Wind tunnel force and moment tests on a 1/12 scale model of the H.J.T-16 (basic jet trainer aircraft) at speeds up to M=0.82

Abstract

Tests have been made in the 8' x 6' ' Transonic Tunnel to determine the aerodynamic characteristics of the Hindustan Aircraft Ltd. H.J.T-16 over the possible flight ranges of incidence, sideslip, and Mach number. Various configurations were tested to investigate the aircrafts longitudinal and directional stabilities, elevator, tailplane and aileron effectiveness and dive brake performance. The results show that for an axis at the ¼ chord of the aerodynamic mean chord the H.J.T-16 has marginal longitudinal stability up to M=0·50, and at low Cl will become unstable with increasing Mach number. At all test Mach numbers the aircraft is directionally stable. The elevators and ailerons are effective under all test conditions and control reversal does not occur. Opening the dive brake causes large changes in lift and pitching moment in addition to the required increase in drag.