Cox 25% and 35% 1/2 A FUEL

[Frank Imbriaco]

Hobbico distributes both in quarts.  Both have 20% oil (equal parts castor and synthetic)

Does anyone know who  manufactures this fuel  with the Cox label ?

Has anyone run it in 35-36 sized engines ? Results ?

[Dan McEntee]

  I don't know who makes it but it is good fuel. Originally, it was only 18% oil, but they listened to the serious 1/2A community and went up on the oil content. I see no reason why it should not run in any other engine if you were so inclined. The fuel doesn't know the difference in displacement!!
   Type at you later,
    Dan McEntee
  PS: A copy of an original work order for mixing Cox fuel has made the rounds of the internet and posted on several web sites. It cleared up a lot of mystery for those who wondered exactly what the two diferent can colors contained as far as nitro and oil content. Blue can was 15% nitro, red can was 30%, with both having 20% all castor oil. (If I remember correctly)

[Garf]

Have a look at this. I have the other 2.

[Frank Imbriaco]

Garf:

Would you mind sharing the other two that you have ?
 I'm interested in comparing.
Thanks,
Frank

[Andre Ming]

The Cox "Work Order": Very interesting.

I was never involved in the mixing room at Fox (looked like boring work, anyway), but was out there quite a bit getting various ingredients.  What surprised me reading that "Work Order" was the gallons they were dealing with. Our mixing tub was nowhere near that capacity.  In fact, it looked suspiciously like a large galvanized metal live stock watering trough. (Which I'm sure it was.)  Upon my first hiring at Fox, I recall being somewhat disappointed in learning the manner fuel was produced.  The contents were simply poured into the elevated trough, and once all the ingredients were in, the fuel man used a canoe paddle to stir it for "x" minutes!  Very hi-tech.

However, back to Cox:

Unfortunately, in spite of all of the above attention to detail, quality controls, etc, Cox fuel will forever be INFERIOR to quality, sure'nuf glow FUEL because...

There AIN'T no PURPLE DYE!!

[Garf]

Here they are.

[Andre Ming]

Thanks Garf.

Interesting they were using a smidgen of Klotz way back when, the 18% castor and 2% Klotz resulting in 20% oil.

[Dan McEntee]

   Hey Mingster;
     The Klotz they are referring to Dow KA-1186 or (what ever) is what I believe some refer to as Ucon oil, and has no color. Cox fuel was always clear with no tinting. If Ii was mixing my own, I would not hesitate to add a pinch of Klotz Techniplate just for the detergent action and cleaning properties it has. I have learned that a bit of synthetic added to an all castor mix helps keep things from varnishing up too soon and engines don't get as sticky. I have opened up cans of cox fuel that have been anywhere from 20 to 40 years old, and it always has a certain smell, and has always run in an engine just fine.
   I am just finishing up cleaning and fixing up two Cox P-40s, the tan version with green spinach on the top side and up right engine. These are rare enough, but what is really rare about these two is that they BOTH STILL HAVE THEIR ANTENNAE!! It is almost impossible to find these and several other Cox models that had antennae on the top of the turtle deck. I think it was the first thing to get broken when the exited child reached into the box to remove the airplane and they snap off the antennae reaching for it! These had been run, but I have no idea what they used for fuel. The sticky residue on the airplane was almost impossible to remove without a little heat and careful application of elbow grease.! The engines were similarly stuck, and the tanks were full of a gray/green mud. Yes I said full! Heat from a heat gun would melt it, but until that it was like clay or putty! I replaced the decaying and flat spotted tires with tires from some Perfect brand balloon wheels. Just roll (or more like crumble!) the old ones off the hubs, roll the new tires off their hubs, then roll them on the Cox hubs. All these need now is new decals and they will look like new. I am just amazed at how they retained there antennae after being run and mishandled to the point where the boxes have fuel stains and such on them. Still quite presentable though.
    Type at you later,
    Dan McEntee

[Andre Ming]

Hi 'ya Dan!

Ah yes, the Cox P-40: What boy didn't dream of owning one?  As for me, I'm a'feared they've gotten way too rich for my blood to ever seriously consider purchasing one.  Besides, if I did want to purchase a vintage Cox plastic plane, I would be more interested in purchasing a Cox that I did own: The Super Cub, Helldiver, PT-19 (w/Babe Bee), and Skyraider.  But those too, go for too high a price for my spending habits.  Instead it makes much more sense to spend my money on IMPORTANT vintage stuff... like Fox 36X engines, Johnson engines, vintage combat kits... 

Purple Dye:

My tongue-in-cheek comment was in reference to my old sentimental favorite: Fox Missile Mist.  As a youngster, I always thought it MUST have been the exotic ingredients within the "Purple Brew" that caused that color. Upon employing at Fox, imagine my disappointment to learn that it was nothing more than purple dye, and that it was only added as a means to distinguish an unmarked container of Missile Mist from the other fuel mixes at Fox.  FWIW: We used Missile Mist and cut-down wooden 9x6 props to run-in all C/L engines all the years I was at Fox. The idea was safely maximize RPM without unduly increasing heat. I've heard* some 35 Stunts hit some pretty impressive RPM doing so!

* Well, "heard" as in pre-Fox days back when I could actually hear without this constant infernal ringing that's in there now, courtesy in large part to Fox Mfg!

[Brett Buck]

Hobbico distributes both in quarts.  Both have 20% oil (equal parts castor and synthetic)

Does anyone know who  manufactures this fuel  with the Cox label ?

Has anyone run it in 35-36 sized engines ? Results ?

   I have run several 40s and 45s on Cox Racing Fuel. In most cases had a remarkable increase in the overall "power" and showed no negative effects otherwise. One was a 4-2 break engine back in the day and it was absolutely astonishing how much more line tension there was. It also ran out of fuel in the square 8. Even at that time cost about $64 a gallon. Other than that, and as clear from the specification posted above, it's not that much different from any other fuel, doesn't have anything exotic, so no surprise that it runs like it has more nitro and works fine otherwise.

    That's when I learned the value and the effects of nitro, and how far from the edge we run on compression. Even a teeny increase in the compression ratio on an ST46 due to head gasket crushing can cause problems, but the same engine ran fine on anything from 5% to 35%.

    Sometimes the extra power was minimal. At a constant altitude/air density, you will usually get great increases of "power" up to a point, and then get diminishing returns. Lowering the compression lowers the power overall, at which point adding more starts helping again, but the flat part of the curve seems to be the same in terms of "power".

    BTW, not surprisingly, Cox Racing Fuel tremendously improves the run on any Cox engine I have tried, and in particular, the Medallion .049 on Cox Racing fuel has the most perfectly smooth run you can imagine in a model airplane engine. Turn your back to the circle and aside from Doppler effects, you can't tell whether it is maneuvering or not. It also smells different than most, just like any almost-all-castor fuel run at high temperatures (like Fox Superfuel in a Fox) - it just smells  *right*.

     Brett

   

[Phil Krankowski]

Over on CEF we got a response from them.

http://www.coxengineforum.com/t7143-cox-super-power-fuel?highlight=fuel
after quite a bit of a long discussion
http://www.coxengineforum.com/t5113p60-hobbico-s-cox-super-fuel?highlight=fuel

I wish I would ave jumped on a sample, but I have had too much going on.  I have not yet tried the current formulation.

Phil

[Frank Imbriaco]

Garf: Thanks for the formula charts.  And, thanks to others who contributed.
The Tower site lists the two fuels( 25% & 35%) and it appears as though they've been re-formulated with increased oil (20%, half castor, half synthetic).

Frank

[Mark Mc]

Phil and Frank,

I was one of the lucky ones who got to test the fuel from Hobbico.  The big thing that we Cox fanboys disliked about the previous version of "Cox Superfuel" sold by Hobbico was that even though it had 18% castor/synthetic oil blend, the actual castor content was only 1.8%.  Hobbico listened to us and mixed up a batch of 50/50 castor/synthetic blend to send to a few guys to try.  I used a brand new cast case engine and ran the provided quart as quickly as I could reasonably do so.  If my logged time was correct, I put 8 hours and 3 minutes on the engine using up the full quart.  I didn't do any cleaning of the engine, inside or out, in the full test.  After the initial break in period, the engine kept about the same peak RPM start to finish, but the fuel consumption went down by about 16% by the end, which I attribute to a thin varnish buildup on the cylinder walls.  Tearing the engine apart after the 8 hours showed it nice and clean inside.  Just a little varnish buildup on the glow head and cylinder fins, as I never cleaned up the castor oil left on after running the engine.  I was trying to run it like a novice would run his engine.  The new Hobbico Cox Superfuel is a winner in my book.

Now, think about that.  8 hours and 3 minutes on a quart of fuel.  At the $11.99 for a quart my local hobby shop charges, that's 2.5 cents a minute.  And some people ask me why I waste my time on those dinky, obsolete engines...

Mark

[Garf]

When I mix .049 fuel, I use 20% castor and 20% nitro. Works for me.