I have been making parts to convert an Irvine 15R to 12 class speed specification.

The parts are being made according to the excellent article that Peter Halman wrote in Aeromodeller  issue 1035

Back issue 1035 link

The Super Silencers are part way through manufacture, I am making a few for my friends as well, the turbo cone plug head are done and all of the fixtures for modifying the cylinder porting on the milling machine are manufactured and ready for use.

I will be flying in the 12 Open Class not 12 PRR