AANCS uses the principle of destructive interference of waves to
... How ANR Cancels Noise
Active Noise Reduction, or ANR, reduces noise exposure by introducing sound waves
180 degrees out of phase with the noise, resulting in destructive interference, causing a
net reduction of noise at the ear. ANR headsets identify and reduce unwanted noise,
allowing improved inte ...
VS-300 Helicopter (1939) - American Society of Mechanical Engineers
... were provided by adding two lifting (horizontal) tail rotors which had differential
collective pitch. Each rotor was 40 inches
in radius. The azimuth control was removed from the main rotor, leaving only
collective pitch control. Control of the aircraft was now satisfactory except in forward flight. ...
Principles Of Rotary Flight
... above airfoil must move faster in order to meet up
with the air molecules moving under the airfoil. This is
due to the fact that the air molecules moving above
the airfoil have longer distance to cover. This Creates
a low pressure above the airfoil, and high pressure
beneath the airfoil. The Higher ...
The Fairey Rotodyne was a 1950s British compound gyroplane designed and built by Fairey Aviation and intended for commercial and military applications. A development of the earlier Gyrodyne, which had established a world helicopter speed record, the Rotodyne featured a tip-jet-powered rotor that burned a mixture of fuel and compressed air bled from two wing-mounted Napier Eland turboprops. The rotor was driven for vertical takeoffs, landings and hovering, as well as low-speed translational flight, and autorotated during cruise flight with all engine power applied to two propellers.One prototype was built. Although promising in concept and successful in trials, the Rotodyne programme was eventually cancelled. The termination has been attributed to the type failing to attract any commercial orders; this was in part due to concerns over the high levels of rotor tip-jet noise generated inflight. Politics - the development was government funded- had also played a role in the lack of orders, which ultimately doomed the project.