hi tezza,
You write : engine villiers 3T.
This engine it's stand alone or for a motorcycle with gearbox integer. ?
Planning to use your blade for 1800/2000 rpm.
18 HP it's little and your blade can have a high angle
This it's corect for Multiwing blades.
23kg for 18 HP (your villiers)
45kg for 20HP (ours B&S without gear reduction system, 55kg with gearbox)
Pascall
Ps: You can start with One engine and if you see it's not enough, you put a lift engine same a 4storke for lanwmower