Cox 550 formula?

[Terry Caron]

Hi all -

What nitro and castor % is the old Cox 550 fuel?

Thanks.

Terry

[Terry Caron]

Thanks to Steve Pollock  - oil is 18% castor/2% Dow lube.
I found nitro % for Glow power (10), Flight Power (15) and Race Power (30).
How about Super Power - is it 25% nitro, as I have the vague memory?

Terry

[Dan McEntee]

  Do a search here on this forum, the 1/2A section and on Stuka Stunt for a thread where some one posted a scan of the actual work order for mixing fuel at Cox back in the day. Can't remember who it was, may even be on the Cox Engine Forum. My recollection is that there was blue can and red can in my area. Blue can was standard fuel at 15% nitro, and red can was racing fuel at 30% nitro. B&B 1000 was also a 30% fuel and ran really well in Cox engines. I do reserve the right to have a foggy memory though!
  Type at you later,
   Dan McEntee

[Terry Caron]

Thanks Dan, yes, I found those mentioned above but not for Super Fuel.
I'm thinking (foggily also) that it's 25%, but not sure.

Terry

[Dan McEntee]

  Been working in the garage and have examples of each can in front of me. The 550 number I think denotes the pint can size of Super Power Fuel, and I have a quart can that says the same thing that has 551 on it. I think Super Power fuel is the same fuel that we bought in the old blue cans back in the day. I'm betting its 15% nitro. The quart red can of Cox Racing Fuel that I have doesn't have a part number, and neither does the old blue pint can that I have and it says "Thimble-Drome Glow Fuel. I don't ever recall anyone talking about three different blends from Cox, just 15% and 30%. Maybe Larry Renger will see this and have some behind the scenes insight.
  Type at you later,
  Dan McEntee

[Motorman]

There was also an orange can that I think was called competition fuel. As I recall it was hotter than red can.


MM

[Larry Renger]

I only know of the standard fuel at 15% and racing at 30% except for a brief period whrn they used synthetic oil and ruined a lot of engines. Otherwise it was pure castor or castor with 2% Lubricin.

Having said that, I prefer a 50/50 mix of castor and synthetic. Lower viscocity, high temp protection and no vaarnishing. But also 20 to 22% total oil. Oil only costs you fuel economy, not power. If anything it lets you drive an engine harder.

[Terry Caron]

This link, in the 1st post, has the Cox formulas I referred to, dated Mar. '77:
http://www.coxengineforum.com/t7866-cox-original-fuel-formulas?highlight=cox+550+fuel
I haven't found anything specific about Super Power Fuel.
All I know is what other people tell me.   

Terry

[Dan McEntee]

  Well, after viewing the work orders again, I'm thinking that the blue can was 10% and the Super Power fuel 15%. and the red can racing Fuel the 30%. In my memory, once the yellow and orange Super Power Fuel cans came out, you didn't see the blue cans anymore. The 550 cans were the pint cans that came with the starter kits. I don't ever remember seeing the blue cans in the starter kits, but I could be wrong. I have a LOT of the pint 550 cans. What's left inside them still smells like it did back then!
  Type at you later,
  Dan McEntee

[Phillip Kenney]

Dan, I bet a  chemical analysis of some of the antique fuel you have, that still smells like the original, would start a really good discussion on the storage of model fuel.

[Dan McEntee]

  I have opened blue cans of Cox fuel that was known to be 30 to 40 years old, and the engine that old also. and they started right up and ran fine. I store my extra fuel in a stable temp environment in my basement in the card board boxes the fuel came in. I'm flying on SIG fuel that is at least 4 years old or older that I picked up at the SIG contest. I have had fuel go bad, right in the middle of a jug from one flight to the next. I know it can happen. But I have used one whole heck of a lot more of stored fuel than I have ever thrown away and my engines performed as expected on it.
   Just my personal opinion formed from actual practical experience.
   To my nose, Cox fuel just had it's own special smell!
  Type at you later,
  Dan McEntee

[Garf]

Cox Fuel Formulas: