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Thrust Characteristics of Multiple Lifting Jets in Ground ProximityAn investigation has been made to determine the thrust characteristics within ground proximity of a series of models which might represent vertical take-off-and-landing (VTOL) aircraft with multiple exit jet engines exhausting vertically downward beneath a lifting surface. Variations in simulated engine configurations were provided by a series of nozzle insert plugs in which the number of jet exits, located symmetrically on a fixed circle, was varied, or the diameter of the circle was varied for a given number of jet exits. represent lifting surfaces, and high-pressure air was used to simulate jet-engine exhaust. Plywood plates were used to The results of the investigation showed that increasing the number of exits, such that an annular jet configuration was approached, provided more favorable thrust characteristics within ground proximity than any other variation in the geometry of these multiple jets. Tests of a configuration with two nozzles approximating a fan-in-wing VTOL aircraft with fans located at different spanwise locations indicated that the augmentation in thrust within ground proximity was greater for the arrangement with the more inboard location of the nozzles.
Document ID
20040030507
Acquisition Source
Langley Research Center
Document Type
Other - NASA Technical Note (TN)
Authors
Davenport, Edwin E.
(NASA Langley Research Center Hampton, VA, United States)
Spreeman, Kenneth P.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 21, 2013
Publication Date
September 1, 1960
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
L-868
NASA-TN-D-513
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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