2061

Item 2061

DESIGN: Electrotor-SloMo - Rotorhead - Synchronization - Magnetic & Pitch Change

Objective:

To provide an effective and simple means of eliminating any deviation from rotor-rotor synchronization in an Intermeshing configuration.

Combined methods:

Create an in-plane force between the two rotors that opposes any rotational deviation.
Create a change of collective pitch between the two rotors, and thereby a short duration of change in their profile drag.
Physical resistance to azmithual deviation.

Drawing:

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Picture of Mockup:

Description of Operation:

The spar roots of all six blades contain a permanent magnet at the lower portion of their leading edges and another magnet at their trailing edges.

The three leading slopes and the three trailing slopes in the top of the two rotorhubs contain a magnet.. The magnets in the leading and the trailing slopes will be of opposite polarity and connecting flux strips will increase their forces.

The magnets in the blade roots oppose the magnets in the hubs In other words, the magnets attempt to center the blades of a rotor in the 'valleys' of the other rotor's hub.

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The vector of the opposing force between the two magnets has an angle that is greater than the plane of the rotor disk and less than the normal to this plane.

This force can be decomposed into an inplane vector and an out-of-plane vector.

The inplane force acts to keep the blade root away from the lead and the trailing walls of the 'valley' of the other rotor. This synchronizing force works on both rotors.

The out-of-plane force acts to increase the pitch and the drag of a rotor when its blade is ahead of the desired azimuth, or, lower the pitch and the drag of a rotor when its blade is behind the desired azimuth.

The change of the pitch in one blade is transmitted to the other two blades in the same rotor since the force on its pitch arm is transmitted to the motor's rotor, which interconnects all three blades.

Elaboration on the Three Methods of Maintaining Synchronization:

The rotors and their blades are as close to being 'absolutely' rigid as is practical.

This means that any conceivable rotor-rotor contact will take place at the hubs; where the direction of motion between the two rotors is in the same direction. This differs from earlier teetering rotors, both intermeshing and coaxial, where the potential clashing would take place at the closing tips.

There is no electrical activity involved. Both 1 & 2 below are magnetic and 3 is physical (mechanical).

The inplane (horizontal) component of the magnetic force vector works directly on the other rotor. If a blade is further advanced then it should be, in respect to the other rotor, then the blade (and its rotorhub) will experience a 77.5 hertz retarding force. At the same time the other rotorhub will be experiencing a 77.5 hertz advancing force. Conversely, if the blade is lagging the opposite forces will apply.
The out-of-plane (vertical) component of the magnetic force vector works directly on collective pitch of alternating rotors at a rate of 38.75 hertz. An advanced blade will be subjected to a force that increases its pitch. This is the result of the leading magnet in the blade being in close proximity to magnet in the 'trailing slope' in the hub of the other rotor. This pitch change is transmitted to the other two blades in the same rotor via the floating electrical rotor in the motor. The increased pitch will result in an increased induced drag, which in-turn will retard the rotor. Conversely, a retarded rotor will experience a reduced drag visa-vie that of the other rotor and it will advance.
Should the misalignment of the two rotors exceed the positioning forces of the motors and of the above magnetic forces 1 and 2 then the leading or trailing edge of the blade spar will make physical contact with a 'hump' on the hub of the other rotor. It is assumed (or hoped) that a difference in angular acceleration/deceleration, which was developed within 60º of rotation, between the two rotors could be great enough to cause a blade to climb over a hump.

During Autorotation:

The natural action of the blades should only result in a relatively light difference of aerodynamically applied rotational force. The above three non-electrical methods of synchronization should be capable of maintain synchronization.

Should the autorotation be the result of a loss of stored electrical energy (battery, capacitor, etc) then there is the possibility that the drive system can be put into a motor-generator state (regeneration) and it could also contribute to the synchronization. Perhaps the subject of using regeneration as a means of providing synchronization should be covered on its own separate page.

Notes:

The magnets at the blade's leading edge will have the opposite polarity from the magnet at its trailing edge. A flux strip to increase their forces will connect these two magnets (green in the above drawing).

The strip magnets on the rotor (red on the above drawing) are to be located between the air holes so that they do not inhibit the flow of cooling air to the motor.

A means of damping an oscillating deviation on rotor alignment may be required.

Pros & Cons:

Pros:

It does not require electricity.
It does not change the profile of the rotors.
It is simple to implement.
It has no moving parts.

Cons: It is a poor substitute for a hard mechanical interconnection such as gears. Item 3 above may provide the same level of reliability

Frequency of Corrective Action:

2 rotors x 3 blades x 750 rotor rpm = 4,650 cycles per minute = 77.5 cycles per second.

Angles between Rotors:

The ration of electrical rotations to mechanical rotations is; 360º / (36 coils / 3-phase) = 12:1 = 30º. There is info on another page that discusses the amount of physical misalignment required before the motor will try to jump 30º to be electrically aligned with the other motor.

Clearances for Intermeshing Configuration shows the blades vertical closure for 20º out-of synchronization.

Initially displayed: June 2, 2011 ~ Posted on Rotary Wing: June 5, 2011~ Last Revised: June 5, 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.