Airborne Magazine - Issue #249 | Page 41

which is sealed with a screw in cap, very small “C” circlips that require very fine circlip pliers for removal. • The connecting rod is machined from high tensile bar stock aluminium, offset big end, needle roller bearing on big end, bronze bush in little end, connecting rod and needle roller bearing retained by a special left hand thread screw. • Liner is heat treated carbon steel-very hard-deep multi hone scoring for oil retention , extremely large transfer and exhaust porting (high performance design), liner located by pin in cylinder fitting into slot on rim of the liner. • Crankshaft is almost standard design from OS-high tensile alloy steel, heat treatedexcellent finish on all surfaces. • The heat sink style finned head is sealed onto the liner rim with a brass shim and is retained to the cylinder with 6 screws. The head is threaded for CM10 spark plug which is supplied. • CDI module is manufactured to high standard required by OS, delivering very high voltage to the plug and is capable of extreme high speed operation and has proven reliability. An important note here; ensure the plug cap is pushed down onto the plug as far as it will go. A piece of wood or a plastic handled screwdriver helps get it down and tight. Best per- formance will come from using the maximum voltage advised and a high capacity battery. • Read and understand the instructions that come with the engine-particularly the section of the setting of the carburettor. WARNING Do NOT use motorcycle or lawn mower oil in the fuel as the flash point is too low for model engine operation. Suggest PETROMAX from Model Engines, Morgans Blue CoolPower, Klotz Original Techniplate (KL2000) or Klotz R50. Also do NOT use Ultra petrol as unleaded (95RON) is all that is required. What Brian has said just confirms how good this engine is. The version of the GT15HZ engine I ordered came with a specially designed Power Boost pipe. It is the perfect pipe for the engine and is suited to be mounted in a model helicopter. I really can’t wait to get this into a suitable 90 sized model helicopter. But so far the weather gods have been extremely unco-operative, so I won’t get any of the flying stuff done until the next edition. Until next time HAPPY DRY HOVERING. Peter R Airborne 41