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Improving the Efficiency of Engines for Large Nonfighter Aircraft (2007)

Chapter: Appendix F Background Information on Re-engining the C-130

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Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
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Appendix F
Background Information on Re-engining the C-130

This appendix contains some of the information and analysis used in preparing the section on re-engining the C-130 in Chapter 3 of this report.

ENGINE OPTIONS AND ECONOMICS

The acquisition and support options for retrofitting the engines and props on selected C-130 aircraft range from, on the one hand, conventional military competitive purchase of engineering services and hardware and maintenance and support using indigenous assets to, on the other hand, full operating lease arrangements in which equipment is contractor owned and supported. A review of current military practices for acquiring propulsion systems in this class of aircraft indicates that a hybrid approach may be most suitable for some of the re-engining options reviewed here. For example, the engines for the V-22 and C-130J aircraft are purchased in the normal way and the engines are supported on an operating-time basis, with a contractor supplying labor and service for parts (Freestone, 2006). This approach is representative of current commercial practices in the civil airline business and is now also favored by the military services.

Evaluating the impact of savings associated with such maintenance contracting approaches is beyond the scope of this review since a portion of the savings comes from reducing the government payroll and relief from inventory and logistic requirements. The economic evaluations shown here are therefore based on conventional hardware and engineering service procurement and fuel savings. In addition to straightforward hardware purchase arrangements it may be possible to negotiate trading in the existing T56 engines, which have residual value in the marketplace. Such an arrangement was used in past Army engine upgrade programs. Also, no attempt has been made to evaluate the possible effect of eliminating a portion of the fleet and staffing requirements, which can result from increased aircraft performance, in turn a consequence of the reduced fuel consumption and improved operational capability offered by a re-engined fleet.

The first-order financial component of retrofit development, hardware acquisition, and fuel savings

Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×

is shown in Table F-1. Note that the engine cost data shown here were supplied by the contractors and have not been through any form of procurement verification.

A financial analysis using the information in Table F-1 and the cost assumptions shown in Table F-2 produce the cash flow trends shown in Figure F-1. The trends indicate that the most affordable option is an upgrade of the existing T56; the second most affordable is a retrofit with an existing derivative of the T56. The new AE 2100 is the least affordable based on the comparisons of maximum negative cash flow and payback time.

However a focus on fuel savings relative to re-engining investment (Table F-3) indicates that the new engine option provides the greatest fuel savings for an initial investment. The financial analysis shown here is extracted from a single study to provide consistency (Egbert and York, 2006). That study did not include the PW150, but it should be noted that this engine offers an attractive alternative to the AE 2100 in that the engine is of approximately the same power level and is somewhat less expensive

TABLE F-1 Components of Financial Evaluationa

Costs

T56/S3.5

T56/A427

AE 2100

PW150

Engine costs

0.433

0.753

1.0

0.965

Propeller costs (million $)

0.225

0.225

0.250

0.250

Nonrecurring costs of the re-engining (thousand $)

50

17

30

70

Nonrecurring costs of modifying the airframe (thousand $)

10

15

15

25b

Annual fuel savings (million gal)

8

13

28

27

aEngine costs for the AE 2100 were provided from an average of contractor-provided data; costs for the other engines were calculated using the percentages in Egbert and York (2006). They are expressed here as relative to avoid the use of proprietary data; other costs and the fuel savings are from Egbert and York (2006) or other contractor data.

bCommittee estimate.

FIGURE F-1 Cash flow for C-130 re-engining options. SOURCE: Rolls-Royce.

Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×

TABLE F-2 Cost Assumptions

 

Base

 

 

Fuel burn/hr/engine (gal)

200

 

 

Fuel cost per gallon ($)

2.20

 

 

Maintenance cost/engine flight hour ($)

239

 

 

No. of aircraft

267

 

 

Annual flight hours

469

 

 

Normal overhaul (hours on wing)

2,426

 

 

 

T56-S3.5

T56-A427

AE 2100

Upgraded fleet

 

Fuel saving (%)

8

13

28

Maintenance savings (%)

30

40

50

Kit cost/engine (relative)a

0.5

0.67

1.00

Relative cost (%)

50

67

100

Program costs (million $)

 

 

 

Engine development

50

17

30

Flight qualification

5

10

10

Production preparation

5

5

5

Support preparation

2

2

2

Financial assumptions (%)

 

 

 

Discount rate

7

7

7

Fuel cost escalation

5

5

5

Maintenance escalation

5

5

5

Key output data (discounted $)

 

 

 

Upgrade rate (%)

19

19

19

Fuel saved (million gal)

111

181

390

Investment (million $)

187

351

743

Fuel cost savings (million $)

204

331

714

Maintenance savings (million $)

416

554

693

Net present value (million $)

432

535

664

Max negative cashflow (million $)

(109)

(203)

(503)

aCosts are expressed here as relative to avoid the use of proprietary data.

SOURCE: Rolls-Royce.

TABLE F-3 Fuel Savings Relative to Investments

 

T56-S3.5

T56-A427

AE 2100

PW150

Annual fuel savings (million $)

8.04

13.06

28.13

27

Fuel savings (gal/yr/million $ [nonrecurring cost])

140,992

384,100

598,467

280,000

SOURCE: Egbert and York (2006).

Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×

and lighter than the AE 2100 (Croswell, 2006). The fuel consumption rate of the PW150 is slightly higher than that of the AE 2100. A more detailed study including installation, operational, and financial analysis is needed to make a selection between these two candidates.

REFERENCES

Unpublished

Bennett Croswell, Vice President for Military Development Programs, Pratt & Whitney, “Pratt & Whitney presentation,” Presentation to the committee on May 24, 2006.

Norm Egbert, Vice President for Engineering and Technology, and Ron York, Vice President for Special Projects, Rolls-Royce, “Rolls-Royce presentation,” Presentation to the committee on May 24, 2006.

Paul Freestone, Vice President and Customer Business Executive, Rolls-Royce, “Commercial airlines business transactions,” Presentation to the committee on June 13, 2006.

Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×
Page 165
Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×
Page 166
Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×
Page 167
Suggested Citation:"Appendix F Background Information on Re-engining the C-130." National Research Council. 2007. Improving the Efficiency of Engines for Large Nonfighter Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/11837.
×
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Because of the important national defense contribution of large, non-fighter aircraft, rapidly increasing fuel costs and increasing dependence on imported oil have triggered significant interest in increased aircraft engine efficiency by the U.S. Air Force. To help address this need, the Air Force asked the National Research Council (NRC) to examine and assess technical options for improving engine efficiency of all large non-fighter aircraft under Air Force command. This report presents a review of current Air Force fuel consumption patterns; an analysis of previous programs designed to replace aircraft engines; an examination of proposed engine modifications; an assessment of the potential impact of alternative fuels and engine science and technology programs, and an analysis of costs and funding requirements.

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