B473

OTHER: ~ Rotor Concept - Reverse Velocity Utilization

~ Reverse Airflow Utilization ~

Overview: Clean up wording??

To derive lift from the reverse velocity region on the retreating side of the rotor's disk.

To take full advantage of the reverse velocity it will require;

Rates of pitch change that exceed 1/rev. [azimith]
Independent pitch change along the span of the blade. [radius]
Airfoil profiles that are optimized for the positive and negative velocities, at different elements along the span of the blade, during different flight conditions.

To actively vary the twist of the blades during flight, at the rate of 1/rev.or higher, so that at fast-forward velocities there is negative twist on the advancing blade and positive twist on the retreating blade. The pitch at the root of the retreating blades goes negative at high forward speeds, which thereby creates lift from the reverse airflow (from trailing edge to leading edge).

This is currently being developed for the UniCopter. Ref; UniCopter ~ Flight Control and UniCopter ~ Rotor Blade

For related mathematical cancellations see; [Source ~ RWP1 p.201]

For related concept see: OTHER: ~ Rotor Concepts - Rotor X Wing

".. it is found that the effects of the reverse flow region are negligible up to an advance ratio of about mu = 0.5" ~ [Source ~ HT p.152].

Detail Pages:

	Name	Item
	OTHER: Rotor Concept - Reverse Velocity Utilization - General & Miscellaneous	1108
	OTHER: Rotor Concept - Reverse Velocity Utilization - Existing Work	1055
	OTHER: Rotor Concept - Reverse Velocity Utilization - Patents	1545
	OTHER: Rotor Concept - Reverse Velocity Utilization - Concerns	0422
	OTHER: Rotor Concept - Reverse Velocity Utilization - Reverse Velocity - Blade (alternative A)	1485
	OTHER: Rotor Concept - Reverse Velocity Utilization - Reverse Velocity - Blade (alternative B)	1600
	OTHER: Rotor Concept - Reverse Velocity Utilization - Reverse Velocity - Rotor	1124
	OTHER: Rotor Concept - Reverse Velocity Utilization - Reverse Velocity - Configuration
	OTHER: Rotor Concept - Reverse Velocity Utilization - Traversing Root Pitch Axis	1516
	OTHER: Rotor Concept - Reverse Velocity Utilization - Traversing Root Pitch Axis - Profile Morphing	1470
	OTHER: Rotor Concept - Reverse Velocity Utilization - Traversing Root Pitch Axis - Blade profile	1609
	OTHER: Rotor Concept - Reverse Velocity Utilization - Sharp Leading & Trailing Edges at Root of Blade	1613

Alternative Concept:

	Name	Item
	OTHER: Rotor Concepts - Traversing Ideal Twist	B456

Related Pages:

	Name	Item
	OTHER: Rotor Concept - Independent Root & Tip - Reverse Pitch Rotor	1357
	DESIGN: UniCopter ~ Rotor - Disk - Large Chord & Low Tip Speed	1090
	OTHER: Helicopter - Outside - Single (large) - Sikorsky's Reverse Velocity Rotorcraft Proposal	1281
	DESIGN: UniCopter ~ Control - Flight - Independent Root & Tip - Blade Root ~ Reverse Velocity	1364
	UniCopter ~ Pusher Prop - Variable Speed Rotors and Prop	Page

Initially displayed: September 16, 2002 ~ Latest revision; November 30, 2010

The above application of reverse velocity utilization in a twin main rotor helicopter 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.