Sport_Pilot

Finally going to test a few 1/2 A engines I bought but need fuel. I noticed on tower that the Cox 1/2A fuel is half castor and half synthetic. I thought it was supposed to be 100% synthetic for Cox engines, but probably good for the Norvel engine. I can mix my own but the only nitro I have ran through my son's windshield washer, LOL.

combatpigg

My Feedback: (3)

That's a good starting point for typical running. You can always bump the total oil content up to 25%+ if you are curious to see how that works. You'll need more paper towels, though.

049flyer

My Feedback: (18)

I've always thought that 1/2A engines need a good bit of castor oil and to never run fuel that was all synthetic.

I mix my own 1/2A fuel starting with 30% Car fuel as a base. Just add a bit of Castor Oil and you are good to go. Ends up at 25% Nitro, 20% oil and the rest methanol, my engines love it.

aspeed

I always hear the castor is the way to go too, at least 5% anyway. I have used it that way for years, but the reedies still seem to wear out the front bearing after a couple hours, and then they run erratically from the air leak. Then it is 25% castor and more nitro to make up for it until I get a new case. Same for the old Foxes.

MJD

My Feedback: (1)

100% synthetic is actually the opposite of what is good for Cox engines.. you want a high percentage of castor. 100% not necessary, but 50% is good.

Is SIG Champion 15% or 25% nitro available where you are? It is 20% oil, 10% synthetic, 10% castor.

Even Omega 15% or 25% (17% 70/30 syn/cas) plus 5% castor is good.

I don't like the idea of using all synthetic fuels and adding castor.. you are automatically restricting the castor content.

It is no problem to fire up a Cox 1/2A on many fuels and say "look, they run great".. maybe they do for now, but when you factor in wear and service life, esp. in the event of lean runs (they happen) it may be a totally different story. No sense fighting what has been known and recommended for decades.

Andrew

I'm usually in agreement with Mike (MJD) 100 % of the time, but I have had pretty good luck blending Sidewinder Pro 30/10 and Sidewinder Pro 20/10 with additional castor to get a fuel that has been satisfactory. An email from Morgan Fuels verified that the lube package is a 50/50 castor/syn mix. Starting with a high nitro / low oil fuel, I can add sufficient castor oil to raise the overall oil percentage and not dilute the fuel appreciably.

His post talked about all synthetic oil, and I certainly agree that adding castor is restrictive in that the overall lube percentage could get high. That's where the 10% total oil gives quite a bit of leeway; plus the Sidewinder Pro is less expensive than some of the other COX specific fuels. I can mix close to a half gallon of fuel for $22.50.

MJD

My Feedback: (1)

We're still in agreement actually.. I didn't realize the total oil % was that low in those fuels! Obviously you can make a good blend with those.

1QwkSport2.5r

The highest oil content car fuel I've come across had 16% oil by volume but the ratio of castor/synthetic is unknown for that one. I'd assume 80/20 synthetic/castor. Most car "sport/basher" fuels are around 12% oil. I've had good luck with Byron's, blue thunder, and Trinity monster horsepower fuels in my cars over the last 15 or so years. I can see those fuels being better for "spiking" with extra oil for the little guys that need a bunch of nitro to run well.

049flyer

My Feedback: (18)

Powermaster car fuel is 9% total oil of which some is castor. I buy a gallon of 30% nitro car fuel for about $22 and add enough castor to bring the fuel up to 20% total oil of which over 50% is castor. The final nitro percentage is just under 25% by my calculation. My total cost per quart including the castor is just under $8.00. All of my Cox engines run great on the stuff.

MJD

My Feedback: (1)

Obviously I never paid enough attention to car fuels as blending stock.. now I is edugated good. Hmm.. how low does the nitro go.. gotta look that up.

Andrew

MJD --

Here's a link to Powermaster car fuels. Looks like they have 16/9, 20/9, 25/9, 30/9, 40/9 and 50/9. They say their lube package is a syn/cas blend, but I don't know the split. I've never used their fuel, only Morgan's Sidewinder Pro car fuel.

http://www.powermasterfuels.com/inde...&id=7&Itemid=9

andrew

MJD

My Feedback: (1)

Morgan fuels are more available up here AFAIK - but, I don't look in the car department much. Certainly will check it out.

Super Techniplate is 80/20, but 70/30 seems to be a common oil blend too. Dunno if that is due to the existence of another OEM oil pre-blend, or if the fuel manufacturers blend to spec on site.

smallrc

I have used Sig Champion 15 & 25 for years in Cox engines with good results. Straight 15 for .049 reedies, half & half mix for TD 049's & straight 25 (with a bit of castor added) for .020's & .010's.

MJD

My Feedback: (1)

Since the quarts became a regular on the LHS shelves here in the last few years, it is my 1/2A and smaller fuel of choice these days as well. 20% total oil, 50/50 blend. 25% plus 3% castor has become my standard .010/.020 blend.

Pond Skipper

The new re blended Cox Super Power 25% and 35% - after great efforts on the Cox forum to have it improved.
They let some folks on that sight field test it prior to selling.

http://www3.towerhobbies.com/cgi-bin...&I=LXEYHA&P=ML
[TABLE="width: 100%"]
[TR]
[TD="bgcolor: #f0f0f0"]SPECIFICATIONS[/TD]
[/TR]
[/TABLE]
Contains 25 or 35% Nitromethane
45% Methanol
10% Synthetic Oil
10% Castor Oil

I have some custom blend 25% castor 40% Nitro for my .010 and .020 engines I called Arctic R/C Fuels about a year ago.

But for now on I will buy the Cox Super Power 35% and just add a dab of castor to bring it to 15% / 10% synthetic

MJD

My Feedback: (1)

Wayyy back to this old thread. I was at the LHS today picking up some 15% sport fuel and some other stuff. Then I remembered this thread... so into the car department I go and there is a variety of O'Donnell race blend car fuels.. 8% oil. Yeehah,, I grabbed a jug of 25% and will brew up some new small engine fuel.

1QwkSport2.5r

My LHS that specializes in RC cars actually carries Cox "SuperFuel".. The bottle doesn't say what exactly is in it (nitro or oil volumes), but it is cheapish.. $12/qt.

MJD

My Feedback: (1)

And ours has Sig Champion in quarts, good stuff.

Now here's yer 1/2A basestock..

http://www.odonnellracing.com/index.html

The new Speed Blend formula takes it to the next level. Using superior ingredients, an advanced oil package and computer-controlled blending, Speed Blend delivers the extreme rpm and long run time that high-stakes competition demands.

I love it - this Speed Fuel is a castor/synthetic blend versus the regular Racing Fuel which is synthetic.