Item 1022
OTHER: Aerodynamic - Drag - Profile [DO]
Caused
by the friction of air to the rotation of the rotor blades.Excluding that caused by the vortices at the tips ??? . In other words, profile drag is the sum of the drag caused by surface friction and the pressure drag. ???
Clean up the above definition. This page was started to record info on Reverse Flow Drag Effect.
Experiments show that an airfoil, which is subjected to a reverse airflow, will experience a profile drag that is 2.6 time greater than that from normal airflow.
Discussion and calculation related to the airflow passing from trailing edge to leading edge.
Technical Documents on ABC, Forward Flight Performance of a Coaxial Rigid Rotor, page 6, ~ V. M. Paglino, May 1971
See
Laminar Flow, As opposed to Turbulent FlowJust a random though; on a conventional airfoil operating in reverse velocity with negative pitch (i.e. providing lift); the complete chord of the upper surface is probably in turbulent flow, and the leading 75% approximately of chord of the lower layer is probably experiencing laminar flow.
http://www.aeronautics.nasa.gov/docs/rpt460/discuss.htm
Related Web Pages:
OTHER: - Rotor Concept - Reverse Velocity Utilization
OTHER: Helicopter - Outside - Single (large) - Sikorsky's Reverse Velocity Rotorcraft Concept. It might be noted that the proposed airfoil is double ended but the 'leading' and the 'trailing' edges are not completely identical. I have hard copy. View on front page.
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Last Revised: December 23, 2010