RE: KMP Cessna Skymaster
ASP 91 FS weighs 23oz each vs Saito 100 Twin at 29oz each. Yup 3/4lb heavier. I had 1 100 twin and 1 90 twin sitting and would not use these in any of my aerobatic planes for the very reason. However, I'm not looking to do any stall maneuvers with cessna's but looking for more scale and realism. BTW, I have replaced Saito 90 twin in the back with 100 twin as the 90 twin died and no parts avail from Horizon. Once you hear 2 twin 4 stroke running up the engine for takeoff, you will be convinced this is only way to go ( provided you can afford ).
On top of realism in awesome sound (best if 2 identical engines are used and in near identical rpm) your airframe will appreciate it as it produces significantly less engine vibration ( provided props and spinners are also balanced).
Mass center ratio of front to back engine wrt CG is 1.5:1. What this means is that 50% of the engine weight contributes to balancing and correcting the tail heavy situation. If the front engine is closer to cg than rear, then the reverse is true and using heavyier engines will cause more tail heavy situation.
It appears that Saito 100 twin is far superio to 100 single in fuel consumption as 15min flight results in 1/2 tank consumption with stock fuel tank.