A wind tunnel investigation of the longitudinal and lateral aerodynamic characteristics of a Canard Aircraft model Part 1 Tests at M = 1.04 and M = 2.02 Part 2 Tests at M = 2.47

Abstract

PART I. Tests were made in the Royal Aircraft Establishment No. 19 (18 in. x 18 in.) supersonic wind tunnel to measure the overall normal and side forces, rolling, pitching and yawing moments on a typical canard aircraft layout at M = 1.40 and M = 2.02. The complete configuration and configuration less fin, with foreplane angles, η, 0 deg and 10 deg were tested for combinations of incidence and sideslip up to α = β = 10 deg. Additional breakdown tests were made at M = 1.40, and supplemented by oil flow and vapour screen tests. The tests have shown that the foreplane has a reduced lifting, but an increased moment, effectiveness due to the download induced on the mainplane. The longitudinal stability increases with incidence and Mach number; neither normal force nor pitching moment is affected significantly by sideslip. The lateral and directional characteristics are less satisfactory. When sideslip is present the foreplane-wing interaction produces a large negative rolling moment which increases in magnitude with incidence and control setting. There is a reduction in δCn/δβ with application of incidence, and the evidence suggests that this becomes more marked as the Mach number increases. The tests indicate that further investigation is required into the effect of a free vortex on the load distribution over a lifting surface if satisfactory estimates are to be made of control-wing and control-fin interference. PART II. Tests were made in the R.A.E. No. 8 (9 in. × 9 in.) Supersonic Wind Tunnel to measure the overall normal and side forces, rolling, pitching and yawing moments on a typical canard aircraft layout at M = 2.47: These tests are an extension of those at M = 1.40 and M = 2.02 recorded in Part I of this R.& M. The foreplane lifting effectiveness, although still reduced due to the download induced on the mainplane, is greater than at the lower Mach numbers. The neutral point is further aft at the higher Mach number and shows less variation with incidence; neither normal force nor pitching moment is affected significantly by sideslip. There is a large negative rolling moment induced by foreplane-wing interference when positive sideslip is applied. This rolling moment increases with increase of incidence and foreplane setting. δCn/δβ at α = 0 deg is considerably reduced (compared with M = 1.40) and shows further reduction with increasing α, and for the moment reference chosen becomes negative for a > 7 deg. The tests emphasise that considerable attention will have to be given to lateral and directional characteristics at the higher Mach numbers.