Download or read book Some Static Longitudinal Stability Characteristics of an Overlapped-type Tandem-rotor Helicopter at Low Airspeeds written by Robert J. Tapscott and published by . This book was released on 1958 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flight measurements of some longitudinal static stability characteristics with an overlapped-type tandem-rotor helicopter at low airspeeds are presented. The data show that a critical amount of longitudinal control is required to maintain trimmed flight at certain combinations of airspeed and rate of descent. Estimates based on theoretically predicted interference effects indicate that the front rotor downwash acting on the rear rotor could cause variation of the longitudinal moments of the same order of magnitude as the measured variation.