Item 1092
DESIGN: UniCopter ~
Control - Flight - Swishring - Fixed Azimuth OverviewThis method is directed at overcoming lateral dissymmetry of lift and drag; plus reduce vibration.
Drawing:
Overview:
By Higher Harmonic Control
The primary harmonic is the only one that can reverse the direction of pitch change.
Higher harmonics will only vary the rate of change; or maybe make small reversal, if primary is close to 0º.
This may minimize the size of the moments required to overcome the inertia about the feathering hinge.
Initial Thoughts re Design:
Three conventional control rods will provide the majority of the motion to the swashring, for collective and cyclic. These control rods might be hydraulic cylinders. This is because 1/ the loads on the control linkages might be fairly high and 2/ the blades may be given a constant pitch moment to cause the swashring's cam-followers to hold against one track and thereby maintain anon-reversing direction of rotation.
There might be second set of three cylinders that offset by 60º azimuthfrom the primary set.. The two pair act as redundancy.
This swash ring will consist of 12 only 30º segments (or maybe 24 only 15º segments ~ for finer control and maybe handle rotor to rotor interaction, plus tail boom), which interlock with each other to form the ring. They are allowed to move vertically in respect to the adjoining one by plus and minus two degrees. The inter-movement between the segments is by a special type of hydraulic force devices. Any failure here should not be serious because the inter-movement between the segments is phycally limited to one or two degrees. A failure could result in high vibration but not fatality. They would be capable of providing up to
12 / 2 = 6P harmonics. Inside this ring frame are the upper and lower tracks, which consist of spring steel. Might consider 24 only 15º segments.The 12 segments should be sufficient to handle the Lateral Dissymmetry of Lift & Drag. The 24 segments might handle all sources of vibration.
Later Thoughts re Design:
There are two independent hydraulic systems.
Each has three cylinders positioning the swashring,
The two cylinder sets are rotationally offset from each other by 60º around the swashring.
The swashring frame consists of 6 only 60º segments.
Each segment is interlocked with the following and the preceding one.
There is a single hinge between any two segments and they are limited to approximately 1º of movement between the two.
Should one hydraulic system fail, there can only be a small amount of unwanted movement in the ring.
The above provides 1P and 3P harmonic control.
This looks ideal for
lateral dissymitry of lift and H-force drag.The collective and the cyclic determine the extrnsion of the six cylinders. The forward airspeed determines the extra extension of the cylinder at 30º, 130º and 270º azimuths.
Even Later Thought re Design:
The oscillation in roll due to a lateral dissymmetry of lift only occurs in forward flight, and it increases with speed. See;
DESIGN: UniCopter ~ Rotor - Disk - Lateral Dissymmetry of Lift and Drag? - (3-blades)Consider the swashring as having six controllers located at 60º intervals around its circumference. The three odd numbered controllers consist of conventional control rods coming from a mixer-box. The three even numbered controllers consist of strong yet slow activating devices. An example of this might be a swishring made of a pair of strong bimetal rings that are warped by the application of a certain amount of heat at the three locations. Since changes in craft's forward velocity are relatively slow and the warping of the swashring is only about 1º, slow but strong actuators may be ideal.
Even Later Thoughts re Design:
Consider shaping the ring by piezoelectric or bimetallic means. The piezoelectric will be fast but might have limited 'warping'. The bimetallic will be slow but should result in a greater 'warping'.
Back to top | UniCopter Home Page | SynchroLite Home Page | Nemesis Home Page
Initially displayed: July 2, 2002 ~ Last Revised: June 27, 2005
The 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.