1470

Item 1470

OTHER: Rotor Concept - Reverse Velocity Utilization - Traversing Root Pitch Axis - Leading and Trailing Edge Exchanging

This is a sub-page of; OTHER: Rotor Concept - Reverse Velocity Utilization - Traversing Root Pitch Axis

The intent of this page is to look for and evaluate possible means of swapping the leading edge and the trailing edge profiles, near the root end of the blade, at a rate near to that of the rotor's RPM.

Objective:

To 'morph' the root end edges of a blade at a rate near the one per rotor revolution during forward flight so that the airflow passing the blade is as close as possible to that experienced at a conventional airfoil's leading edge and trailing edge.

Have the pitch axis at the root of the blade as close to 25% of chord from the temporal leading edges as possible. This is covered in 1516.html.

Consider actively increasing the weight at the temporary leading edges (somehow) by the spar's movement to that edge.

Notes:

Leading Edge Weight:

The traversing spar could drive a fluid into a chamber at the edge, which is to temporarily become the leading one. This fluid (air, water, oil, or mercury) would cause the skin of the leading edge to bulge out and it would add weight to the leading edge. At the same time the 'fluid' is being removed from the temporary trailing edge. The objective is to place the center of mass slightly ahead the axis of pitch.
This fluid and the orifice through which it must past could act as a damper to the final portion of the spar's traversing.

Traversing Action:

The primary means and sensory determinant is aerodynamic however this could be supplemented by magnetic; and many other means.
The magnetic action could be just at the vary root or along a portion of the blade's span at the root end.

Calculation of Speeds so as to have the location of zero velocity at 75% of radius at 275º azimuth and the blade velocity at 85% of Mach 1 at the tip at 90º azimuth:

Velocity of blade at 90º azimuth at 100% R: 543 ft/ sec = 370 mph

Airspeed of craft [V]: 277 mph

Combined airspeed at 90º azimuth at 100% R: 949 ft/sec = 647 mph = 0.87 mach

Airspeed at 270º azimuth at 75% R = 0

Sketch of a Proposed Means of Swapping the Leading and Trailing Edges at a Rate of 1/Rev:

The intent is that the edge of the blade root, which is moving toward the spar, is force to assume a leading edge profile. Meanwhile, the other edges, which is moving away from the spar, 'springs' back to its default trailing edge profile.

Additional force, as mentioned above, maybe required to assist the aerodynamic profile drag of the blade.

Obviously, today it will be impossible to obtain a perfect profile, But in the future ...........

Tip Leading and Trailing Edges:

There may be little reason to consider swapping the leading and trailing edges at the tip end. This is because the airfoil at the tip is thin and there is not too much distinction between the two edges.

In addition, at under MU =1 the airflow is conventional.

Also, at MU = 1 and greater the velocity of the air at the retreating tip will be the least of any location on the rotor disk.

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Initially displayed: May 20, 2007 ~ Last Revision: January 16, 2008

The above application of reverse velocity utilization in the main rotor(s) of a helicopter is openly and publicly disclosed on the Internet to negate an entity from patenting 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.