Chapter Synopses
Chapter 1 – Basic Principles of Composites
Chapter 2 – Overview of Techniques
Chapter 3 & 4 – Materials Handling
Chapter 5 – Basic Layup Techniques
Chapter 6 – Flat Tool Vacuum Bagging
Chapter 7 & 8 – Joining Parts: Basic Corners
Chapter 9 – Formed Curves
Chapter 10 – Flanges & Closing
Chapter 11 – Attachments
Chapter 12, 13 – Molds & Mold Techniques
Self-Paced Exercises
Chapter 1 – Basic Principles of Composites
 Read Chapter 1 for free (214k, PDF)
A very brief summary of the basic principles and properties of composites, particularly when composites are formed as thin sheets. The problems of torsion and buckling in thin sheets are described. ^ Top
Chapter 2 – Overview of Techniques
Summarizes the materials and techniques for making lightweight sandwiches, which will be described in much greater detail in the following chapters, including the cutting and handling of glass cloth and foam core materials. Wetting-out techniques are described. The basic principles of vacuum-bagging using materials obtainable from home supply stores are introduced. ^ Top
Chapter 3 & 4 – Materials Handling
Chapters 3 and 4 tell how to handle the special materials used in homebuilt composite construction, including, storage, cutting, and measuring of glass fabrics and plastic resins. The use of colored tinting powder in mixed epoxy to make bubbles or other variations visible while wetting out is emphasized. Chapter 4 gives particular attention to the techniques for cutting, perforating, splicing and bending the relatively stiff foam materials used for cores. Hot-wire cutting of polystyrene foam is described. The process for hot-wire cutting shaped foam cores from blocks, as would be used to form an airfoil, is described. ^ Top
Chapter 5 – Basic Layup Techniques
Describes the methods for wetting out a basic open layup to make a cored-skin panel. ^ Top
Chapter 6 – Flat Tool Vacuum Bagging
Describes the tools and techniques used to cure a layup under vacuum, using materials available from the home supply or hardware store. The emphasis is on the use of tool surfaces formed from easily available standard sheets of shower liner plastic or Masonite. Double-bagging is described, where an inner bag of release film pulled against a tool surface is used to form a reliable molding surface, then a second outer bag is used to enclose the entire layup to complete the cure. Rather than use the sealing materials sold for the mainline composites industry, ordinary 2-inch package mailing tape is used for bag sealing. ^ Top
Chapter 7 & 8 – Joining Parts: Basic Corners
Cover the basic principles of adhesive joints and the methods used in joining the large formed parts typical of composite designs. Adhesives suitable for bonding non-permeable composite structures cannot cure by reaction with the atmosphere (“drying”), so the several types of adhesives that are suitable are described. Different types of joints are described in Chapter 7, including, straight lap joints, joggles, and the joining of thick panels. In aircraft construction, it will frequently be necessary to join two separate sheet surfaces at an angle to form a corner. Several types of corners are described. Detailed instructions are given for making and efficiently applying wetted composite tape over a joint. “Taping” is a skill that will frequently be required by a builder. ^ Top
Chapter 9 – Formed Curves
Most conventional aircraft surfaces will be found to be generated from straight lines; i.e., the surfaces may be duplicated by bending a flat sheet into some combination of flat surfaces, cylinders, and cones. There is a very great advantage, therefore, to be able to cure large sections of skin on a flat tool, then to bend the skin to the desired shape. This method allows the use of very simple bending jigs because the bends are easily forced at the desired places. Chapter 9 describes the processes for making accurate bent surfaces from cured flat surfaces. The sandwich skins discussed in this book are very stiff, so special techniques, such as slotting the core, must be used if a bend is to be made at a thick section. In most cases, the folds will be made in areas which do not contain a sandwich core. Several techniques are described for making large bent joints.. ^ Top
Chapter 10 – Flanges & Closing
An assembly composed of cured surfaces, such as the top skin of a typical wing, with the ribs and shear webs installed, may be considered to be basically an open box, without a top, as shown. It is necessary to provide an adequate surface for mounting a closing skin so that the finished outside surface, after the bonding, is located exactly where required. This mounting surface is the flange. Essentially, the flange is formed similarly to the tape in a regular taped joint, except that one bonding face must be removable. Practical techniques for making accurate flanges are described. ^ Top
Chapter 11 – Attachments
The thin-skinned, light-cored, panels used in this book require that concentrated attachment loads must be spread over a sufficient amount of strong skin to carry those loads. Practical aircraft designs require removable wing attachments, struts, inspection panels, and hinges, so that the large-area structure can accept high stress points like bolts. Describes several practical ways to modify cored sandwich structures or non-cored skins so that bolts can be used. ^ Top
Chapter 12 & 13 – Molds & Mold Techniques
Discuss the techniques used by the home builder to make practical sheet molds for use with vacuum-bagging, including the case where a large bend radius is required, as with a wing leading edge. The molding practices used by commercial shops, such as aircraft kit builders are briefly described. (It is assumed that the home builder and potential kit builder will not wish to duplicate these techniques, but only wishes to understand the process.) ^ Top
Exercises
The book provides a self-teaching course of 17 Exercises. Each exercise describes in detail how to do specific operations so that the builder can gain useful direct experience without making a commitment to a full-scale aircraft project. All of the Exercises can be done in the relatively small space of a typical single-car garage, nearly all with a working surface of a standard 4 x 8-foot sheet. The series begins with instruction in how to make a small multi-layer pane as a very simple open glass-epoxy layup. The builder then repeats this simple panel with improving techniques, adding vacuum-bagging very early in the sequence. The builder then makes the same panel under vacuum with a light foam core.
Later Exercises take the builder through simple forming operations, including a full-scale section of a fuselage. The series ends with the reader making a full-chord section of a practical wing, using curved wing skins. After completing this series, the reader will have the confidence and judgment to undertake an airplane project. ^ Top |
