More Arithmatic ("Math" makes it sound hard)
BTW, the calculated HS is assuming you're at full throttle when you tach the heli.
So in your case:
3559 x what% = 3009?
3009/3559 = .85 x 100% = 85% Pretty durn close!!
BTW, you don't have to calculate the gear ratio separately if you use the formula above
