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