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Design and Conduct of a Flight Test to Investigate Hover In-Ground-Effect Performance over Sloped Terrain

John Holder, KBRwyle
John Tritschler, US Naval Test Pilot School

May 13, 2019

https://doi.org/10.4050/F-0075-2019-14735

Abstract:
This paper presents flight test results from a research investigation into the effect of sloping terrain on hover power required. The investigation involved flight test data that were collected for a UH-72A Lakota helicopter while hovering inside ground effect above sloped terrain of varied gradients, in several aircraft orientations and multiple heights above the ground. Performance data were collected over a range of thrust coefficients by varying aircraft weight, rotor speed and environmental conditions over two sorties. The data are compared and contrasted to provide specific insight into the effects of slope magnitude, slope orientation, and rotor hub height. The results demonstrate that hovering over sloping terrain yields performance effects that are both non-intuitive and operationally significant. In particular, the effect of the sloping terrain was seen, in some conditions, to cause power requirements that exceed those for hover out-of-ground-effect, a traditional worst-case value for pre-mission performance planning.


Design and Conduct of a Flight Test to Investigate Hover In-Ground-Effect Performance over Sloped Terrain

  • Presented at Forum 75
  • 13 pages
  • SKU # : F-0075-2019-14735
  • Test and Evaluation

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Design and Conduct of a Flight Test to Investigate Hover In-Ground-Effect Performance over Sloped Terrain

Authors / Details:
John Holder, KBRwyle
John Tritschler, US Naval Test Pilot School