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Fuels - Under Construction. |
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Questions about fuel have come up both last week and this; each for entirely different flying...err, one for flying (R/C....OK, no smart alack remarks by ME here...) and one about ½A race/toy cars. I'm not guilty on the first count, but have some real interest in tether cars. Suggestions for what you'd like to see here most welcome. Bob@TheAeroSmith.com
Presented here, a quick reply to Rodney's question about fuel for his .049 cars. Fuel can run from 80 octane unleaded to full-boogie 130 octane...zero Nitro up to fill 'er up...and save a little room for oil.
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Some phuel photos phor here soon.
Rodney: First off, where are you? Just curious. And where'd you find me? Just curious, again. Both should run on fuel that's at the very least 20% oil, and at least half the oil should be castor if possible. Most of the plastic fantastic RTF 'hobby' shops have fuel, but not good for half-A's. I can't tell you a brand, as I don't pay any attention to fuel on the shelf since I always mix my own. Not because it's any better mind you, it's just always 'fresh' when I make it for a contest or test session. If you can find fuel that's 20% oil and it's pink, chances are it's all synthetic. It might say if there's castor in it. In any case, for a tender old buggy and a Testies car...Testor's(!) motor should be pretty happy on the same fuel. For some 20% oil fuel (make sure you're seeing oil not Nitro - though Nitro is good from zero to at least 40%), I'd mix castor in and above the 20% to make it 25% just to be sure these little motors are oiled well enough. 8 ounces of castor oil to a gallon of 20% oil makes it right at 25% (24.7) which is a good number I think. Finding 25% oil fuel that's half castor and half synthetic would be better, but take what you can get. Of course, 2 ounces of castor for a quart of fuel works out the same. You can get the raw materials, but not always easily available anywhere. Klotz synthetic oil is available at most any motorcycle shop. There are two: KL 200 is 100% synthetic, KL 100 is 20% castor. I like the straight stuff as it's easier to do the math. Same place will likely have castor oil, too. See Klotz 'Blendzall' brand. It's 100% castor oil. I'd not take any substitutes unless a hobby place has the stuff Sig packages (It's Klotz under the Sig label). You can mix the oil, and find the alcohol much more easily than Nitro. Try the Yellow Pages under Chemical Supplies and the like. Guaranteed, others have their own brew. I've been known to run 70% Nitro, 5% propylene oxide*, 5% Alky, and the balance 20% 50/50 oil. Not good for them, but they may go really fast assuming the motor is set up to run on it. If you happen to be close by, I'd be happy to stir some up for you. Thanks for the question. I think I should put something about fuels on my Web site. Anything else that I might venture a guess on for you? Bob *Nasty, nasty stuff; only for the foolhardy who really, really want to go fast.
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The next item will speak to going fast with 80/20.
And another authored by George Aldrich about castor oil when I can find it. He made me a believer about castor oil, and he was the man to know about it from his livelyhood. Coming soon.
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Hot Rod to Hell super fuel for ½A if you have the gonads, and know what you're doing.
My favorite fuel for NFFS Nostalgia Gas here:
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Hey, Rodney:
Thanks for the scoop RE how you came across my site. I honestly don't know how it's gotten hooked up to so many things that Google finds and put the site
up near the top somewhere.
The fuel you have is FAI fuel (Fédération Aéronautique Internationale - FAI). The FAI fuels are limited to 80% alky and 20% oil (of one type or another or a mix...not specified). Interestingly, in FAI contests, the fuel is provided by the contest management; everyone uses the same fuel, pretty literally, as it all comes from the same jug or jugs. I guess if all the models ran from one tank, that'd be literal. Kidding aside, they do use the same fuel.
Not so good for most ½A engines as they are set-up normally. You need some Nitro for them to fire up easily. The 2.5cc (.1525 cu in) FAI motors run very high compression ratios to run well on the no-Nitro fuel. They start pretty easily, but they have to use a starter because of the folding propellers. Anyway,
you want fuel with some Nitro, and you'll have them fire up just fine, assuming everything else is right, of course. A generalization, and oversimplified, it is the case that the more Nitro one uses, the lesser the C/R needs to be to keep the timing (actual firing) right. Too high a C/R, premature ejac...err...ping...knock...
is bad for the motors and doesn't help power for sure.
Sure wish I had a couple of big ticket items I could sell and have some real money set aside for the CNC stuff I'm trying to get together. I do have a street rod that can go, but I have to go through the motor - has a dead cylinder - broken valve.
The tether cars, freeflight, and probably U/C models, too, will do a lot for you and your children I think. Torrance is just a hop-skip-and a jump from Fallbrook. I'm trying desparately to get my place sorted out. Quite a mess right now. Anyway, come on by most any time. Half an hour from the farthest point of Oceanside from us, and five or ten minutes from the eastern edge of Oceanside. No trick stuff, really. It's mostly pretty old stuff...me, too, I'm afraid. That's OK...I just try to remember that I will never be as young as I am today. Think about it. So, onward with the learning curve on CNC, CAM, CAD, G&M code, etc.
Bob
-------Original Message-------
From: Rodney
Date: 2/22/2007 4:24:40 PM
To: theaerosmith@roadrunner.com
Subject: Fw: fuel
----- Original Message -----
From: Rodney
To: Rodney
Sent: Thursday, February 22, 2007 4:02 PM
Subject: Re: fuel
I was just typing in Cox gas on the internet and came across your site.I been using a mixture that's not easy to get the cars started with. its called FIA and I forgot the brand name the Hobby People shop guys told me it would work for the old Cox engines.its 100% castor and I think it said 80/20 on it also? I am at work right now and I don't have a computer at home yet! but I will check tonight.my two sons and I are really getting into this for many reasons other than there dad remembering the toys from the past,getting them out doors away from the x-box and gameboy junk is the main reason and to help teach them about the mechanics of engines.it looks like we will be ending up with about 20 or more cars ,spare engines and parts we have won and are waiting for from ebay.I have sold a couple of restored motorcycles lately and decided a different hobby to share with my kids would be nice.we will be getting some planes also.but no new RC stuff just the simplicity of the free running,tether line and free flight stuff.I live in Torrance but my sister lives in ocean side and my nephew lives Anza.may be some day we can check out your trick stuff.
Thanks Again,Rodney
