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Tradespace Exploration of Distributed Propulsors for Advanced On-Demand Mobility ConceptsCombustion-based sources of shaft power tend to significantly penalize distributed propulsion concepts, but electric motors represent an opportunity to advance the use of integrated distributed propulsion on an aircraft. This enables use of propellers in nontraditional, non-thrust-centric applications, including wing lift augmentation, through propeller slipstream acceleration from distributed leading edge propellers, as well as wingtip cruise propulsors. Developing propellers for these applications challenges long-held constraints within propeller design, such as the notion of optimizing for maximum propulsive efficiency, or the use of constant-speed propellers for high-performance aircraft. This paper explores the design space of fixed-pitch propellers for use as (1) lift augmentation when distributed about a wing's leading edge, and (2) as fixed-pitch cruise propellers with significant thrust at reduced tip speeds for takeoff. A methodology is developed for evaluating the high-level trades for these types of propellers and is applied to the exploration of a NASA Distributed Electric Propulsion concept. The results show that the leading edge propellers have very high solidity and pitch well outside of the empirical database, and that the cruise propellers can be operated over a wide RPM range to ensure that thrust can still be produced at takeoff without the need for a pitch change mechanism. To minimize noise exposure to observers on the ground, both the leading edge and cruise propellers are designed for low tip-speed operation during takeoff, climb, and approach.
Document ID
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Borer, Nicholas K.
(NASA Langley Research Center Hampton, VA, United States)
Moore, Mark D.
(NASA Langley Research Center Hampton, VA, United States)
Turnbull, Andrew R.
(Analytical Mechanics Associates, Inc. Hampton, VA, United States)
Date Acquired
September 8, 2014
Publication Date
June 16, 2014
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
AIAA Paper-2014-2850
Meeting Information
Meeting: AVIATION 2014 (The Aviation and Aeronautics Forum and Exposition)
Location: Atlanta, GA
Country: United States
Start Date: June 16, 2014
End Date: June 20, 2014
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 794072.
Distribution Limits
Public Use Permitted.
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