Planes for Brains. Michael G. LaFosse

sides are equal, so the ratio of a square’s adjacent sides is 1:1. To prepare the largest possible square from any rectangle simply fold one of the short edges to match an adjacent long edge. If you do not want to make a diagonal crease, use two sheets of the same size rectangle, overlapping them at one corner while aligning the second perpendicular to other. Trim the excess of each for two clean squares.

      The technical specifications of a square.

      To turn a long rectangle into a square, fold at a 45-degree angle, short edge to long edge. Unfold, and trim. Don’t toss those trimmed strips into the recycling bin just yet! See page 87 for a great use for these scraps.

      A Word About A-Series Paper and the Silver Rectangle

      A4 letter paper is a common format outside of North America. The A-Series format, prescribed by the International Organization for Standardization (ISO), is a Silver Rectangle, with adjacent sides having an aspect ratio of 1: √2. The larger side is as long as the length of the diagonal of the largest possible square. One particularly desirable characteristic of paper in this format is that when a Silver Rectangle is divided in half through its long edges, the resulting, smaller rectangles have adjacent sides in the same proportion as the parent rectangle.

      If a diagonal crease is not desired, simply take another sheet of the same dimensions, turn it 90 degrees, and lay it atop the first sheet. Trim away the excess.

      The technical specifications of A4 paper.

      Turn US letter size paper into a Silver Rectangle by executing the steps depicted in the series below.

      Scale Any Rectangle

      It is useful to know how to cut smaller or larger rectangles of the same proportion to make paper planes that perform well and look better on display. No matter the kind of rectangle, the method is the same. Inscribe a diagonal line that spans two corners of the rectangle. Intersect this line at any desired point, and connect that point back to each edge with perpendicular cut lines leading to the vertical and horizontal edges.

      Forming a US Letter Proportion from a Square

      Letter paper commonly found in North America measures 8½ inches by 11 inches. You can measure and cut these rectangles from odd stock and you can use the above method (see “Scale Any Rectangle”) to make larger or smaller examples. However, there is a quick approximation you can use to make rectangles with proportions close enough for the projects in this book. Fold the square in half, edge to edge, but make only a pinch to mark the center. Open. Fold one edge to the pinch and trim off the resulting flap. The remaining rectangle will have an aspect ratio of 1: 0.75, which is acceptably close to the proportions of US letter paper (1: 0.77) to be used for the majority of the planes in this book.

      Forming a US Letter Proportion from an A4 sheet

      A4 paper is handy to paper plane enthusiasts in Europe and Asia. Though some of the models in this book can be easily adapted to the A4 sheet, most of the US letter models will look better and fly best if folded from rectangles with those proportions. It is an easy task to trim the A4 sheet to the correct proportions: simply cut a 1-inch (2½-centimeter) strip from a short edge of the sheet. Incidentally, these slightly smaller models fly extremely well!

      It’s a simple matter to scale any rectangle up or down: just draw a diagonal line between two corners and intersect at any point.

      The technical specifications of US letter paper.

      You can quickly adapt any square to approximate US letter proportions using the steps shown here.

      You can quickly convert any A4 size sheet to US letter size using the steps shown here.

      CHAPTER 2

      Masterful Folding Techniques

      Crisp, precise and neatly folded paper airplanes look best and fly best. Making sharp creases without bruising the paper also takes a degree of skill, which comes with practice. It is also true that freshly folded planes fly best. Here are some tips that will help you fold neatly.

      Creasing Carefully

      Assuming that the corners are square, neat folding begins with properly aligning the parts of the paper before committing the fold with a crease.

      Secure the alignment by first pressing at the middle of the fold, and then slide from the center to the right, (if using your right hand), or to the left (if using your left hand). Return to the center and create the other half of the crease. This simple technique decreases the amount of creep (or deviation) away from the fold line.

      Whether you use a folding tool or just your fingers, first coax the paper gently to decrease the radius of the bend uniformly along the crease line, adjusting the placement several times before committing the decision with a fold, then sharpen the crease.

      Once paper planes have had a chance to sit for a while, the folds will begin to relax. Dramatic changes in temperature and humidity make this happen rapidly. Always re-sharpen your creases before flying a plane that has been sitting for a while.