reason not to think the fuel is fresh as they
>do high volume.

Of course, it may or may not be a problem with the entire batch. It might be a particular problem with this gallon (say, something in the can when they filled it).

I think that 47xx is a pretty recent batch. It's as high a number as I have seen and they are apparently sequential.

Brett

Brett,
Thanks for the head-up. I just bought 8 gallons of Powermaster 10-22 and would be most interested in the batch number.

Randy C

I'm not sure what you mean by recent I had a batch shipped from Powermaster in early Feb that was #4948. Latest batch shipped in May was #5033 (Randy thats what you've got). I suspect your suspect batch was from late last year, probably nothing to do with Nitro shortage.

As most of you know, I can get pretty irate when seeing a post which points fingers at products and/or manufacturers.

Not this time. Would those of you inclined to bad-mouth a company just because you discovered one prop which you think might have one defect please go over the entire thread?

Credible to highly credible people on site.

Some pretty serious testing and comparing and analyzing, again done on site.

Some early concerns stated, but with cautions.

A potential way of avoiding the problem with batch numbers for the fuel.

This issue is being handled in the best way possible, with maximum benefit to those of us in the CL Stunt community.

Brett, very nicely done.

Dan

>
>This issue is being handled in the best way possible, with
>maximum benefit to those of us in the CL Stunt community.
>
>Brett, very nicely done.

Thank you! I thought about it for a while before I posted it, but it was such a serious (potentially very destructive) problem that we needed to get the word out before the entire story was available. We have all had very good results with Powermaster fuel and having a batch number is proving it's worth. With the community working the issue it can quickly be determined where the problem lies.

Brett

Thanks, Pete. You saved me a trip to the shop. In my current condition, that's a good thing.

All of the fuel I have is apparently later batches than that listed.
They are all in the 4900's with the oldest (from about Jan 08)4920 and the newest 4980.
Haven't had any problems to date with Powermaster fuel.

Randy C

Ron Sheldon, Sheldon Hobbies, got a bad name for a while. He finally found out that the delivery driver was stopping by some of his friends
places and switching out the new Nitro for their old Nitro. After he tracked the problem down he the made the company call him when the delivery left the dock and if it wasn't at his door in an allotted amount of time, he would refuse the order. It cleared up all the problems. I use to run his 5% in all of my RC engines, Rossi, OS, Webra, Picco etc. I thought it was a great fuel and the price was right.
When I couldn't get it anymore I tried a brand in a plastic jug and nothing worked right. After switching to Powermaster, the problems went away. Maybe somebody pulled the same trick on PM.

Bruce

>Ron Sheldon, Sheldon Hobbies, got a bad name for a while. He
>finally found out that the delivery driver was stopping by
>some of his friends
>places and switching out the new Nitro for their old Nitro.
>After he tracked the problem down he the made the company
>call him when the delivery left the dock and if it wasn't at
>his door in an allotted amount of time, he would refuse the
>order. It cleared up all the problems. I use to run his 5% in
>all of my RC engines, Rossi, OS, Webra, Picco etc. I thought
>it was a great fuel and the price was right.

That's what was wrong with it? I wouldn't have guessed, but I do recall that there was a problem with his fuel in that the engines corroded *while they were running*. Orange exhaust from iron-liner motors! We all assumed it was the oil, not the nitro.

Brett

I was using Sheldon's fuel back in the early 1990's, and lost two of my RC engines due to rust. One engine was a Como 40 (Super Tigre), and the other was an OS FS 26. I always used after run oil, but in the end, both engines died from the same disease. It is interesting to hear now it may have been an issue with "cheap" Nitro...

Since then, I have used Sig, Powermaster, and Omega fuels. The only problem I have had is recently with a couple of gallons of Powermaster RC 10% nitro, 18% oil fuel. I do not get consistent engine runs with this fuel. No changes to the engine, tank, or airplane that used to produce respectful runs on other fuels (including Powermasrer.) I will look into the lot numbers.

Hmmmmm...

That's about the time a nitro plant in the US blew up. People were getting Chinese nitro then that had something bad in it-- maybe nitric acid. It dissolved metal fuel cans.

Howard Rush
Bellevue, WA

If the problem is with the fuel Power Master will make it good. Not long ago I bought a case of Power Master fuel and a few cans were light on content I brought it to Power Masters attention and they sent me a check for a full case. I informed them that it only involved a few cans, but they insisted I keep the check for the full case.
My fuel is pink and comes in cans.

Terry

http://www.dustersrcclub.com/
http://www.flyrc.info/
http://www.hansenscalevideos.com

Another two interesting data points on the fuel front. Today, we found a can of what was marked 10/18 R/C fuel, but was colorless - not the usual light pink. It ran fine in David's airplane, but it certainly wasn't the same as the usual fuel. We guess that it may have been GMA that was mismarked. The batch number was 4955. I happened to have a can of 10/18 from batch 4956, and it was apparently normal.

Another bad fuel story - a very prominent modeler who certainly knows engines well called me and related a story where he ran the engine for 4 flights, after which it couldn't be flipped or turned over with a starter. This was Powermaster 10% with low-viscosity helicopter oil (the green stuff). On inspection, the piston was stained green, and had to be sanded with 2000 sandpaper to remove the green 'plating'. It ran fine for 3-4 more runs, then, same thing. He said that it was a very tightly-fit piston but not grossly out of the ordinary.

Howard Rush made observation that the low-vis helicopter oil removed the clear from his airplane! Even just exhaust oil. I haven't run ever run the helicopter oil but I was planning on trying it at some point - not any more!

The way it stands now, my buddies and I are taking a very large sampling of fuel to the NATs to hedge our bets against bad cans/batches. So far, all the 10/18 R/C fuel I have run seems to be just fine but I'm not driving 2500 miles just to find out I have bad fuel and can't get any more! So beware, something is going on - I'm not sure what exactly, but something.

All this is going to be tracked down with the manufacturers, but given the severity of the issue and fact that the NATs is only a week away, please be advised.


Brett

I have verified this weekend that I have several gallons of Powermaster GMA 10/22 that is bad. It's an older lot, #4493, however, the cans had not been opened until recent weeks. I can't get decent engine runs with this fuel. Switching over to other fuels solved my woes. I have used GMA 10/22 in the same engines in the past - no issue...

Pete, Reno NV

Matt just got a batch of 40 gallons from Rich's Brew and another 56 gallons from SIG (after they got their new stuff in.) He has tried both and both run fine in his set-up. He's running 5% nitro and 20% oil. He's running a blend of 25% castor, 75% synthetic by mixing a jug of 50-50 with another jug of all synthetic. He has synthetic from Rich's Brew and Synthetic from SIG. The synthetic Rich's Brew is green and overpowers the red SIG when mixing the two together. Don't know what the green dye is, but experiencing no problem with the fuel. (Also has SIG all synthetic to blend with the SIG 50-50, so can go either way.) He has also set up three engines, so has back-ups should any problems develop along the way.

Now if the weather would just clear up so he could fly. Thunderstorms forecast for the next three days. Maybe it will get it out of its system by Nats time.

Sure glad never got into hard core contest action. Have four gallons of older fuel. Hope they can get it right by the time I need more. Good ole tree hugger's sure make it nice. Sure looks like begining of the end. Hope I am wrong on this.
Dan

Dankar,
Since you seem to be against being able to drink the water and breathe the air, I suggest you move to China, where the source of the nitro problem is. The air is so "great" that all industry has to be apparently shut down so that the Olympic athletes can breathe. Maybe you like that type of progress.

Ron really emphasized the nitro but he also had concerns over the Alky and other products supplied by that particular vendor. He sent some of the bad nitro to a lab and that is how he found out what was going on.
Bruce

Brett,

I checked another can in the second case of PowerMaster 10-18. Marked as the same batch as the funny colored fuel, Batch #4955. It is also clear. NO pink color.

Still seems to run fine. I think you are right, probably mis-marked 10-22. The fuel I gave to Jimby for our friend is from this same batch.