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Chapter 7

Tools, Materials, Methods, Accessories

This chapter is concerned with the hows, whys and wherefores of the things which are used in kite making and flying. We begin with a few words about tools, of which the following are recommended.

Tools

First, a fretsaw, for cutting the small joints which are sometimes used. Second, a small hacksaw, or a small tenon saw, for cutting lengths of wood. Third, for a hammer, use what is called a pin hammer. Other tools include a craft knife with spare blades; a small screwdriver; a small file; a hand drill, with bits up to £ in. diameter; a fretsaw drill or an awl for making nail and screw holes; a small brad punch to drive nails home; a rule; a pair of scissors; a soft-grade pencil; a few assorted paintbrushes. In addition, a woodworker's vice comes in handy, as also do one or two cramps for holding down glued joints.

Materials

In considering the various materials which are used we come first to wood for the framework. It is possible to make a kite from odd scraps of wood, or even hedgerow sticks, but in the long run it pays to use the best. The wood must meet with certain requirements, namely; it must be light in weight, smooth, strong, and flexible. Fortunately, this kind is readily obtained in the form of hardwood stripwood. It can be obtained at woodworkers' and model-makers' shops. It comes in lengths up to 8 ft. and is of different thicknesses. When you are buying wood it is a good thing to tell the shopkeeper what you want it for, and he will help you in the choice. This stripwood is most suitable for the purpose, because besides being light and strong it is also fairly flexible, though not to the same extent, of course, as cane.

Cane is often specified in kite making, generally for the crossbars when these have to be bowed. That which is generally referred to is known as gardener's or staking cane. The hard outer skin gives great strength and flexibility to small diameter lengths. It is supplied both in the form of whole cane and split cane. Of course, one may split the cane at home when necessary by using a sharp knife or fretsaw.

Other cane mentioned in this book is called centre cane. It is cut from rattan, a species of climbing palm belonging to the East Indies. The hard outer skin of the rattan is stripped off, leaving the centre cane. It provides lengths of uniform thickness, but, however, it does not possess the strength of whole cane, as it lacks the hard outer skin. It may be used in suitable diameters when difficult shaping is called for, as it may be easily worked. Handicraft stores usually stock centre cane.

Covers for kites can be made in several materials. The most common is tissue paper. It is chosen mainly because of its lightness, but it is flimsy stuff and must be handled with care. Sheets of the paper measure 20 in. x 30 in., and various colours may be obtained. Following correspondence with a well-known paper manufacturers, and after testing, the writer recommends the following as being superior to tissue paper: one, pure unbleached greaseproof (17/18 lb.); two, mg. pure ribbed kraft (16 lb.). Both are light in weight and very strong. A good quality adhesive should be used for gluing the greaseproof. Both papers are obtainable in sheets measuring 20 in. x 30 in. A cloth cover is specified for some kites. This may be made of fine smooth silk, very fine calico or cambric. The usual width of these is 36 in.

The right kind of glue is an important factor in kite making, since the joints must be of the maximum strength. Generally speaking, glues are divided into the synthetic; the animal, and the fish glues. The two latter, when properly used, are very strong. They are gap-fillers in joints which do not fit too well. Another advantage is that they do not deteriorate so quickly in the tin or tube as do some other types. 'Croid' or 'Seccotine' are especially recommended.

The cellulose cements are very much to the fore in the synthetic adhesives. They are widely-known as 'balsa cements' and are used for their strength and quick-setting properties. Unless they are properly sealed when not in use, they have a tendency to harden. As a general rule, the quicker in setting the cement is, the shorter is the time that it will keep in a working condition, particularly when once the container has been opened. Most kinds of cellulose adhesives are suitable for balsa wood, paper, and card, but for ordinary wood a slower drying kind is needed. This is known as 'high strength' balsa cement.

Mention may also be made of an adhesive derived from poly-vinyl acetate (p.v.a.). This is an excellent general purpose glue. It is quick-setting and very strong, and provides slightly flexible joints. It is non-staining and therefore is a good choice where cloth covers are glued and not sewn down.

The synthetic resin glues, of which there are many, make up another great group. They give great joint strength, and are waterproof. Certain proprietary brands are supplied with the resin and hardener ready mixed, requiring only the addition of water.

String comes next in the list of materials. This is the general name for the material used for the bracing, bridle, tail, and kite line. The string is required in different strengths and thicknesses according to the purpose it serves, and the size of the kite. The writer, after consultation with a manufacturer, and after many tests, recommends the following as being suitable for the kites listed in the book.

In the case of the larger kites, up to 3 ft. 6 in. in length, use fine flax line for the bracing, and No. 68 hemp whipcord for the bridle and the kite line. Flax line may also be used for the tail. The line is available in knots of 17-20 yards. For the smaller kites and to serve a general purpose, use No. 10 or 104 coloured cotton, or linen tent thread. These should serve for kites up to say, 2 ft. in length.

The appearance of a kite is improved when it is decorated in some way. A few simple designs are given later in the chapter. These may be cut from coloured gummed paper, or painted directly on to the kite cover. Use fabric painting oil colours for cloth covers. Lacquer is most suitable for paper covers. It spreads easily, gives a clear-cut outline and dries fairly quickly.

Methods  

Joints

The simple butt joint is all that is generally needed in kite making. It may be formed in two ways: first, by laying one piece of wood across another, and fastening together with glue and binding thread; second, by fastening two ends together with glue and a nail. When properly made, the butt joint combines simplicity with strength.

The halving joint is used to make a framework all on one level, that is, one part does not stick out above or below another. This makes for neatness, and enables the kite cover to lie flat upon all the framework. This joint, to be effective, must be made accurately. A good joint is one in which the parts need a gentle tapping home with a mallet. Both these joints are described and illustrated in the instructions for making kites in Chapters 1-6.

 Gluing

When using glue, first read the directions on the container. It is surprising how many people don't do this, and then blame the glue because it won't stick. These directions usually state the approximate drying time, that is, the time to be allowed before the parts are brought together. Drying time is fundamental to successful gluing.

Don't use too much glue. Too much is nearly as useless as none at all, and far messier. After they have been set aside for a while to dry, the two parts are pressed firmly together. The ultimate strength of the joint depends upon the closeness of contact of the two pieces of wood. The aim is to expel all air bubbles, which are the enemy of good joints. The work is best done in a fairly warm room. It is an advantage to cramp the joints and to allow the glue to set hard overnight. Metal cramps can be bought quite cheaply.

Binding

In addition to the use of glue, most kite framework joints are bound round with thread or fine string. Use thread for small kites and fine string for the larger sizes. Smear the binding with glue to keep it in place. Illustrations in Chapters 1-6 will show how to achieve neat and effective binding of joints.

Shaping Wood and Cane

We will take wood first. When the framework is to be bowed and suitable cane cannot be obtained, it is possible to shape hardwood stripwood. Many kinds of wood may be shaped by steaming. Professional woodworkers use a steaming box; but as an alternative, the wood may be soaked for a minute or two in warm water, and then laid across a pan of hot water. It should, after a while, be sufficiently pliable to be formed, gently but firmly, into the required shape, which shape should be fixed by the use of a bowstring. The shaping should be done before the parts are glued and assembled.

Cane, being naturally flexible, is readily formed into curves. Whole or split cane is more easily bent by the application of dry heat (e.g. gas jet, or electric fire). This method prevents cracking or splitting. Again, in the case of kite crossbars, the shape is retained by the immediate use of bowstrings. Other shaped parts should be fixed in position as soon as possible.

Centre cane, which may be used when small sharp curves have to be made, is rendered more pliable by soaking it in hot or cold water. After the parts have been shaped, strings can be run across the ends to prevent the cane from springing back while it dries out.

Cane may be cut, split, and drilled quite easily. The best way of cutting it is to use the knife so that it rolls the cane round at the same time as it is cutting through it. This will prevent the ends from splintering. Cane can be split with a sharp-pointed knife. Don't use it as though it were a chisel, but draw it firmly, using the point, along the cane. It will be necessary to repeat the action in order to separate the cane. Nodes or knots are best cut through with a fretsaw. It is a good plan to drill through the cane near the ends, and pin it to a board. This will prevent the cane from rolling while the splitting is being done. When drilling cane, care must be taken not to split it. As soon as the drill pierces the underside, turn it over and drill through again.

Knots And Hitches

The difference between a knot and a hitch is that a knot makes a more lasting fastening. Again, a knot may be formed on the string itself, whereas a hitch usually requires some other object to which it can be attached. There are various knots and hitches, and from among them a few have been chosen as being useful in kite making and flying.

1	Most knots are formed from a loop or bight, A. The parts belonging to it are, the standing part, B, and the end, C. (Fig. 21).
2	Overhand knot. This is the simplest to make and forms a part of many other knots. It is the one used for knotting the sewing thread when a cloth cover is required for a kite. It may also serve, when repeated once or twice, for tying the bracing strings (Fig. 21).
3	Reef knot. Known also as the square knot and the sailor's knot, it is undoubtedly the simplest and best with which to fasten together two strings of equal thickness. It is chosen, along with the bowline knot, for attaching the kite line to the bridle (Fig. 21).
4	Bowline knot. This is called the king of knots. It is so called because of its general usefulness and reliability. Fig. 21 shows the correct way of forming it.
5	Clove hitch. It may be said that this is the best known hitch, being widely used because it is easy to form, and is very reliable. The stronger the pull against it, the firmer it holds. It may be used for fastening the paper pieces to the tail string and for similar attachments. A and B (Pig. 21) show the stages in forming the hitch.
6	Clove hitch slip knot. Because it forms what is called a running noose, it is recommended when one wishes to secure the kite line temporarily to a post or other anchor whilst the kite is in flight (Fig. 21).
7	Fisherman's bend. When there is a varying strain on the string, this will prove to be most reliable. It may therefore be used for tying bracing strings and bowstrings. When it is correctly formed, it may be readily untied in order to make any necessary adjustments of the strings (Fig. 21).

The reader is advised to practise making these knots and hitches so that they may be quickly and properly formed.

Accessories

In this section there will be found instructions and illustrations for making a number of things which add to the enjoyment of kite flying.

Reel

A reel or winder may be regarded as a necessity. It is not merely something upon which the line is wound. If the line is thought of as being the 'motor', then obviously the reel assists it in its important function. Obviously, the size of the reel will be governed by the size of the kite, and the amount and thickness of the line Therefore the measurements given here may be suited to individual requirements.

PLATE II. Sir George Cayley’s glider, 1804

Courtesy Radio Times Hulton Picture Library PLATE III. Boy flying kite (c.1600)

PLATE iv. Hargrave box-kite, first made in 1893

Courtesy Radio Times Hulton Picture Library PLATE v An early reproduction illustrating a Chinese man and child flying kites

The reel shown in Fig. 22 is of a convenient size. As will be seen, it is a revolving spindle type, with a simple locking device, which enables the operator to have a hand free at times to attend to other things.

The reel is made up of eleven separate parts, and is constructed as follows. Cut two 4 in. diameter circles from 3/16 in. plywood, as at A. Cut 7/8 in. diameter holes through the centres. The spindle, B, is formed from I in. diameter round rod, and measures 61/4 in. in length. Cut two side pieces, as at C, measuring 5 in. x 41/8 in. Use wood, 1/2 in. thick.

Drill 7/8 in. diameter holes through them at the positions shown. Make them slightly over-size, by means of a round file, so that the spindle revolves freely. The base, D, measures 5 in. x 41/8 in. and is made from wood, 1/2 in. thick.

Fig. 22. Kite line reel (No. 1)

Fit the spindle to the circular pieces. The left-hand piece is glued 5/8 in. from one end of the spindle; the right-hand piece, 11/4 in. from the other end. Attach the side pieces to this unit. Place thin washers on the spindle between these sides and the circular pieces. Next, add the base, D. Use glue and 1 in. fine flat-headed screws, and counter-sink the holes for them. Place the base between the sidepieces, otherwise the subsequent measurements will be wrong.

The handle is in two parts, E and F. E measures 33/4 in. x 2 in. and is cut from wood which is 1/2 in. thick. Cut two 7/8 in. diameter holes, 1/2 in. from the top and the bottom. Make them slightly under-size, to ensure a good fit for the spindle, and the rod, F, both of which should need tapping home with a mallet. The rod, F, is 41/2 in. in length and is cut from 7/8 in. diameter round rod. Fit it into one of the holes, and secure it with glue and a 1 in. fine screw, which is driven through at the position shown. Now place E on the spindle and make fast with glue and a 1 in. fine screw, the position of which is shown in Fig. 22. Place a thin washer on the spindle between the side piece and the handle.

The bottom handle, G, is 5 in. in length and is cut from 7/8 in. diameter round rod. Make a small holding block, H. This is 3 in. in length and 2 in. in width. Drill a 7/8 in. diameter hole through the centre, and insert the handle, G. The latter should fit tightly in its hole, so that it requires tapping home with a mallet. Secure with glue and a 1 in. fine screw, which is driven through at the position shown. The holding block is then glued and screwed to the base.

The method of joining the parts by means of a screw has been chosen for its simplicity. Those who prefer it may use the square mortise and tenon joint, as shown at I.

Fig. 23. Kite line reel. (No. 2)

The locking device, J, is a strip of wood, 1/2 in. thick; or better still, a metal strip. It measures 2 in. x 1/2 in., and is secured to the side at the position shown, by means of a screw. When it is turned to the horizontal position, it locks the handle.

Sandpaper all parts thoroughly. Apply a coat of size to fill the grain, and when this is dry, enamel in bright colours. In order to ensure the smooth

running of the spindle, coat the edges of its holes with blacklead or graphite paste. The things just mentioned are best done before the reel is finally assembled.

A Simpler Type of Reel

This is illustrated in Fig. 23. The upright strips, A and B, are 6 in. in length and are cut from 1 in. square stripwood. Drill two holes, 1/2 in. in diameter at positions 1 in. from the top and the bottom. Cut two pieces of dowelling, 1/2 in. diameter and 10 in. in length. These are attached to the upright strips in the manner shown. The ends of the rods form handles, which measure 4 in. in length. Sandpaper all parts thoroughly; apply a coat of size, and when this has dried, finish with enamel.

Parachutes

Fig. 24 illustrates the stages in the making of these. They are easily made, and add to the enjoyment of kite flying. They travel up the kite line, to which a stop block is tied. When they reach the block, a sharp jerk of the line will release them, whereupon they will float gently down to earth.

Fig. 24. Parachute

Cut a circle of tissue paper, 12 in. in diameter. At the centre of this, paste a 1 in. diameter circle of thin cardboard. Cut eight slits in the paper, extending to the cardboard centre-piece, as shown at A. Shape the paper by overlapping the slits to an extent of 3/8 in. at the bottom and narrowing to a point at the centrepiece. Glue cardboard strips, 1/2 in. square, over the ends of the joints. Pierce small holes in these strips, and insert small loops of thread. To these tie pieces of stout thread, 1 ft. in length, B. Before they are tied, wax the pieces of thread. Use beeswax or a stiff furniture polish.

This will stiffen them, and prevent them from getting tangled in flight. Gather their ends together and bind round with cotton. A loop of thread hangs from the binding, as shown at C. A hook is formed from a 6 in. length of wire. The wire must not be too fine, as it provides the weight, which keeps the parachute in the right position as it descends. One end of the wire is securely attached to the thread loop; the other end, D, hooks on to the kite line. The parachutes look most attractive when they are made from tissue paper of various colours.

To operate them, first tie a 4 in. strip of 3/8 in. square stripwood to the kite line, a few yards below the kite. This forms the stop block. Now place the parachutes on the line, one at a time. Agitate the line, but not in such a way that the parachutes jump off. The wind will carry them up the line until they reach the stop block, where they are released.

Wind Funnels (Fig. 25)

These may be fitted to plane-type kites. They are obviously decorative, but also serve to supply a light current of air to the kite on a calm day. The air travels through them at increased pressure, which improves the kite's upward movement.

To make them, first form a circle of thin wire, 3 in. in diameter, and join the ends together with thread. The wire may be shaped round a tin or a bottle. Next, take a piece of fairly stiff paper, measuring 10 in. x 5 in., and shape it in the following way. Hold it at the bottom corners. Twist the left-hand corner over and downwards. Wrap the other corner over to form a funnel. Cup one hand round the funnel to retain the shape. The funnel may then be adjusted to a diameter of 31/2 in. at the top and 1 in. at the bottom. Having done this, apply glue to the overlap and stick down. Now cut the edges straight at the top and bottom, and make slits in the top edge to a depth of 1/2 in. Apply glue to this 1/2 in. margin, fold over the wire rim and press down.

Fig. 25. Balancing funnels

Now add the fringe. Take a piece of tissue paper which is 1 in. square. Fold it down the centre and paste the ends together. Cut 1/2 in. slits in the paper along the pasted side. This forms the margin. Wrap the paper round the funnel, and mark the overlap, which is then pasted down. Apply paste to the top margin, fold it over the rim and fasten down. Now cut the tissue paper into fingers, 1/2 in. in width, to form a fringe.

Next, pierce the top in four places, representing 12, 3, 6 and 9 o'clock positions. Insert thin strings which are 1 ft. 3 in. in length, and form them into loops. Tie the loops together at the top so that there is an equal tension on all of them. Attach the wind funnels to the kite by means of strings, as shown for the *Star' kite. Please note that the funnels which have been described are intended for kites which are 2 ft. to 2 ft. 6 in. in size. The measurements given may be adapted for larger or smaller kites.

Tassels

hese are illustrated in Fig. 26, and are designed to be tied to the end of the kite tail; to the backbone, or to the bottom corners of the framework. The appearance of the 'Festoon' or the 'Tonking' kites is improved by the addition of tassels.

Fig. 26. Tassels

The method of making them is as follows. Cut a circle of tissue paper, 12 in. in diameter. Draw on it an inner circle, which is 3 in. in diameter. Fold the paper into four, as shown at A, with the marking for the smaller circle on the outside. Next, cut into fingers which extend to the circumference of the smaller circle, as at B. Take a piece of thin string, 6 in. in length, and tie it in the form of a loop. Glue one end of this to a segment of the inner circle, as at C. Roll the paper round at the top, and bind round with thread. The tassel is now ready to be tied to a trailing string by means of the loop.

Windmill or Whizzer (Fig. 27)

A novel touch is added when one of these is fixed to the top of a kite backbone. The windmill described is suitable for the larger kites; the measurements given may be adapted for smaller ones. You will need an 8 in. square of fairly stiff but pliable cardboard. Draw lines on it, to divide it into four equal parts, and make a small hole through the centre. Next, draw the pattern on the square, as shown, and cut out the shaded parts

Fig. 27. Windmill

Following this, bring the corners, A and B, over in curves to the centre. Allow a sufficient amount of the corners to overlap, and fasten them together with glue. Bring C and D together in the same way, over A and B. Make a small hole in the glued parts, which will be in line with the first centre hole.

Cut a piece of 1/4 in. diameter dowelling, 91/2 in. in length. Flatten it at the top with a sharp knife, as at E. Take an 8 in. length of thin strong wire, and wrap 31/2 in. of this tightly round the flattened part of the dowelling, so that the wire will not move about (see F, Fig. 27). Now take a 4 in. x 1 in. strip of thin cardboard, roll it round a knitting needle, and glue the end down to form a narrow tube, which fits on to the wire. Glue two strong cardboard washers round the centre holes in the windmill, and thread the wire through them. Place another free washer on the wire, and then bend the end of the latter round to prevent the windmill from slipping off.

Lanterns

These may be made in different sizes to suit large or small kites. They are suspended in the same manner as wind funnels and tassels. Fig. 28 illustrates the stages in making them.

Fig. 28. Lantern

A square of thin cardboard will make two lanterns. Cut it in half. Take one of the halves and mark a narrow margin at the top and the bottom. Crease the margin lines with a blunt knife. Fold the piece in hah" lengthways. Make a crease at the fold. Cut slits up to the margins, as at E, and open out again.

Glue reinforcing strips along the margins. Glue AD to CB. Attach string or thin wire in the form of a loop to make a handle. Compress the top and the bottom, so that the lantern will assume the shape shown at F.

Fringes (Fig. 29)

These are simply strips of paper, folded and cut in the manner shown. Paste the bottom margin round the kite strings. The small V-shapes in the margin indicate where to cut slits, which will help when the fringes are formed in curves.

Tail Pieces (Fig. 30)

The neatest method of making these is to take pieces of paper, and fold them as indicated. It is sometimes necessary to make a tail lighter or heavier, by altering the number of paper pieces it carries. Therefore, to make this adjustment easy, the pieces are tied to the string by means of a clove hitch, as illustrated in the section on 'Knots and Hitches' in this chapter.

Fig. 30. Kite tails

Buzzers

A strip of paper is folded in half and glued, by means of a margin, round a convenient string or frame piece. The edges of the paper vibrate in the wind.

Fig. 31. Designs

Fig. 32. Designs

Climbing Discs

Make circles, with centre holes, from thin cardboard. They may be covered with metalled paper, so that they shine in the light. Cut a slit up to the centre hole, by means of which the discs are placed on the line. Agitate the latter and the wind will carry them up to the top.

Pennants

A pennant is a long narrow flag, and one may be attached to the top of a kite backbone.

Cut a strip of tissue paper, measuring 5 in. x 20 in. Fold it in half to make a length of 10 in. Now cut it so that one end narrows to a point. Open it out, and glue a 1 in. length of 3/16 in. diameter dowelling along the centre. Paste the edges, and bring the two parts together.

Another style may be made in the same way, but instead of its tapering to a point, cut the end in a V-shape. The pennants may be left plain, or decorated with simple designs. Where a kite club is formed, the pennants may bear the club emblem.

Designs

The appearance of a kite is improved by the use of effective design, which should be simple and bold and finished in deep colours. Two examples are offered in Fig. 31. These may be enlarged to a suitable size for a particular kite by increasing the size of the squares and then copying the patterns on them. This work is done not directly on to the kite cover, but on a separate sheet of paper. The pattern is then transferred to the cover either by means of carbon paper; or the pattern is coloured, cut out and then glued on to the cover. Figs. 32 and 33 show some simple but effective designs.

Kite Anchor

Here is a very useful device to which the line may be temporarily attached while the kite is in flight. This enables both hands to be free for a while, which on occasions is a welcome and useful relief. Fig. 34 shows the component parts and the assembled anchor.

Fig. 34. Kite anchor

A is the upright bar which is 2 ft. 6 in. in length and formed from hardwood, 11/2 in. square. Shape it to a point at one end, as shown. Drill two holes, 1/4 in. diameter; one through the side at a point which is 2 in. from the top; the other, through the front, 6 in. from the top.

The crossbar, B, is formed from hardwood which is 1 in. square and 1 ft. 6 in. in length. Drill a hole, 1/4 in. diameter, through the centre. Take two pieces of strong cord about 5 ft. in length, and make one end of each into a loop, as at C. These act as stirrups.

Now fit a 5 in. x 1/4 in. diameter bolt with the thread running up to the head, into the side hole of the upright bar A. Two nuts are used to lock the bolt in position, so that 3 in. of it projects from one side of the bar. Next, fasten the two wooden pieces together with a 3 in. x 1/4 in. diameter bolt.

To use the anchor, first drive the pointed end of the bar into the ground. Slip the feet into the cord loops, and bind round and tie the other ends to the crossbar so that the cords are taut. When the kite line is wrapped round the top bolt for a few times, the kite is securely anchored for as long as the operator wishes. The anchor, because it can be dismantled quickly, may be easily carried from place to place.

Shield (Fig. 35)

The suggestion for the award of a shield in club or inter-club competitions is found in Chapter 11, under the heading No. 4, * Arrange Activities'.

The squares in dotted lines may be enlarged to a suitable size on paper, and the design copied on them. Transfer the design, by means of carbon paper, to plywood about | in. in thickness. Cut out the shield with a fretsaw, and then paint in suitable colours. When the paint is dry, a wall hanger or a strut is fixed to the back and the shield is complete.

Protecting Covers

Kites, when not in use, may be protected by storing them in large polythene bags, or bags made from sheets of strong brown paper, provided with string handles, by which they may be suspended from a wall. It may be difficult to do this in the case of a box kite, owing to its shape, but at least it may also be suspended from a wall when not in use. This will do much to prevent accidental damage.

Anemometer

This is an instrument for measuring the speed of the wind, and a simple type is shown in Fig. 36. The crosspieces, A and B, are formed from 1/8 in. x 1 in. strip-wood. Each piece is 3 ft. in length. They are joined together at right angles at the centre. Use glue and small fine nails. Check with a set square to ensure that the angles are true. Drill a small hole exactly at the centre. Now take two large glass or wooden beads about 18 mm. in diameter and place them on the crossbars, one at the top and one underneath, exactly over the centre hole in the bars. Glue the beads in position and when the glue has set, pack round the beads with plastic wood, as at C. Allow sufficient time for the plastic wood to harden. Note that the hole in the crossbars is the same diameter as the holes in the beads. Following this, fix four small cups, D, to the ends of the crossbars. Use table-tennis balls, cut in halves with a sharp knife. Screw them in position, using 1/4 in. screws. The cups are fixed underneath the crossbars, and small 1/8 in. thick blocks of stripwood are glued above them.

The next stage is to make the spindle, E. The base is two cotton reels, glued together, into the holes of which is inserted a piece of dowelling, which is glued in place and must be a tight fit. The dowelling is cut off level with the top and bottom of the reels. A strong knitting needle is required, of such a diameter that the crossbars revolve freely but not too loosely on it. Drill a hole in the dowelling in the reel, and drive the needle securely into it. Slip a few 18 mm. beads on to the needle with a small washer on top of them.

Fig. 35. Shield

The third stage is to make the stand, F. This is a piece of 1/4 in. plywood, 3 ft. square, and strengthened underneath with battens, which is screwed to an upright bar of convenient height. The bar may be pointed at the end, so that it can be driven into the ground; or it may be attached to a base-piece, G. Drill a hole at one corner of the stand, F, and insert a 11/4 in. length of dowelling, H, and paint it red. This is the marker. One of the cups is also painted red. Place the crossbars on the spindle, and the anemometer is ready for use.

If it is to be left permanently out of doors, then it may be given a coat of size, and when this is dry, enamelled in a suitable colour which offers a strong contrast to the red cup and marker.

In order to calculate the speed of the wind, one must first count the number of times which the red cup passes the red marker in the space of one minute. This having been done, the speed in miles per hour can be estimated by an arithmetical calculation. It will be realized that the red cup, as it is blown by the wind, describes the circumference of a circle, the diameter of which is 3 ft. which the reader will realize is the length of the arms.

Fig. 36. Anemometer

The measurement of this circumference is found by multiplying the diameter by (22/7). When this result is multiplied by the number of revolutions in one minute, the reader will then have found the speed of the wind in feet per minute. From this he can then calculate the speed in miles per hour.

For example:
 
Number of revolutions in 1 minute =80  

Therefore speed in feet per minute =

3 x 22 x 80 1 x  7 x 1

Therefore speed in miles per hour =

3 x 22 x 80 x   60 1 X 7   x 1   x 5,280

=60/7=84/7

This size of anemometer is only adequate for registering wind speeds of up to 18 m.p.h. For greater accuracy, and for registering higher wind speeds, it is advisable to construct a larger instrument.

Weather Vane

A simple model is shown in Fig. 37. The spindle, A, is the same as the one used for the anemometer, but three cotton reels are used. The arm, B, is formed from 1/2 in. diameter dowelling, which is 1 ft. 6 in. in length. Drill a hole through the centre, of such a diameter that the arm will turn freely on the spindle. Make fine saw cuts, which are 3 in. in length at each end of the arm. Next, cut the two shapes, C and D, from thin tin and make them 6 in. in length and 3 in. at the widest points. Insert these in the saw cuts, and secure them by means of glue and fine nails driven through the arm.

Fig. 37. Weather vane

Now prepare the stand. For the base piece, E, use 1/4 in. plywood or hardboard which is 2 ft. square and battened underneath to prevent it warping. Cut the cardinal points from thin tin or plastic. Each letter is cut from a 3 in. square of the material and is pegged to a small piece of dowelling as at F. Drill holes at the corners of the base piece and insert the pegs. Glue them securely in place. The base piece is mounted on a centre column, as for the anemometer, but in this case it is round in shape.

Assemble the vane by slipping the arm on the spindle. Place a brass washer above and below the arm. Make a cap from a small block of wood, as shown at G, and wedge this on top of the spindle by means of a centre hole, drilled halfway through. Make this hole a little less in diameter than that of the spindle, so that the cap needs tapping home with a mallet. Secure with glue. The arms should balance evenly on the spindle and should revolve freely. Paint the vane in black enamel, first applying a coat of size to the wooden parts. Lubricate the hole in the arm with a little fine machine oil.

The vane may be fixed at some convenient place which is open to the wind: for example, to the top of a shed, or a post. It must be secured so that the base is truly horizontal and the spindle truly vertical. The cardinal points are found in the first place by means of a compass, and the vane is set up to correspond to compass reading.

Compass

Though a good compass can be bought quite reasonably, some readers may find it interesting to make this simple type for themselves (Fig. 38).  

The first stage is to make a compass card, A, which is 2 in. in diameter. Draw two concentric circles on thin card; the outer one is 2 in. in diameter; the inner one is 1 in. in diameter. Mark on it the cardinal points, as shown. Cut out the centre portion.

Fig. 38. Compass

Next, make the pieces B and C from thin card. B has a raised part in the centre, and from the underside of this a small depression is made by means of a round point. C is a flat strip with a small hole punched in the centre. Magnetize a steel safety razor blade by drawing a magnet across it, one way only. Before this is done, for safety's sake, place the blade in a vice and blunt the edges with a fine file. Glue the blade to the underside of the flat strip. Now, make a small cardboard box to house the compass, with sufficient clearance for the compass card to turn freely in it.

Assemble the parts upon a needle which is stuck into a piece of cork. Glue the strips B and C to the underside of the compass card; B so that the raised part fits through the centre hole; and C so that the blade is underneath. Glue two small beads above and below the hole in the strip C. The top of the needle rests in the small depression in the raised part of B.

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