1341

Item 1341

DESIGN: SynchroLite ~ Rotor - Hub - 3-blade - CVJ & HS - Bearing - Mast - Combined

Objective:

To develop a constant velocity spherical elastomeric teetering bearing for a three (or any number) blade rotor, which;allows teetering (longitudinal & lateral) with some resistance (hub spring) resists rotation about the vertical axis. (I.e. it transmits torque). resists linear motion alone any of the three axis. (I.e. hub maintains concentricity with the mast).

Methodology:

Theory of Elastomeric Bearings:

Consider a conventional spherical elastomeric bearing, which consists of a number of cupped elastomer sheets alternately located between, and bonded to, cupped shims. This arraignment will satisfy # 1 and 3 above, but it will not satisfy # 2.

The elastomer allows the shims to slide in respect to each other and rotate in respect to each other In other words, there are two allowable directions of linear motion and one of rotational motion.

Now, if the elastomer can be restricted from moving in one direction, the #2 above will be satisfied also.

Options:

Consider wound carbon thread embedded in the elastomer. See spool test.

Consider a thick elastomer or composite semi-sphere, which has fiberglass radial threads and carbon, wound threads.

Consider some means of changing the polymer linkage inside the epoxy/elastomeric, which is located between two shims, so as to allow slightly restricted motion in one direction and extremely restricted motion in the other direction. I.e. a unidirectional polymer.

Consider:

The portion of the inner 'ball', the outer base half-sphere, and the outer partial-sphere cap that will be in contact with the elastomer have knurled or splined surfaces. Will the threads bond sufficiently to the inner and outer spheres? If not, it will be fatal for intermeshing rotors.

Consider a mix of flexible epoxy and chopped carbon or fiberglass threads. The threads should constitute a high percentage of the mix, say 50%. The mix is stirred in a circular fashion in the final outer sphere. The sphere might have to be rotating as well so that the centrifugal force will locate the mix evenly over the inner surface of the sphere

When the threads are all aligned in a circular direction and the mix has started to solidify, the stir stick will be removed and the inner sphere inserted. The thickness of this mix will be roughly 1/2"

Consider doing #4 but laying down parallel chopped fibers and spray the epoxy to build up the thickness of the elastomeric bearing while the ball is spining.

Theory:

The threads or polymer strings will move easier in the two directions that are normal to their direction then they will move in the direction of the strings. This is because they 'roll' visa vie each other in the first situation, where as they 'tear' visa vie each other in the second.

Prototype:

Eureka; the prototype worked.

Potential Problem:

When teetering about a horizontal axis the elastomer at circumferences about this axis will move and the further the radius to the circumference the more the movement. Segments on these circumferences above and below the axis will be pulling in the direction of the threads and these threads may excessively resist the motion or alternatively break

The areas of elastomeric above and below the horizontal plane through the center of the CV joint are not equal. This might result in a loss of concentricity when the disk tilts.

As the elastomer bearing and the hub get larger, the lateral inward teetering must be reduced. This is because the inside of one hub has moved up while the blade on the other hub has moved down, and the larger the hub the further the rim moves up. Might be having a hub spring located around azimuth 270º to restrain the inward lateral teetering of the rotors.

Because of the lack of shims, the bearing may not be able to resist liner motion on the X (mast) axis.

Ideas:

Consider composite hub and mast 'ball'

The inside of the hum and the outside of the ball are knurled or splined

Drawing:

Description:

The elastomer does not have shims, which divide it up into a number of layers (like an onion). The elastomer is a one-piece 'bowl', which has a very dense concentration of composite threads or unidirectional chains of polymer arraigned in a horizontal circular fashion.

It is similar to Sikorsky's patents in function and operation, but differs in the means of resisting rotational motion about the vertical (mast) axis. The threads or polymer chains allow 'shifting' normal to the direction of the thread, but with a reasonable amount of resistance (hub spring). The threads or polymer chains present very strongly resist to any 'shifting' of the elastomeric that is in-line with the threads or polymer chains.

Components:

Mast c/w ball
Elastomeric
Hub
Hub cap

Design Torque:

The maximum torque at each rotor hub is 396 / 2 = 198 ft-lb = 2,352 in-lb.

The bearing might require a much-increased strength to handle the rotor generated inplane loads. Note that the masts will absorb some of the loading but this will affect the inter-azimuth phasing of the two rotors, slightly.

Thread:

Carbon for strength or fiberglass for elasticity?

Elastomer:

xx.

Information ~ Outside Site:

xx.

Information ~ This Site:

OTHER: Flight Dynamics - Rotor - Hub - Elastomeric CVJ - Patents Specifically the Sikorsky patent 4,575,358 and the related ones.

OTHER: Mechanical - Bearing - Elastomeric

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Initially displayed: May 28, 2004~ Last Revised: October 5, 2004

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.