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Author Topic: Original cox fuel  (Read 1718 times)

Offline Frank Sheridan

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Original cox fuel
« on: July 20, 2009, 04:16:28 PM »
Does anyone happen to know what the recipe is for the original Cox sport fuel that came in the light blue cans back in the seventies? I'd like to blend some. My Cox engines don't seem to like the r/c car fuel that's available in my area.
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Offline Larry Renger

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Re: Original cox fuel
« Reply #1 on: July 20, 2009, 06:02:07 PM »
I will give you the answer, but a "search" on Cox fuel would have gotten it for you quicker.  Cox fuels had 15% Nitro in the Blue Can and 30% Nitro in the Red Can.  Both fuels had 18% Castor oil as the lubricant.  In the Gallon cans, the blue fuel had 2% lubricin added (whatever the heck that was).
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Offline Frank Sheridan

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Re: Original cox fuel
« Reply #2 on: July 20, 2009, 06:39:01 PM »
I've heard plenty of formulas for Cox fuel, but I never heard of the Lubricin additive. I Googled lubricin and apparently it is a secretion which lubricates cartilage in joints of animals (humans included). I guess that they(Cox) used a bovine extract of the stuff. I wonder why it was in the gallons and not the smaller quarts and pints of fuel. I personally have never seen a gallon can of Cox fuel. Just think how long a Babe Bee would run nonstop on a gallon of fuel!
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Offline Mark Misegadis

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Re: Original cox fuel
« Reply #3 on: July 21, 2009, 11:29:31 AM »
I missed this thread and had just posted a similar threadin the Engine Tips area. I will paste my post below.

 1/2 A fuel - What percentage do you recommend?
« on: July 21, 2009, 11:11:48 AM »
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Currently we are running Cox motors with an AP .061 tossed in for fun. We are running either 18 or 20% Caster with 35% nitro. Sig or Wildcat are the two brands.

The 20% caster seems to leave things a little messier than the 18%. I have read numerous posts with widely varying opinions on the percentage of nitro to use.
We are at 6000 feet so therefore things work a little different here and perhaps this is why for the regular sport flying I see lower percentage answers from everyone else in their similar posts.

Cox fuel worked fine back in the day. Does anyone have a figure on what the percentages were for it.

Thanks in advance for your advice.

Mark
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I recall the motors running at a higher pitch back in the day on the cox stuff. Now that I have the luxury of a tach we have been checking them and a good tune gets us 11300 to 12000 rpm for our Cox .049's

How does this sound to everyone and are you sure on those posted percentages?

Thanks again, Mark
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Offline Robert McHam

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Re: Original cox fuel
« Reply #4 on: July 21, 2009, 12:45:43 PM »
Here are some graphs depicting numbers and sources that might help.
http://www.mh-aerotools.de/airfoils/cox_frameset.htm

Click on the "performance" button from the menu on left.

Robert
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Offline George

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Re: Original cox fuel
« Reply #5 on: July 21, 2009, 03:08:28 PM »
Actually, Cox fuel could allow the cylinder to gather a layer of varnish that would occasionally need to be removed either by disassembly and scouring with a "Brillo" pad, or using gun cleaner. You could also add gun cleaner to fuel for an occasional run.

By adding some synthetic lube to the castor, the varnish layer is removed while running (or does not form). This would occur more on engines run hard, as in racing or combat.

George
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Offline GGeezer

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Re: Original cox fuel
« Reply #6 on: July 21, 2009, 06:54:13 PM »
Quote from: Frank Sheridan on July 20, 2009, 06:39:01 PM
I personally have never seen a gallon can of Cox fuel. Just think how long a Babe Bee would run nonstop on a gallon of fuel!

I have 4 gallon cans of Cox Power fuel.................. though not actual Cox gallon cans.
A friend of mine, who is in the toy business, bought a large quantity of surplus Cox ready-to-fly products and sold them all on Ebay. In order to get around shipping problems, he emptied all of the fuel cans which came with the product and not having a use for the fuel and knowing my love for small engines, gave me 4 gallon cans of the stuff.
If the fuel didn't work so well, we could hook up a Babe Bee and see how long it would run. I'm going to guesstimate about 13 hours.
My McCoy .19 also really runs well on the stuff, of course, I add some extra caster.

Orv.
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Offline Frank Sheridan

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Re: Original cox fuel
« Reply #7 on: July 21, 2009, 07:30:29 PM »
That settles it - I need better friends. LOL
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Offline Larry Renger

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Re: Original cox fuel
« Reply #8 on: July 21, 2009, 11:08:02 PM »
My Cox fuel formulas are from the Cox specification drawings, no guesswork here.
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Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Mark Misegadis

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Re: Original cox fuel
« Reply #9 on: July 23, 2009, 09:26:58 AM »
May we ask what they are Larry?

Mark
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Offline Frank Sheridan

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Re: Original cox fuel
« Reply #10 on: July 23, 2009, 03:13:45 PM »
Does anybody know what purpose the lubricin served in the fuel? Or why it was only used in the gallon cans?
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Offline Larry Renger

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Re: Original cox fuel
« Reply #11 on: July 23, 2009, 11:13:41 PM »
I gave the formulae above.   ::)

Lubricin was to increase lubricity (sorry, couldn't resist).  That is it reduced the viscous drag and thus increased rpm.
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Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline dennis lipsett

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Re: Original cox fuel
« Reply #12 on: July 24, 2009, 08:08:40 AM »
Quote from: Larry Renger on July 23, 2009, 11:13:41 PM
I gave the formulae above.   ::)

Lubricin was to increase lubricity (sorry, couldn't resist).  That is it reduced the viscous drag and thus increased rpm.




Sig sold Lubricin for years. Perhaps it's still in their catalogue. At any rate it really isn't worth the cost to add it to your fuel.
dennis
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Offline Jim Thomerson

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Re: Original cox fuel
« Reply #13 on: July 24, 2009, 11:21:54 AM »
I have a quart of Sig lubricin which is maybe 30 years old. As I understand it, it is a castor oil derivative which is a detergent.  If you go over one or two percent it interfers with lubrication.  I asked Mike Pratt about it many years ago.  He said it was better to run some synthetic oil rather than use lubricin. The synthetic did a better job and didn't interfere with lubrication.  That's to the best of my recollection.   
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