Development of advanced rotorcraft configurations has highlighted a need for high-quality experimental data to support the development of flexible and accurate analytical design tools. To provide this type of data, a test program was conducted in the Langley 14- by 22-Foot Subsonic Tunnel to measure the flow near the empennage of a 15-percent scale powered helicopter model with an operating tail fan. Three-component velocity profiles were measured with laser velocimetry (LV) one chord forward of the horizontal tail for four advance ratios to evaluate the effect of the rotor wake impingement on the horizontal tail angle of attack. These velocity data indicate the horizontal tail can experience unsteady angle of attack variations of over 30 degress due to the rotor wake influence. The horizontal tail is most affected by the rotor wake above advance ratios of 0.10. Velocity measurements of the flow on the inlet side of the tail fan were made for a low-speed flight condition using conventional LV techniques. The velocity data show an accelerated flow near the tail fan duct, and vorticity calculations track the passage of main rotor wake vortices through the measurement plane.
Development of advanced rotorcraft configurations has highlighted a need for high-quality experimental data to support the development of flexible and accurate analytical design tools.
Finally, we compare cluster dynamics and the institutional setup in Europe and the U.S., with the purpose of identifying regulations that seem to hinder a conducive environment for expanding and dynamic European clusters."--Jacket.
The role of private venture capital is particularly critical within new, knowledge-
intensive industries such as biomedicine/biotechnology, where investments are
often intangible and future potential difficult to assess (Gompers, 1996).
Graphics, was looking for an new venture. He recruited Andreesen without a
clear idea of what kind of business to pursue. Together, they traveled back to the
Illinois campus and successfully recruited most of original Mosaic team to join
this ...
