OTHER: Helicopter - Inside - Principal Assembly - Electrotor - MicroLite - Intermeshing  

• Principal assembly for the Interleaving MicroLite. OTHER: Helicopter - Inside - Intermeshing - Electrotor ~ MicroLite
• Electrotor-MicroLite lead page

Bill of Material 1839

• Rotor-rotor Interaction: from Rotor - Disk - Interaction Forum

• The Interleaving will be similar to the Side-by-Side and/or the Intermeshing. I.E. w/ or w/o roll control linkage.
• General Arrangement of Principal Assembly
• Unlike all previous intermeshing helicopters this craft has vertical axes of rotation.
• The blade-to- blade clearance is provided by the large precone angles at the two rotor hubs.
• The rotor-hubs and their blades are extremely rigid, especially in the out-of-plane direction.
• The aerodynamic disadvantage of the large precone may be no worse than that of the intermeshing's 'V' angle between the masts
• The only forces that will try to change the actual coning angle from the precone angle (i.e. flexing the blades in the out-of-plane direction) will be pilot cyclic inputs and perturbations. In both cases these forces cannot exceed the strength of the pilot's arms.
• There is one shaft that passes from the coupling at one motor, through the pinion gears of both crown & pinion gear boxes, to the coupling at the other motor.
• Both motors drive both rotors.
• This configuration offers;
• Simplicity of design.
• Stock gears.
• No pitch change on the blades is necessary. The blades have a positive pitch and there is no requirement for autorotation.
• Details;
• The X-shaft between the two gearboxes should perhaps be enclosed in a tube, which has a different rotational oscillation frequency from that of the shaft.
• There may not need to be a bearing in the reducer at the entry point from the motor (only a seal). Alternatively, it may be better to put one bearing at both openings and thereby straddle mount the pinion gear.
• Safety:
• There is redundancy of motors, controllers and battery packs.
• Put a ski on the leading edge of the blade tips to assure that they cross correctly. Add a small wear strip at the appropriate place on the leading edge.
• Direction of Rotor Rotation: It appears that the outside-forward rotation offers a couple of advantages.
• Firstly, the fact that the rotors' axes of rotation eliminate the torque-pitch coupling on the fuselage that is inherent in the conventional intermeshing arrangement where the two masts have an outward lateral lean.
• In forward flight the slow turning, high aspect rotors will result in the root end of the retreating blades putting little to no downwash on the pilot. The downwash at the centerline between the two rotors (over the pilot) will be zero when the forward velocity is 90 mph.
• Autorotation: See: OTHER: Electrotor-MicroLite ~ Concerns & Tasks ~ Autorotation
• Speed stability: The large precone angle should offer speed stability in forward flight.
• Cyclic control works by longitudinal and lateral weight-shifting of the pilot and battery pack(s).
• The lateral control (roll) could be enhanced by locating a CV joints co-centric with the intersection axe of the crown and pinion gears. This allows one rotor disks to tip outward while the other remains horizontal.
• Vibration: 3-blade rotors will remove the 2/P rev that comes from cyclic inputs on a 2-blade rotor.
• Gimbal: Note that on the gyrocopter the mass of the fuselage is slightly ahead of the longitudinal center of the disk. Apparently this is done so that an updraft will tend to pitch the disk downward at the front. It is probably effective for forward flight but might it be detrimental during hover, which a gyro does not experience?
• Coupling between motor and Gearbox:
• Consider the Dynaflex coupling as an alternative to the Jaw type
• The Dynaflex LCR Series coupling LCR-275-400-004A will handle 12 hp, weighs 0.52 lbs, and has a permissible misalignment of +/- 5º. This means that the inboard rotor disk can only be tilted an additional 3º for roll assistance.
• The Dynaflex LCR Series coupling LCR-275-400-009A will handle 20.4 hp, weighs 0.52 lbs also, but has, a permissible misalignment of +/- 4º. This means that the inboard rotor disk can only be tilted an additional 2º for roll assistance.
• The 3º and the 2º do not make much difference. Perhaps the misalignment can be more for short intervals.
• Obliquity Angle: There may be a desire to an angle between the two masts to provide greater blade-to-blade clearance. Assuming that the blades are turning outside forward, there will be a slight pitch up upon a lowering ov power. This is determined by the obliquity angle and it should not be significant .
• Efficiency:
• The slow speed rotor and the large aspect ratio will improve the efficiency of the craft.
• Gears:
• Boston, Rush and others have straight tooth bevel gears 6:1 ratio, 20º pressure angle.

• UniCopter ~ Rotor - Disk - Enhanced Pre-cone
• Schoeffman's Ultralight Helicopter
• Previous strap-on autogyro glider, for sporting use. Baumgartl Heliofly I. Also see Article THE HELIOFLY by Paul Baumgartl in the Homebuilt Rotorcraft / September 1992. Hardcopy in Electrotor-MicroLite binder.

Introduction Page | SynchroLite Home Page | Electrotor Home Page | UniCopter Home Page | Nemesis Home Page | AeroVantage Home Page: