
Accession Number : AD0864924
Title : Maximum Speed of Helicopters and Possibility for Increasing It,
Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHTPATTERSON AFB OH
Personal Author(s) : Witkowski, R.
Report Date : 15 OCT 1969
Pagination or Media Count : 16
Abstract : The paper contains a detailed mechanical and mathematical analysis of a rotor with controlled blade movement in the transverse (rotational) plane. This rotor is based on the introduction of a forced oscillatory blade motion in the plane of rotation, so selected as to eliminate the velocity asymmetry in the flow around the blade ends in the two critical azimuthal positions, thus avoiding the attainment of the critical angles of attack and flow line disruption at fast forward speeds. Pertinent expressions are derived in the paper, including equations for the velocity distribution in the flow past the blades for arbitrary azimuth, the dimensionless velocity of the flow past a blade element, the law governing blade vibrations as a function of the first harmonic of the rotations, and, ultimately, the expression for velocity of the flow past a blade element of a Derschmidt rotor; the latter is shown to be far more complex than the corresponding expression for a conventional rotor and, since it is inconvenient for use in calculations by virtue of its containing trigonometric functions, is transformed by means of Maclaurin series. (Author)
Descriptors : *FLIGHT SPEEDS), (*HELICOPTERS, ROTOR BLADES(ROTARY WINGS), OSCILLATION, OPTIMIZATION, MATHEMATICAL ANALYSIS, AIRSPEED, AZIMUTH, ANGLE OF ATTACK, POLAND.
Subject Categories : Helicopters
Distribution Statement : APPROVED FOR PUBLIC RELEASE