RE: OS 91 VRDF experts wanted
I see a few things that need a change. First, I would say 20% nitro is minimum. On a glow engine there are 3 components to ignition " Timing " Compression, load and nitro. Running too little nitro will " Retard " the timing. Bumping up the compression would help with the lower nitro as previously stated but adding nitro will have more benifit. While we are on the subject of timing, the pipe is too small ( Looks like a .60 size pipe ) and too short. So you now have an engine that is firing too late and the pipe pulse is hitting too early. This will really knock the RPMs down. Zinger props are not all that great either. I would bump up the nitro first. Some YS 20/20 would work well, run an OS 8 or Enya 3 plug, an APC 10X10, please get rid of that spinner before you kill yourself, it was never intended to be spun that fast. You need a .90 size pipe and start with a 3" header. This should get you into the 21-22K range. To get max power everything has to work together right now you have a few components working in opposite directions.