Page A4 October,
1935 NEWNES PRACTICAL
Joining the Sides
The two sides now have to be joined by the back of the pilot's seat, made of 3 mm plywood as is shown in Fig. 13. The holes. reinforced with circles of plywood, give access to the luggage compartment. The holes and the plywood circles can be out quite easily with a carpenter's compass, of which one arm has been ground to a knife edge. Any ironmonger's shop will provide upper face. one of these tools.
On the panel you should only place the bar and nail the sides in front of the laths. Then put on the crosspiece, making its edge bevelled and level with the underside of the longerons.
The short strips in front will then be joined by the panel (Fig. 8). cut out in such a way that the crossbar fits on to the block, and its crossbar on to the lower end of the short strips; thus, the crossbar and the ends of the short strips all come level with longerons. The height of the panel will be decided on the spot. Do not forget to reinforce the hole with a circle of plywood. File away anything which might obstruct the straps.
The short strips, in the rear are also joined at their lower ends by a slat and double gussets. In the same way, the short strips are united by the panel with the crossbars. The slats are all on the same level, and serve to support the plank which forms the seat, of which the underneath view is shown in Fig. 10. This panel is fixed by 12 screws with round heads. It is double ; that is to say, two thicknesses of 6 mm. are glued together under weights. There is no point in nailing it together. Two strips connect the crossbars near the edges to the central hole in which the joystick works. At each end of these reinforcing strips use a wood screw with a washer.
The Front Point
The lyre-shaped piece of wood will be cut out from a plank of 20 mm. of hard wood as shown in the sketch Fig. 9.
Because of its sloping position to the fuselage it will be necessary to bevel off its outaide faces in order to diminish the upper face. The arms of this piece of wood will be separated a distance of 550 mm. by adjusting the flat faces, and they will be joined underneath by a triangle of plywood which is glued to them; and again in the middle by the plank of hard wood of 40 mm., thinned down at the ends to 20 mm., well fitted and held ftom underneath by the gussets, which are 6 mm. thick. All are fixed simply by gluing. This plank, later on reinforced by bolted metalwork, will support the motor.
Bevelling, adjusting. and fitting should be commenced with a plane and finished off with a large half-round file - a metal file bought and kept for this purpose. This file will be used only on wood. It is better than a wood rasp, and after the glue in dry the file eats into the wood just as well as a rasp, even if it hits up against some nails. The rasp or the plane would very soon be damaged if it struck projecting nails.
Enclose the two arms of the lyre between the bits of plywood (fig 9), gluing them together and nailing it in such a way that the two sides, when drawn together, go a little bit beyond the desired shape. Nail the plywood carefully all along the edge of the arms with one nail every 10 mm. Cut off the edges which go beyond the end of one lyre, and plane off the amount which extends above it. (This has been allowed for in Fig. 2 by using 30 mm. instead of 20 mm.) You now have a smooth joint which allows the whole to be covered by a triangular sheet of plywood.
From a plank of hard wood 20 mm. thick cut out a piece and nail it on to the panel which is 6 mm. thick; this will join the two arms of the lyre and the laths.
Turn the skeleton upside down. Cut out the tongue at. 20 mm. and fit it to the edge. Copy this fourteen times in plywood of 3 mm. thickness. Seven thicknesses glued together, one on top of the other along the edge, will make a longeron curved in two directions to which you can nail, one after the other, the two bits of 3-mm. plywood (Fig. 3). Put one on top of the other, and glue, which will make the planking of the cockpit.
The planking is supported at the rear with the batten adjusted in front of the panel. With a file smooth off all the lower faces of the curved strips so that a piece of 3-ply 3mm., curved in a triangular form can be well glued everywhere from the point right up to the batten. This will make a part of the base of the fuselage. Now cover the lyre right up to the panel with plywood of 3 mm.