A120

DESIGN: Electrotor-SloMo ~ Objectives, Concerns & Tasks (all)

Objectives:

IF the electrical system never totally fails;

If the electrical system never totally fails, then the rotors can have smaller diameters.

If the rotor diameters are smaller, then the weight-shift control will be easier.
If the rotor diameters are smaller, then the power requirement will be greater.
If the rotor diameters are smaller, then the weight will be less.

If the weight is less, then the power requirement will be less.
If the weight is less, then the weight-shift control will be easier.

If the electrical system never totally fails, then synchronization of the rotors can be by motor control.

See Electrotor ~ Objectives

Overview:

A listing of Tasks, Potential Concerns and Thoughts, regarding the Electrotor-SloMo.

Ideas for Future Consideration:

A Progression of the ELECTROTOR - SloMo into large and more advanced aircraft.

Backpack helicopter 2 x 10 = >20 HP
Ultralight (SynchroLite fuselage) Extra 40-50 lbs GW. 2 x 15 = >30 HP
Light UniCopter (Interleaving?) electric (w/ pusher) 2 x 40 + 1 x 40 = 120 HP
AeroVantage 2 x 50 =100 HP or 4 x 40 = 160 HP

Proposed Improvements:

Longitudinal trim tab for the weight-shifting rotor head to reduce the physical effort from the pilot.

Electrical servos on weight shifting head plus a Gimballed battery pack with controlled longitudinal and lateral springs and dampers to give more weight-shift force while removing a portion of the 2P vibration from the fuselage. Total unthoughtout. Only recorded.

Concerns (general): Eventually link the concerns on this page to the specific working page.

Perhaps a serious problem for Intermeshing and Interleaving configurations. The motor might offer a resistance to turning (cogging) during non-powered autorotation. It appears that significant cogging can be eliminated.

If two rotors are located with only an airgap between them, would it be better to have the adjacent poles as having the same polarity. This will make the normal rotational location halfway between each other and the repelling force will increases exponentially as the rotors are rotated in respect to each other. The pitch? Between the magnets is

On this blade pitch concept; will a rotationally offset of the poles of the two rotors reduce the total torque?

Balancing Torque and Thrust:

The Torque-Pitch mechanisms in the two rotors must be very equal in there performance because if not it may effect the synchronization of the two rotors. Synchronization of Rotors

Cooling:

The Mica and Aramid paper between the coils and the iron core have poor heat conductivity.

Rotor-Rotor Synchronization:

It looks like the rotors must have their azimuths > 45º out of phase for them to clash. This includes the chord width. Hopefully, the electrical system can overcome any chance of rotor getting that much out of synchronization.

Downwash on Pilot:

Should be of little significance to recreational pilot.

The two controllers could be located over the pilot's head to be cooled and deflect some of the downwash away from the pilot.

Flight Control during Autorotation:

Overrunning Clutch: See; DESIGN: Electrotor-SloMo - Rotor - Hub - Torque/Pitch/RRPM Coupling - Outrunner - F&P - Thin

Collective Response:

Will the Aero-Tips detract from the fast response of the torque-pitch collective; because the increase pitch of the blades will cause the floating tips to reduce their pitch.

If collective pitch is by torque tube to the tips

It will significantly defeat the aero tip idea.
Can a simple means of cyclic be added to the torque tube that automatically works from the weight shifting and works in conjunction with the collective?

Static Electricity Discharge:

Is there the possibility of static electricity discharge apron landing, which is done by the feet on the backpack.

Potential Solutions:

The pilot wears rubber boots.

The frame trails a cable, which the pilot might trip on.

Insulated discharge cables that run from seat, which is part of the rear leg, or from battery holders, which are attached to the gimbal and pilot's harness, down to metallic pads on the bottom of both the pilot's insulated shoes.

Concerns - All configurations:

Autorotation and Yaw control:

If the rotors and their motors are totally freewheeling, the pilot's application of differential collect will have little, if any, effect on the craft; other than perhaps rolling the craft due to a slight differential in lift.

Air Gap in Motor:

Consider using, large diameter, radial flux, Outrunner or Inrunner, gearless motors for bilateral and coaxial motors. Small amounts of un-coplanarness will not affect the air gap in the motor nor result in potential rubbing in a worst case scenario.

2P Vibration:

- due to the 2-blade 'absolutely' rigid rotors. See; DESIGN: Electrotor-SloMo ~ Rotor (aerodynamic)

Overrunning Clutch:

- Perhaps the use of a fiberglass bandage over the rotor's magnets or pinned horseshoe magnets will negate the need for an overrunning clutch.

Concerns - Coaxial specific:

How to start rotor rotation with the blade crossings take place at 45º + (x*90º) azimuths. Could there be nylon gearing which maintain the relationship between the rotors during their initial startup.

This is not the most aerodynamic efficient configuration and this is particularly important when considering electric drive. How efficient is a rotor (PM) - stator (windings) - rotor (PM) motor in countering the aerodynamic inefficiency?

YAW BY COLLECTIVE PITCH DIFFERENTAL WILL NOT WORK. It will result in one rotor having to deliver more drag and lift (torque) then the other rotor. The rotor that is requiring this additional torque will want to lag behind the other rotor. This may cause the lagging rotor in the motor to skip phases if the sensor is on the other rotor in the motor.

A potential solution might be to have sensors on both rotors in the motor and have the controller use the timing from the sensors on the lagging rotor. Hopefully, this will result in the leading rotor 'backing off' so as to be in sync with the control phasing.

Tasks (to do):

Motor

Controller

Rotor

Torque-Pitch Coupling

Aerodynamically Active Blade Twist

Same Page Different Craft: ~ Electrotor-Simplex ~ Electrotor-MicroLite ~ Electrotor-Plus ~ SynchroLite ~ UniCopter

Initially displayed: July 23, 2006 ~ Last Revised: July 2, 2010