scandtours
11-26-2006, 07:30 AM
This thread can be foun in ASRA
with tittle Rotor heads and Advanced Teeter Movement, by Anto Mose.
Its an interesting thread.
Giorgos
The last 5 years I have been machining rotor heads and did a lot of research in teeter movement of the unique gyrocopter. The testing of various brands of rotor blades has been an enormous satisfaction to see, that all the new rotor blades have come a long way and perform a lot better then the early ones.
Unfortunately the rest of the machine has not caught up at the same rate. Since we have extruded blades and composite blades with a twist the lift has improved considerably. After that time of research, development and testing of teeter angle, I came to the result of 4° advanced rotor hub setting.
To explain and start from the beginning. Our rotor system has the greatest lift on the right hand side of the machine and the forward movement of the machine the higher the ratio of airspeed different from right to left. The teeter movement forces the right hand side to climb up because of airspeed increase on the advancing blade which hits the oncoming air molecules, at the same time the left hand side will drop down because less airspeed throw the blades profile.
The stiffer the blade the greater the kick to the push rod - joystick system which can be corrected by 4° advanced teeter angle. Through this 4° teeter angle it allows the climbing blade to decrease the pitch while the down blade will increase the pitch by the same rate. As the two blades fight each other it results in very little teeter movement. If your tracking, string line and rotor head centre line is in order and still experience frequent joystick kicks, consider teeter angle change as your next move. Do Not go the easy way and move the rotor blades into an advanced position at the hub bar - blade straps connection (diagram 1) to avoid stress factors out of centrifugal force - line.
with tittle Rotor heads and Advanced Teeter Movement, by Anto Mose.
Its an interesting thread.
Giorgos
The last 5 years I have been machining rotor heads and did a lot of research in teeter movement of the unique gyrocopter. The testing of various brands of rotor blades has been an enormous satisfaction to see, that all the new rotor blades have come a long way and perform a lot better then the early ones.
Unfortunately the rest of the machine has not caught up at the same rate. Since we have extruded blades and composite blades with a twist the lift has improved considerably. After that time of research, development and testing of teeter angle, I came to the result of 4° advanced rotor hub setting.
To explain and start from the beginning. Our rotor system has the greatest lift on the right hand side of the machine and the forward movement of the machine the higher the ratio of airspeed different from right to left. The teeter movement forces the right hand side to climb up because of airspeed increase on the advancing blade which hits the oncoming air molecules, at the same time the left hand side will drop down because less airspeed throw the blades profile.
The stiffer the blade the greater the kick to the push rod - joystick system which can be corrected by 4° advanced teeter angle. Through this 4° teeter angle it allows the climbing blade to decrease the pitch while the down blade will increase the pitch by the same rate. As the two blades fight each other it results in very little teeter movement. If your tracking, string line and rotor head centre line is in order and still experience frequent joystick kicks, consider teeter angle change as your next move. Do Not go the easy way and move the rotor blades into an advanced position at the hub bar - blade straps connection (diagram 1) to avoid stress factors out of centrifugal force - line.