Obolel,

We have found that it last longer and holds up to the Nitro better, I have tried the OS number 8 I think it was ( the plug that they reccomend ? ) and I had proplems with it, In the early stages of setting up the engine I did have the Iron bay models fuel regulatior in place for the first 18 flight during testing and we would go thru a plug about evert 2 flights , then the night before the contest we where showing this at, almost lost the plane from the regulator, in a mad scramble we went to basics and the first round of the contest was also a test flight.. The set up is: OS91 fx with a KM header and macs 1062 pipe with 25% nitro and OS F plug and and a 15x10 or 14x10 APC prop, fuel tank is on the CG and ONLY pipe pressure and NO head shims for me.. Also I have use some other plugs since and I just keep going back to the OS F plug.
The photo is Viper OS project 1 and 2. Mine is OS Viper # 1 ( red/white/blue)

scott