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Building Tips and technical articles. => 1/2 A building. => Topic started by: Bill Little on January 22, 2007, 02:01:43 PM

Title: Cox .049 fuel
Post by: Bill Little on January 22, 2007, 02:01:43 PM

HI All,

Boy do I feel dumb! 

This a question about fuel for my Cox engines.  "Back in the day" I could get teh Cox fuel in the local hardware store.  It's long gone!

I have various "full size engine" fuels.  One is a gallon of Cooper 20% nitro, mostly synthetic oil.  I took some of that and added a good bit of castor to it.

I do have the Sig Champion 10% 1/2-1/2 fuel.

What is "usuable", and which would be best?

Thanks!
Bill <><

Title: Re: Cox .049 fuel
Post by: frank carlisle on January 22, 2007, 02:41:38 PM

Bill...........Jan and I have been using Norvel Fuel....It comes in different amounts of nitro. We have 25% nitro 18% oil.
The Cox engines we have seem to like it pretty well.

Title: Re: Cox .049 fuel
Post by: James Lee on January 22, 2007, 02:57:10 PM

Bill
Around here we've found the Sig 25% Champion fuel to be a good 1/2 A fuel.  The Cox has to have a fair amount of castor to keep the piston ball socket from coming apart.  That was from Dale Kirn, many years ago...  I think the old Cox fuel was all castor, but I don't know what percentage.
Jim

Title: Re: Cox .049 fuel
Post by: Bill Little on January 22, 2007, 09:01:04 PM

Thanks, guys.  Main problem is that I don't have a really "local" source of anything, fuel or otherwise.  I CAN, however add castor to fuel that I have.  Or mix and match.  That is why I referenced the Cooper, it is 20% nitro.  Everything lse is not over 10%, basically.

I was thinking that the Cox needed castor from some long forgotten bit of memory......

I finally got me a Davis "rod setter" for the Cox engines and took a couple apart to check them.  All of them had rods that were getting loose in the pistons!

Bill <><

Title: Re: Cox .049 fuel
Post by: George on January 22, 2007, 11:22:51 PM

Bill,

I believe Cox fuel was 15% nitro and their Racing Fuel was 25% nitro (perhaps 30% at one time). I believe it was either 18% or 20% all castor lube.

George

Title: Re: Cox .049 fuel
Post by: minnesotamodeler on January 23, 2007, 01:38:07 AM

Quote from: Bill Little on January 22, 2007, 09:01:04 PM

Thanks, guys.  Main problem is that I don't have a really "local" source of anything, fuel or otherwise.  I CAN, however add castor to fuel that I have.  Or mix and match.  That is why I referenced the Cooper, it is 20% nitro.  Everything lse is not over 10%, basically.

I was thinking that the Cox needed castor from some long forgotten bit of memory......

I finally got me a Davis "rod setter" for the Cox engines and took a couple apart to check them.  All of them had rods that were getting loose in the pistons!

Bill <><

Happens to every Cox.  If left untouched, the rod will eventually drive itself through the top of the piston.  I had a really cool picture ("had"--since lost) of one of mine that did just that, broke out a circular piece that left a hole so perfect it looked like it had been drilled.  That was my introduction to the Cox loose-rod syndrome.  A rather poor piece of engineering in my opinion.

--Ray