Chapter V

AËRIAL TOYS

The Elastic Flying-machine

To have a flying-machine is the dream of every boy. To build a large one is exceedingly difficult, but a small one run by a rubber band can be easily constructed. You will not be able to fly up to the roofs of houses and spires of churches, but it will furnish you much amusement, without the danger of a broken neck.

I will tell you exactly how I constructed one of these machines, and then you can make one for yourself. The backbone was a knitting-needle. The wings, or more properly aëroplanes, were light bamboo strips (taken from a Japanese fan) and covered with the Japanese paper which is used for napkins. (Fig. 1.)

Fig. 2 shows the backbone and its parts. Cut from thin brass or copper a piece shaped like No. 1, and bend the top over, as shown at No. 2. Brass suitable for this may be bought at any hardware-store, or an old article made of proper metal may be cut up. The shell of a metallic cartridge is excellent. The brass should be as thin as possible, to be light, and so that it may be cut with an old pair of shears and bent easily. First cut the piece out roughly with the shears, and then trim it into shape with a small file. Scrape that part of the metal bright and clean which will form the inside of the roll, and then bend it around the needle so that it will fit nicely and snugly.

This must be fastened to the forward end of the backbone. The best and lightest way is to braze it, as the tinsmiths call it. File the polish from the end of the needle, and wet it with soldering fluid, which may be bought at a tinner’s, or made by adding zinc to muriatic acid until no more is dissolved. Slip on the brass support just where you want it, and lay on a piece of solder about half the size of a grain of wheat. Now hold this in the flame of a candle, in the gas, or near a hot stove, until the solder melts. Take it away and let it cool, and you will find that the solder has run into all the cracks and joined the pieces beautifully. File off any excess of solder or rough ends, and you will have a neat and workman-like joint, as well as a very light one.

Cut out the piece No. 3, and bend it into the shape shown at No. 4. In this case you will need to file the upper surface of the groove bright and clean. Take off the polish from the other end of the needle, and then put the stern-post, as it may be called, in place, and hold it there by twisting a fine wire around it and the needle. Be careful to get both supports turned the same way. Then braze and finish it as before.

Make the piece No. 5, and form it into the shape No. 6. This is fastened by brazing to the backbone, as shown in the lower diagram. Take a piece of another knitting-needle, and make a shaft like No. 7 by heating red-hot and pounding the end into a hook with a small hammer.

Put the straight end of this shaft through the hole in the stern-post which was formed by bending the metal, and then make a shoulder on it, as follows: bend a piece of fine wire into a ring the size of the needle, and braze this to the shaft about a quarter-inch from the stern-post. This ring of wire keeps the shaft from slipping through the hole when the rubber is stretched. File a flat point on the straight end of the shaft.

Next make the wings. For the ribs I used the thin bamboo strips taken from a Japanese fan. The paper is pulled or soaked off, and the thin strips cut close to the handle. The front of the wings is made as in the upper diagram of Fig. 3. Take one of the largest and stiffest strips of the bamboo, find the exact middle, and lay it evenly across the wing-support (No. 6 in Fig. 2), which is already in place on the backbone. Lash it to the support with waxed sewing-silk. Over this piece lay two others of equal length, making them come together (but not lap over) just above the backbone. When well secured, add three pieces of the same length above the two, placing them in such a way that the joinings shall not come over the joinings of either of the other pieces, and thus weaken the wings.

The ribs are made from the bamboo strips, cut the proper length and lashed to the front edge. The other ends are fastened to a cross-rib to make them take the same curvature. The lower diagram of Fig. 3 shows how the ribs are spaced.

Cover the wings with thin, strong paper. The best is Japanese paper, such as is used in making napkins. This is exceedingly light and very strong. It should be sewed, not gummed, as the gum makes the paper tear easily, and your sticky fingers spoil the whole cover very quickly. The paper is tough enough to be sewed, using a fine needle and white cotton, and you will get a neater and much more satisfactory job.

Make a triangle by lashing together three pieces of bamboo, two being about two inches long, and the third one inch. This triangle is lashed to the backbone just behind the wings, with the short side down; its position may be seen by a glance at the picture of the finished machine. It is kept rigid by running stays, made of waxed sewing-silk, from the lower corners to the stern-post, from the right-hand corner to the middle of the left wing, and from the left-hand corner to the middle of the right wing.

Just in front of this triangle fasten a piece of the bamboo, and make two small guiding vanes or rudders. These are made in a similar manner to the wings. Tie threads to the lower corners of the wings, and then to the triangle, drawing them down until they have the proper angle. The guiding-vanes should have a greater angle than the wings—that is, they should be drawn farther down.

It only remains now to make the screw and attach the rubber band. For the hub of the wheel you will need a small cork. This cork must be kept from turning on the end of the shaft. If the sharpened end of the shaft carrying the hook for the rudder was simply stuck into the cork, it would soon wear loose and turn easily. To make a firm hold for the shaft, bore a hole through the cork about a quarter-inch from the large end, and drive a plug of soft wood into this hole. The flat-pointed end of the shaft can now pass into the cork and be forced into the wood, being careful to have the end of the point parallel to the grain of the wood. This will give a firm hold and prevent the screw slipping.

The blades of the screw are made of thin paper gummed on to short pieces of bamboo. Lay one of the bamboo spokes on a piece of thin, stiff paper, and then gum over it a small strip of the thin Japanese paper before referred to. When this is dry, cut it down to the proper shape and sharpen the end of the spoke. Force these spokes into the cork so that all the blades will turn the same way, as shown in the picture—_i. e._, so that when the screw is turned the blades will all strike the air in the same manner and tend to force the machine forward, not so that some try to push it forward and some backward.

Select a rubber band of the proper size—such a one as will stretch the length of the backbone easily and not be so strong that, when stretched, the backbone is bent into a bow. Tie this band to the forward support with a string, and then draw it back and slip it over the hook on the shaft.

To wind up the machine, hold it by the backbone and turn the screw the wrong way until the rubber is twisted tight. Then hold the machine up, let go the screw, and when it is revolving rapidly, give it a gentle push forward. If it pitches head-first, draw down the wings; if tail-first, let up the wings or turn the screw the other way. If the wheel does not revolve rapidly cut off part of the blades or use a stronger rubber. Some little adjustment of the kind is usually required before the thing moves properly.

A contrivance of this sort should be very light. The one before me has wings two feet from tip to tip, and it weighs when complete—backbone, wings, rubber, screw, etc.—only one-third of an ounce.

Self-acting Aërial Car

Here is an idea for a mechanical toy to be used either on a kite-string or a cord stretched from a flag-pole in the yard or a handy tree. The only condition is that the lower end of the cord is directly against the wind. The elevation at which the car can run will depend on the strength of the wind and sail area of the machine. The only wood used is the lightest and driest pine that can be procured. The carriage is made entirely of one-half by one-quarter inch wood, and is composed of two strips, fourteen inches long, placed one inch apart. The two guiders are two inches from each end, and have a small screw-eye on the lower extremity, through which the cord is passed. On the upper side of the carriage, exactly in the centre, are screwed two eyes, which should measure a little over a half-inch in diameter of the inside of their circle. Through these is passed the spar of the sail, allowing enough space to insure easy turning, as the spar acts as an axis on which the sail turns when on its downward trip. This spar is at right angles with the carriage. Two upright sticks measuring twenty inches, and the same dimensions as the material used for the construction of the carriage, are next added. These should be slightly pointed at both ends, and a cross-bar at the top of these uprights securely fastened gives additional strength. The balancing-bar is made of three-eighths by three-eighths inch pine, tapering at the lower end, and is ten inches in length, and fastened to the carriage by two strips of wood—five by one-quarter by one-eighth inch. The wheels are formed as follows: Take a piece of one-eighth inch pine, which should be at least three inches wide. On this place a strip of wood, we will say, for instance, ten by one-quarter by one-half inch. By driving a small wire nail through both pieces of wood, and inserting a sharp knife-blade through the upper piece of wood, and turning (the upper piece) slowly from left to right, you will find you can cut a perfect circle in the lower piece of wood. The wheels are formed by this process. It takes four pieces of stiff card-board and two of wood to make the wheels for the carriage. The diameter of the wooden wheel is one and one-half inches, while the card-board disks are two and one-quarter inches. The wheels in the draught are a trifle smaller, but by experiments it is found that the above-sized wheel makes faster time. You will see that after cutting out your disks the hole made by the wire nail is exactly in the centre. Run a small wire nail through the three disks, placing the wooden disk in the centre and the card-board ones on each side (this makes three disks for each wheel). Put some glue on touching surface, and clinch the three together with pins or wire brads. The place where these nails go is shown by the spots on side draught of the wheel. The axle-tree is made of oak, and at the extremities a piece of stout wire is inserted, which extends one-eighth of an inch beyond the wood of the axle-tree. The hardest axle-tree is one made from the shafts of an old clock. Take particular care that the wheels run very true, as the success of the machine depends to a great extent upon this.

From the lower extremity of the balancing-rod hangs a weight. The easiest way to make this weight is to take a small bag, and fill it with sand until the machine balances (the sail in horizontal position). Having progressed thus far in the construction of the machine, turn the sail in a horizontal position, and attach a cord from one side of the cross-bar to a small grooved wheel at the aft end of the carriage. From the screw-eye at lower extremity of the balancing-bar is attached a small rubber band; when stretched it will reach within three-quarters of an inch of the small wheel at the aft end of the carriage. It will be found, after the cord and rubber band have been joined, that upon letting go the perpendicular bars the sail will turn in a horizontal position. At the forward end of the carriage is a catch, to which is fastened a ring. The catch comes in contact with a block (previously placed three-quarters up the string). The detail drawings show the formation and working of the catch. Fig. 4.

The sail is made of light muslin, and extends in the form of a pair of wings, the cloth only reaching from the outside of the uprights to the ends of the spar, leaving a free space in the centre for the sail to pass through the carriage. The parachute is a small Chinese umbrella (pick out one that opens easily), and can be bought for a few cents. A small weight is attached to the handle with a few feet of cord. We will say that now you have completed the machine—you have a kite flying; run the string through the two guiders, place the two wheels of the carriage upon the kite-string, set the sail perpendicular, and fasten the catch with the cord. A stop-block has been previously placed on the cord twenty feet from the kite; now attach the parachute (Chinese umbrella). The force of the wind acting on the sail forces the machine up the incline of the kite-string at a rapid rate, skyward, until it reaches the block, which throws off the catch. The sail swings back to a horizontal position, letting the parachute drop. The sail being folded and presenting no resistance to the wind, the force of gravitation acting on the weight of the machine causes it to descend the kite-cord quickly, and return to the original starting-point of its flight. See Fig. 5, a side and end view, and Fig. 6, the parachute and the car on its return.

Aërial Boat-sailing

Study with care the accompanying plans. The materials are one-half by one-quarter-inch pine, free from knots, ten common brass rings three-quarters of an inch in diameter, two round-headed brass screws one inch in length, two flat-headed ones of the same dimensions, two small screw-hooks, and eight assorted brass screw-eyes, there being two of each size. Now that we have the material for the frames, we will begin with Fig. 7, which shows the sail and sheer plan. The frame is made of six pieces of wood. The top piece is exactly two feet in length. The two uprights which hold the wheels are each one foot and one inch long. The two angle pieces are one foot nine inches each. The lower horizontal strip measures two feet three and one-half inches, and is joined to the two angle strips by means of a screw-eye and screw at each extremity. Now cut a strip of pine, making it exactly three feet in length. Set it on the frame in an upright position, allowing a half-inch clearance from the upper horizontal piece. It should be eleven inches from one of the angle pieces at the lower end. Round the upper part above the horizontal strip; it should be brought to a taper at the upper end. This forms the mast. The lower part is uniform, and allows the weight to be moved up and down to insure a correct balance, which is regulated according to the force of the wind. The weight is made of one-and-a-half-inch lead pipe, and is two inches in length. A round plug of pine is driven in the centre of the lead pipe, and a hole is bored in the centre of the plug to fit the balancing-bar.

One of the screw-eyes is inserted through the piece of lead pipe, and by this means the weight can be elevated or brought down the shaft and held firmly in the required place, which will depend on the force of the wind. In regard to the wheels, Fig. 8 shows the simplest constructed. They are made in three parts. Take two of the largest-sized wooden button moulds and a piece of thin board (cut in a circle) smaller than the button moulds. We will say, for instance, the button moulds are one and one-half inches in diameter, and the centre piece of pine is one inch in diameter and one-eighth of an inch thick. The way to get a true circle on this soft pine is to take the one-eighth-inch wood and measure on a separate piece of pine one-half inch, drive in a small wire nail in one extreme of the previously measured strip, and on the other extremity insert the point of a sharp knife. Place on the board used for centre of wheel, and turn in a circle from right to left several times. If the distance between the knife-blade and nail is one-half inch, the wheel cut out will be exactly one inch in diameter.

Insert a wire nail through the two button moulds, and place the inch wheel in the centre, gluing it at each contact surface. This will give you the grooved wheel.

The drawing (Fig. 7) indicates how this wheel is fastened to the frame. The wheel can be made of two card-board disks two and one-half inches in diameter, and one wooden wheel two inches in diameter placed between them. They are joined by clinched pins, shown by the circle of dots in Fig. 8.

The dimensions of the sail are as follows: Main-sail—hoist, ten and one-half inches; gaff, eight and one-half inches; leech, nineteen and one-quarter inches; boom, fourteen and one-half inches. Jib—foot, eleven inches; hoist, sixteen inches—on the stay, twenty and one-quarter inches. The jib carries a boom, and the main-sail a gaff and boom. The material used for the sails is light muslin with hemmed edges.

Take a long chalk-line or heavy cord, and stretch at right angles to the direction of the wind. If the wind is from the north, the cord must reach east and west. Each extremity of the cord must be the same height from the ground, and can be attached from tree to tree, or from an upper-story window to a house near by.

When the boat reaches the extremity of the cord the operator at that end of the cord turns it, and starts it on the return journey.

If the cord is strung between two houses you will find the boat will sail back and forth, except when the wind is dead ahead or a few points either way.

A “High-flyer”

To make the “flyer” you will need a piece of thin sheet tin, zinc, or iron, that may be purchased from a tinsmith for a few cents; and for the engine a linen-thread spool, a piece of hard-wood stick, and a few steel wire nails will be required.

To begin with, obtain an empty linen-thread spool having a smooth hole through it, and in one end drive four one-inch steel-wire nails at regular distances apart, so as to form the corners of a perfect square; drive the nails in half-way, then file the heads off, and the spool will appear like Fig. 9. Next get a round hard-wood stick seven inches long, and around it, two inches from one end, make a deep cut with your knife. From this cut to the end of the stick shave the wood away so it will look like Fig. 11.

These two parts will complete the engine, and the next thing to make will be the flyer. Thin sheet-zinc will be found the best to make it of; and having obtained a piece, mark on it with a compass a circle five inches in diameter; mark two lines across this circle from edge to edge, at right angles, as shown by the dotted lines in Fig. 14.

From a piece of stiff paper cut a pattern in the form of one of the ears shown in Fig. 14. Lay this pattern on the zinc so that one of the lines will be in the centre of it, and mark the shape on the zinc; mark the other three ears in a similar manner, and then with a stout pair of shears cut out the flyer.

In the centre of it make a hole large enough for the small end of the stick to pass through it, and around it make four small holes at the centre of each ear, to correspond with the pins on the spool.

The flyer will then fit over the stick and pins and lay flat on top of the spool; bend its ears with your fingers so they appear like the propeller-blades of a steamboat, or like a windmill, and it will then be ready to fly. Fig. 10.

When bending the ears they must be arranged so that the edge that catches the wind first will be inclined upward, as otherwise the flyer, instead of flying, will hug the spool tightly.

Another style of flyer is shown in Fig. 12, and is made of a circular disk of zinc four inches in diameter.

Make the five holes in the centre fit over the stick and pins. When all the places have been cut, bend the ears down as shown in Fig. 13, and when flying it turn it upside-down, letting the ears project upward.

To put the flyer in action, take the stick in your left hand, and over the small end of it place the spool, against which put your thumb to keep it from slipping. Wind strong cord around the spool, to the end of which a button is fastened to keep the cord from slipping through your fingers; on top of the spool place the flyer, and give the string a vigorous pull, at the same time releasing the spool with your thumb, and the centrifugal force will cause the flyer to revolve rapidly, shoot upward, and sail to a height of fifty or a hundred feet in the air, slowly descending as the revolutions diminish.

Larger flyers can be made in a similar manner; and to make a very large one, plant a post in the ground, having its upper end reduced to form a shoulder, as explained for the small stick. Get a round piece of wood several inches in diameter, and arrange four very stout steel-wire nails in the top of it. Make a tin or iron flyer twelve or fifteen inches in diameter, and use a piece of small clothes-line or cotton line to spin it with.

To operate it, wind the spool with the rope, and have some one under it to keep it from slipping. When you are ready to pull the rope, place the flyer on the pins, and as the spool is released give the rope a quick, strong pull, and the flyer will rise.