Improving the Efficiency of Engines for Large Nonfighter Aircraft (2007) / Chapter Skim
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6 Other Considerations
6 Other Considerations
Pages 69-86
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From page 69... ...
AERODYNAMIC MODIFICATIONS This section discusses three areas—winglets, laminar flow nacelles, and airframe modifications unique to the C-130—where aerodynamic modifications may increase fuel efficiency in the large nonfighter aircraft fleet. Winglets As presented by the Air Force Scientific Advisory Board (AFSAB)
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From page 70... ...
. Though this study is focused on fuel savings, blended winglets also reduce maintenance costs because the aircraft do not need as much thrust to achieve the same climb and cruise performance.
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From page 71... ...
If the modification cost plus the cost of the hit were $4.5 million per aircraft, the payback period would be correspondingly longer, as shown in Figure 6-1. In this specific example, at a replacement rate of 24 new aircraft per year, it would take the Air Force more than 17 yr to replace the 417 aircraft, and at 12 new aircraft per year, the time to replace would be 34.8 yr.
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From page 72... ...
Laminar flow nacelles should be considered as an option when re-engining aircraft that have pod-mounted nacelles. Airframe Modifications for Fuel Savings Unique to the C-130 Several modifications could result in fuel savings.
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From page 73... ...
OPTIMIZATION OF OPERATIONS Commercial airlines have been able to reap significant cost savings by optimizing their planning and operations. For example, United Parcel Service management credits an optimization-based plamning system for its aircraft network with having identified operational changes that had saved more than $87 million as of 2003, and it is anticipating additional savings of $189 million through 2014 (Armacost et al., 2004)
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From page 74... ...
By moving to a centralized operations center, each operational department within the airline is better able to understand and appreciate the impact of its decisions on downstream decisions and dependent activities. The development of the airline operations control center and the introduction of real-time decision support systems have enabled airlines to minimize flight cancellations and delays and ultimately improve operating profits (Clarke et al., 2000)
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From page 75... ...
On-wing condition and failures are being bound together in a holistic approach, whereby maintenance shops and maintenance on the line and away from the shops and the actual operating events are being slowly tied together. As the maintenance process evolves, it becomes easier to track more subtle deterioration such as fuel burn and aerodynamic degradation and not just pending mechanical failures.
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From page 76... ...
Mechanical Condition of the Aircraft A program must be developed that takes into account some of the systems that if not operating properly can adversely impact fuel burn. Some engine instrumentation, such as instruments measuring engine pressure ratio, requires accurate air data.
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From page 77... ...
If no such wash program exists, the committee recommends that one be introduced for the entire Air Force engine inventory. Engine Maintenance Programs Once the engine is in the shop, restoring its proper operating parameters is the goal.
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From page 78... ...
The Air Force should undertake a review of maintenance requirements and how they affect fuel efficiency and/or fuel conservation. Additionally, it should have in place an organizational structure that will have the focus and authority to establish maintenance requirements across all operations.
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From page 79... ...
· Only fly the flying hours required to accomplish mission requirements. Air Force flight plams often call for fixed mission durations.
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From page 80... ...
One airline executive claims such actions saved his airline more them 100 million gallons of fuel last year against a 2004 baseline. OTHER BENEFITS OF RE-ENGINING Operational Benefits The operational benefits and impacts of any gnen modification divide naturally into two categones: · Internal mission improvements, which result in directly calculable fuel savings on the same mission profile, and · Basing accessibility impacts, which can be translated into greater equivalent capability.
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From page 81... ...
OTHER CONSIDERATIONS 600 500 c, 400 o 300 200 100 o in 0 500 1 000 FIGURE 6-2 Scenario I—Southwest Asia.
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From page 82... ...
medium (7,000-9,000 ft) , suitable for moderately loaded and often even heavily loaded aircraft equipped with modern, higher thrust (generally higher-bypass-ratio)
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From page 83... ...
. CO2 emissions are directly related to fuel consumption, so that any fuel efficiency improvements directly reduce global warming.
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From page 84... ...
0. · O ~ ~ · · ~O , ,0 22 24 · O O CFMS6-7 · CFMS6-3 · CFMS6-2 · CFMS6-7bw 11 1~ O CFMS6-56/P emissions combustor O CFMS6-SC 1 1 1 1 1 26 28 30 32 34 Pressure ratio NOX is 80% of All Aircraft Engine Pollutants~ 'based on a tw n eng ne a ~crae 500 nm m ss on FIGURE 6-5 CFM56 envirommental NO~ emissions.
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From page 85... ...
2000. The development of the airline operations control center.
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From page 86... ...
"Quick-look study on technology options forimpreved air vehicle fuel efficiency," Presentahon to the committee on May 23, 2006. Jack O'Banion, DirectorofAirMobilityRequirements, Lockheed Ma tin Corporation, "C130 Re-engine discussion,"Presentation to the committee on May 23, 2006.
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