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|Document Type: ||Thesis or dissertation|
|Title: ||Investigations into the operational effectiveness of hybrid laminar flow control aircraft|
|Authors: ||Young, T. M.|
|Supervisors: ||Fielding, John|
|Issue Date: ||Oct-2002|
|Abstract: ||Hybrid Laminar Flow Control (HLFC) is an active drag reduction technique that
permits extended laminar flow on an aircraft surface at chord Reynolds numbers
normally associated with turbulent flow. The operational effectiveness of HLFC
aircraft relates to the probability of a partial or complete loss of laminar flow. Four
factors were considered: (1) Ice particles in cirrus clouds; (2) Insect contamination; (3)
Mechanical failure; and (4) Damage to the suction surfaces.
Two computer programs capable of determining the required fuel for a given
mission profile have been developed for aircraft in the classes of the B757-200 and the
A330-200. The programs were validated against published payload-range data, and
modified to emulate the installation of a HLFC system, by incorporating changes to the
drag polar, Specific Fuel Consumption (SFC) and Operating Empty Weight (OEW).
Sensitivity studies were conducted. The results permit estimates to be determined of the
trip fuel reduction of HLFC aircraft compared to equivalent turbulent aircraft.
A conceptual design of a HLFC system has been developed for the reference
aircraft. A SFC penalty of 1.6% was determined for the B757-200 class aircraft (range:
3272nm, payload: 19147kg) and 2.1% for the A330-200 class aircraft (range: 5980nm,
payload: 24035kg) for a system capable of reducing the drag by approximately 14%.
The installed system weight represents 2.0% and 1.6% of the OEW for the B757-200
and A330-200 classes of aircraft respectively. The reduction in trip fuel, compared to
the turbulent baseline vehicles, was estimated to be 7.4% for these conditions. To
obtain the greatest benefit for a HLFC aircraft, the fuel planning must consider the
probable time-in-cloud that will result in a loss of laminar flow. An optimised fuel
planning approach, which requires a forecast of en route cirrus cloud, has been
estimated to further reduce the trip fuel for long-range missions by 2.5 - 3.8%.|
|Appears in Collections:||PhD and Masters by research theses (School of Engineering)|
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