Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
May 26, 2020, 07:21:49 PM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1]   Go Down
Print
Author Topic: Cox Racing Fuel  (Read 213 times)
0 Members and 1 Guest are viewing this topic.
newg4ff
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 41

Topic starter


Ignore
« on: April 04, 2020, 07:35:51 PM »

Does anyone know the formula for the old Cox red can fuel of the 60's?  I never had a cranky .049/.051 when using it.
Logged
faif2d
Platinum Member
******

Kudos: 31
Offline Offline

United States United States

Posts: 1,227


Sun came up I was here to see it = good day



Ignore
« Reply #1 on: April 04, 2020, 08:28:22 PM »

The biggest challenge is finding pre-mixed fuel that contains castor oil, as most fuels sold
nowadays contains synthetic oil only, which can lead to premature failure of the engine’s
crankcase bushing and/or piston ball and socket. There are some “½A” fuels on the market that
contain 100% synthetic oil. DO NOT run your Cox engine on such a mixture.
Cox recommends a fuel mix containing 20% castor oil. Under strict racing conditions, as little
as 5% castor oil (and the balance synthetic) is required to protect the engine for it’s short racing
life but is not recommended for recreational flying, where longevity of engine life is desired. To
be on the safe side, we recommend at least 10% castor oil and 10% synthetic oil. The upside
of using a 50/50 castor/syn mix is that it will help reduce varnishing and leave less oil residue on
the model.

How do I obtain pre-mixed ½A fuel? The first place you should check would be your local
hobby shop. If they sell ½A fuel, ensure it contains an appropriate amount of castor oil. If they do
not, ask for fuel that contains castor oil. To obtain diesel, Davis Diesel manufactures an excellent
diesel fuel and it can be purchased from the manufacturer and other on-line stores. Please see
the chart contained in this guide for a list of suggested fuel brands and where to get them.
If you cannot find fuel with castor oil, you can add your own! Simply purchase a good fuel
with 25-35% nitro and low oil content. Purchase castor oil separately and add to fuel. It is
recommended that you use a fuel chart or do the math to figure out how much castor oil to add
to fuel. A Castor Oil Calculator is available @ www.coxengines.com/files/castor.xls (must
have MS Excel 2003 or later to open / use it).
Can I mix my own fuel? Absolutely! Many modelers mix their own fuel. Mixing your own fuel
allows you to make a custom mix for your application. Mixing fuel is quite simple and easy
although getting the ingredients may not be as fun. Your local “Yellow Pages” is likely a good
place to start your search for the proper ingredients.
Cox engines typically run on what is termed “½A fuel”, a fuel with high
nitro content and containing some castor oil instead of synthetic oil
only. This fuel mixture is becoming increasingly difficult to obtain. Often,
when referring to “½A“ in hobby shops, it will elicit blank stares. ½A fuel in
loose terms is 15-35% nitro (a.k.a. nitromethane), 20% (castor) oil and the
balance methanol (a.k.a. methyl alcohol, carbinol, wood alcohol, wood
naphtha or wood spirits).
Cox engines will run best on a fuel mix that contains 25% to 35% nitro,
whereas the higher nitro content will lead to higher RPM’s but also leads to
higher heat and a shortened engine life. The Tee Dee series are better
suited to higher nitro content, whereas the basic production engines are
best run with a lower nitro content. Operating your Cox engine with less
than 20% nitro content might make adjusting the needle valve somewhat
quirky.
The 35% nitro was the racing fuel (red can) The blue can was 15% I think.
Logged

I used to like painting with dope but now I can't remember why!    Steve Fauble
gossie
Platinum Member
******

Kudos: 49
Offline Offline

Australia Australia

Posts: 1,776



Ignore
« Reply #2 on: April 04, 2020, 09:19:19 PM »

Just mix your own fuel.
General use, 50% methanol, 25% castor oil, 25% nitromethane.
For competition use, 50% nitromethane, 25% methanol, 25% castor oil.......You might need 2 or 3 of the thin gaskets under the head with this fuel.
From the 1970s I ran many TDs on these mixes, seldom blew plugs even on the hot mix, with very small props. and high revs.
Logged
flydean1
Platinum Member
******

Kudos: 24
Offline Offline

United States United States

Posts: 1,079



Ignore
« Reply #3 on: April 04, 2020, 11:31:46 PM »

Normally I would echo the comments about obtaining pre-mixed fuel.  However, I have had good service from Red Max.  They used to have a 65% fuel that still had some castor as well as synthetic.  USA modelers should be able to find them on the web.

When I lived in Florida, twice a year I had to go to an eye clinic in Tarpon Springs.  There was a hobby shop there, House of Hobbies, that stocked Morgan Racing fuel with 40% nitro and 20% oil which was half castor.  I would buy castor and add it to "de-tune" it to 35%, the extra castor was for my plain bearing engines.

Well, I moved from Lakeland to Dothan, Alabama over 8 years ago.  The nearest hobby shop was in Montgomery, 2 hours away, and overrun with rc car stuff.  Being desperate,  I did a web search for the Morgan web site.  Maybe they would sell direct.  Guess what, their headquarters, and production facility is in Enterprise, Alabama!!  Not only would they sell direct, I could even get castor to add, and they even had some 65% available.  A 30-minute drive was all it took.

Sometimes, you luck out.
Logged
newg4ff
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 41

Topic starter


Ignore
« Reply #4 on: April 06, 2020, 09:23:13 AM »

Thanks for all the info!  I should be back in business.
Logged
CajunFokker124
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 20




Ignore
« Reply #5 on: April 20, 2020, 01:27:07 PM »

Ritchs Brew is another option. Can make you any mix you want and ships too.

Sent from my SM-G965U using Tapatalk

Logged

"Hoorah for ze next man that die!!!
Pages: [1]   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!