January 2014 

NASA/CR–2014-218149 

PRSEUS Panel Fabrication 

Final Report 

Kim A. Linton, Alexander Velicki, Krishna Hoffman, Patrick Thrash, 

Robert Pickell, and Robert Turley 

The Boeing Company, Huntington Beach, California 
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Space Administration 

Langley Research Center Prepared for Langley Research Center 

Hampton, Virginia 23681-2199 under Contract NNL13AA11C 

 

January 2014 

NASA/CR–2014-218149 

PRSEUS Panel Fabrication 

Final Report 

Kim A. Linton, Alexander Velicki, Krishna Hoffman, Patrick Thrash, 

Robert Pickell, and Robert Turley 

The Boeing Company, Huntington Beach, California 
Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320

443-757-5802 

Acknowledgments 

Acknowledgment is also made to the following individuals at NASA LaRC, Ms. Dawn 

Jegley, Mr. Marshall Rouse, and Mr. Andrew Lovejoy for their technical support. 

The use of trademarks or names of manufacturers in this report is for accurate reporting and does not constitute an 

official endorsement, either expressed or implied, of such products or manufacturers by the National Aeronautics 

and Space Administration.
FOREWORD 

This document summarizes work performed by The Boeing Company, through its Boeing 

Research & Technology group located in Huntington Beach, California under the 

Environmentally Responsible Aviation (ERA) Project. This report documents the work that was 

performed to fabricate several large integrated stitched panels and associated hardware, which 

would ultimately be used to assemble a combined loads fuselage test section to validate the 

feasibility of a future Hybrid Wing Body (HWB) pressure cabin. 

The NASA technical monitor was Dawn Jegley of the Structural Mechanics and Concepts 

Branch, NASA Langley Research Center. 

i
THIS PAGE INTENTIONALLY LEFT BLANK 

ii
TABLE OF CONTENTS 

FOREWORD .............................................................................................................................. i

ACRONYMS ........................................................................................................................... vii

Introduction ................................................................................................................................. 1

1.0 Panel Fabrication ............................................................................................................. 2

1.1 Stringer Preform Fabrication ....................................................................................... 2

1.2 Cap Fabrication ............................................................................................................ 6

1.3 Pultruded Rod Preparation ........................................................................................... 8

1.4 Frame Fabrication ...................................................................................................... 11

1.5 Crown Panel ............................................................................................................... 16

1.6 Floor Panel Fabrication .............................................................................................. 37

1.7 Outer Rib Panel Fabrication ....................................................................................... 45

1.8 Upper Bulkhead Panel Fabrication ............................................................................ 51

1.9 Upper/Lower Center Rib Panel Fabrication ............................................................... 60

1.10 Lower Bulkhead Panel Fabrication ............................................................................ 64

2.0 Metallic Fittings ............................................................................................................. 70

3.0 Panel Hardware ............................................................................................................. 76

iii
LIST OF FIGURES 

Figure 1. HWB Large-Scale Test Article Configuration ................................................................. 1

Figure 2. Metallic Fittings Required for the MBB Assembly ......................................................... 2

Figure 3. Nested Flat Patterns for Stringer Preforms CNC Cut from Multi-Axial Carbon Fiber 

Fabric ....................................................................................................................................... 3

Figure 4. Leader Wire with Adapter Positioned Over Stringer Flat Pattern ................................... 4

Figure 5. Stringer Flat Pattern Folded Over Leader Wire ............................................................... 4

Figure 6. Stringer Preform on Gantry Style Sewing Machine ........................................................ 5

Figure 7. Insertion of Stitch Seam into Stringer Web ..................................................................... 5

Figure 8. Completed Stringer Preforms with Leader Wire in a Poly Bag ....................................... 6

Figure 9. Nested Flat Patterns for Crown Panel Cap Preform ........................................................ 6

Figure 10. Stitching of Crown Panel Cap Web on the Gantry Sewing Machine ............................ 7

Figure 11. Rough Cutting of a Pultruded Carbon Fiber Epoxy Rod to Length ............................... 8

Figure 12. Removal of Fillet Feature from End of Rod Using Abrasive Sanding Disk .................. 9

Figure 13. Drilling of Rod End to Accept Nylon Set Screw for Mounting of Leader Wire Adapter

 ................................................................................................................................................. 9

Figure 14. Grit Blasting of Rod to Prepare Outer Surface for Bonding ........................................ 10

Figure 15. Prepared Rods Ready for Deionized Water Rinse and Water Break Test ................... 10

Figure 16. Foam Core Details are N/C Machined and then Stored in Controlled Packaging ....... 11

Figure 17. Frame Core Details are Located Using an Assembly Template .................................. 12

Figure 18. Foam Core Rework was Required to Bring the Stringer Key Hole Locations within 

Tolerance ............................................................................................................................... 13

Figure 19. Frame Web Doublers Added at Rod Pass-Through Locations .................................... 14

Figure 20. Wooden Assembly Tool Used to Attach Fabric to Foam Core ................................... 15

Figure 21. Completed Frame Lifted from the Frame Assembly Tool ........................................... 15

Figure 22. Panel Preform Details Prior to Assembly .................................................................... 16

Figure 23. Crown Panel Stitch Tool Preparation and Checkout ................................................... 17

Figure 24. Loading Preform Details into Stitching Tool ............................................................... 17

Figure 25. Single-Sided Stitching of Crown Panel Preform Started ............................................. 18

Figure 26. Completed Crown Panel Preform Stitching ................................................................. 19

Figure 27. Stitch Tool Rotation with Preform ............................................................................... 19

Figure 28. Stitch Tool and Preform Placed onto Cure Tool .......................................................... 20

Figure 29. Removal of Stitch Tool Foam Blocks and Wood Frame Tooling Details ................... 20

Figure 30. Self-Supporting Crown Panel Preform Placed on the Cure Tool ................................ 21

Figure 31. Preform Preparation on Cure Tool ............................................................................... 22

Figure 32. Under Bag IML Tool Details Located ......................................................................... 22

Figure 33. Pleating Operation for Primary Bag Installation .......................................................... 23

Figure 34. Secondary Bag is added to Maintain Vacuum Integrity during Infusion and Cure ..... 23

Figure 35. Part is Transferred and Loaded into Oven ................................................................... 24

Figure 36. Automated Infusion Equipment Used for Resin Infusion ............................................ 25

Figure 37. Infusion and Initial Cure Completed ............................................................................ 26

Figure 38. Bag and Tool Removal Prior to Post Cure ................................................................... 26

Figure 39. Final Cured Crown Panel Read for Edge Machining .................................................. 27

Figure 40. Thermal Expansion of Caul Sheets Caused Mark-off on the Crown Panel OML ....... 28

Figure 41. Schematic of Groove Location and Depth Measurements ........................................... 29

iv
Figure 42. Perforated Caul Sheets from Crown Panel Infusion (Revised for Subsequent Panels)

 ............................................................................................................................................... 29

Figure 43. Repair Technique and Validation Approach ................................................................ 30

Figure 44. Repair Patch Laminate Architecture Created Using Warp-Knit Fabrics ..................... 31

Figure 45. Precured Patch Overlap and Edge Taper Dimensions ................................................. 31

Figure 46. Coupon Testing Used to Validate Repair Design and Processes ................................. 32

Figure 47. Dry Fabric Lay-up Used to Create Precured Patches ................................................... 33

Figure 48. Patches were Infused and Cured in an Oven and then an Adhesive Layer was Applied

 ............................................................................................................................................... 33

Figure 49. Crown Panel OML Surface Prepared for Repair ......................................................... 34

Figure 50. Bonding Surfaces were Prepared and Reading for Repair Patches .............................. 34

Figure 51. Precured Repair Patches were Taped into Position Prior to Applying the Vacuum Bag

 ............................................................................................................................................... 35

Figure 52. Bagged Crown Panel with IML-side Up and Repair Patches Taped to the OML ....... 35

Figure 53. Region of Bonded Repair Patches Shown on OML .................................................... 36

Figure 54. Completed Bonded Repair Patches on Crown Panel OML ......................................... 36

Figure 55. Completed Floor Panel Stitched Preform .................................................................... 37

Figure 56. Integral Cap Tooling Plate Installation ........................................................................ 38

Figure 57. Bagging Aids on Frames and Stringers ........................................................................ 38

Figure 58. New Pre-Conditioned Vacuum Bag Delivery Packaging ............................................ 39

Figure 59. Added Lanyards to Support Bag During Unrolling Operation .................................... 40

Figure 60. IML Vertical Plate Corners were Tearing the Bagging Film ....................................... 41

Figure 61. Primary Bag Installed and Leak Checked .................................................................... 42

Figure 62. Secondary Bag Installed and Leak Checked ................................................................ 42

Figure 63. Floor Panel Preform Placed in Oven Ready for Heat-up, Infusion, and Cure ............. 43

Figure 64. Post Cured Part Prior to Bag Removal ......................................................................... 43

Figure 65. Cured Floor Panel ........................................................................................................ 44

Figure 66. Floor Panel IML and OML Cured Part Surfaces ......................................................... 44

Figure 67. Outer Rib Preform Assembly – Frame Installation ..................................................... 45

Figure 68. Outer Rib Preform Assembly – Frames and Stringers Installed .................................. 46

Figure 69. Outer Rib Preform Assembly – Stitching Complete .................................................... 46

Figure 70. Two Outer Rib Preforms were Fabricated Simultaneously ......................................... 47

Figure 71. IML Tooling Placed on Preform .................................................................................. 47

Figure 72. Bagged Outer Rib Panel During Vacuum Check ......................................................... 48

Figure 73. First Untrimmed Cured Outer Rib Panel - IML and OML Surfaces ........................... 48

Figure 74. Second Untrimmed Cured Outer Rib Panel - IML and OML Surface ........................ 49

Figure 75. Trimming the Outer Rib Panel ..................................................................................... 49

Figure 76. Finished Outer Rib Panel – OML Surfaces ................................................................. 50

Figure 77. Finished Outer Rib Panel – IML Surfaces ................................................................... 50

Figure 78. Additional Core Butt Splices Required to Adjust the Stringer Cutout Positions ......... 51

Figure 79. Frame Installation on First Upper Bulkhead Panel ...................................................... 52

Figure 80. Integral Cap Stacks at Panel Floor Line Installed ........................................................ 52

Figure 81. Integral Cap Features Installed .................................................................................... 53

Figure 82. Integral Cap Features Installed and Folded Down ....................................................... 54

Figure 83. Upper Bulkhead Stringer Stacks Inserted into the Stitching Tool ............................... 54

Figure 84. 30-ft Rods were Inserted into the Preform ................................................................... 55

Figure 85. All Stringer Rods Installed in Preform ........................................................................ 55

Figure 86. Tear Straps Placed First, Followed by Skins and Skin Stack Splices .......................... 56

v
Figure 87. First Upper Bulkhead Panel Stitching Completed ....................................................... 56

Figure 88. Transferring the Upper Bulkhead Panel Preform onto the Cure Tool ......................... 57

Figure 89. IML Cure Tooling Located on the Upper Bulkhead Panel .......................................... 57

Figure 90. Upper Bulkhead Panel Preform Fully Bagged and Ready for Infusion ....................... 58

Figure 91. Cured Upper Bulkhead Panel Ready for Trim ............................................................. 58

Figure 92. Upper Bulkhead Loaded on the Shipping Cart ............................................................ 59

Figure 93. Upper Bulkhead Panel Trimming ................................................................................ 60

Figure 94. Trimming Solid Laminate Core Details ....................................................................... 61

Figure 95. Precured Facesheets Trimmed Net Plus 0.060-inch for Final Trimming .................... 62

Figure 96. Dry Fit of the Separate Details Prior to Bonding ......................................................... 63

Figure 97. Tooling Pins Held the Details Together During Bonding ............................................ 63

Figure 98. Drill Template was Fabricated to Drill DA Holes on the Panels ................................. 63

Figure 99. Upper Center Rib Panel Completed by Vendor ........................................................... 64

Figure 100. Preform Assembly Starts with the Inserting the Frames and then the Stringers ........ 65

Figure 101. Flanges are Folded Down then Tear Straps and Doublers are Added ....................... 65

Figure 102. Skin Splice Geometry ................................................................................................ 66

Figure 103. IML Skin Splice Straps are Located on the Preform Assembly ................................ 66

Figure 104. Lower Bulkhead Skin Splice ...................................................................................... 67

Figure 105. Lower Bulkhead Preform Stitching Complete ........................................................... 67

Figure 106. IML Cure Tool Positioned on the Preform ................................................................ 68

Figure 107. Vacuum Bagging Complete Ready for Transporting the Assembly to the Oven ...... 69

Figure 108. OML and IML Surfaces of the Cured Lower Bulkhead Panel Prior to Trimming .... 69

Figure 109. Increasing the Fuselage Length by 14 Times would only Increase the Number of 

Fittings by 3 Times ................................................................................................................ 70

Figure 110. Typical Mid Fuselage Fitting Arrangement without the Pressure Bulkheads and Load 

Introduction Fittings .............................................................................................................. 71

Figure 111. Fittings were Stored on Shelves in the MBB Assembly Area ................................... 76

Figure 112. Fasteners Required to Assemble the Multi-Bay Box for Different Technologies 

(State-of-the-Art Aluminum, State-of-the-Art Graphite Epoxy, and PRSEUS) ................... 76

Figure 113. Fastener Cage at the Multi-Bay Box Assembly Site .................................................. 87

LIST OF TABLES 

Table 1. List of Machined Fittings Ordered for the MBB Assembly ............................................ 71

Table 2. Fastener Ordered for the MBB Assembly ....................................................................... 77

vi
ACRONYMS

BHD Bulkhead 

CAPRI Controlled Atmospheric Pressure Resin Infusion 

DA Determinate Assembly 

DMS Douglas Material Specification 

ERA Environmentally Responsible Aviation 

HWB Hybrid Wing Body 

IML Inner Moldline 

MBB Multi-Bay Box 

NDI Non Destructive Inspection 

OML Outer Moldline 

PRSEUS Pultruded Rod Stitched Efficient Unitized Structure 

SoA State of the Art 

vii
1

INTRODUCTION 

NASA created the Environmentally Responsible Aviation (ERA) Project to explore and 

document the feasibility, benefits and technical risk of advanced vehicle configurations and 

enabling technologies that will reduce the impact of aviation on the environment. A critical 

aspect of this pursuit is the development of a lighter, more robust airframe that will enable the 

introduction of unconventional aircraft configurations that have higher lift to drag ratios, reduced 

drag, and lower community noise. The primary structural concept being developed under the 

ERA program in the Airframe Technology element is the Pultruded Rod Stitched Efficient 

Unitized Structure (PRSEUS) concept. 

The PRSEUS design and fabrication approach is a conscious progression away from 

conventional laminated and bonded assemblies toward larger one-piece panel designs with 

seamless transitions and damage-arrestment features such as stitch rows and tear straps. It is a 

new structural concept that integrates skin, stringer, frame and cap elements into a single large 

panel assembly in which all elements are stitched and cured together. The resulting structure is a 

novel solution for addressing the demanding out-of-plane loading requirements inherent in the 

flat sided pressure cabin of the Hybrid Wing Body (HWB) airplane. 

The objective of the large multi-bay test article is to demonstrate that such a flat-sided structure 

is capable of withstanding bending and internal pressure loadings representative of a HWB

aircraft. The test article was designed primarily of PRSEUS cover panels, pressure bulkheads 

and floor structures that can be assembled into a double deck test article that measures 

approximately 30-ft wide, by 14-ft tall, and 7-ft deep (Figure 1). In this contract, the crown, 

floor, both upper bulkheads, both lower bulkheads, both outer ribs, both upper center ribs and 

both lower center ribs were fabricated as well as all of the fittings (Figure 2) required to 

assemble the Multi-Bay Box (MBB). All of the hardware (fasteners) required to assemble the 

MBB was also purchased. 

Figure 1. HWB Large-Scale Test Article Configuration
2

Figure 2. Metallic Fittings Required for the MBB Assembly

The work statement described within this report is a subset of a larger multi-year effort to design, 

fabricate, and test the Multi-Bay Box test article. The detail design, analysis and tool design for 

the MBB test article was completed under contract NNL04AA11B, task order NNL10AB00T in 

2011. Tooling was procured under contract NNL04AA11B, task orders NNL10AB00T and 

NNL11AA68T. Acceptance and nonconformance reports for the panels delivered under this 

contract were submitted to NASA in June and September 2013 and are not included in this 

report. 

1.0 Panel Fabrication 

This new design and manufacturing concept exploits the unique processing advantages inherent 

in dry warp-knit fabrics and the superior out-of-plane strength afforded by stitched laminates to 

effectively carry structural loads in multiple directions. The basic panel geometry has 24-inch 

frame pitch and 6-inch stringer spacing, with 0.052-inch thick skins in the center of the panel and 

gradually increases the thickness to the ends where the concentrated loads will be introduced 

during testing of the MBB. The MBB test specimen requires 15 composite panels. This contract 

provided 12 of the 15 panels for the MBB. 

1.1 Stringer Preform Fabrication 

Stringer preforms were fabricated for the eight PRSEUS panels of the MBB test article. Nested 

flat patterns were cut from 55-inch wide DMS2436, Type 1, Class 72 warp/knit multi-axial 

carbon fiber fabric using a Gerber CNC ply cutting table. The individual flat patterns were 

subsequently folded over a steel leader wire and placed inside a large assembly fixture to stitch. 

A CNC gantry style lock stitch sewing machine was used to insert two seams of stitching into the 
3

stringer web using Vectran 1200d thread. The first stitching seam was positioned at the apex of 

the fillet at the base of the stringer bulb feature. The second stitch seam was located at the apex 

of the fillet for the web-to-flange radius. With the flanges still laid out flat and the bulb feature 

collapsed the stringer preform was placed inside a polyethylene bag. Pictures in Figure 3 through 

Figure 8 show the stringer subassembly process. 

Figure 3. Nested Flat Patterns for Stringer Preforms CNC Cut from Multi-Axial Carbon Fiber Fabric
4

Figure 4. Leader Wire with Adapter Positioned Over Stringer Flat Pattern

Figure 5. Stringer Flat Pattern Folded Over Leader Wire
5

Figure 6. Stringer Preform on Gantry Style Sewing Machine

Figure 7. Insertion of Stitch Seam into Stringer Web
6

Figure 8. Completed Stringer Preforms with Leader Wire in a Poly Bag

1.2 Cap Fabrication 

Preforms for the cap components were produced in a similar fashion to the stringer details. Net 

flat pattern ply stack details were cut from 55-inch and 99-inch width multi-axial carbon fiber 

fabric (Figure 9) and placed inside a rectangular stitching frame located over the open bed of a 

gantry style stitching machine. The first stitch row at the base of the cap web goggled up to 

account for the additional thickness of the stringer flange and tear strap. All of the remaining 

stitches were all straight and parallel spaced 1⁄2-inch apart (Figure 10). 

Figure 9. Nested Flat Patterns for Crown Panel Cap Preform
7

Figure 10. Stitching of Crown Panel Cap Web on the Gantry Sewing Machine
8

1.3 Pultruded Rod Preparation 

The PRSEUS panels of the MBB test article utilized a pultruded carbon fiber epoxy rod in the 

top of the bulb shaped stringers. The rod is pre-cured and subsequently bonded to the carbon 

fabric of the stringer surrounding it in-situ with resin infusion processing of the panel dry fiber 

preform. The pultruded rods were manufactured by Lawrie Technologies in Girard, PA. using 

Applied Poleramic Inc. PUL6 epoxy resin system and standard modulus GRAFIL 34-700WD 

carbon fibers. Preparation of the rod began with a post-cure cycle in an oven at 350°F for two 

hours. The rods were then cut to length using an abrasive cut-off wheel mounted on a portable 

power tool. The fillet feature was then abrasively removed from approximately 0.5 inches at the 

end of the rod to enable insertion of the rod into pockets created at the top of the stringer 

preform. A hole was drilled axially in one end of the rod and a nylon set screw installed for 

subsequent attachment of an adapter to connect the rod to the metal wire leader inside the 

stringer preform. The outer surface of the rod was prepared via grit blasting and rinsed with 

deionized water. A water break test was then performed to verify the surface was properly 

prepared for bonding. The rods were dried inside an oven and subsequently wrapped in craft 

paper to minimize moisture absorption. The prepared rods were ultimately packaged inside a 

heat sealed poly bag and forwarded to the panel preform assembly jig for installation into the 

stringer preforms. Pictures in Figure 11 through Figure 15 depict the key steps in the process. 

Figure 11. Rough Cutting of a Pultruded Carbon Fiber Epoxy Rod to Length
9

Figure 12. Removal of Fillet Feature from End of Rod Using Abrasive Sanding Disk

Figure 13. Drilling of Rod End to Accept Nylon Set Screw for Mounting of Leader Wire Adapter
10

Figure 14. Grit Blasting of Rod to Prepare Outer Surface for Bonding

Figure 15. Prepared Rods Ready for Deionized Water Rinse and Water Break Test
11

1.4 Frame Fabrication 

From the outset of the program, it was well understood that maintaining the dimensional stability 

of the Rohacell foam over its 30-ft length in the shop air assembly environment would be 

difficult. To mitigate this concern, a 30-ft test piece was conditioned, machined and then 

delivered back to Boeing where it was dimensionally inspected to verify that the new machining 

and handling processes developed for these details would in fact produce a part with the intended 

dimensional tolerances. Once this was accomplished, several key aspects of the new approach 

that differed from conventional foam machining practices were identified. They were 

documented in the overall foam core procurement package that would be completed by the 

Evonik Company. 

Prior to machining, the foam blanks were conditioned in ambient shop air for four weeks at the 

Stitching Center at Huntington Beach to stabilize their moisture content. They were then shipped 

to Evonik in Alabama for the shaping operations before being sent back to Boeing in 

environmentally controlled bags (Figure 16). 

Figure 16. Foam Core Details are N/C Machined and then Stored in Controlled Packaging
12

Solid fiberglass core details were used at all fitting locations to react the clamp-up forces created 

by the fasteners. These details were purchased from a local vendor and then joined with the foam 

core pieces to create the frame core subassemblies (Figure 17). The details were located and 

checked by a tooling template with pins placed at each stringer key hole location. The template 

also served as a bonding jig. 

Figure 17. Frame Core Details are Located Using an Assembly Template

It was during this rigging step, the dimensional tolerance between the stringer key holes in the 

foam was discovered to be out of tolerance on a cumulative basis, so that the last cutout at either 

end of the 30-ft section was off by as much as 0.25-inch (Figure 18). After a thorough review 

with the vendor, it was discovered that the machining feed rates and cutting sequence were 

modified (without notifying Boeing) to reduce the overall machining time. These changes resulted 

in excessive foam growth that was not present in the original process check-out test article. 

With all of the foam details delivered, the decision was made to remove slices of the core to bring 

the stringer locations back into tolerance. Although the number of slices differed from frame to 

frame, typically about a dozen slices were required to achieve drawing tolerances on the longer 

frame subassemblies. All of the frame details were reworked in this fashion and then bonded back 

together to maintain the proper stringer key hole spacing. 
13

Figure 18. Foam Core Rework was Required to Bring the Stringer Key Hole Locations within 

Tolerance

The final step in completing the core subassemblies was the addition of local web doublers that 

were placed into machined recesses on both sides of the core (Figure 19). This was the first time 

this feature was used in a panel and is the result of the high stress concentrations apparent around 

the key hole feature in the FEM analysis at some locations. Adding web doublers during the core 

assembly sequence was straight-forward and did not present any problems. These doublers were 

only added to the crown and keel panel frames. 
14

Figure 19. Frame Web Doublers Added at Rod Pass-Through Locations

Next, the pre-cut warp-knit fabric was rolled out onto bonded core subassembly and then stapled 

into place (Figure 20). A wooden frame assembly tool was used to locate the fabric relative to 

the core, and then used to flip the frame over to attach the fabric on the other face. 
15

Figure 20. Wooden Assembly Tool Used to Attach Fabric to Foam Core

When the final face was stapled in place, the tool was rotated into the vertical position and then 

the completed frame assembly was lifted from the tool and placed in a storage box (Figure 21) 

until it would be needed for the preform assembly operation. 

Figure 21. Completed Frame Lifted from the Frame Assembly Tool
16

1.5 Crown Panel 

The 55-inch wide warp-knit multi-axial dry carbon fiber fabric, which is delivered on cardboard 

support tubes to Boeing, was rolled out by hand onto the table cutting surface. A plotter program 

was then executed and the nested flat patterns for the skin, doublers and tear straps were cut out 

of the fabric. Once cut, the individual pieces of material were then removed from the cutting 

table and organized into kits for their respective components. The stringer, frame and cap 

subassemblies along with the precut fabric (Figure 22) were all delivered to the large preform 

assembly and stitching tool. 

Figure 22. Panel Preform Details Prior to Assembly

The preform assembly takes place in the stitching tool. The tool is a collection of wooden frame 

elements and foam blocks that is used to hold the dry fabric details in position when the preform 

was stitched together. The tooling elements were accurately N/C machined details that were 

indexed to a common steel base. The details were designed to fall away from the base when the 

tool is rotated to place the preform onto the cure tool. Each panel configuration requires a 

specific block set to accommodate the differences in panel design features. The initial set up for 

the crown panel configuration is shown in Figure 23 as it nears completion and checkout. 
17

Figure 23. Crown Panel Stitch Tool Preparation and Checkout

Once the stitch tool was assembled and covered with a thin fiberglass layer to support the fabric 

backside during stitching, the crown panel preform details were loaded into their respective 

holding slots (Figure 24). 

Figure 24. Loading Preform Details into Stitching Tool
18

The frames were installed into the assembly tool first by simply dropping the frame 

subassemblies into the corresponding slot for each frame station with the top of the frame facing 

down. Next, the stringers were installed in between the wood picture frames. Using the wire 

leaders, full size carbon rods were then pulled through the stringers. As the rod passed through 

the stringer, the fabric surrounding the rod, expanded forming the bulb feature at the top of the 

stringer section. In addition, the carbon fiber rod had now locked the stringer into the foam core 

of each frame web. The stringer and frame flanges were formed next by folding the web plies flat 

against the assembly tool. Strips of fabric making up the stringer and frame bases (or tear straps) 

were then placed over the flattened flanges. Then the skin ply stacks were positioned over the 

entire assembly. 

Finally, using one-sided stitching technology, the two needle system was used to form a 

modified chain stitch. The industrial robot arm gives the end effector six degrees of freedom for 

stitching in 3-D space. The initial seams were inserted into the preform to attach the frame and 

stringer flanges to the skin (Figure 25). 

Figure 25. Single-Sided Stitching of Crown Panel Preform Started

After stitching of the preform was completed (Figure 26), it was transferred to an outer mold line 

(OML) cure tool for resin infusion processing. This was accomplished by strapping the dry 

preform to the preform assembly tool so it could be inverted without dropping the preform. Once 

the preform was flipped (Figure 27) and positioned over the cure tool (Figure 28), the straps 

were removed and the steel base was lifted off. 
19

Figure 26. Completed Crown Panel Preform Stitching

Figure 27. Stitch Tool Rotation with Preform
20

Figure 28. Stitch Tool and Preform Placed onto Cure Tool

With the steel base detached, access to the foam blocks and wood picture frame details was now 

possible. All of the foam blocks and wood frames were easily removed and concerns that the 

one-piece wood frames might be locked into the preform were not realized. The relative 

flexibility of the stitched preform was adequate to release the wood frame details without having 

to pull the rods out. Once these tooling details were removed (Figure 29), only the selfsupporting preform remained on the cure tool (Figure 30). 

Figure 29. Removal of Stitch Tool Foam Blocks and Wood Frame Tooling Details
21

Figure 30. Self-Supporting Crown Panel Preform Placed on the Cure Tool

The preform was then prepared for resin infusion and cure cycle processing. The first step was to 

install all of the IML cure tool details onto the preform (Figure 31). Then peel ply (beige colored 

material in the photos) layers were added to eliminate resin ridges caused by the pleated vacuum 

bagging system. Location paddles and forming plates were used to accurately position frame and 

integral cap feature stations. Frame cap covers were used to maintain frame straightness. Silicone 

bagging aids were added to the stringers to reduce vacuum bag elongation in the sharp corners. 

The rigged cure tool with all of these IML cure tool details is shown in Figure 32 for the crown 

panel. 
22

Figure 31. Preform Preparation on Cure Tool

Figure 32. Under Bag IML Tool Details Located

A two bag system is used to seal vacuum the part against the tool. First the primary pleated nylon 

vacuum bag is draped over the preform, pleated and then sealed down against the OML tool 

(Figure 33). A secondary textured vacuum bag (green bag in Figure 34) was also added to 

provide a level of safety should any leaks develop in the primary bag. 
23

Figure 33. Pleating Operation for Primary Bag Installation

Figure 34. Secondary Bag is added to Maintain Vacuum Integrity during Infusion and Cure
24

After successfully passing a vacuum check, the bagged part was then transported from the 

Stitching Center to the oven. (Figure 35) 

Figure 35. Part is Transferred and Loaded into Oven

The 3-D preform was infused using CAPRI process. The resin was a Hexcel two-component 

amine cured epoxy system known as HEXFLOW VRM34. Resin infusion processing took place 

with the preform held in a cure tool, which was the only hard tooling required. The preform was 

infused and cured out. An automated machine was used to prepare and handle the resin (Figure 

36). With this machine, the resin and hardener components were kept separated until just prior to 

entering the part mold fill line. The two components, resin and hardener, were automatically 

degassed, metered, mixed, and delivered on demand to the mold at the predefined temperature 

and pressure. The time that the mixed material was at elevated temperature within the machine 

was reduced to mere seconds, and more importantly, the volume of mixed material is minimized 

to reduce the chance of an adverse exothermic reaction and clean up time. 
25

Figure 36. Automated Infusion Equipment Used for Resin Infusion

Upon completion of the initial cure, the infused part was removed from the oven (Figure 37) 

where the bagging materials and resin lines could easily be removed to expose the IML surface 

of the part and the IML cure tool details (Figure 38). The vertical standing IML tooling plates 

were then broken away to expose the final cured interior surface of the part. The cured part was 

then placed back in the oven for the final 350°F free-standing post-cure cycle. 
26

Figure 37. Infusion and Initial Cure Completed

Figure 38. Bag and Tool Removal Prior to Post Cure
27

The final cured crown panel is shown in Figure 39. Generally, all aspects of the design approach, 

tooling concepts, and processing elements worked as expected to produce a useable panel for the 

test article. Considering the panel size and complexity, along with the simultaneous introduction 

of new concepts for the IML cure tools, it was encouraging that the first panel off the tool was 

successfully infused and cured without major complications that would preclude its use, or lead 

to major tool modifications or process changes on subsequent panels. 

Figure 39. Final Cured Crown Panel Read for Edge Machining

All of the internal panel features were fabricated within drawing tolerances. The frame and 

stringer quality was good - straightness and resin penetration. The integral cap features at the 

center rib stations were also straight and perpendicular as intended, and the fillet radii shaped by 

the vertical plate edges was accurately formed and located. Going into the first-article 

fabrication, the quality of the integral cap features around the panel’s perimeter was the largest 

concern due to the increased cap thickness/bulk, density of the stitching through the web, and 

unbalanced stack architectures on the interior versus the exterior sides of the cap web. How this 

unique combination of physical characteristics would influence the perpendicularity of the cap 

web would not be readily apparent until the first part came off the tool and the relative warping 

of the caps could be assessed. 

Visual inspection of the caps, along with some simple hand measurements, indicated that the 

caps are molded accurately and that excessive amounts of shimming will not be required during 

panel joining. 
28

Although no rework will be required on the IML features of the panel, there was a problem 

encountered on the OML side of the panel. Once the peel layer was removed, it was immediately 

apparent that a rectangular pattern of grooves had been molded into the OML surface of the 

panel. Since the grid pattern matched the splice locations of the perforated plates, the problem 

was quickly diagnosed as an interference problem at the perforated plate splices (a layer of 

perforated plates is inserted between the cure tool and preform to prevent the carbon fabric from 

imprinting into the flow media which results in a roughly textured OML surface). 

Unlike prior PRSEUS panel infusions, this was the first time an Invar cure tool was used. With 

panels almost 30-ft long, the mismatch in thermal growth between a steel cure tool and carbon 

fiber part would have created out of tolerance panels. During fabrication of the crown panel, a 

mark-off pattern occurred on the OML surface of the part during the infusion and cure cycle. 

This was caused by the edges of the perforated caul sheets that are placed between the preform 

and cure tool. Driven by thermal expansion, the sheets pressed together and then dug into the 

preform during the cure cycle to mold a permanent groove in the OML surface of the part. 

(Figure 40), their relative locations and groove depths are called out in Figure 41. 

Figure 40. Thermal Expansion of Caul Sheets Caused Mark-off on the Crown Panel OML
29

Figure 41. Schematic of Groove Location and Depth Measurements

Since the resulting pattern matched the edges of the individual caul sheets, it was quickly 

determined that the difference in thermal expansion between the low-carbon steel perforated 

sheets and the Invar cure tool caused the interference. In addition to the mark-off, permanently 

buckled regions occurred in the caul sheets themselves along the spliced edges indicating that the 

sheets had grown during the cure cycle and caused permanent deformations in the regions with 

the smallest gaps between the sheets (Figure 42). On subsequent panel infusions, this problem 

was resolved by increasing the spacing between the caul sheets which eliminated the interference 

condition that led to the grooves in the first panel (Figure 66). 

Figure 42. Perforated Caul Sheets from Crown Panel Infusion (Revised for Subsequent Panels)
30

Rather than build a new crown panel, a decision was made to repair it. To accomplish this, the 

grooves were filled in with a rigid adhesive/filler and then sanded flush, while the repair 

technique and validation approach outlined in Figure 43 was developed. This basic repair 

methodology and process control was first developed and tested at the coupon level. In addition 

to validating the repair approach, the testing also generated repair allowables that were used to 

write margins for the repaired panel condition on the Multi-bay Box test article. 

Figure 43. Repair Technique and Validation Approach

Initially two different repair approaches were considered before down selecting a pre-cured 

bonded patch approach where the patches would be built up using thinner 2-ply warp-knit fabric 

stacks to replace the missing load path across the grooves. The “equivalent” stack architecture 

used to replicate the basic Class 72 skin stack is depicted in Figure 44. This basic four stack 

lay-up of DMS 2436 Class 75/76 stacks is used in the skin regions of the repair and then was 

locally doubled up to eight layers at the frame intersections. 
31

Figure 44. Repair Patch Laminate Architecture Created Using Warp-Knit Fabrics

The primary design objective of the repair patch was to maintain a minimum taper ratio while 

providing an adequate overlap across the groove. Based on an FEM investigation of the load 

transfer across the patch, it was determined that a minimum patch width of at least 4-inches 

would be needed. This result drove the specimen cross-section design depicted in Figure 45. 

Figure 45. Precured Patch Overlap and Edge Taper Dimensions

The coupon specimens were fabricated and tested under tension and 4-point bending loads to 

simulate the critical conditions for the crown panel (Figure 46). In both cases, as expected, a 

classic first-ply failure separation occurred between the outer +/- 45-deg layers of the skin stack 

at a far-field strain averaging 0.0085 in/in, which exceeded the notched tension design allowable 

used to design the crown panel. 
32

Figure 46. Coupon Testing Used to Validate Repair Design and Processes

With the repair design validated by analysis and test, the approach was scaled up for the crown 

panel repair. In addition to being larger than the coupons, the minimum width of the patches was 

also increased to six inches to match the stringer spacing on the crown panel. This facilitated 

maintaining a minimum 2- inch overlap (measured from the groove centerline to the patch edge), 

while still being able to position the patch edges over skin build-ups in the stringer flange and 

tear strap regions. The in-process lay-up of the repair patch dry fabric is shown in Figure 47. 
33

Figure 47. Dry Fabric Lay-up Used to Create Precured Patches

Once the patches were infused and cured in the oven, small bleed holes were mechanically 

drilled approximately 2-inches apart (to vent trapped air during bonding), and then an FM-209 

film adhesive was applied to the back side of the patch (Figure 48). 

Figure 48. Patches were Infused and Cured in an Oven and then an Adhesive Layer was Applied

Simultaneously, the crown panel OML surface was prepared by filling in the grooves, sanding 

them flush, grit blasting the bonding regions, and then conducting water-break tests to verify the 

prepared surface condition. (Figure 49 & Figure 50) 
34

Figure 49. Crown Panel OML Surface Prepared for Repair

Figure 50. Bonding Surfaces were Readied for Repair Patches

The prepared patches were then located into position, taped along the edges to secure them, and 

marked to aid in finding the bleed holes after the bonding cycle (Figure 51). The panel was then 

flipped over onto the cure tool and vacuum bagged (Figure 52). 
35

 

Figure 51. Precured Repair Patches were Taped into Position Prior to Applying the Vacuum Bag

Figure 52. Bagged Crown Panel with IML-side Up and Repair Patches Taped to the OML

To minimize thermal distortion and out-gassing during the bonding operation, the combination 

of an FM-209 adhesive and a 250oF cure cycle was used. The processing parameters were 

identical to those used for the test coupons and no abnormal conditions were encountered. The 

post-bond inspection of the patch edges and bleed holes showed normal adhesive wet-out 

without any indications of voids or trapped air beneath the patches. (Figure 53) 
36

Figure 53. Region of Bonded Repair Patches Shown on OML

Due to the large variation in geometric complexity of the internal structure covered by the 

patches, the use of common inspection techniques via pre-sampled reference standards was not 

practical, therefore no ultrasonic non destructive inspection was performed. The repair was 

bought-off based on using the same process control standards as the test coupons, visual 

inspection of the adhesive wet-out, tap testing of the completed repair, and ultimately the 

favorable results of the coupon test effort. The repaired panel was then delivered to the assembly 

site (Figure 54). 

Figure 54. Completed Bonded Repair Patches on Crown Panel OML
37

1.6 Floor Panel Fabrication 

The floor panel design is similar to the crown panel except that it does not have the integral cap 

features at the forward and aft edges. As such, the preform was built on the common stitching 

table, but required some new foam blocks and wooden frames for the edges that were 

specifically developed for the floor panel configuration. The preform details were loaded into the 

tool and stitched in the same manner as the crown panel described earlier before being flipped 

onto the cure tool, where the internal foam blocks and wooden frames could be removed to 

reveal the self-supporting dry carbon fabric preform (Figure 55). 

 

Figure 55. Completed Floor Panel Stitched Preform

The preform was then positioned onto the cure tool and located by the IML tooling details 

around the perimeter. The vertically positioned IML cure plates were placed underneath the bag 

to form the smooth tooled surfaces on the integral cap features (Figure 56). The remaining IML 

cure tool details, silicon rubber bagging aids and aluminum channels on frame caps were also 

added (Figure 57). 
38

Figure 56. Integral Cap Tooling Plate Installation

 

Figure 57. Bagging Aids on Frames and Stringers
39

Once these details were positioned, the bagging operation was started. Due to the problems 

encountered in the crown panel vacuum bagging sequence, where numerous leaks were detected 

in both the primary and secondary bags, that ultimately led to replacing both bags and starting 

over with a new sheet of bagging film, a revamped bagging handling approach was developed in 

conjunction with the bagging film supplier (AirTech) that was first tried on the floor panel bags. 

The first step in the new process was to receive the bagging film from the supplier in a rolled and 

fully moisture-saturated condition, rather than the loosely controlled folded state where high 

stress concentrations at the double-folded corners were becoming initiation sites for bag 

cracking. In addition to having the vendor initially steam treat the bags, tighter control of the bag 

moisture content was also maintained during transport, storage, and the pleating operation on the 

shop floor. The first new precondition bag and packaging packing system received is shown on 

the cutting table in Figure 58 prior to use. 

Figure 58. New Pre-Conditioned Vacuum Bag Delivery Packaging

Next, two lanyards were added at the edges of the tool to help the bag clear the IML tooling plates 

as it was unfurled onto the cure tool (Figure 59). Both changes were helpful in reducing the 

trauma inflicted on the bagging film by the previous method of unfolding, dragging, and pleating 

the bag across the part and tooling surfaces. Ideally in a production scenario, the vacuum bags 

should arrive in a pre-pleated, rolled-up state, and packaged in an environmentally-controlled bag 

media that maintains the high moisture content needed to maximize the workability of the 

bagging film. 
40

Figure 59. Added Lanyards to Support Bag During Unrolling Operation

Although the emphasis on the new approach focused on changes to the bag conditioning and 

handling procedures, it also became apparent that the on-tool pleating process was creating 

damage sites that could later develop as leak paths as the bag was cycled during subsequent leak 

checks (and again potentially during the heat-up cycles and additional leak checks in the oven). 

After leaks were detected in the primary bag after a heat cycle, it was also determined that the 

damage sites were being created as the bag was pulled across the tool to start the pleating 

operation (i.e. as it was dragged across the top corners of the vertical forming plates shown in 

Figure 60). After closely inspecting the tool edges, it was clear that the sharp edge at the corners 

of the vertical plates were not adequately broken per the drawing general note and that further 

hand filing was required to eliminate the sharp edges that were puncturing and/or weakening the 

vacuum bags. 
41

Figure 60. IML Vertical Plate Corners were Tearing the Bagging Film

Once the tool benching was completed and the preform was re-bagged with new primary and 

secondary vacuum bags, it easily passed the vacuum checks without further leaks (Figure 61 and 

Figure 62). The floor panel was then placed back in the oven and cured without incident (Figure 

63 and Figure 64). 
42

Figure 61. Primary Bag Installed and Leak Checked

 

Figure 62. Secondary Bag Installed and Leak Checked
43

Figure 63. Floor Panel Preform Placed in Oven Ready for Heat-up, Infusion, and Cure

Figure 64. Post Cured Part Prior to Bag Removal
44

As the bagging problems were eliminated, the other key focus on the floor panel fabrication task 

was fixing the perforated plate gaps that caused the grooving condition on the crown panel. After 

running some subscale infusion tests to determine the optimum gap conditions for the perforated 

plates, the nominal gap used for the floor panel infusion was increased to 0.017-inch which 

solved the problem. 

The resulting floor panel (Figure 65) had high quality IML features and did not have any of the 

grooves or excessive mark-off (Figure 66) that was prevalent on the crown panel. The cured 

floor panel was inspected and then placed in storage until the edge trim operation could be 

scheduled at the machining vendor. 

Figure 65. Cured Floor Panel

 

Figure 66. Floor Panel IML and OML Cured Part Surfaces
45

1.7 Outer Rib Panel Fabrication 

Due to their smaller size and reduced complexity, the two outer rib panels provided an excellent 

opportunity to demonstrate the process improvements based on the lessons learned with the 

crown and floor panels. Once the reworked frame elements were loaded in the stitching tool 

(Figure 67), the remaining details came together quickly (Figure 68), and the stitching (Figure 

69) was completed ahead of schedule. 

Figure 67. Outer Rib Preform Assembly – Frame Installation
46

Figure 68. Outer Rib Preform Assembly – Frames and Stringers Installed

Figure 69. Outer Rib Preform Assembly – Stitching Complete

The first stitched preform was then set aside until the cure tool could be cleaned and rigged with 

the IML tooling details. Meanwhile, the stitching tool details for the second outer rib panel were 

quickly reassembled and the second preform was brought together and stitched. The two 

completed dry preforms are shown together in Figure 70. 
47

Figure 70. Two Outer Rib Preforms were Fabricated Simultaneously

Once the cure tool was ready, the first preform was loaded into position so the IML cure tool 

details could be positioned (Figure 71). It was then covered with the primary and secondary bags 

using the newly developed bagging procedures, and then vacuum checked (Figure 72). 

Figure 71. IML Tooling Placed on Preform
48

Figure 72. Bagged Outer Rib Panel During Vacuum Check

The bagging improvements were immediately apparent and repeated on both panels. Neither 

panel leaked during any of the vacuum checks. This single improvement had a substantial impact 

on reducing the processing schedule for the outer rib panels, shaving 2-3 weeks off the span 

time. Both panels were infused and cured in a two week period without any defects. The IML 

and OML surfaces for outer rib panel #1 are shown in Figure 73, and outer rib panel #2 in Figure 

74. The cured panels were trimmed to their final shape (Figure 75). A completed outer rib is 

shown in Figure 76 and Figure 77. 

Figure 73. First Untrimmed Cured Outer Rib Panel - IML and OML Surfaces
49

Figure 74. Second Untrimmed Cured Outer Rib Panel - IML and OML Surface

Figure 75. Trimming the Outer Rib Panel
50

Figure 76. Finished Outer Rib Panel – OML Surfaces

Figure 77. Finished Outer Rib Panel – IML Surfaces
51

1.8 Upper Bulkhead Panel Fabrication

Having demonstrated the improved fabrication process on the outer rib panels, the focus once 

again returned to the largest of the 30-ft panels. The primary difference between this panel and 

the crown and floor panels that were previously fabricated is that the frame and stringer elements 

are now rotated 90 degrees, so that the stringers are running lengthwise in the 30-ft direction 

rather than transversely as in the prior panels (which substantially increases the length of the 

stringer rod pull). Even though the frame elements are shorter now, they still required foam core 

reworking to adjust the stringer spacing. The gray spliced regions in the core are evident in the 

photograph in Figure 78, showing four lines where the core was cut and then glued back together 

before being assembled into the frame detail. 

Figure 78. Additional Core Butt Splices Required to Adjust the Stringer Cutout Positions

Due to the shorter length, the frame installation went quickly (Figure 79); as did the installation 

of the integral cap stacks around the edges (Figure 80). 
52

Figure 79. Frame Installation on First Upper Bulkhead Panel

Figure 80. Integral Cap Stacks at Panel Floor Line Installed
53

Once all of the integral caps were installed, the flange edges were folded down (Figure 81 and 

Figure 82). The stringer subassemblies were then loaded into their respective slots. (Figure 83). 

Figure 81. Integral Cap Features Installed
54

Figure 82. Integral Cap Features Installed and Folded Down

Figure 83. Upper Bulkhead Stringer Stacks Inserted into the Stitching Tool
55

The next step was to pull the rods through the 30-ft length of the tool. The frictional forces build 

up as the rod moves through the preform and were primarily driven by the key hole size 

(diameter) in the frame core and the relative key hole alignment from frame to frame. In this 

case, the technicians applied hand forces to pull and simultaneously push the rods through the 

cavities without the use of any specialized tooling (Figure 84 and Figure 85). Once the rods were 

inserted, the tear straps were added, followed by the skin stacks (Figure 86). The completed 

stitched preform shown in Figure 87 was ready for infusion. 

Figure 84. 30-ft Rods were Inserted into the Preform

Figure 85. All Stringer Rods Installed in Preform
56

Figure 86. Tear Straps Placed First, Followed by Skins and Skin Stack Splices

Figure 87. First Upper Bulkhead Panel Stitching Completed

The completed preform was transferred onto the cure tool by rotating the preform assembly tool 

and releasing the preform from the assembly tool (Figure 88). Hard tooling points were used to 

precisely index the preform on the cure tool. IML cure details were then pinned into position to 

accurately locate the key features of the panel (Figure 89). The primary and secondary vacuum 

bags were installed. The completed preform is then ready to be moved into the oven as shown in 

Figure 90. The untrimmed cure panel is shown in Figure 91. A special shipping cart (Figure 92) 

was designed and built to transfer these large panels to and from the vendors for panel trimming. 

This shipping cart fits into a standard Sea Van container to protect the panel from damage during 

shipment. The panel was trimmed on a machine that was large enough to trim the entire panel in 

a single set-up to maintain the tight tolerance of the Determinate Assembly (DA) holes used 

during assembly of the MBB (Figure 93). 
57

Figure 88. Transferring the Upper Bulkhead Panel Preform onto the Cure Tool

Figure 89. IML Cure Tooling Located on the Upper Bulkhead Panel
58

Figure 90. Upper Bulkhead Panel Preform Fully Bagged and Ready for Infusion

Figure 91. Cured Upper Bulkhead Panel Ready for Trim
59

Figure 92. Upper Bulkhead Loaded on the Shipping Cart
60

Figure 93. Upper Bulkhead Panel Trimming

1.9 Upper/Lower Center Rib Panel Fabrication 

Since the center rib panels are not a critical element in the overall HWB fuselage design, they 

were designed to minimize the overall cost to the program - which in this case was primarily 

driven by the tooling costs. Therefore a conventional sandwich panel design was selected with 

heavy build-up regions around the center cutout and perimeter of the panel. Such an approach, is 

not necessarily the most weight-efficient design solution but it was an effective way to minimize 

tooling costs, while also simultaneously moving non-critical structures away from the critical 

schedule path that converged at the stitching machine. The four panel sections were fabricated by 

an outside vendor and delivered to Boeing. All of the laminates were fabricated with pre-preg 

intermediate modulus carbon plan weave cloth fabric per BMS8-276, Class 2A, Style 6K-70-

PW, Form 1. The honeycomb was Hexcell’s Aramid fiber reinforced 1/8-5 lb hexagonal core per 

DMS 1974, Type 3, Class 2, Grade A. 

The core design is a combination honeycomb core and full-depth solid laminate. The entire 

perimeter of the center rib panel was solid laminate to support the fasteners clamp-up loads. 

Straight beams in the panel tied the frames of the crown and floor or floor and side keel panels 

together. The edge of the large cutout was also reinforced with the solid laminate. The solid 

laminate details were machined from a large panel. This was the thickest solid laminate that had 

been fabricated using this material system and a special cure cycle was developed to prevent an 

exothermal reaction from occurring during the cure cycle. The cure went as planned and a void 

free laminate was fabricated (Figure 73). 
61

Figure 94. Trimming Solid Laminate Core Details

The face sheets were also pre-cured and trimmed to shape leaving an excess of 0.060-inch to 

trim after the panel was bonded together (Figure 95). Prior to bonding, all of the details were dry 

fitted together to check for gaps and any mismatch between the core and laminate heights 

(Figure 96). Then the parts were prepared for bonding. The secondary bond operation for the 

solid laminate and core to the face sheet was cured at 250° F using FM73 film adhesive per DMS 

2169, Type 2. The honeycomb core was simultaneously bonded to the solid laminate using 

FM410 foaming adhesive to make the shear tie connection. Tooling pins were used to keep the 

details in position during the bonding cycle (Figure 97). Separate drill templates were developed 

for drilling the DA holes in the panel to maintain the positional and perpendicularity tolerance of 

the holes (Figure 98). Once the holes were checked and bought-off by Boeing personal in the 

template, the DA holes were drilled in the ribs. The completed sandwich panel assembly is 

shown in Figure 99. 
62

Figure 95. Precured Facesheets Trimmed Net Plus 0.060-inch for Final Trimming
63

Figure 96. Dry Fit of the Separate Details Prior to Bonding

Figure 97. Tooling Pins Held the Details Together During Bonding

Figure 98. Drill Template was Fabricated to Drill DA Holes on the Panels
64

Figure 99. Upper Center Rib Panel Completed by Vendor

1.10 Lower Bulkhead Panel Fabrication 

The last two panels that were delivered under this contract were the lower bulkhead panels. All 

of the frames were spaced at 24-inch on centers like all of the other panels. However the stringer 

spacing on these panels was not the standard 6-inch spacing and ranged from 4.9-inch to 

7.6-inch. The lower edge of the lower bulkhead attaches to the underside (keel) of the fuselage 

where the sides are at an approximate 30 degree slope. To create better fit between the lower 

bulkhead and side keel panels, the stringers spacing on the lower bulkhead panel was adjusted. 

The basic construction and materials for the panels remained the same. All of the frames and 

shear tees were loaded into the preform assembly tool. Next, all of the stringers were loaded in 

the tool (Figure 100). Skin doublers were incorporated into the flanges of the stringers to reduce 

the number of separate stack (ply) details. This can be seen when the flanges of the stringers 

were folded down. The edges of the flanges flare out creating a butt splice at the center of the 

bay between the stringers (Figure 101). Additional large doublers were also added to the preform 

at these high stress areas (Figure 101). A couple of these higher loaded areas were the door 

cutout located at the center of the panel and the skin splices. The maximum width material 

purchased for this program was 99-inches wide. This meant that the skin of the 30-ft lower 

bulkhead (and upper bulkhead) panels required splicing. To achieve this, a double shear joint 

was used (Figure 102). Layers of DMS2436, Class 75 and 78 were used on the OML and IML 

surfaces to form the joint. Figure 103 shows the two IML splice strap layers position on the 

preform assembly. The nine-ply skin stack segments were then positioned. The skin segments 

were butt spliced together with a maximum gap of 0.060-inch (Figure 104). These simple nineply butt splice joints work because only 12% of the fibers in the skin are perpendicular to the 

joint, and the loads across these joints are low. 
65

Figure 100. Preform Assembly Starts with the Inserting the Frames and then the Stringers

Figure 101. Flanges are Folded Down then Tear Straps and Doublers are Added
66

Figure 102. Skin Splice Geometry

Figure 103. IML Skin Splice Straps are Located on the Preform Assembly
67

Figure 104. Lower Bulkhead Skin Splice

With the skin in place, the OML skin splice doublers were located. The preform assembly was

now ready for stitching. Figure 105 shows the lower bulkhead panel fully stitched. Stitching was

inserted in all of the frame and stringer flanges. It is also inserted at the edges of the skin 

doublers to prevent any ply delaminations when the nine-ply stacks were terminated (Figure 

105). Without stitching, dropping nine plies off at a time in the direction perpendicular to the 

loading would be prohibitive for unreinforced laminates. 

Figure 105. Lower Bulkhead Preform Stitching Complete
68

With the preform on the cure tool, the IML cure tool details were added around the perimeter of 

the preform assembly (Figure 106). The primary and secondary vacuum bags were then installed. 

All of the inlet and outlet plumbing lines for resin infusion were attached. The part was now 

ready to be transferred to the oven for infusion (Figure 107). The infusion process for both lower 

bulkhead panels was successful without issues. The OML surfaces were flat and smooth and the 

IML stringers, shear tees and frames were straight and completely filled with resin (Figure 108). 

Figure 106. IML Cure Tool Positioned on the Preform
69

Figure 107. Vacuum Bagging Complete Ready for Transporting the Assembly to the Oven

Figure 108. OML and IML Surfaces of the Cured Lower Bulkhead Panel Prior to Trimming
70

2.0 Metallic Fittings 

There are 723 fittings required to build the MBB assembly. Figure 2 shows the fitting rigged in 

space. This quantity of fittings was the collection of 249 different configurations (includes left 

and right hand (mirrored) parts). The load introduction areas on each end of the MBB required a 

total of 108 fittings. For fully integrated panels this may seem like a lot of fittings, but the MBB 

test specimen is a very short fuselage section. The forward and aft pressure bulkheads are only 

7-ft apart. For an actual aircraft, were the forward and aft pressure bulkheads could be 100-ft 

apart, full 100-ft length integrated panels would be fabricated. Now the pressure bulkhead 

fittings would be averaged out over 100-ft instead of 7-ft. Increasing the fuselage section from 

7-ft to 100-ft increases the fuselage length 14 times. Calculating the total number of fitting for 

the 100- ft fuselage section would only increase the total number of fitting by 3 times. Or another 

way to look at it would be to just look at the number of fitting that would be required for the 

fuselage not considering the pressure bulkheads or the load introduction fittings. Using this 

scenario, there would only be 152 fittings in the entire 30-ft x 7-ft double-deck fuselage section. 

Figure 109. Increasing the Fuselage Length by 14 Times would only Increase the Number of 

Fittings by 3 Times
71

Figure 110. Typical Mid Fuselage Fitting Arrangement without the Pressure Bulkheads and Load 

Introduction Fittings

A complete list of fittings with qualities that were procured is provided in Table 1. All of the 

fittings have been transferred to the Multi-Bay Box assembly site for assembly (Figure 111).

Table 1. List of Machined Fittings Ordered for the MBB Assembly

Item	

No. Part	No. Qty. Description

1 ZJ153343-1 2 Upper	Test	Adapter	Box

2 ZJ153344-1 2 Lower	Test	Adaptor	Box

3 ZJ153345-1 2 Upper	OML	Load	Introduction	Fitting

4 ZJ153346-1 2

Upper	IML	Load	Introduction	Fitting

5 ZJ153346-2 2

6 ZJ153346-501 2

7 ZJ153346-502 2

8 ZJ153346-503 2

9 ZJ153346-504 2
72

Item	

No. Part	No. Qty. Description

10 ZJ153346-505 2

11 ZJ153346-506 2

12 ZJ153347-1 6 Upper	IML	External	Frame	Load	Intro	Fitting

13 ZJ153348-1 4

Upper	IML	Internal	Frame	Load	Intro	Fitting	(outside	frames) 14 ZJ153348-2 4

15 ZJ153348-501 2

Upper	IML	Internal	Frame	Load	Intro	Fitting	(Center	frame) 16 ZJ153348-502 2

17 ZJ153349-1 2 Auxiliary	Outer	Rib	Plate

18 ZJ153650-1 2 Lower	OML	Load	Introduction	Fitting

19 ZJ153651-1 4

Lower	IML	Load	Introduction	Fitting 20 ZJ153651-501 4

21 ZJ153652-1 2

Lower	IML	External	Frame	Load	Intro	Fitting

22 ZJ153652-2 2

23 ZJ153652-501 6

24 ZJ153652-502 6

25 ZJ153653-1 6

Lower	IML	Internal	Frame	Load	Introduction	Fitting	(Keel	&	Floor)	 26 ZJ153653-2 6

27 ZJ153654-1 2

Lower	External	Side	Load	Introduction	Fitting	 28 ZJ153654-2 2

29 ZJ153655-1 2 Mid	Continuous	Load	Introduction	Fitting

30 ZJ153656-1 2

Mid	Discontinuous	Load	Introduction	Fitting

31 ZJ153656-2 2

32 ZJ153656-501 2

33 ZJ153656-502 2

34 ZJ153657-1 2 OML	Skin	Splice	Plate

35 ZJ153658-1 4 Keel	Splice/	Bulkhead	Intercostal	Fitting	

(frame	to	cap)

36 ZJ153658-501 4 Keel	Splice/	Bulkhead	Intercostal	Fitting	

(frame	to	frame)

37 ZJ153658-503 4 Keel	Cap	Flange	Splice	Plate

38 ZJ153658-505 4 Keel	Cap	Splice	Fitting

39 ZJ153659-1 2

40 ZJ153659-2 2 Keel	Splice	Intercostal	Fitting

41 ZJ153659-501 4

42 ZJ153659-503 2 Keel	Splice	Strap

43 ZJ153660-1 20

Bulkhead	Frame	to	Panel	Stringer	Fitting

44 ZJ153660-2 20

45 ZJ153660-501 2

46 ZJ153660-502 2

47 ZJ153662-1 8

Bkhd	Frame	Splice	Fitting

48 ZJ153662-2 8

49 ZJ153662-501 4

50 ZJ153662-502 4
73

Item	

No. Part	No. Qty. Description

51 ZJ153662-503 4

52 ZJ153662-504 4

53 ZJ153662-505 4

54 ZJ153662-506 4

55 ZJ153663-1 1 Access	Door,	Lower	Bulkhead

56 ZJ153663-501 1 Access	Door,	Upper	Bulkhead

57 ZJ153663-503 1 Access	Door,	Lower	Bulkhead	w/	Instrumentation	Holes

58 ZJ153663-505 1 Access	Door,	Upper	Bulkhead	w/	Instrumentation	Holes

59 ZJ153664-1 2

Bkhd	Frame	to	Canted	Stringer	#14	Fitting

60 ZJ153664-2 2

61 ZJ153664-501 2

62 ZJ153664-502 2

63 ZJ153664-503 2

Bkhd	Frame	to	Canted	Stringer	#18	Fitting

64 ZJ153664-504 2

65 ZJ153664-505 2

66 ZJ153664-506 2

67 ZJ153664-507 2

Bkhd	Frame	to	Canted	Stringer	#22	Fitting

68 ZJ153664-508 2

69 ZJ153664-509 2

70 ZJ153664-510 2

71 ZJ153664-511 4

Bkhd	Frame	to	Stringer	#2	Fitting

72 ZJ153664-512 4

73 ZJ153664-515 2

74 ZJ153664-516 2

75 ZJ153666-1 4 External	Center	Keel	Stringer	Support

76 ZJ153666-501 20 External	Crown	Stringer	Support

77 ZJ153667-1 6

Keel	Gusset

78 ZJ153667-2 6

79 ZJ153668-1 3 Wire	Clamp	Fitting

80 ZJ153669-1 6

Crown	Gusset

81 ZJ153669-2 6

82 ZJ153669-501 6

83 ZJ153669-502 6

84 ZJ153900-1 2

Gang	Channel	for	Access	Door

85 ZJ153900-501 1

86 ZJ153900-503 1

87 ZJ153900-505 2

88 ZJ153900-506 2

89 ZJ153900-507 2

90 ZJ153900-509 2

91 ZJ153900-511 2

92 ZJ153901-1 2

External	Bulkhead	Cap	Load	Introduction	Fitting 93 ZJ153901-2 2
74

Item	

No. Part	No. Qty. Description

94 ZJ153902-1 2

Internal	Bulkhead	Cap	Crown	Load	Intro	Fitting 95 ZJ153902-2 2

96 ZJ153903-1 20

Bkhd	Frame	to	Floor	Cap	Clip

97 ZJ153903-2 20

98 ZJ153903-501 4

99 ZJ153903-502 4

100 ZJ153904-1 8 Lower	Bkhd	Skin	Splice	Strap

101 ZJ153904-501 4 Floor	Skin	Back-Up	Plate

102 ZJ153905-1 6

Lower	Center	Rib	Clip 103 ZJ153905-2 6

104 ZJ153905-501 2

Upper	Center	Rib	Clip

105 ZJ153905-502 2

106 ZJ153905-503 2

107 ZJ153905-504 2

108 ZJ153905-505 2

109 ZJ153905-506 2

110 ZJ153906-1 2

Outer	Rib	Frame	to	Floor	Fitting

111 ZJ153906-2 2

112 ZJ153906-501 4

113 ZJ153906-502 4

114 ZJ153906-503 6

Radius	Block

115 ZJ153906-504 6

116 ZJ153907-1 4

Auxiliary	Outer	Rib	Access	Cover 117 ZJ153907-501 4

118 ZJ153908-1 6

Floor	Strut

119 ZJ153908-2 6

120 ZJ153909-1 2

Floor	Corner	Fitting	– Lower	Center	Rib

121 ZJ153909-2 2

122 ZJ153910-1 2

Keel	Corner	Fitting	– Lower	Center	Rib

123 ZJ153910-2 2

124 ZJ153911-1 2

Mid	Internal	Side	Load	Introduction	Fitting 125 ZJ153911-2 2

126 ZJ153912-1 2

Lower	Internal	Side	Load	Introduction	Fitting 127 ZJ153912-2 2

128 ZJ153912-501 2

Stringer	Shear	Fitting	(Lower	Bkhd	Panel) 129 ZJ153912-502 2

130 ZJ153913-1 2

Corner	Fitting	– Upper	Center	Rib 131 ZJ153913-2 2

132 ZJ153915-1 4

Lower	Center	Rib	to	Keel	Center	Fitting

133 ZJ153915-2 4

134 ZJ153915-501 2

135 ZJ153915-502 2

136 ZJ153916-1 2 Center	Rib	to	Bulkhead	Fitting
75

Item	

No. Part	No. Qty. Description

137 ZJ153916-2 2

138 ZJ153916-501 2

139 ZJ153916-502 2

140 ZJ153917-1 2

Center	Rib	to	Crown/Floor	Corner	Fitting

141 ZJ153917-2 2

142 ZJ153917-501 2

143 ZJ153917-502 2

144 ZJ153918-1 4

Center	Rib to	Floor	Center	Fitting 145 ZJ153918-2 4

146 ZJ153918-501 2

Center	Rib	to	Crown	Center	Fitting 147 ZJ153918-502 2

148 ZJ153918-503 2

Center	Rib	to	Crown	Center	Fitting 149 ZJ153918-504 2

150 ZJ153918-505 2

Center	Rib	to	Floor	Center	Fitting 151 ZJ153918-506 2

152 ZJ153918-507 2

Center	Rib	to	Floor	Center	Fitting 153 ZJ153918-508 2

154 ZJ153919-1 2

Upper	Center	Rib	to	Floor	Fitting	(flat	side) 155 ZJ153919-501 2

156 ZJ153945-1 44

Corner	Strut	Fitting 157 ZJ153945-2 44

158 ZJ153945-501 44

Corner	Strut	Fitting 159 ZJ153945-502 44

160 ZJ153956-1 44 Strut,	Corner	Brace

161 ZJ153957-1 4

Shim,	Side	Keel	Tee	to	Center	Rib 162 ZJ153957-501 4

163 ZJ153957-503 4 Shim,	used	with	3910-1

164 ZJ153957-505 12 Shim,	used	with	3908-1	at	Floor	Struts

165 ZJ153957-507 8 Shim,	used	with	3658-1	Keel	Splice

166 ZJ153957-509 8 Shim,	used	with	3653-1	at	Outer	Frame

167 ZJ153957-511 4 Shim,	used	with	3652-1	at	outer	Frame

168 ZJ153957-513 4 Shim,	used	with	3652-1	at	Cap	

169 ZJ153957-515 4 Shim,	used with	3653-1	at	Center	Frame

170 ZJ153957-517 2 Shim,	used	with	3652-501	at	Center	Frame
76

Figure 111. Fittings were Stored on Shelves in the MBB Assembly Area

3.0 Panel Hardware

A quick study was conducted comparing the number of fasteners that would be required to 

assemble a Multi-Bay Box specimen using different technologies. The first comparison was

made to a typical aluminum fuselage construction with separate skin, stringers, frames and frame 

shear tees. The second was a typical state-of-the-art (SoA) composite fuselage with co-cured skin 

with stringers, separate frames and frame shear tees (Figure 112). The integrated concept using 

stitching to support the out-of-plane loads and damage containment would only require 35% of 

the fasteners required to assemble a comparable state of the art composite fuselage or 20% of an 

aluminum fuselage.

Figure 112. Fasteners Required to Assemble the Multi-Bay Box for Different Technologies (Stateof-the-Art Aluminum, State-of-the-Art Graphite Epoxy, and PRSEUS)
77

All of the expected hardware to assemble the MBB was ordered under this contract and are listed 

in Table 2. Additional fasteners that attach the panel-to-panel joints were ordered one grip length 

(0.062-inch) less as a risk mitigation step. The first step in the assembly of the Multi-Bay Box 

was to assemble the panels together then install all of the fittings. Waiting for shorter grip length 

fasteners to assemble the panels together would have delayed the entire assemble task with no 

work around plan. All of the fasteners were transferred to the assembly site and are stored inside 

a locked cage (Figure 113).

Table 2. Fastener Ordered for the MBB Assembly

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

1 3D0006-4 400 1/4"	Self-Aligning	Nut

2 3D0006-5 200 5/16"	Self-Aligning	Nut

3 3D0006-6 50 3/8"	Self-Aligning	Nut

4 3D0031-4-17 18

Bolt-Tension,	Double	Hexagon	Flanged,	220	

KSI,	1/4"	diam.,	1-1/16"	grip

5 3D0031-4-18 18

Bolt-Tension,	Double	Hexagon	Flanged,	220	

KSI,	1/4"	diam.,	1-1/8"	grip

6 3D0031-4-20 9

Bolt-Tension,	Double	Hexagon	Flanged,	220	

KSI,	1/4"	diam.,	1-1/4"	grip

7 3D0031-8-38 13

Bolt-Tension,	Double	Hexagon	Flanged,	220	

KSI,	1/4"	diam.,	2-3/8"	grip

8 3D0096-8 500 Collar,	Pin	Rivet,	Threaded,	Torque	

Controlled,	Alum,	1/4"

9 3D0097-12-13 5

Pin	- Rivet,	Threaded,	3/8"	dia.,	100°	Flush	

Crown	Hd

10 3D0097-12-16 18

Pin	- Rivet,	Threaded,	3/8"	dia.,	100°	Flush	

Crown	Hd

11 3D0097-8-10 48

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

12 3D0097-8-11 88

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

13 3D0097-8-12 26

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

14 3D0097-8-14 5

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd NAS7604U14

15 3D0097-8-16 31

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

16 3D0097-8-7 141

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

17 3D0097-8-8 92

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd
78

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

18 3D0097-8-9 57

Pin	- Rivet,	Threaded,	1/4	dia.,	100°	Flush	

Crown	Hd

19 3D0098-8-10 158

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	100°	Fl	

Crown	Shear Hd WC198-8-10

20 3D0098-8-13 106

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	100°	Fl	

Crown	Shear	Hd WC198-8-13

21 3D0098-8-7 211

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	100°	Fl	

Crown	Shear	Hd

22 3D0099-10-15 9

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

23 3D0099-10-18 101

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

24 3D0099-10-19 9

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

25 3D0099-10-21 9

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

26 3D0099-10-22 70

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

27 3D0099-10-32 40

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head NAS6705U32

28 3D0099-10-7 18

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

29 3D0099-10-8 18

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

30 3D0099-12-11 18

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

31 3D0099-12-16 106

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6706U16

32 3D0099-12-17 158

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

33 3D0099-12-18 59

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

34 3D0099-12-19 304

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

35 3D0099-12-20 9

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

36 3D0099-12-21 176

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6306U21

37 3D0099-12-22 9

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

38 3D0099-12-23 26

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head

39 3D0099-12-26 13

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6706U26
79

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

40 3D0099-12-27 15

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6306U27

41 3D0099-12-29 9

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6706HU29

42 3D0099-12-8 18

Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	Protruding	

Head NAS6706HU8

43 3D0099-14-22 9

Pin	- Rivet,	Threaded,	Ti,	7/16"	dia.,	

Protruding	Head

44 3D0099-14-23 5

Pin	- Rivet,	Threaded,	Ti,	7/16"	dia.,	

Protruding	Head

45 3D0099-14-25 26

Pin	- Rivet,	Threaded,	Ti,	7/16"	dia.,	

Protruding	Head NAS6307U25D

46 3D0099-6-6 53

Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

47 3D0099-6-7 53

Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

48 3D0099-6-8 26

Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

49 3D0099-6-9 18

Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head WC199-6-9

50 3D0099-8-10 26

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head WC199-8-10

51 3D0099-8-11 211

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head WC199-8-11

52 3D0099-8-12 244

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head WC199-8-12

53 3D0099-8-13 44

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

54 3D0099-8-14 40

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

55 3D0099-8-15 141

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

56 3D0099-8-16 48

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

57 3D0099-8-17 150

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head HST528DL8-17

58 3D0099-8-18 22

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head WC199-8-18

59 3D0099-8-19 35

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

60 3D0099-8-28 53

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head NAS6404U28

61 3D0099-8-31 5

Pin	- Rivet,	Threaded,	1/4"	dia.,	Protruding	

Head NAS6404U31
80

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

62 3D0099-8-32 5

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head NAS6404U32

63 3D0099-8-33 5

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head NAS6404U33

64 3D0099-8-6 35

Pin	- Rivet,	Threaded,	Ti, 1/4"	dia.,	Protruding	

Head WC199-8-6

65 3D0099-8-8 26

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head

66 3D0099-8-9 88

Pin	- Rivet,	Threaded,	Ti,	1/4"	dia.,	Protruding	

Head WC199-8-9

67 44615K434 4 1/2"	Nipple

68 4513K293 1 3"	Union

69 4513K93 4 1/2"	Union

70 4D0012-4C 66 Washer

71 4D0012-4P 66 Washer

72 4D0012-8C 15 Washer

73 4D0012-8P 15 Washer

74 7733K319 1 3"	Nipple

75 92511A053 310 Spacer,	0.252"	id	x	0.9375"	Long

76 92620A703 12 3/8"	Bolt	1.38	Long,	Wire	Feed	Thru	on	Door

77 98017A200		 12 3/8"	Washer	- NAS1149C0663R

78 BACN10JZ3B2CM 105 3/16"	Nut	Plate,	Self	Sealing

79 BACN10JZ5B2CM 5 5/16"	Nut	Plate,	Self	Sealing

80 MS21042L3 525 Nut,	Self-locking,	dry	film	lubricant,	3/16"

81 MS21042L4 990 Nut,	Self-locking,	dry	film	lubricant,	1/4"

82 MS21042L6 248 Nut,	Self-locking,	dry	film	lubricant,	3/8"

83 NAS1080-08 313 Collar,	Swage	Locking,	1/4"	

84 NAS1080-10 365 Collar,	Swage	Locking,	5/16"	

85 NAS1149C0332R 590 3/16"	ID	x	.032"	thick	washer

86 NAS1149C0432R 1353 1/4"	ID	x	.032"	thick	washer

87 NAS1149C0532R 390 5/16"	ID	x	.032"	thick	washer

88 NAS1149C0632R 398 3/8"	ID	x	.032"	thick	washer

89 NAS1401-3C3 100 3/16"	Fillet	Washer

90 NAS1401-4C3 300 1/4"	Fillet	Washer

91 NAS1401-5C3 100 5/16"	Fillet	Washer

92 NAS1401-6C3 100 3/8"	Fillet	Washer

93 NAS1401-7C3 100 7/16"	Fillet	Washer

94 NAS1401-8C3 100 1/2"	Fillet	Washer

95 NAS1805-7L 11

Nut,	Self-locking,	CRES	steel,	Dry	film	lube,	

7/16"	diam.

96 NAS1805-8L 115

Nut,	Self-locking,	CRES	steel,	Dry	film	lube,	

1/2"	diam.
81

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

97 NAS6803U10 202 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

98 NAS6803U11 114 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

99 NAS6803U5 114

Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.

100 NAS6803U6 106 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

101 NAS6803U7 141 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

102 NAS6803U8 26 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

103 NAS6803U9 35 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

104 NAS6804U10 9 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.

105 NAS6804U11 9 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

106 NAS6804U12 70 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

107 NAS6804U13 141 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

108 NAS6804U14 44 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

109 NAS6804U15 9 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

110 NAS6804U16 246 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

111 NAS6804U17 48 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

112 NAS6804U18 92 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

113 NAS6805U10 31 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

5/16"	diam.,	

114 NAS6805U6 24 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

5/16"	diam.

115 NAS6805U8 79 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

5/16"	diam.,	

116 NAS6805U9 90 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

5/16"	diam.,	

117 NAS6806U13 97 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.

118 NAS6806U20 79 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,

3/8"	diam.,
82

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

119 NAS6806U21 9 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,

120 NAS6806U22 26 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,

121 NAS6807U14 26 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

7/16"	diam.

122 NAS6808U11 5 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.

123 NAS6808U12 70 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

124 NAS6808U13 31 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

125 NAS6808U14 26

Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

126 NAS6808U15 48 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

127 NAS6808U16 31 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

128 NAS6808U17 31

Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

129 NAS6808U18 9 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

130 NAS6808U19 31 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

131 NAS6808U20 26 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	 NAS6308U20

132 NAS6808U21 123 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	 NAS6708U21

133 NAS6808U22 75 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	 NAS6408U22

134 NAS6808U23 114

Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

135 NAS6808U24 157 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

136 NAS6808U25 123 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

NAS6808U25

NAS6308U25

137 NAS6808U26 108 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	 NAS6308U26D

138 NAS6808U27 100 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

139 NAS6808U30 5 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

140 NAS6808U31 62

Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	
83

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

141 NAS6808U32 5 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

142 NAS6808U33 136 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	 NAS6408U33

143 NAS6808U37 173 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/8"	diam.,	

144 NAS9308M-4-05 40

Rivet-Blind,	100°	Flush	Head,		Monel-Cres,	

1/4"	dia.,	.251-.312"	grip	

145 NAS9308M-4-06 40

Rivet-Blind,	100°	Flush	Head,		Monel-Cres,	

1/4"	dia.,	.313-.375"	grip	

146 NAS9308M-4-07 125

Rivet-Blind,	100°	Flush	Head,		Monel-Cres,	

1/4"	dia.,	.376-.437"	grip	

147 NAS9308M-4-08 70

Rivet-Blind,	100°	Flush	Head,		Monel-Cres,	

1/4"	dia.,	.438-.500"	grip	

148 NAS9308M-4-09 90

Rivet-Blind,	100°	Flush	Head,		Monel-Cres,	

1/4"	dia.,	.501-.562"	grip	

149 S124682-3E12-6 50 Fender	Washer,	CRES	steel,	.203"	inner	dia.,	

.750"	outer	dia.,	.064"	Th

150 S124682-3E8-5 40

Fender	Washer,	CRES	steel,	.203"	inner	dia.,	

.500"	outer	dia.,	.051"	Th

151 S124682-4E14-9 20 Fender	Washer,	CRES	steel,	.265"	inner	dia.,	

.875"	outer	dia.,	.091"	Th

152 S124682-4E16-9 10 Fender	Washer,	CRES	steel,	.265"	inner	dia.,	

1.0"	outer	dia.,	.091"	Th

153 S124682-5E14-9 20 Fender	Washer,	CRES	steel,	.328"	inner	dia.,	

.875"	outer	dia.,	.091"	Th

154 S4932869-08-04 112

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

155 S4932869-08-05 123

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

156 S4932869-08-06 212

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

157 S4932869-08-07 348

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

158 S4932869-08-08 937

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

159 S4932869-08-09 588

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

160 S4932869-08-10 889

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

161 S4932869-08-11 1138

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

162 S4932869-08-12 826

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd
84

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

163 S4932869-08-13 554

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

164 S4932869-08-14 332

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

165 S4932869-08-15 722

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

166 S4932869-08-16 526

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

167 S4932869-08-17 53

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

168 S4932869-08-18 24

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

169 S4932869-08-19 114

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

170 S4932869-08-21 22

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

171 S4932869-08-28 53

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

172 S4932869-08-29 313

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

173 S4932869-08-30 713

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd NAS6804U30

174 S4932869-08-31 216

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

175 S4932869-08-32 44

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd

176 S4932869-08-33 31

Pin-Rivet,	Grooved-P-Type,	Ti,	1/4"	dia.,	

Crown	Protruding	Hd 3D0010-8-33

177 S4932869-10-09 235

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

178 S4932869-10-10 235 Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

179 S4932869-10-11 418

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

180 S4932869-10-12 353

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

181 S4932869-10-13 216

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

182 S4932869-10-14 251

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

183 S4932869-10-15 106

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd NAS6705U15

184 S4932869-10-16 132

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd
85

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

185 S4932869-10-17 136

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

186 S4932869-10-18 35

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

187 S4932869-10-19 40

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

188 S4932869-10-20 31

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

189 S4932869-10-23 5

Pin-Rivet,	Grooved-P-Type,	Ti,	5/16"	dia.,	

Crown	Protruding	Hd

190 S4932869-12-10 9

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

191 S4932869-12-11 5

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

192 S4932869-12-13 18

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

193 S4932869-12-14 22

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

194 S4932869-12-16 48

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd NAS6706U16

195 S4932869-12-18 57

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd NAS6306U18

196 S4932869-12-19 57

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd NAS6406U19

197 S4932869-12-20 145

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

198 S4932869-12-22 51

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd

199 S4932869-12-23 51

Pin-Rivet,	Grooved-P-Type,	Ti,	3/8"	dia.,	

Crown	Protruding	Hd NAS6406U23D

200 3D0099-6-5 9 Pin - Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

201 3D0099-12-14 5 Pin	- Rivet,	Threaded,	Ti,	3/8"	dia.,	

202 NAS6807U15 26 Bolt,	Hex	Head,	Close	Tolerance,	

Unplated	Ti,	7/16"	diam.

203 NAS1474R3 160 Sealing	Nutplate

204 MS20426M3-4 310 Monel	Rivet

205 92620A703 20 3/8"	Bolt	1.38	Long,	Wire	Feed	Thru	on	

Door

206 91030A430 20 3/8"	Nut

207 11255A13 16 Handle

208 91771A196 100 8-32	CSK	Screw

209 4513K425 4 1/2"	Pipe	Plug	- Used	for	testing	only
86

Item	

No. Part	No.	* Qty. Description Substitute	Part	No.

210 3D0099-6-10 9 Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

211 3D0099-6-12 9 Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

212 3D0099-6-14 5 Pin	- Rivet,	Threaded,	Ti,	3/16"	dia.,	

Protruding	Head

213 3D0099-10-23 14

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,

Protruding	Head

214 3D0099-10-24 14

Pin	- Rivet,	Threaded,	Ti,	10/32"	dia.,	

Protruding	Head

215 3D0031-4-15 9 Bolt

216 3D0031-4-16 9 Bolt 3D0108H4-16

217 3D0031-4-21 5 Bolt

218 3D0031-5-15 10 Bolt

219 3D0031-5-17 5 Bolt 3D0073-5-17

220 3D0031-5-18 5 Bolt

221 3D0031-5-19 9 Bolt

222 3D0031-6-25 22 Bolt

223 NAS6804U19 31 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

1/4"	diam.,	

224 4D0012-5P 30 Washer

225 4D0012-5C 30 Washer

226 4D0012-6P 22 Washer

227 4D0012-6C 22 Washer

228 3D0042-4 16 Nut

229 3D0042-5 30 Nut

230 3D0042-6 24 Nut

231 NAS6403U6 135 Bolt,	Hex	Head,	Close	Tolerance,	Unplated	Ti,	

3/16"	diam.,

* Fastener part numbers may be substituted with an equivalent part number based on

fastener availability
87

Figure 113. Fastener Cage at the Multi-Bay Box Assembly Site
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

2. REPORT TYPE 

Contractor Report

 4. TITLE AND SUBTITLE

PRSEUS Panel Fabrication Final Report

5a. CONTRACT NUMBER

NNL13AA11C

 6. AUTHOR(S)

Linton, Kim A.; Velicki, Alexander; Hoffman, Krishna; Thrash, Patrick; 

Pickell, Robert; Turley, Robert

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center 

Hampton, Virginia 23681 

 

 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

 8. PERFORMING ORGANIZATION

 REPORT NUMBER

10. SPONSOR/MONITOR'S ACRONYM(S)

NASA

13. SUPPLEMENTARY NOTES

Langley Technical Monitor: Dawn C. Jegley

12. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Category 39

Availability: NASA CASI (443) 757-5802

19a. NAME OF RESPONSIBLE PERSON

STI Help Desk (email: help@sti.nasa.gov)

14. ABSTRACT

NASA and the Boeing Company have been working together under the Environmentally Responsible Aviation Project to 

develop stitched unitized structure for reduced weight, reduced fuel burn and reduced pollutants in the next generation of 

commercial aircraft. The structural concept being evaluated is PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure). 

In the PRSEUS concept, dry carbon fabric, pultruded carbon rods, and foam are stitched together into large preforms. Then 

these preforms are infused wiht an epoxy resin into large panels in an out-of-autoclave process. These panels have stiffeners in 

the length-wise and width-wise directions but contain no fasteners because all stiffeners are stitched to the panel skin. This 

document contains a description of the fabrication of panels for use in the 30-foot-long Multi-Bay Box test article to be 

evaluated at NASA LaRC. 

15. SUBJECT TERMS

CAPRI; Composites; Graphite-Epoxy; Out-of-Autoclave Processing; PRSEUS; Pultruded Rod; Stitching

18. NUMBER

 OF 

 PAGES

99

19b. TELEPHONE NUMBER (Include area code)

(443) 757-5802

a. REPORT

U

c. THIS PAGE

U

b. ABSTRACT

U

17. LIMITATION OF 

 ABSTRACT

UU

Prescribed by ANSI Std. Z39.18

Standard Form 298 (Rev. 8-98)

3. DATES COVERED (From - To)

July 2013 - December 2013

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

699959.02.22.07.01.01 

11. SPONSOR/MONITOR'S REPORT

 NUMBER(S)

NASA/CR-2014-218149

16. SECURITY CLASSIFICATION OF:

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gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and 

Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person 

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

1. REPORT DATE (DD-MM-YYYY)

01- 01 - 2014