What fuel do they use for 1/2a Proto at the nats? The last time I tuned my engine the fuel was 70% nitro.

Thanks,
MM

Spec fuel across the board:

7. Fuel
Fuel of standard formula will be supplied by the contest organizers. The
percentages of ingredients in the fuel mixture supplied must be accurate,
consistent with careful and accurate mixing techniques. Fuel for two-cycle glow
plug engines shall contain 10% nitromethane, 20% lubricant, and the rest shall be
methanol. Fuel for jet engines shall consist of 80% methanol and 20%
Nitromethane.

Yes, there is castor oil in the lube package. Klotz is the synthetic. The blend is either 20% or 25% castor. Racing (NCLRA) uses one and Speed (NASS) the other but I can't remember which is which right off the top of my head. I don't have time right now to dig out the information. Klotz Super Techniplate has 20% castor.

As Dave responded, S&W is the NASS fuel supplier. There is a web site but the NASS Special Blend fuels are not listed. I suggest you call Stan at S&W and ask him.

The regulations don't specify a particular lube package as a matter of convenience. The respective SIG's settled on a blend for the fuel each provides for contests. It would be next to impossible to manage that level of detail through AMA.