Hello j0rrit,

throw that stinkin' Master Airscrew into the bin and get you a black Graupner Speed Prop 6.5x6.5 To be then shortened to 5.5" in
diameter.

That makes this little MVVS 2.5 really come alive - if you use a full length tuned pipe (MACS 1110 for instance). The stock black magic muffler is too restrictive. The MACS Pipe length between glow plug and biggest part of the pipe should be set about 21 to 23 cm.

You need to widen the MVVS speed venturi carb up to 6 mm of inner diameter.

Presupposition is that you MUST increase engine exhaust timing up to 170 degrees. Then 25 thousand rpm in flight will be no problem. That makes approx 140 mph with your Blizzard airframe...

Regards

slomo

P.S. The conrod of the UCTKAM .15 = MDS .15 Speed Pylon (or M+R .15 engine rpectively) does not feature a bronze bushing on both ends - just to remember that.