By WILLIAM GROTZINGER

A simple glider of the monoplane type can be easily constructed in a small workshop ; the cost of materials is not great and the building does not require skilled workmen. Select the material with care and see that the wood is straight-grained and free from knots. The following list of spruce pieces is required:

4 main winy spars. 3/4by 1 1/4 in. by 17 ft. 2 rudder spars. 3/4by 1 in. by 8 ft.

8 wing crosspieces, 3/4by *i in. by 4 ft. 4 rudder crosspieces. 1/2by 1/2 in. by 2 ft.

1 piece for main-frame crosspieces. 1/2by 1 in. by 12 ft.

2 arm pieces. 1 1/2 by 2 in. by 3 1/2 ft.

The following list of poplar pieces is required in making the supports for the cloth covering on the wings and rudders.

34 main-wing ribs. 1/4by 3/4by 64 in. 8 rudder ribs. 1/4by 1/2by 36 in.

5 rudder ribs. 1/4by 3/4by 48in.

The following list of oak pieces is needed:

1 piece. 5/8by 1 1/4in. by 12 ft. i piece. 5/8by Wx in. by 6 ft.

1 piece. 3/4by 3/4in. by 3 1/2 ft.

2 pieces. 5/8by 1 1/2in. by 5 ft. 4 pieces. 3/4by 1 by 28 in.

In addition to the lists given, four pieces of bamboo, 16 ft. long, tapering from 1 or 1 1/4in. at the large end to 3/4in. at the small end, are used for the main frame.

Construction

The first part to make is the main frame A which is constructed of the four bamboo poles. They are made into a rectangular frame with crossbars marked B cut to the right length from the 12-ft. piece of spruce, 1/2in. by 1 in. The bars C and D are of oak cut from the 6-ft. piece, 5/8 in. by l1/4 in. All of these crossbars are fastened together in rectangular form by means of stove bolts. The bamboo poles are then bolted to the inner corners of the frames with 3/16. bolts. Place the bolts through the bamboo close to a joint to prevent splitting. The frame is then rigidly trussed by diagonal wires marked E crossing all rectangles. The wire used for trussing all the parts throughout the glider is piano wire, 16 gauge. The arm pieces are bolted to the sides of the rectangular frames beneath the wings.

Monoplane Glider in Flight

Ill: Monoplane Glider in Flight

SIDE ELEVATION

Ill: SIDE ELEVATION

FRONT ELEVATION

Ill: FRONT ELEVATION

Details Of Monoplane Glider

The framework of the main wings or planes should be put together by bolting the cross struts F at regular intervals on the under side of the main spars G. Brace the frame diagonally with the piano wire. The ribs are nailed to the main spars by using 1-in. brads. The ribs are spaced 1 ft. apart, and curved so that the highest part will be 5 in. from the horizontal. Each rib extends 15 in. back of the rear spar. The rudder is made in the same manner.

The vertical rudder is made to fold. A small pocket arrangement H is made from which the rigs of the vertical rudder diverge.

The covering of the wings and rudders should be a good quality of muslin or some light aeronautical goods. The cloth should be tacked to the front spar, to the ribs, and then sewn to a wire which connects the ends of the ribs.

Construct the triangular arrangement marked J to which the wings are braced. The wing bar supports are shown in the illustration. The bottom wires are braced to the crossbar K shown in the front elevation.

The bracing wires are all fastened to a snaphook which can be snapped into the rings at the places marked L. This method will allow one quickly to assemble or take apart the plane and store it in a small place. The vertical rudder should be braced from each rib to the front spar of the horizontal rudder and then braced by the wires M to hold the rudder from falling back. The rudder is then braced to the main frame and the main frame is braced by the wires N to the wings. This will hold the plane rigid. Use snaphooks and eyebolts wherever possible so that the plane can be quickly assembled. Assembling

The triangular arrangement J is bolted to the wings and the top wires put in place. The wings are then put on the main frame and bolted to the bars marked C and D, after which the bottom wires are fixed in place.

Gliding

Take the glider to the top of a hill, step into the center of the main frame just a little back of the center of the wings. Put your arms around the arm pieces, face the wind and run a few steps. You will be lifted off the ground and carried down the slope. The balancing is done by shifting the legs. The glides should be short at first, but by daily practice, and, as the operator gains skill, glides can be made up to a length of several hundred feet. Do not attempt to fly in a wind having a velocity of more than 15 miles an hour.