Accession Number : ADP002269

Title :   The Effect of Wing Tip Devices on the Far-Field Wake of a Paris Aircraft,

Corporate Author : CRANFIELD INST OF TECH (ENGLAND)

Personal Author(s) : Spillman,J. J.

Report Date : JUL 1983

Pagination or Media Count : 9

Abstract : Studies made of the flow about the wing-tip of a windtunnel model showed that the vortex-type flow generally associated with the rolled-up vortex sheet well behind the tip existed just behind the trailing edge and seemed to be forming over the top of the wing-tip itself. As a result small cambered aerofoils were attached to the wing-tip to redirect the flow locally in such a way that each experienced a force with a significant thrust component. The effect is similar to that generated by the sail of a close-hauled yacht; consequently these small tip extensions were called sails. Reference 1 describes the original windtunnel and the preliminary flight test of sails mounted from the tip tanks of the Paris aircraft of the Cranfield Institute of Technology. These initial tests showed that a considerable reduction in the lift-dependent drag results from fitting the sails but there was a marked scatter in the results which detracted from their credibility. The first part of this programme was to extend the flight tests made on the Paris in two ways, firstly to measure engine characteristics in steady level flight to obtain drag and fuel consumption comparisons and secondly to fly another aircraft across the wake of the Paris to measure the effect of sails on the decay of the trailing vortex system.

Descriptors :   *Vortices, *Wing tips, *Wake, *Flow fields, Aircraft models, Wind tunnel models, Sailwings, Lift to drag ratio, Trailing vortices, Far field

Distribution Statement : APPROVED FOR PUBLIC RELEASE