Improving the Efficiency of Engines for Large Nonfighter Aircraft (2007) / Chapter Skim
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4 TF33 Series Powered Aircraft
4 TF33 Series Powered Aircraft
Pages 40-54
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From page 40... ...
Since major overhauls account for most of the maintenance cost associated with engine ownership, the true cost to the Air Force of these modern engines may be less than their cost based on a standard cost-of-ownership estimate, which spreads the overall mainten;mce cost over the total operating hours. A second new consideration is the dramatic and rapid increase in the Air Force's overhaul cost for TF33 engines.
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From page 41... ...
The program utilized Boeing 707-320C (Air Force designation C-18) senes aircraft obtained in the commercial marketplace as they were being phased out by the major and secondary commercial carriers.
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From page 42... ...
In the early 1990s, an early deployment of the two full-scale-development JSTARS aircraft during Operation Desert Storm demonstrated the operational effectiveness of the weapons system; however, a number of areas were identified that would need significant improvements in aeronautical performance to meet the original Operation Desert Storm requirements and to gain maximum utility from the E-8 system. The main areas identified were these: · Reduced takeoff distances at maximum weight under military flight rules.
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From page 43... ...
These older engines are resulting in low mission-capable rates, the highest in-flight engine shutdown rate of all nonfighter aircraft, and a spiraling increase in engine depot costs. Demand by theater commanders for the aircraft continues to grow, raising senous concerns about flight safety and reliability (see Figures 4-2 and 4-3 for E-8 JSTARS data)
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From page 44... ...
Since FY03 the depot cost for TF33 engine overhaul has increased by 300 percent, to $1.25 million per engine. With the increasing tempo JT3D in-Flight Shutdowns Nearly 70 X New Engine Rate 045 0.4 _ 0.35 0.3 _ 0.25 _ 0.2 0.15 0.1 _ 0.05 _ O _ Failure Rates Exceed Resupply Spare Engines (RFI)
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From page 45... ...
E-3 AWACS PLATFORM The AWACS aircraft can also be traced to the commercial Boeing 707-320B advanced passenger model that was produced at the end of the Boeing 707 production run. These aircraft had some of the same structural characteristics as the B 707-320C combi/cargo variation that was used as the input aircraft for the JSTARS program.
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From page 46... ...
Other modifications that eliminate line replaceable units like analog gauges, older autopilots, and flight director systems or that add capability like digital displays, data links, and improved navigation systems seem to find their way into the re-engining program. As it has done ~ 'I Am_ FIGURE 4-6 U s E3-C AWACS powered by P&W TF33- 100 engines SOURCE Air Force.
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From page 47... ...
TF33 SERIES POWERED AIRCRAFT -, ~ ;~' ~~ r FIGURE 4-6 NATO ERA AWACS powered by P&W TF33- 100 engines.
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From page 48... ...
The studies reached similar conclusions: Newer commercially available engines offer significant fuel savings; a re-engining program would be very expensive, more than can be justified by fuel savings alone; and significant improvements in operational employment and performance cam be expected. However, all these previous life-cycle studies significantly underestimated the increase in costs for both TF33 repair at the depot and fuel.
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From page 49... ...
Like the other TF33-powered Air Force platforms, re-engining the B-52 would reduce both fuel and maintenance costs as well as provide operational benefits such as access to shorter runways, higher takeoff weights at high ambient temperatures, and longer range and endurance. Reduced dependence on foreign oil, improved operational capabilities, and enhanced Global Power projection are important considerations that should be taken into account in the decision to proceed or not proceed with a re-engining program for the B-52.
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From page 50... ...
Figure 4-9 depicts the various modifications made to the KC-135A that accommodated the CFM56 engine and allowed increasing the maximum gross weight of the aircraft from 301,000 lb to 322,500 lb. Although no modification was required for putting on the new CFM56 engines, the landing gear and nose wheel steering were modified, allowing an increased gross weight, which in turn allowed the Air Force to utilize the full capacity of the integral fuel tanks.
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From page 51... ...
. ~ of_, CFM56 Engine · New Engine Buildup · Turbine Engine Monitor system · New Fire Detection and Extinguishing System · New Electrical Power Generation System · 27 percent improvement in fuel efficiency, · 98 percent reduction in noise area impacted during takeoffs, and · 20 percent reduction in critical field length at increased takeoff weight.
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From page 52... ...
The latest, sent to this committee in June 2006, estimated start-up costs of approximately $25 million and recurring costs of $33 million per aircraft. The KC-135R does offer significant improvements in reliability, maintenance, and operational performance over the KC-135E with TF33-PW102 engines: · 18 percent reduction in specific fuel consumption, · 20 percent improvement in critical field length, · 25 percent improvement in time to climb, and · 20 percent improvement in fuel offload.
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From page 53... ...
Several candidate engines have attributes that could contribute to significant fuel savings and reduced maintenance costs. Finding 4-9.
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From page 54... ...
Rafael Garcia, B-52 Systems Program Office, Tinker Air Force Base, "B-52 re engine study," Presentation to the committee on April 26, 2006. Michael O'Grady, Joint STARS Re-Engining Program Manager, "Joint STARS re-engining:'Presentation to the committee on May 24, 2006.
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