Item 1497
DESIGN: Single-Bladed All Electric Rotor-
Rotor Hub - Hub #7
~ Move the crown gear and the Z-axis rotational bearings outside the universal joint ~
Concern:
Drag will have an effect on pitch, by trying to force the pitch down, and this may/will be bad.
Pictures of Mockup:
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The outer housing of the hub (white), spur gears (brown wood), and torque- pitch device (silvar banded) are firmly affixed to the blade & counterweight unit.
The universal joint (black) allows this unit to pitch and teeter about the mast. |
The lower shaft is from the motor. It is coaxial with the pitch axis of the blade. |
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The pinion shaft is aligned with the center of the universal joint.
The wooden block represents the spur gearbox.
The sliver-taped disk represents the torque pitch coupling between the torque from the motor and the blade and counterweight unit. It moves the mass of the blade & counterweight unit in the direction of the leading edge of the blade. The mass of the blade & counterweight is used instead of a separate small counterweight. |
The crown gear is located below the pinion gear.
The mockup must be modified slightly since the crown gear and the universal joint do not rotate about the static mast. The pinion drives the blade & counterweight unit around the crown gear. |
Drawing:
See drawing on
1490.html (Hub #1) for the Flapping Motion.
Gears:
The spur gears will have a ratio between 1:1 and 1:2.
The crown and pinion will be essentially the same as that of Idea #1
A third reduction may still be required. Probably a planetary one at the motor.
The spur gears can probably be eliminated by having a jackshaft and two universal joints between the planetary gears and the hub housing or slope the motor and use one shaft an a constant velocity joint.
Torque-Pitch Coupling:
The input shaft to the final gear reduction will have a shaft extension on the opposite end from the pinion. This shaft will have a higher torque than the lower shaft and it is ideally located, since it is concentric with the pitch axis. For more see; DESIGN: Single-Bladed All Electric Rotor- Rotor Hub - Pitch-Torque Coupling
Drag and Pitch:
The aerodynamic drag on the motor and blade will attempt to push pitch out of the blade. This drag will assist the spring in the torque-pitch coupling and they both will be opposed by the torque of the motor.
During forward flight this drag will attempt to remove pitch on the advancing side and add pitch on the retreating side. This could/should be good.
Pitch-Flap Coupling:
This will be conventional.
Response Time of Couplings:
The rotational inertia about the pitch axis will be relatively small and hopefully the pitch change response time will be fast. (Fast as in Higher Harmonic Control)
The rotational inertia about the teetering axis will be relatively large. Hopefully the flap change response time will be slow. (Slow as in 90º of rotation about the mast)
Delta3:
The torque-pitch coupling and the pitch-flap coupling both have the same arm length 0f 2.78". In addition, they both have the same rotor-cw mass. One way to effect a different response between the two of them is to add a certain amount of delta3. This will cause upward flapping to remove some of the pitch.
Electronic Sensors [Input]:
See;
DESIGN: ~ Single-Bladed All Electric Rotor - Flight & Power Control
Electronic Actuators [Output]:
See;
DESIGN: ~ Single-Bladed All Electric Rotor - Flight & Power Control
Vibration Reduction:
The offset compensation for varying thrust is linked to the flap change.
The offset compensation for varying drag is linked to the pitch change.
The undersling for the flap axis is (preliminarily) correct at 2.7836" This means that the undersling for the pitch axis will have to be the same 2.7836". This undersling will not be correct. It will be too little or too much.
- If it is too little, a small counterweight with an appropriate linkage to the pitch change, could supplement the lateral weight shift of the blade-arm unit.
- If it is too much,
Delta3 ??? Can this even be incorporated?
A small amount of delta3 might be employed since the weight shift in the incorrect direction could be offset by the pitch offset.
It may be advantageous to have a sensor for angle of attack at some location on the blade
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Initially displayed: February 4, 2006
~ Last Revised: February 21, 2006
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.