Accession Number : ADA298180

Title :   Flight Measurements of the Dynamic Longitudinal Stability of Several Airplanes and a Correlation of the Measurements with Pilots' Observations of Handling Characteristics,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC

Personal Author(s) : Soule, Hartley A.

PDF Url : ADA298180

Report Date : 1936

Pagination or Media Count : 11

Abstract : The dynamic longitudinal stability characteristics of eight airplanes as defined by the period and damping of the longitudinal oscillations were measured in flight to determine the degree of stability that may be expected in conventional airplanes. An attempt was made to correlate the measured stability with pilots' opinions of the general handling characteristics of the airplanes in order to obtain an indication of the most desirable degree of dynamic stability. The results of the measurements show that the period of oscillation increases with speed. At low speeds a range of periods from 11 to 23 seconds was recorded for the different airplanes. At high speeds the periods ranged from 23 to 64 seconds. The damping showed no definite trend with speed. A general tendency for airplanes that were stable with power off to become unstable with power on was noted. The maximum damping recorded was sufficient to reduce the amplitude of oscillation by one-half in 9 seconds, or approximate one-fourth cycle. The opinions of two pilots concerning the handling characteristics of the airplanes apparently were not influenced by the stability characteristics defined by the period and damping of the longitudinal oscillations.

Descriptors :   *FLIGHT TESTING, *AERODYNAMIC STABILITY, *HANDLING, MEASUREMENT, PITCH(MOTION), AIRCRAFT, DYNAMICS, PILOTS, CYCLES, FLIGHT, POWER, OSCILLATION.

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE