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September 15, 1917

Vibrations of a Rotating Air-screw and Its Shaft

Digest of the Foreign Aeronautical Press

News of the Fortnight


Vibrations of a Rotating Air-screw and Its Shaft

A.R.C.Sc. The present paper gives the mathematical theory of the transverse vibrations of a rotating air-screw and its shaft, and also an application of the method to several practical problems. For generality, the calculations have been made for a two-bladed air-screw when the transverse vibrations are in a plane parallel to both the axis of the air-screw blades and the axis of rotation, and also when in a plane at right angles to the axis of the air-screw blades and parallel to the axis of rotation.


Digest of the Foreign Aeronautical Press

Aircraft Losses in July.—Our Air Service overseas had three famous days last month. The first was July 11, when our aerial activity seems to have borne no special relation to operations in the field. At any rate, our men destroyed fourteen German machines and drove down sixteen out of control, while another was shot down by gunfire from the ground.

News of the Fortnight

Legal Status for Aircraft Board The Sheppard bill giving a legal status to the Aircraft Board, having charge of the $640,000,000 aircraft program, was passed in the Senate on September 12. The board, if the bill becomes a law. will consist of the Chief Signal Officer of the Army, the Chief Constructor of the Navy, and seven civilian members who will receive salaries of $7,500 each. No contracts can he made by the board without the approval of the War and Navy Departments.

The 260 Horsepower Mercedes Aero-engine

The 200 hp. Mercedes aero-engine herewith described is typical of German ideas at the moment, and resembles in general design and even in minor details the well known 150 and 175 hp. models of the same manufacturers. The complete engine, including the propeller boss, measures 6 ft. 5½ in. over all, and from the bottom of the sump to the top of the overhead camshaft casing measures approximately 3 ft. 10 in.

Wire and Cable Standards Recommended By S. A. E.

The following extracts from the report of the Advisory Committee for Airplane Material, Specifications and Inspection were recommended for standardization at the Washington meeting of the S, A. E. Aircraft Round Wire This specification covers solid high strength steel wire, round section, used in the construction of aircraft when flexibility is of minor importance.

Completion of the Liberty Engine

The successful completion of the U. S. A. or Liberty aircraft engine was announced in an official statement issued by the Secretary of War on August 12. The statement reads: “ The United States aviation engine has passed its final tests. They were successful and gratifying.

The Nieuport 1½ Plane Fighter

The Nieuport 1½ plane has, during the last year, become one of the most important fighter airplanes of the French Flying Corps, being in no mean way responsible for the aerial supremacy achieved by the Allies both on the Western and the Italian fronts.

The Sylphon Motor Thermostat

Proper control of the temperature of the cooling medium of an internal combustion engine, adds much to the efficiency, economy, and satisfactory operation. There is one temperature of the medium at which the motor will give best results, and the ideal condition is to maintain this temperature constant.



The Boyce Motometer

September 11917 October 11917