1947

Item 1947

DESIGN: Electrotor-SloMo - Rotorhead - Synchronization - Mechanical

Idea 1:

Initial consideration:

The rotors on the Intermeshing configuration are a 18 centers [Hub-A] and 15" centers [Hub-B]. It may be easy to locate very short blades or lobes around the circumference of each hub. The lobes of each rotor will never make contact with the lobes of the other rotor unless the rotors should try to get more than (or near) 15º +/- out of synchronization with each other. In other words, the lobes physically restrain the rotors from getting more than 15º out of synchronization with the controller or 30º out of synchronization with each other and then leave it up the motors to pull them selves magnetically back into synchronization.

In addition, all of the lobes might be equipped with sensors on their leading and trailing edges. Activation of these sensors will result in one rotor receiving increased power and perhaps the other rotor experiencing a reduction in power. This is a lot of sensors!

Alternatively to the above: substitute bronze/brass slip-ring segments on the leading and trailing edges of the lobes. The contact of leading commutators on one rotor with the trailing commutators on the other rotor will provide additional power to the slower rotor whose trailing commutators are in contact.

This additional power might be provided by a smaller and partial secondary winding over the existing coil windings.

Consider cutting a face gear into the lower edge of the rotorhub. This (aluminum?) hub would be interconnected to the other hub by pinion gears and cross-shaft. This cross-shaft and its mounting bearings may serve a dual purpose as being the mount for the back leg's gimbal.

Notes:

Should one rotor advance and then physically 'push' the other rotor this push might temporarily decrease the electrical torque of the pushed rotor, which would decrease the pitch of the pushed rotor, which will allow it to accelerate; perhaps. Albeit with a slight loss of thrust; perhaps.

Remember the rotors MUST be able to retain synchronization if there is a loss of power in both rotors.

This is a critical argument for total electrical redundancy; in each motor, or,

Redundancy due to two motors and a 100% mechanical interconnection.

Idea 2:

Gears:

Add 1, 2, or 3 pair of light stock nylon gears.

They can move with spring and damper;.to reduce shock forces and allow for foreign objects to pass through,

They must be below the hublets.

RPM Concern: The Hub-B diameter is 12.5" and is turning at 750 RPM. The small spur gears will be about 1.5" diameter and this will mean that they will have a very fast 6,250 RPM.

Idea 3:

Timing Belt:

Notes:

The guides (or pulleys) that keep the belts apart at their crossing might be used to read the T! and T2 tensions and electronically adjust the pwoer between the motors. Or would this add complexity and possible ossilation?

There is also the possibility of using a conventional V-belt. Slippage will be OK if;

It is less than 90 electrical degrees.
It can 'slip back' into alignment after the perturbation has gone. This return to alignment would, hopefully' be caused by a resynchronization of the two motors.
This V-belt idea maybe no good for a total loss of power; without some modifications.

Idea 4:

Hub-A ~ Teeth on Rotorhead:

15" between rotorhub to rotorhub centers.

9 teeth.

See; DESIGN: Electrotor-SloMo - Rotorhead - Hub-B - Overview & Layout and DESIGN: Electrotor-SloMo ~ Rotorhead - Hub-B - Clearances

Concern: Items may get caught in exposed teeth.

Hub-B ~ Teeth on Rotorhead:

The above drawing is a copy of that on 1991.html

Greater than 15" between rotorhub to rotorhub centers.

Perhaps 9 teeth.

This differs from alternative A in that a large diameter worm is located between the pair of wheels. The ration between worm and wheel would be 10:1 or preferably less.

Concerns:

Items may get caught in exposed teeth.
The worm must fit under the blade roots and this will limit the diameter of the worm and therefor the smallness of the ratio.

Idea 5:

Crown and Pinion:

Cut teeth on underside edge of rotorhubs. Teeth to be underneath the maximum diameter of the rotor and mus miss the torque-pitch arm.

Face Gear:

See; OTHER: Mechanical - Gear - Face

Idea 6:

Interlocking Rotors ~ for Intermeshing:

With rotorhub centers at 15" it may be possible for each rotorhub to intermesh with the blades of the other rotor The interlockind would probably be at 7.5" radius on each rotorhub and the engagement would have to be equal to or greater than (360º/6 blades) 72º of rotation.

See; DESIGN: Electrotor-SloMo - Rotorhead - Hub-B - Overview & Layout and DESIGN: Electrotor-SloMo ~ Rotorhead - Hub-B - Clearances

Idea 7:

Interlocking Rotors & Teeth ~ for Intermeshing:

With rotorhub centers at 15" it may be possible for each rotorhub to intermesh with the blades of the other rotor The interlocking would probably be at 7.5" radius on each rotorhub. The engagement would be the blade and the 2 pins on the flange attachment engaging with pockets in the other rotor. The total count of blade plus pins is 3 x 3 = 9 doubled by the same number of 'pockets' equals 18. The angle between each blade, pin or pocket is 360º / 18 = 20º, which is an arc of 2.6190". This is a workable dimension for the pin locations on the blade's root flange

Taper pins go down through the stub pins, which extend from the hub.

See; DESIGN: Electrotor-SloMo - Rotorhead - Hub-B - Overview & Layout and DESIGN: Electrotor-SloMo ~ Rotorhead - Hub-B - Clearances

This might also work for Electrotor-SloMo ~ Rotorhead - Hub-A if the three cutouts for the blades of the other rotor to intermesh can be deepened sufficiently. Drawing 2036 shows that the elevation change for the top of the hub is 1.75". The elevation change on Item 1031 is 1.1771", therefore the depth of the hub would have to be increased by over 1/2" to around 4.25" and the high hub, c/w 1/5" allowance for deeper stator is 5".

This idea is intended for torque-pitch by blade twist.

Idea 8:

Interlocking Coil Spring Bands ~ for Intermeshing:

On the lower outer surface of both aero-rotorhubs (where the spur gears would go) cut concave diagonal notches into the material. Take two special coil springs that have been made endless, in a diameter slightly less than that of the aero-rotorhub, and snap one into the notches on each hub. The coils on one hub will intermesh with the coils on the other hub, with a certain amount of clearance.

The springiness of the coils will physically work to keep the rotors in synchronization.

In addition, if there is reasonable clearance (play) between spring-to-spring contact then coil-to-coil contact could connect an electrical circuit that would activate an alarm for the pilot.

Reduced Distance between Rotors:

Increasing the precone angle can reduce the distance between the rotors. However, this may have detrimental consequences in other respects.

Excessively Fast Change Possibility:

The maximum pitch change on the blades will be < 15º. The reasons for a sudden large angular change might be; a loss of power in one or both rotors and the fast application of full throttle. Both would change the torque before the RRPM. This 15º change in pitch will be the result of a 4.83º physical change in the motor-rotor to hub and this equates to a 57.96º electrical change. Is this too much?

Initially displayed: August 12, 2010 ~ Last Revised: September 13, 2011

The above utility invention is openly and publicly disclosed on the Internet to negate an entity from patenting it, to the exclusion of all others whom may wish to use it. ~ Reference patent law 35 U.S.C. 102 A person shall be entitled to a patent unless - (a) the invention was known ... by others in this country, ..., before the invention thereof by the applicant for patent.