1096

Item 1096

OTHER: Rotor Concept - Independent Root & Tip - Torque Tube Method

~ A proposed means of achieving Active Blade Twist ~

Proposed Method of Providing Independent Root and Tip Pitch Control:

The skin of the blade is firmly attached to the spar at all locations along the span. The spar consists of unidirectional pultruded carbon thread running spanwise. The skin and the spar twist in unison. The root of the blade is controlled by the root pitch horn. The tip of blade is controlled by the tip pitch horn. The tip and the tip pitch horn are connected by a torque tube, which is located in the middle of the spar. The torque tube consists. Of filament wound carbon thread at a bias.

The torque tube is bonded to the inner surface of the spar by an elastomeric material along much of the span. This elastomeric assists in transmitting a progressive twist to the tip of the blade

This method is currently being developed for the UniCopter.

For Blade details see; UniCopter - Rotor - Blade - NACA 00xx - IRAT - Torque Tube Method

For Blade manufacturing see; CNC Workstation

For Flight-Control details see; UniCopter - Control - Flight - Independent Root & Tip

Cyclic Control:

The intent is that the tip control be the main or sole provider of pitch and roll. Therefore, it must be noted that on the retreating side, as the tip speed ratio approaches 1 the effectiveness on the retreating side will diminish.

More importantly, at speeds greater than mu = 1 the pitch at the tip when near azimuth 270º will be in reverse velocity. This will result in the blade tip pitch generating a force that is the opposite of what is desired.

Potential Concern:

Will the torque tube c/w the elastomeric bearing resist blade flutter, particularly when the blade is subjected to reverse airflow?

If this method ends up not looking feasible then the next option is OTHER: Rotor Concept - Independent Root & Tip - Floating Root Method.

Note that if the Torque Tube Method is unable to provide sufficient torque to twist the Absolutely Rigid Rotors blade then the Aerodynamic Tip Method will probably be unable to do it. Perhaps, the Aerodynamic Tip Method may work well for conventional flexible rotors.

Related Patents:

US patent 5730581, March 24,1998 is similar to the above except that it uses tension in the spar to effect torsion in the skin. Have hard copy.

US Patent 6,382,556 ~ VTOL airplane with only one tiltable prop-rotor ~ Filed December 18,2000. It describes a blade twist method similar to the one on this page. Have hard copy.

6,974, 105 ~ High performance VTOL convertiplanes ~ Filed Jan 9 2004 This is very similar to his previous 6,382,556 above. However it adds a propulsor. In addition, the variable pitch for the rotor blades has not been included, since he probably now realizes that a large twist is required for hover (rotor) as well as for propulsion (prop). And/or the design is becoming similar to the CarterCopter.

US patent 7,695,249, April 13, 2010, Bearingless rotor blade assembly for a high speed rotary-wing aircraft

Initially displayed: April 17, 2003 ~ Last Revised: April 24, 2010

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.