Performance Analysis of the Slowed-Rotor Compound Helicopter Configuration

Abstract

The calculated performance of a slowed-rotor compound aircraft, particularly at high flight speeds, is examined. Correlation of calculated and measured performance is presented for a NASA Langley high advance ratio test to establish the capability to model rotors in such flight conditions. The predicted performance of an isolated rotor and a wing and rotor combination are examined in detail. Three tip speeds and a range of collective pitch settings are investigated. A tip speed of 230 ft/s and zero collective pitch are found to be the best condition to minimize rotor drag over a wide speed range. Detailed rotor and wing performance is examined for both sea level and cruise altitude conditions. Rotor and wing power are found to be primarily from profile drag, except at low speed where the wing is near stall. Increased altitude offloads lift from the rotor to the wing, reducing total power required.

Stability and Control Analysis of the Slowed-Rotor Compound Helicopter Configuration

“…The contributions to drag and power for this rotor are discussed in detail in Ref. 7. For the present study, the only interest is sharp gradients with respect to collective pitch angle, especially with tightly stacked horizontal contours that indicate rapid changes with collective pitch.…”

“…7). The purpose of the present analysis effort in the Aeroflightdynamics Directorate of the US Army Aviation and Missile Research, Development and Engineering Center is to examine the stability and control of slowed-rotor compound aircraft, particularly at high advance ratios.…”

A Fast Method of Aerodynamic Computation for Compound Gyroplane

“…When the rotor achieved a steady status in the forward flight, the torque of the shaft should be zero, that is: (2) Where K is the number of blade; β is the waving angle. By solving equation (2), the steady speed of rotor at different forward flight status can be obtained, and the lift L and the drag D of the rotor can be derived as follows:…”

“…In the course of developing XV-1, McDonnell-Douglas corporation conducted some system researches on the three flight modes of the aircraft, and released a series of aerodynamic performance reports. The corporation also studied the interference of rotor and fuselage [2][3][4]. Vu [5] investigated aerodynamic characteristics of a compound gyroplane in preliminary design and optimization phrase.…”

Trim Range and Characteristics of Autorotation(II): Advance Ratio Variation and Flapping Characteristics

“…이 문제는 Floros 등에 의해 연구되었는데 [3,4], 플래핑 방정식을 로터의 토크가 0이 되는 조 건에 의해 풀어 피치각을 구하는 고전적인 헬리 콥터 다이나믹스 이론으로는 로터 제어의 포괄적 인 변수의 범위를 구하는데 한계가 있었다. Schank …”