A new blade profile, RAE(NPL) 9615, has been developed for the Lynx helicopter using two-dimensional aerofoil tests. The complex nature of the rotor environment makes it essential to confirm that the designed improvements are realised in flight. The present tests, planned before the Lynx first flew, have simultaneously compared the new profile with the NACA 0012 profile in hovering flight. Each profile took the form of a fairing or 'glove' on a pair of opposing blades of the Wessex helicopter and both local surface pressures and wake pitot pressures were measured. The flight results confirm the comparative reduction in local supersonic velocity and in shock-induced profile drag for the new profile. However, differences between flight and tunnel attributable to three-dimensional effects are evident. The results also indicate the complex nature of the flow due to blade vortex interaction and small translational velocities. (Author)
Comparative Performance Measurements of Two Helicopter Blade Profiles in Hovering Flight
1974
56 pages
Report
No indication
English
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