Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft (2007) / Chapter Skim
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Appendix B Additional Methods for Improving Fuel Consumption
Appendix B Additional Methods for Improving Fuel Consumption
Pages 77-87
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From page 77... ...
Other methods include making other aerodynamic modifications to the aircraft, improving engine efficiency, changing maintenance and operation practices, and improving weight management. Many of these strategies have already been adopted by the commercial airlines, which operate in an intensely competitive environment,1 and others have been touched upon by several recent studies.2 The committee believes it is important for these strategies to be considered, and while they were not the focus of this study, nor was the extent to which the Air Force may already be using some of them examined, some examples are discussed below for the reader's benefit.
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From page 78... ...
AERODyNAMICS Lessons learned from the commercial airplane industry suggest that aerodynamic improvements using strategies other than wingtip modification are worth consideration for the Air Force's fleet of aircraft. Many of the its transport aircraft were designed in the early days of swept-wing trans 3NRC, 2007, Improing the Efficiency of Engines for Large Nonfighter Aircraft, Washing ton, D.C.: The National Academies Press.
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From page 79... ...
7 APPENdIX B port design and do not take advantage of some more recent technological advancements, such as supercritical aft-loaded wings; low-interference, podmounted engine installations; reduced static stability; and digital designs with low excrescence drag. Wing Modifications A number of common performance improvements have been incorporated into the commercial fleet, both by the original equipment manufacturers (OEMs)
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From page 80... ...
These procedures are effective and relatively easy to implement. Where these procedures make operational sense and are not currently used by the Air Force, military managers should consider implementing the practices that have merit.
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From page 81... ...
APPENdIX B Maintenance Initial efforts to improve performance generally rest with an attempt to regain the original tolerances and material conditions for in-service aircraft. These efforts are generally accomplished according to priorities that are jointly developed with the OEM.
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From page 82... ...
ASSESSmENt oF wINgtIP modIFICAtIoNS • Pneumatics. Pneumatic leakage through door cutouts, improper seal ing, airframe damage, and fuselage attach fittings adversely affects fuel burn in two ways: (1)
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From page 83... ...
APPENdIX B Operations A number of operational procedures and practices have been developed by the air transport industry to reduce fuel consumption. Their effectiveness is dependent on (1)
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From page 84... ...
ASSESSmENt oF wINgtIP modIFICAtIoNS • Match the airplanes and engines that perform best with respect to fuel burn to fly the longest range/endurance missions. If a specific aircraft is flagged as having excessive fuel burn, maintenance action is initiated to determine, and correct, the cause of that unnecessary burn (the preceding section on maintenance gives details)
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From page 85... ...
5 APPENdIX B • Trim the rudder to eliminate rudder control force and sideslip/ turning flight. • Trim the aileron to eliminate control force.
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From page 86... ...
ASSESSmENt oF wINgtIP modIFICAtIoNS craft empty weight will increase over the life of the aircraft (to the detriment of payload capability and fuel burn performance)
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From page 87... ...
7 APPENdIX B swamp areas. Check insulation blankets for condensation which can increase the weight of the blankets significantly -- by, for example, more than 1,000 lb in the case of 707 blankets.
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