The R/C Proving Grounds YS Engines


	What type glow plugs are recommended for the the YS 4 stroke engines?
	We highly recommend the OS Type F glow plug. Our testing has shown that this plug displays superior running characteristics.

	What are the crankshaft thread sizes on YS engines?
	YS 45 8x1.25mm, YS 61 ST-2 8x1mm, YS 63 8x1mm, YS 91 8x1mm, YS 120 8x1mm, YS 140 8x1mm

	What are the horsepower ratings of YS Engines?
	YS45 - 1.5, YS63 - 1.5, YS91 - 2.0, YS120 - 2.4, YS140 - 2.9

	What is the recommended fuel for YS Engines?
	We use Powermaster YS 20/20 Fuel. Several other manufacturers make 20/20 fuels as well. Many of our customers use lower percentages of nitromethane with good results. However, for optimum performance, 20% nitro (or more) is a must. Many of our customers use 30% Heli fuel with good success, although it is a bit hard on the budget! Also note that the YS factory recommends no less than 18% oil in the fuel mixture. Many commercial fuels contain less than this. Use of these fuels may cause damage to the engine or poor running characteristics. Fuels containing large percentages of castor oil can cause fuel pump/regulator trouble. Straight synthetic oil fuels work better in YS Engines. ALWAYS USE FUEL FILTERS!

	What do you recommend for propeller sizes on YS Engines?
	Always remember that RPM range is the most important consideration. Many prop sizes outside of our recommendation may be used as long as you keep the RPM within recommended limits. YS45: These run best if allowed to wind up. A 10 x 6 or 10 x 7 prop for general flying or 11 x 4 for fun fly type airplanes. Recommended RPM range 12,000 to 16,000. YS63: Keep the RPM in the 10,500 to 11,500 range. We have been running 12 x 7 APC Props with good success for general sport flying. YS91 FZ: The correct range is 8,800 to 9,300 RPM. A 14 x 10 or 15 x 8 APC should work well in most applications. YS120 FZ: Use a 9,000 RPM peak. 15 x 10 or 16 x 8 APC for general sport flying. YS140 L: Works well from 8,300 to 9,000 on props up to 18 x 6. Use 15 x 12 to 16 x 12 APC for aerobatic flying. PROPELLERS ON ALL MODEL AIRCRAFT ARE DANGEROUS! ALWAYS WEAR EYE AND HAND PROTECTION WHEN STARTING AND RUNNING ENGINES, AND ALWAYS HAVE A HELPER HOLD YOUR AIRCRAFT DURING STARTING AND RUN-UP.
	What is the fuel consumption for YS four stroke engines?
	YS 63FZ: 1/2 oz per minute YS 91FZ: 1.1 oz per minute YS 120FZ: 1.5 oz per minute *YS 140L:* 1.5 oz per minute *YS 140DZ:* with venturi restrictor- 1.75 oz per minute without venturi restrictor-2 oz per minute All tests were run with Powermaster YS 20/20 fuel and standard prop sizes for each displacement. Use of other fuels and prop sizes will affect fuel consumption slightly.
	What's happening with the new engines?
	The new YS 80 and 140 DZ have been delayed until August 2001. We have made some improvements in the engines which caused the delay. Sorry for the inconvenience.