Revolutionary Blade for High-speed Rotorcraft

[Rotor Rooter]

The purpose of this posting is to place the following invention in the public domain, so that it is freely available to all.

In addition, any comments or critique will be appreciated.
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Potential Features;
. ` . ~ An advance ratio far beyond 1 (mu >> 1).
. ` . ~ Stopped rotor.
. ` . ~ High lift/drag ratios in high-speed forward flight and in hover.

http://www.unicopter.com/1369-2.gif

Quick Explanation;
. ` . The rotor incorporates ideal twist. This ideal twist traverses the span of the blade as the blade rotates through the retreating side of the disk. The center of this ideal twist moves so that it is always concentric with the location on the blade of zero forward airflow.

Additional Material:
. ` . ~ Overview of the invention; (http://www.UniCopter.com/1369.html)
. ` . ~ Construction of Simplistic Blade; (http://www.UniCopter.com/1504.html)

[Al_Hammer]

Very interesting.
Ignoring the fact that you say:
It is totally impossible to build at this time.

One possible problem is the fact that the blade sections are oscillating and this will require a driving force. Also, the response is not instantaneous, due to inertia of the segments, so I would think that if you use aerodynamic forces in opposition to spring pressure, that the lag in response might ruin the scheme, unless I'm not understanding it correctly.

[Luc De Keyser]

you may not need elastomeric bearings - just let the segments rotate freely around the 25% chord (weight balanced) axis - the apparent wind will orient them at each point in time, with very little inertia.

Such a rotor can be viewed as composed of blades that are made up of a "string" of segments that each behave like a small free wing. You could add to each segment one of the controls that are typical to free wings to add collective control and synchronise the AOA of each segment with the rotation cycle to optimize performance.

A similar topic was discussed with Craig Wall in Norman's forum.

Luc

[Rotor Rooter]

Al,
The advanced method (http://www.unicopter.com/1503.html)would be impossible to build at this time. The simplistic method (http://www.unicopter.com/1504.html) should be quite simple to build.

Your understanding of the simplistic method is just about perfect. When the airflow reverses on a segment, the air pressure and the light spring will start the rotation of the segment. Halfway around to the new position the spring will start resisting the rotation, however the continuing air pressure and the inertia will complete the second half of the rotation.

Your concern about overcoming inertia is valid and will be noted on the web page. Thanks. Hopefully, the slow speed rotor (http://www.unicopter.com/1090.html)
, plus the fact that it slows down further as the forward speed of the craft is increased, will help overcome a potential inertia problem.


Luc,you may not need elastomeric bearings - just let the segments rotate freely around the 25% chord (weight balanced) axis Yes. It would certainty simplify the blade. In fact, the initial testing could be done by chopping up a Vortech extruded aluminum blade and inserting the segments on a rod.

The 'free wing' concept will be looked into further. Thanks for mentioning it.


P.S. Where IS Craig Wall?