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Building Tips and technical articles. => 1/2 A building. => Topic started by: philip metzner on December 22, 2009, 03:32:33 PM

Title: cox fuel ???
Post by: philip metzner on December 22, 2009, 03:32:33 PM
   Many years ago i noticed many of my .049's ran much better on cox fuel than they did on other brands with comparable percents. This prompted me to call cox and talk to them about it. That led to many phone calls to fuel suppliers and somewhere along the way i talked to someone who said they used to mix fuel for cox, and i was correct in that there was a extra ingredient in cox fuel that others didnt have. He said it was ether an ignition improver, or a combustion enhancer, i dont remember which. Could it be amyl nitrate, the same stuff in diesel fuel?
Title: Re: cox fuel ???
Post by: Ralph Wenzel (d) on December 22, 2009, 04:13:23 PM
Definitely NOT Amyl Nitrate. My best guess is Propylene Oxide.

Title: Re: cox fuel ???
Post by: philip metzner on December 22, 2009, 04:16:57 PM
Definitely NOT Amyl Nitrate. My best guess is Propylene Oxide.


It could be! I used to race karts and one of my competitors cheeted and used that in his fuel.
Title: Re: cox fuel ???
Post by: Tim Wescott on December 22, 2009, 04:17:44 PM
Amyl nitrate is for diesel fuels, AFAIK it doesn't do any good in a glow fuel.
Title: Re: cox fuel ???
Post by: philip metzner on December 22, 2009, 04:41:57 PM
Amyl nitrate is for diesel fuels, AFAIK it doesn't do any good in a glow fuel.
Hey tim, what does AFAIK mean? I here that alot.
Title: Re: cox fuel ???
Post by: Douglas Ames on December 22, 2009, 07:18:04 PM
Hey tim, what does AFAIK mean? I here that alot.

I'll save ya a reply... As Far As I Know
Title: Re: cox fuel ???
Post by: john e. holliday on December 26, 2009, 10:35:14 AM
I too hate acronyms.  The phone used a lot of them and we spent a lot of time trying to figure out what the educated people were trying to tell us. 
Title: Re: cox fuel ???
Post by: Steve Helmick on December 26, 2009, 12:44:40 PM
Doc...What about ROFLMFAO? Acronyms can be a good thing!  H^^ Steve
Title: Re: cox fuel ???
Post by: Larry Renger on December 26, 2009, 05:14:11 PM
Getting back to the original question, Cox fuel formulae have been published repeatedly if you do a search.  However, in the Christmas Holiday spirit, here they are again:

Sport Fuel  15% Nitro 18% Castor Oil, (2% Lubricin in the Gallon Cans) and the rest Methanol

Racing Fuel 25% or 30% (depending on management's mood) Nitro, 18% Castor and the remainder Methanol.

I currently run 15% Nitro, 10% Castor, 10% Synthetic for Cox engines and 10,10,10 or 10,11,11 for everything else.

Since I fly competition aerobatics, I need total reliability, not expecially great power so the extra Nitro isn't needed.  One of the guys is using an AP Wasp with a drilled venturi, pressure fuel system and 25% Nitro.  It works for him!  230 sq.in. plane on 50' lines and completely reliable performance. (Current holder of the Leprechaun "Pot 'o Gold" Trophy)
Title: Re: cox fuel ???
Post by: dankar on December 26, 2009, 08:34:42 PM
I have some sport jet fuel. 20% P/Oxide 80% alky. Could I add a small amount to 1/2A fuel and not mess it up? Also have some nitro benzene is some gun solvent. Just need a couple engines to try it out on. Have a can of Areo-dyne Dynamite 65% nitro fuel. Could mix up a real mean quart of liquid kick-ass.
Cheers,Dan
Title: Re: cox fuel ???
Post by: Alan Hahn on December 26, 2009, 09:07:03 PM
   Many years ago i noticed many of my .049's ran much better on cox fuel than they did on other brands with comparable percents. This prompted me to call cox and talk to them about it. That led to many phone calls to fuel suppliers and somewhere along the way i talked to someone who said they used to mix fuel for cox, and i was correct in that there was a extra ingredient in cox fuel that others didnt have. He said it was ether an ignition improver, or a combustion enhancer, i dont remember which. Could it be amyl nitrate, the same stuff in diesel fuel?

Hmmm, I have no problem with normal 15-25% nitro fuels (like Sig) in my Cox engines. As long as I have 1) a good igniter, 2) everything is sealed up ok (like tank backs), 3) the reed isn't glued onto the holder by old castor, 4) the needle is not loose and leaky (piece of fuel tubing usually fixes this),  the engine will start and run every time. No extra bug juice is needed.
Title: Re: cox fuel ???
Post by: philip metzner on December 27, 2009, 11:35:35 AM
Hmmm, I have no problem with normal 15-25% nitro fuels (like Sig) in my Cox engines. As long as I have 1) a good igniter, 2) everything is sealed up ok (like tank backs), 3) the reed isn't glued onto the holder by old castor, 4) the needle is not loose and leaky (piece of fuel tubing usually fixes this),  the engine will start and run every time. No extra bug juice is needed.
Alan, i agree, my cox engines run good on most fuels as well. What im talking about is most of my older engines that have glow plugs instead of glow heads, like ok cubs, wen-macs, ect., would run much better on cox fuel. The fuel manufacture that i talked to said he was bound by a secrecy agreement and couldnt tell me what the extra ingredient was.
Title: Re: cox fuel ???
Post by: Larry Renger on December 27, 2009, 12:37:39 PM
Sounds like the "Secret Sauce" as in Kung Fu Panda!
Title: Re: cox fuel ???
Post by: Victor Jeffreys on December 27, 2009, 06:10:30 PM
Actually gray can Wen-Mac fuel (the only fuel Wen-Mac marketed) was a much more potent brew than anything Cox ever put in a can. I know from the skin blisters and glue sniffers' high it gave me when I did a labial pressurization on a Perfect fuel tank to clear glop from a sprawbar. Only Fox Missle Mist was comparable back in my days as a street flying thug.