Placing the Rib piecesTake one of the frames and place on it the nbs, with the arched side up.letting one end of the nbs come flush with the front edge of the forwardframe, and the other end projecting about a foot beyond the rear frameThe manner of fastening the ribs to the frame pieces is optional. In sonases they are lashed with shoe thread, and in others clamped with a metalclamp fastened with 1 /2-inch wood screws. Where clamps and screws areused care should be taken to make slight holes in the wood with an awlbefore starting the screws so as to lessen any tendency to split the woodOn the top frame, twenty-one ribs placed one foot apart will be requiredOn the lower frame, because of the opening left for the operator's bodyyou will need only twenty. Joining the Two FramesThe two frames must now be joined together. For this you will needtwenty-four aluminum or iron sockets which may be purchased at afoundry or hardware shop. These sockets, as the name implies, provide areceptacle in which the end of a stanchion is firmly held, and have flangeswith holes for eye-bolts which hold them firmly to the frame pieces, andalso serve to hold the guy wires. In addition to these eye-bolt holes thereare two others through which screws are fastened into the frame pieces.On the front frame piece of the bottom plane place six sockets, beginningat the end of the frame, and locating them exactly opposite the struts.Screw the sockets into position with wood screws, and then put the eye-bolts in place. Repeat the operation on the rear frame. Next put the socketsfor the upper plane frame in place.You are now ready to bring the two planes together. Begin by insertingthe stanchions in the sockets in the lower plane. The ends may need a littlerubbing with sandpaper to get them into the sockets, but care must betaken to have them fit snugly. When all the stanchions are in place on thelower plane, lift the upper plane into position, and fit the sockets over theupper ends of the stanchions
Trussing with Guy wiresThe next move is to tie the frame together rigidly by the aid of guywires. This is where the No. 12 piano wire comes in. Each rectangleformed by the struts and stanchions with the exception of the small centerone, is to be wired separately as shown in the illustration. At each of theeight comers forming the rectangle the ring of one of the eve-bolts will befound There are two ways of doing this tieing." or trussing. One is to runthe wires diagonally from eye-bolt to eye-bolt, depending upon mairstrength to pull them taut enough, and then twist the ends so as to holdThe other is to first make a loop of wire at each eye-bolt, and connectthese loops to the main wires with turn-buckles. This latter method is thebest, as it admits of the tension being regulated by simply tuming thebuckle so as to draw the ends of the wire closer together. a glance at theillustration will make this plain, and also show how the wires are toplaced. The proper degree of tension may be determined in the followingmannerAfter the frame is wired place each end on a saw-horse so as to lift theentire frame clear of the work-shop floor. Get under it, in the centerrectangle and, grasping the center struts, one in each hand, put your entireweight on the structure. If it is properly put together it will remain rigidand unyielding. Should it sag ever so slightiy the tension of the wires mustbe increased until any tendency to sag. no matter how slight it may be, isovercomePutting on the clothWe are now ready to put on the cloth covering which holds the air andmakes the machine buoyant. The kind of matenal employed is of smallaccount so long as it is light, strong, and wind-proof, or nearly so. Someaviators use what is called rubberized silk, others prefer balloon cloth.Ordinary muslin of good qualty, treated with a coat of light vamish after itts in place, will answer all the purposes of the amateur.Cut the cloth into strips a little over 4 feet in length. As you have 20feet in width to cover, and the cloth is one yard wide, you will need sevenstrips for each plane, so as to allow for laps, etc. This will give youfourteen strips. Glue the end of each strip around the front horizontalbeams of the planes, and draw each strip back, over the ribs, tacking thedges to the ribs as you go along, with small copper or brass tacks. Indoing this keep the cloth smooth and stretched tight Tacks should also beused in addition to the glue to hold the cloth to the horizontal beams
Next, give the cloth a coat of vamish on the clear, or upper side, andwhen this is dry your glider will be ready for useorcing the clWhile not absolutely necessary for amateur purposes, renforcement ofthe cloth, so as to avoid any tendency to split or tear out from wind-pressure, is desirable. One way of doing this is to tack narrow strips ofsome heavier material like felt over the cloth where it laps on the ribsAnother is to sew slips or pockets in the cloth itself and let the nibs runthrough them. still arod 1s to sew 2-imch strips(of the sanmaterial as the cover) on the cloth, placing them about one yard apart, buthaving them come in the center of each piece of covering, and not on thelaps where the vanous pieces are joineUse of Armpieces.Should armpieces be desired, aside from those afforded by the centerstruts, take two pieces of spruce, 3 feet long, by 1 x13/4 mches, and boltthem to the front and rear beams of the lower plane about 14 inches apartThese will be more comfortable than using the struts, as the operator willnot have to spread his arms so much. In using the struts the operator, as arule, takes hold of them with his hands, while with the armpieces, as thename implies, he places his arms over them, one of the strips comingunder each armpitFrequently somebody asks why the ribs should be curved. The answeris easy. The curvature tends to direct the air downward toward the rear and.the air is thus forced downward, there is more or less of an impactwhich assists in propelling the aeroplane upward