All these requirements and others were met by the apparatus finally adopted, which is shown in Plates 23 and 24. It consists of a strong timber frame-work, carrying a track, consisting of two flat iron rails set on edge, upon which runs the launching car, suspended from two small wheels on each side. At the front end of the frame there are two cylindrical air buffers to receive the buffing pistons and thus stop the car after the aerodrome has been released. The car is drawn to the rear end of the track and held by the bell-crank lever ‹A› (Plate 23). The contact points ‹BB› and ‹C› are turned down and the clutch-hook ‹D› set over the clutch-post ‹K›. The aerodrome is thus held firmly up against the three points ‹BB› and ‹C› by the clutch ‹D›, and a distortion from its proper position rendered impossible. All these points are thrown up out of the way of the projecting portions of the aerodrome at the instant of release. This result is accomplished as follows: when the car has reached the proper point in its forward course, the cam ‹E›, which is hinged at 1, is depressed by a roller fixed to the framework of the device. In this motion it pushes down the adjustable connections ‹FF›, which are attached at their lower ends to the bell-crank arms ‹GG›, which turn about a central pivot at 2. Thus the downward movement of the connections ‹FF› opens the jaws of the [p111] clutch ‹D›. While the clutch ‹D› is rigidly attached to ‹G› to prevent transverse movement, it is hinged to the latter at 3 so that it can fold in a longitudinal direction. Screwed to the clutch ‹D› is a narrow plate 4, which, when the clutch is closed, is behind the lug 5, thus preventing any turning about the hinge 3. But when the arms of ‹G› and the jaws of the clamp are thrown out by the depression of ‹F›, the plate 4 is moved out from behind the lug 5 and the clamp is free to fold to the front. The strut, hinged at 6, is under a constant tension from the spring 7 to fold up, and is prevented from doing so only by the connections 8, by which it is held down until the release of the plate 4 from behind the lug 5, when the spring snaps them instantly up and out of the way. As the struts ‹BB› have no fixed connection with the aerodrome, they are released by the relaxation in the rigidity of the other connections and are thrown up by their spring 9 and held in that position by the clip 10 catching beneath the upper cross-piece. The power for the propulsion of the car is obtained by means of from one to nine helical springs working under tension, and multiplying their own motion four times by means of a movable two-sheave pulley, as shown in the drawing. DESCRIPTION OF AERODROME NO. 5