Cyclorotor

These blades are cyclically pitched twice per revolution to produce force (thrust or lift) in any direction normal to the axis of rotation.

The joint action of the advancement produced by the orbital motion and pitch angle variation generates a higher thrust at low speed than any other propeller.

Lift and thrust had to be created by paddle wheels consisting of 12 blades, established in pairs under a 120° angle.

Sverchkov with the grants of the Main Engineering Agency in St. Petersburg in 1909, was demonstrated at the Newest Inventions Exhibition and won a medal.

Lodygin addressed the Russian government with the project of the cyclogiro-like aircraft, his scheme was similar to Sverchkov's "Samoljot".

[5] Oscillating winglets went from positive to negative angles of attack during each revolution to create lift, and their eccentric mounting would, in theory, produce nearly any combination of horizontal and vertical forces.

Its origins date to the decision of the Voith company to focus on the business of transmission gear assemblies for turbines.

This new marine drive could significantly improve the manoeuvrability of a ship as demonstrated in the successful sea trials on the test boat Torqueo, in 1937.

[6] Cyclorotors can produce lift and thrust at high advance ratios, which, in theory, would enable a cyclogyro aircraft to fly at subsonic speeds well exceeding those of single rotor helicopters.

In this condition it is evident that in presence of a sufficiently high advance ratio the velocity of air on the retreating blade is low.

The horizontal axis of rotation always provides an advancement of the upper blades, that produce always a positive lift by the full rotor.

If compared to a helicopter or any other propeller, it is evident that the same blade section in a rotocycloid produces much more thrust at the same Reynolds number.

Actual cyclorotors bypass this problem by quickly increasing and then decreasing blade angle of attack, which temporarily delays stall and achieves a high lift coefficient.

This unsteady lift makes cyclorotors more efficient at small scales, low velocities, and high altitudes than traditional propellers.

Early 20th century cyclorotors featured short blade spans, or additional support structure to circumvent this problem.

[31] They are named in this case variable-pitch vertical-axis wind turbines, with large benefits with respect to traditional VAWTs.

In ships the cyclorotor is mounted with the axis of rotation vertical so that thrust can quickly be vectored in any direction parallel to the plane of the water surface.

In 1922, Frederick Kirsten fitted a pair of cyclorotors to a 32 ft boat in Washington, which eliminated the need for a rudder and provided extreme manoeuvrability.

[35] A cyclogyro is a vertical takeoff and landing aircraft using a cyclorotor as a rotor wing for lift and often also for propulsion and control.

Advances in cyclorotor aerodynamics made the first untethered model cyclogyro flight possible in 2011 at the Northwestern Polytechnic Institute in China.

The smallest cyclogyro flown to date weighs only 29 grams and was developed by the advanced vertical flight laboratory at Texas A&M university.

A large exposed area makes airships susceptible to gusts and difficult to takeoff, land, or moor in windy conditions.

Propelling airships with cyclorotors could enable flight in more severe atmospheric conditions by compensating for gusts with rapid thrust vectoring.

Following this idea, the US Navy seriously considered fitting of six primitive Kirsten-Boeing cyclorotors to the USS Shenandoah airship.