Multi-motored Airplanes, 1933

Primary Force

The versatility of the helicopter in its ability to ascend and descend vertically, hover, rotate, and fly in reverse required multiple applications of physics principles. With versatility comes complexity; rotary-wing aircraft offer many design and operation challenges.

The primary force required is LIFT. Lift is a force dependent on the fluid nature of air. When the helicopter's rotating blades move, they create a downward air flow perpendicular to the horizontal plane of the rotors. The downward force creates an equal and opposite upward force in agreement with Newton's third law. This upward force is lift.

Press clipping concerning the uses of Sikorsky amphibian airplanes, 11/16/1931 (1.5M)

Press clipping concerning the uses of Sikorsky amphibian airplanes, January 1933 (1.2M) | Another clipping (697K)

Summary of Sikorsky's contributions to aviation, undated (3.0M) | Page 2 (2.4M)

Affidavit from Howard Mingos, Affirming that Sikorsky is generally conceded to be the inventor of the first successful multi-motored airplane ever flown (and duplicate), 9/19/1932 (2.7M)

Letter from CSA Secretary, to Samuel B. Eckert, Reporting that sub-committee scope may be extended to cover Sikorsky's multi-motored airplane invention and requesting opinions, 9/21/1932 (4.2M) | Page 2 (4.0M)