OTHER: Helicopter - Inside - Coaxial - Electrotor-SloMo

• To locate a pair of counter-rotating ELECTROTOR-SloMo Principal assembly in a frame that creates a coaxial arrangement.
• Targets:
• An extremely high level of reliability. [No breakdowns. No loss of energy (fuel)]
• A very fast rate of control.
• A principal assembly that has very low-weight.

• Two counter-rotating ELECTROTOR-SloMo Principal assemblies on a small internal frame:

• Electrotor ~ SloMo; Axial Flux Permanent Magnet [AFPM] motor. Axial air gap. Maybe. But probably would go with Radial Flux.
• With parallel (but isolated) wiring double or triple redundancy can be incorporated in the; batteries, power circuit and motor.
• Hopefully, [Blade Pitch Control] can also be incorporated.
• Cyclical control by Direct Control, supplemented by Weight-Shift for greater pilot authority. OTHER: Flight Dynamics - Rotor Hub - Offset Bi-teetering
• Collective control by hand grip throttle.
• Autorotation by automatic entry, with capacitor assisted flare at landing.
• Powered by a single electric motor, which has 1:1 rpm relationship and direct coupling to the two counterrotating rotors. ElectrotorSloMo.
• May go with absolutely mechanically separated motors. This will allow the rotor-motor assembly to be used in any small recreational twin-rotor helicopter. ~ September 18, 2009

• Older coaxial arrangement using a single counter-rotating axial-flux motor:

 See 1751.html for the similar idea in Intermeshing configuration.

1. One heck of a lot of high performance (yet to be developed) batteries. With today's technology the flight time would be logged in minutes.
2. Generator driven by small (yet to be developed) turbine.
3. Ground tether containing electrical cable.
4. Large lightweight Ultracapacitor(s) for flare at the end of autorotation. Could be charged by rotors during autorotation.
5. Capacitors are very light weight. In fact, there is consideration for using the honeycomb core in a composite construction fuselage as a capacitor/battery.
6. Principle Assembly for this craft; Electrotor-SloMo ~ Power Storage Devices

• Have a large coning angle of 4 to 5 degrees.
• To give static stability in forward flight. I.E. to cause the disk to want to tilt back.

• Consider using patent US 5,043,641. Have hard copy.
• See: Electrotor-SloMo ~ Control (flight & power)

• 4,311,080 US ~ Drive mechanism ~ January 19, 1982 ~~ circular linear induction

• Electrotor-SloMo_Motor
• OTHER: Miscellaneous - Thoughtless Ideas - Engine for Coaxial Rotor

• OTHER: Helicopter - Outside - Intermeshing - Little Zipster - B-9
• OTHER: Helicopter - Inside - Coaxial - Ultralight w/ Mid Engines

• This small (25 employee) Canadian company interesting. http://www.micropilot.com/. There is an article on it in the business section May 30, 2006 Globe and Mail.

• See patent; US 4,968,913. When looking at drawing number 1; Consider a Rotor-Stator-Rotor arraignment. Leave the stator as is and make the second rotor a mirror image of the first; to get opposite rotation between the two rotors. Got to check the validity of preceeding statement.
• I do not think that this will assure synchronized rotation for maintaining fixed blade-crossing azimuths. Perhaps additional electric items might be added.
• What would be the best winding configuration for the stator? - Torus ?
• What would be used to start both rotors in the correct direction? A 3rd small starting phase? Or, a few nylon pinion gears between the two rotors so that both can be pre-spun in a counterrotating direction by the hand of the pilot turning the lower one only?

• See A131.html
• See; Perhaps Relevant Patents

• The resistance of the electric motor to turn (cogging) if no power. Overrunning clutches will overcome this potential problem.
• The efficiency (power to weight) of the axial-flux motor.
• The diamond shape of the hub-bar, combined with centrifugal force, will strongly resist pitch change. Use delta-2?
• 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.

• An idea that is intended to assure that the rotors disks have a small gap while not clashing with each other. OTHER: Miscellaneous - Thoughtless Ideas - Coaxial - Rigid-Teetering Rotors

• Motor power and control to be two or three totally independent systems for redundancy.
• Collective by power change and torque-pitch coupling. OTHER: Miscellaneous - Thoughtless Ideas - Torque/Pitch Collective Rotor Hub
• Cyclic control by gimbaled rotorhead. OTHER: Miscellaneous - Thoughtless Ideas - Coaxial - Rigid-Teetering Rotors
• Principle Assembly for this craft; Electrotor-SloMo ~ Control (flight & power)
• Power Storage:
• Have a battery pack that can be dropped during autorotation so as to reduce the disk loading and therefor the descent rate. Consider having a capacitor pack that stays with the craft to be used during flare.
• Electrotor-SloMo ~ Power Storage Devices

• Start with the Schöffman coaxial. Thread on Rotary Wing Forum about Frans Schoeffman's coaxial helicopter.
• Add a simple light seat, skids and frame.
• Replace the two rotor hub bars with composite one that has a Torque/Pitch Collective Rotor Hub at the root for Collective and Autorotation. See; OTHER: Miscellaneous - Thoughtless Ideas - Torque/Pitch Collective Rotor Hub and Torque-Pitch-RRPM: To give electric auto-collective and cyclic control
• Replace the 4 propeller blades with +/- 8 ft very light composite blades.
• The control to be by gimbaled head. Except that the lack of a teetering hinge will cause it to be weight-shifting. Except that the below will allow it to be a compromise.
• Add a somewhat simplified Independent Root & Tip - Torque Tube Method for Cyclic. The control to be Swishring.
• Axial Motor 2 rotors, with Halbach magnet, turning on a central stator. 2-phase. See 1530.html.
• Alternative Motor: See OTHER: Miscellaneous - Thoughtless Idea - Engine for Coaxial Rotor

[Source ~ MDD p.20] Discuses Drag and Flapping Pivots

[Source ~ MDD p.122] Figure 12 shows coincidental drag and flapping Pivots.

• OTHER: Helicopter - Inside - Bilateral - Electric Motors Located In Rotors ~ SloMoSynchro This represents the opportunity to have a lower disk loading.
• OTHER ~ Flight Dynamics - Rotor Hub - Aerodynamically Active Blade Twist
• OTHER ~ Flight Dynamics - Rotor Hub - Hub Spring (Hinge Spring)
• Schoeffman's Ultralight Helicopter

• OTHER: Miscellaneous - Thoughtless Idea - Engine for Coaxial Rotor

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