DESIGN: Electrotor-Simplex ~ Rotor - Hub - Overview of Gimbaled w/ Hydraulic Collective

• The following is a direct copy from part of web page http://www.unicopter.com/0575.html
• William Hunt's, of Sikorsky, idea for an autocollective; [Source ~ HP p.194-196]
• The three pages describing this idea are temporarily viewable at; (Their size can probably be enlarged by downloading the jpg's and then opening them with Paint Shop or other viewer)
• http://www.UniCopter.com/Temporary/WilliamHunt194.jpg
• http://www.UniCopter.com/Temporary/WilliamHunt195.jpg
• http://www.UniCopter.com/Temporary/WilliamHunt196.jpg
• Could the offset between the pitch axis and the mast axis necessitate strong pitch control forces of does inplane bending of the blades place the blade's CG normal to the flapping axis?
• If the hub is non-tilting (see note on fig. 132 A) then how does he get cyclic control?
• It is interesting to compare Hunt's overall hub layout to that of Breguet's G-11E [Source ~ MDD p.152]. Without considering Hunt's Automatic Pitch Control, they have the same general arraignment. However, Breguet's pitch axes intersect the mast axis whereas Hunt's pitch axes lead the mast axis. Note that neither hub tilts; see note on fig. 132 A
• The idea would be to replace his pitch bearings etc. with a longitudinally twistable hub-bar.

• Cyclic control is by conventional gyrocopter offset gimbaled rotorhead plus hydraulic collective.
• The idea for the torque driven collective is to have a hub-bar that will on bend inplane or out-of-plane but can twist about the it's longitudinal axis (blade's pitch axis). The torque that is imparted to the tops of the two stands from the mast should (may) twist the hub-bar slightly about it's longitudinal axis.

• Consider locating a fixed azimuth hub spring at approximately 235º azimuth to assure that the blades cannot hit the spars or pilot.

• For a somewhat similar idea see; US 5,304,036 ~ Autogyro aircraft Groen.

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