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750mm / 30" Balsa Cat.
Twin 1600kv 500class Outrunners, Turnigy
Turnigy 3S+2S=5S (30C) 4500mAh (total)
2x Mystery 100A esc, all air cooled
Graupner K45 props
Speed unknown, estimated to be high 70's kmh or high 40's mph
My speed calc goes like this
1600kv@85% efficiency = 1360kv
3.7v (loaded V) = 18.5v
Rpm = 25160
prop(s) 445 = 63mm bite per revolution less 20% = 50.4mm .......times 60( for rpm) = 3.024m
Multiply prop bite by rpm and I get 76 kmh or 47 mph
This assumes the following
The motors are correctly rated, turnigy cans are notorious for running higher
85% efficiency on the motors being twins and outrunners
20% prop slip which is for a hydro, I guess is similar to a twin cat
My calcs have been gps'd on two riggers and a cat and a canard and all are not to far off. The gps read a little higher than my numbers and that for me is good as I like to have some numbers to work with when putting together a power setup.
Enjoy the clip
Twin 1600kv 500class Outrunners, Turnigy
Turnigy 3S+2S=5S (30C) 4500mAh (total)
2x Mystery 100A esc, all air cooled
Graupner K45 props
Speed unknown, estimated to be high 70's kmh or high 40's mph
My speed calc goes like this
1600kv@85% efficiency = 1360kv
3.7v (loaded V) = 18.5v
Rpm = 25160
prop(s) 445 = 63mm bite per revolution less 20% = 50.4mm .......times 60( for rpm) = 3.024m
Multiply prop bite by rpm and I get 76 kmh or 47 mph
This assumes the following
The motors are correctly rated, turnigy cans are notorious for running higher
85% efficiency on the motors being twins and outrunners
20% prop slip which is for a hydro, I guess is similar to a twin cat
My calcs have been gps'd on two riggers and a cat and a canard and all are not to far off. The gps read a little higher than my numbers and that for me is good as I like to have some numbers to work with when putting together a power setup.
Enjoy the clip
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