The Installation of an Engine Nacelle on a Wing PART I—Model Tests on a Symmetrical Wing PART II—Underslung Nacelles on Cambered Wings PART III—Pitching-moment Changes due to Nacelles PART IV—Effects of Fuselage and Tractor Airscrew

摘要

These tests form the first part of an investigation aiming at location and reduction of the interference drag experienced when an engine nacelle is installed on a wing. As a preliminary, the effects of lift changes have been eliminated by testing only completely symmetrical nacelle-wing combinations.nMeasurements of the drag of a series of 1/5-th scale models of faired shapes of maximum diameter 50 in. in different fore arid aft positions on wings of 9-ft. and 11-ft. chord, thickness/chord ratio 15 per cent., were made with three conditions of flow over the nacelle and wing,n(1) without any induced turbulence,n(2) with turbulence induced over the nacelle by means of a thread around the nose,n(3) with turbulence induced over both nacelle and wing by means of a turbulence screen.nPreliminary tests of the thread and screen methods of producing turbulence were made on a faired shape alone.nThe origin of the drag was then found by observation of the flow with wool-tufts, and by pitot-traverses on the wing and nacelle surface and in the wake.