Hi All:
Must I use Duke's Fuel to get a Fox .35 Stunt to break from a steady 4 cycle to a 2 cycle when flying Stunt? Can this be accomplished from a blend of cator and synthetic or must sthe fuel contain 29% castor oil. I was flying a CG Shoestring today. I have seen Fox .35 engines break very well when mounted upright. Perhaps they will not make a good transition when mounted on a profile.
Duke's fuel does not contain enough oil for a Fox 35, at least for ideal life. Fox Superfuel is what most people used to use, that does have 28-29% castor.
That is not necessary to make the 4-2 break happen, although oil content can affect the way it works. Depends on who you ask what fuel you should use but no one is recommending 20% oil. I would use 28% straight castor, but you can use a blend.
On a profile, it works about the same as upright or inverted, *but only if you make the bypass stuffer modification*.
People have some sort of magical thinking about Fox 35s and 4-2 breaks. There is nothing at all magical about it, just about any stunt engine (and even a Lawn-Boy lawnmower engine) can be set to misfire under low load and fire every stroke when loaded. A 25FP does a beautiful 4-2 break, smooth as silk, but if you are running it that rich, you aren't getting much power out of it. 46VF on a pipe, smooth as silk. PA61 on a pipe, very strong and you can set it for too little boost to WAY too much boost.
The Fox 35 just happens to do it almost instantly (large venturi), with a massive change in the sound but very little change in the power (very low compression), at an rpm and load that works with a 10-6 prop on a Nobler.
Brett
p.s. Randy and I do not have a hotline and we did not collaborate to gang up on you!
Topic: Is Duke's fuel required? (Read 633 times)
