DESIGN: Electrotor-Simplex ~ Control

• See 1475.html
• See A147.html for additional information on controls for the Electrotor-Simplex.

• Collective:
• Current proposed method; DESIGN: Electrotor-Simplex ~ Rotor - Hub - Overview of Gimbaled w/ Torque/Pitch Collective & Teetering Drive:
• By synchronized change in rotor RPMs.
• Lack of torque in one rotor immediately causes the removal of torque to the other rotor. No torque puts all the blades into autorotation.
• Large short-interval capacitor for lift-off and low-battery flare at landing.
• Longitudinal Cyclic:
• Combined longitudinal tipping of rotor heads.
• Lateral Cyclic:
• Lateral tipping of rotor heads. The head on the inside of the roll will tip inward where as the head on the outside of the roll will tip less or may not tip at all. To be controlled by the mixer-box.
• Yaw:
• Opposed longitudinal tipping of rotor heads.
• Mixer-box:
• Mechanical: Located behind pilot's seat with two push-pull rods or Bowden cables to each rotor. The Bowden cables will allow the booms to swing forward for storage and transportation.
• Electrical: The collective is already electrical therefore there is reason for using electrical linear actuators for the 4 [Control Bars].

• The rotor heads with torque-pitch collective only require 2 controls for each of the two rotors. These controls need not be fast acting and only move when the pilot moves the cyclic, therefore they could be a good candidate for an electrical joystick. Yaw could be by electric pedals or vertical rotation of the joystick. Consider a stepper motors with electric actuators and (absolute?) encoders.
• The [Control Bars] and the [Main Housing - Item 1556] could be combined as one part. A large snap ring, located on the bottom of the outer race, could be used to retain the [Main Bearing]
• The electric actuators could be laid horizontal. The pitch actuator would apply its force directly to the [Main Housing]. The roll actuator would apply its force directly to the [Lateral Fork].
• Consider gearing between the electrical actuator and the actual pitch change. This gear must not be so high as to cause the change of pitch be too slow, however the gearing should allow for the electrical device to hold position while consuming a minimal amount of electricity.

• Synchronization may not be a concern. If it is a concern consider using the encoders on the two motors to cause the operational motor to brake or drive so as to match the RRPM of the failed rotor.

• The ratio or torque to pitch can be varied by;
• Changing the composition of the hub-bar.
• Changing the horizontal length of the Pitch Yoke Arm.
• Field adjusting the vertical length of the vertical length of the Pitch Yoke / Pitch Tube arm linkage location.

• From Rick; http://www.vantec.com/ssps105.htm. For collective, by switch on cyclic grip?
• Consider a 'Limited Angle Torque Motor' as an alternative to an electric linear device.
• http://www.electricmotors.machinedesign.com/guiEdits/Content/bdeee3/bdeee3_4.aspx
• http://www.h2wtech.com/latmotors.htm
• http://machinedesign.com/BasicsOfDesignEngineeringItem/714/65783/LimitedAngleTorqueMotors.aspx Have hard copy.
• They may not be strong enough. Perhaps if they were used with a high ratio worm and wheel. A 15:1 ratio will decrease the angular displacement by 15 and increase the torque by 15. IE <180º will be <12º, which should be enough.

• Cross-Coupling with Gimbaled rotors: This does not apply to the chosen Assembly 1475.html; since the motor and the rotor have the same axis of rotation.
• Gyroscopic precession from the rotating portion of the motors may very likely result in a cross-coupling in the flight control system. I.E. when the pilot enacts one cyclical or pedal change the gimbaled primary assemblies may want to move in a different direction then the desired.
• Perhaps the rotating mass will be such a small percentage of the total gimbaled mass that the gyroscopic precession will be insignificant.
• Perhaps the mixed box (mechanical or electrical) can mitigate the cross coupling.
• Unbalanced Collective Pitches on a Rotor with Torque-Pitch Collective:
• Between the Two Rotors:
• If one rotor generates too much thrust;
• The craft will roll to the underpowered side.
• The craft will yaw to the underpowered side.
• This can be adjusted for by an electric trim tab on the cyclic stick, which adjusts the difference between the rpm of the motors (rotors). However, if the motors (rotors) have differing rpm's there may be a low frequency instigation of vibration, somewhat similar to the sound of two engines on a boat being out of synchronization.
• Another way to balance the collective pitch is to vary the arm length on the pitch horn, either manually at the start of flight or electrically in-flight.
• Between the Two Blades on One Rotor:

• Delta3 by control system geometry (Robinson Helicopter)

• Delta3 by flap hinge geometry (proposed Gyrocopter)

• From Rick October 24, 2007 ~ Dave: Check out this site for 45W servo motor/encoder/controller package. Maybe what we need? http://www.coolmuscle.com/?gclid=CIb8p_b8po8CFQflhgodX3FQLg

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