The research reported here was sponsored by the United States Air Force under Contract F49462-01-C-0003. Further information may be obtained from the Strategic Planning Division, Directorate of Plans, Hq USAF. Library of Congress Cataloging-in-Publication Data Younossi, Obaid, 1961– Military airframe costs : the effects of advanced materials and manufacturing processes / Obaid Younossi, Michael Kennedy, John C. Graser. p. cm. “MR-1370.” Includes bibliographical references. ISBN 0-8330-3036-1 1. Airframes—Design and construction—Costs. 2. Airplanes, Military—United States—Costs. I. Kennedy, Michael, 1949– II. Graser, John C. III. Title. TL671.6 .Y68 2001 358.4'183—dc21 2001048132 RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND® is a registered trademark. RAND’s publications do not necessarily reflect the opinions or policies of its research sponsors. © Copyright 2001 RAND All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from RAND. Published 2001 by RAND 1700 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138 1200 South Hayes Street, Arlington, VA 22202-5050 201 North Craig Street, Suite 102, Pittsburgh, PA 15213 RAND URL: http://www.rand.org/ To order RAND documents or to obtain additional information, contact Distribution Services: Telephone: (310) 451-7002; Fax: (310) 451-6915; Email: [email protected] PREFACE This is one of a series of reports from the RAND Project AIR FORCE project entitled “The Cost of Future Military Aircraft: Historical Cost Estimating Relationships and Cost Reduction Initiatives.” The pur- pose of the project is to improve cost-estimating tools available for projecting the cost of future weapon systems. It focuses on how re- cent technical, management, and government policy changes affect cost. This report discusses the effects of airframe material mix and manufacturing techniques on airframe costs, emphasizing the effect of new manufacturing techniques. It also presents statistical analy- ses of a new airframe historical cost data set, MACDAR, which is owned by the Air Force Cost Analysis Agency (AFCAA). This project was requested by Lieutenant General George K. Muellner, SAF/AQ, now retired. The current sponsor is Lieutenant General Stephen B. Plummer, SAF/AQ. The project technical points of contact have been John Dorsett, former Technical Director of AFCAA, and Jay Jordan, current Technical Director of AFCAA. The information collection cutoff date was 2000. The report should be of interest to the cost analysis community, the military aircraft acquisition community, and acquisition policy pro- fessionals generally. PROJECT AIR FORCE Project AIR FORCE, a division of RAND, is the Air Force federally funded research and development center (FFRDC) for studies and iii iv Military Airframe Costs analysis. It provides the Air Force with independent analyses of pol- icy alternatives affecting the development, employment, combat readiness, and support of current and future aerospace forces. Research is performed in four programs: Aerospace Force Development; Manpower, Personnel, and Training; Resource Management; and Strategy and Doctrine. CONTENTS Preface ......................................... iii Figures ......................................... ix Tables.......................................... xi Summary ....................................... xiii Acknowledgments................................. xvii Acronyms ....................................... xxi Chapter One INTRODUCTION .............................. 1 Background and Purpose ........................ 1 Relation to Previous Work ........................ 2 How This Report Is Organized ..................... 5 Chapter Two MATERIAL CHARACTERISTICS .................... 7 Background and Historical Perspective .............. 7 What Are Composite Materials, and Why Are They Used in Producing Aircraft? ....................... 7 Why Aren’t All Metal Parts Replaced by Composites? ... 8 Material Properties Defined ....................... 15 Specific Material Properties ....................... 19 Composite Materials ............................ 19 Reinforcing Material .......................... 20 Matrix Materials.............................. 23 Thermoset Matrices ........................... 23 Thermoplastic Materials ....................... 24 v vi Military Airframe Costs Combining Reinforcement and the Matrix: The Composite Material ......................... 26 Advantages of Composite Materials in Airframe Applications .............................. 29 Weight Versus Strength and Stiffness .............. 29 Directionality of Strength and Stiffness ............. 30 Composite Part Design Issues ................... 31 Part Complexity and Design Automation ........... 31 Composite Unitization ......................... 33 Other Considerations in Using Composites ........... 34 Knowledge Base for Composite Materials ........... 34 Failure Modes ............................... 35 Tooling .................................... 36 Nondestructive Inspection and Test (NDI/T) ........ 37 Metals....................................... 38 Aluminum .................................. 38 Titanium ................................... 39 Steel ...................................... 39 Chapter Three MANUFACTURING TECHNIQUES ................. 41 Composite Manufacturing Techniques .............. 41 Hand Layup................................. 42 Automation in Hand Layup ..................... 44 Automated Fiber Placement ..................... 44 Resin Transfer Molding ........................ 47 Other Current Composite Manufacturing Techniques .. 49 Possible Future Manufacturing Techniques ......... 50 Metal Manufacturing Techniques .................. 51 Conventional Processes ........................ 51 High-Speed Machining of Aluminum .............. 53 High-Performance Machining of Titanium .......... 53 Hot Isostatic Press Investment Casting of Titanium .... 53 Laser Forming of Titanium ...................... 54 Chapter Four AIRFRAME COST INFORMATION .................. 55 Revisiting the Resetar, Rogers, and Hess Study ......... 55 Current Study Results: Aggregate Airframe Data by Functional Labor Category .................... 58 Nonrecurring Engineering ...................... 59 Contents vii Nonrecurring Tooling ......................... 60 Recurring Engineering ......................... 61 Recurring Tooling ............................ 62 Recurring Manufacturing ....................... 63 Recurring Quality Assurance .................... 64 Comparison to 1980s Survey Results ................ 65 Current Study Results: Part-Level Data by Materials, Manufacturing Process, and Part Geometric Complexity ............................... 69 Part Geometric Complexity ..................... 70 Methodology ................................ 71 Results .................................... 73 Cost Improvement Slopes ........................ 76 Weight-Sizing Slopes ............................ 77 Material Costs ................................. 78 Raw Material Costs ........................... 78 Buy-to-Fly.................................... 81 Chapter Five AIRFRAME COST-ESTIMATING METHODOLOGY ...... 83 Application of Survey Cost Ratios to CERs ............ 83 Statistical Analysis of the Recurring Costs of Recent Fighters .................................. 86 The MACDAR Database ........................ 86 “Stylized Facts” .............................. 87 Statistical Results ............................. 89 Chapter Six APPLYING THE RESULTS ........................ 97 Applying the Survey Cost Ratios .................... 97 Applying the Part-Level Data ...................... 99 Comparison of Airframes Manufactured Using Traditional Techniques with Those Using Advanced Techniques ............................... 100 Cost Ratios in the 2000s: Optimistic and Pessimistic Projections ............................... 104 Cost-Estimating Considerations for Airframe Stealth Requirements ............................. 106 Lean Manufacturing and Acquisition Reform .......... 107 Conclusion ................................... 109 viii Military Airframe Costs Appendix A. STRESS-STRAIN DIAGRAM ................... 111 B. AIRCRAFT WEIGHT DEFINITIONS ............. 113 C. AIRCRAFT WORK BREAKDOWN STRUCTURE (WBS) LEVELS (FROM MILITARY SPECIFICATION 881) ... 115 D. AIRFRAME DEVELOPMENT COST-ESTIMATING RELATIONSHIPS ........................... 127 E. SUBJECTS OF THE THREE RAND STUDIES ON INDUSTRY INITIATIVES DESIGNED TO REDUCE THE COST OF PRODUCING MILITARY AIRCRAFT .. 129 Bibliography ..................................... 133 Recommended Readings ............................ 139 FIGURES 2.1. History of Aircraft Composite Use ............... 9 2.2. A Comparison of the Percentage of Composites Used in the Initial Configuration with the Current Configuration of Some Military Airframes ......... 10 2.3. History of Titanium Use ...................... 11 2.4a. F/A-18E/F Substructure Material Use ............ 12 2.4b. F/A-18E/F Composite Use As Compared to the F/A-18C/D ................................ 12 2.4c. F/A-18E/F Overall Material Use ................. 13 2.5. B-2 Overall Material Use ...................... 13 2.6. F-117 Overall Material Use .................... 14 2.7. F-22 Overall Material Use ..................... 14 2.8. V-22 Overall Material Use ..................... 15 2.9. Carbon