Alex Evans
Member
I am new here, but coming from a background of full size....
Let’s use a Trex-600 ESP as an example, and I am using round numbers here
A main rotor blade is 60cm long, Mid blade is 30cm from the root
At an RPM of say 1,500. The midpoint travels a total distance (in one minute) of
30 x 2 x 3.14 x 1,500 = 282,600 cm or 2,826 meters, or 2.826 Km, therefore x 60 = 169.56 Km/h
At the same time, the blade trip is travelling:
60 x 2 x 3.14 x 1,500 = 565,200 cm or 5.652 Km, therefore x 60 = 339.12 Km/h (twice the speed!
No point here to get into the exact amount of lift generated (too many parameters), but one thing is clear, the lift is increased by the power of 2 for each airspeed.
Then, why in full size helicopters, at zero pitch when collective is down at the blade root is at zero degrees, the blade tip is at MINUS 6 degrees (yes, the blade is manufactured with a twist) but in our sport of RC, this is ignored….
Just wondering....
Let’s use a Trex-600 ESP as an example, and I am using round numbers here
A main rotor blade is 60cm long, Mid blade is 30cm from the root
At an RPM of say 1,500. The midpoint travels a total distance (in one minute) of
30 x 2 x 3.14 x 1,500 = 282,600 cm or 2,826 meters, or 2.826 Km, therefore x 60 = 169.56 Km/h
At the same time, the blade trip is travelling:
60 x 2 x 3.14 x 1,500 = 565,200 cm or 5.652 Km, therefore x 60 = 339.12 Km/h (twice the speed!
No point here to get into the exact amount of lift generated (too many parameters), but one thing is clear, the lift is increased by the power of 2 for each airspeed.
Then, why in full size helicopters, at zero pitch when collective is down at the blade root is at zero degrees, the blade tip is at MINUS 6 degrees (yes, the blade is manufactured with a twist) but in our sport of RC, this is ignored….
Just wondering....