All you guys having spool up problems is due to the nitro you are running. I have the 16x4W APC on my Saito 100 and have since day one a year ago. It spools up almost instantly. I run Cool Power 30% Helicopter fuel in mine. 15% won't cut it with that prop you are right. And yes, it is like stepping on the brakes with a 16x4. I love it. Hovers at less than 1/3 throttle and hovering is not the easiest as it wants to climb. Climbs as fast as it flys level. I can get 9,900-10,000 on with a 16x4 and CP 30%. You guys running 15% do need to go to the 15x4. I am a heli pilot mainly and run it and did not want to have two jugs of fuel with me at the field and come to find out how much my plank engines (Saito and YS's) love the same fuel. I knew the YS's did, but come to find out Horizon says to run it in Saito's if you want more power.

I ran a 15x6. I get about identical RPM's but it pulls it too fast for my liking. This thing screams for pulling power not speed. I will do things with this prop that it won't with any other or it does them better. Slow stuff is much better as the thrust is higher.

Norman Ross