US1647619A - Airplane - Google Patents

Description

Nov. 1, 1927.

Filed Feb. 1, 1

,647,619 C. W. HALL AIRPLANE 2 Sheets-Sheet 1 1N VENTOR ATTORNEY C. W. HALL AIRPLANE FildFeb 1934 2 Sheets-Sheet 2 Nov. 1, 1927. 1,647,619

v INVENTOR. I. HAWK-M ATTORNEY Patented Nov. 1, 1927.

UNITED STA Application filed February 1 vided'with a flat open deck upon which the airplanes may alight, but in order that this operation may be accomplished successfully it is necessary to provide means for arresting the motion of the machines within the limits of the necessarily restricted space thereby afiorded. The approved practice at present is to mount above the landing deck spaced series of cables-a longitudinal series which are tightly stretched in horizontal position at a height of about eighteen inches and, substantially midway between such longitudinals and the deck, a few, for instance three, transverse cables which are 'yieldingly held in horizontal position by passing their weighted ends over pulleys at the sides-and to equip the airplanes with a number of small anchors or double-pointed grappling hooks which hang from the spacer-bar, of the forward landing gear in position, when the wheels are running upon the .deck, to engage the longitudinal cables and so hold the airplane down to the deck and with a single long-shanked hook which at its forward end is mounted by universal joint (to allow for a possible side drift) on a bottom stanchion of the machine some seven or eight feet from its stern post and which is brought back and held up against the bottom of the airplane when not require but when about to alight is released and swings down, between two of the longitudinals, to catch one or another of the yielding transverse cables and so arrest the forward movement of the machine.

Experience has shown that this equipment, while otherwise generally satisfactory, has one serious defect in that the momentum of the machine, when its forward movement is arrested by the operative engagement of the hookwith one of the transverse cables, tends to throw the tail up, often causing damage to the propeller and/or nose parts of-the machine and, on the rebound, to the tail skid. I

In another application, Serial No. 684,108,

TES PATENT OFFICE.

LABCHMOHT, NEW YORK.

AIRPLANE.

1924; Serial No. 689317,

filed January 3, 1924, I have described and claimed certain means by which to obviate this very objectionable feature.

My present invention, which has the same end in View, c0nsists, briefly, in shifting the point of attachment of the arresting hook from the usual point, some seven or eight feet in front of the stern post, back to the tail of the machine, pivotally mounting it, for example, upon the lower end of the stern post, straddling the tail skid. Thus, not only 1s there provided a greatly extended lever arm upon which the hook may act but any slight rise of the tail will so elevate the shank of the hook as to project its line of pull far above the center of gravity of the machine. When not required for a landmg, the hook is drawn back and held in rearwardly extended position or, if preferred, may be swung forward and upward against the bottom of the machine and there releasably held in place.

The invention will be-understood by reference to the accompanying drawings, wherein.

Figure 1 is a view, in side elevation, of the rear or tail end of the body framework .of an airplane carrying a suitable 'tail skid and equipped with an arresting hook illustratrng one specific embodiment of my invention; Fig. 2 is a plan view of the same, wlth certain parts omitted for the sake of clearness; Fig. 3 is a view similar to Fig. 1, but showing a modification both of the hook itself and of the mounting thereof upon the framework; Fig. 4 is a section on d theline 4 4 of Fig. 3; Fig. 5 is a detailed view, partly in rear elevation and partly in section, of parts shown in Figs. 3-and 4:; and Fig. 6 is an enlarged broken detail showing in perspective a means for releas ably securing the arresting hook to the bottom of the airplane.

Referring to the drawings, thestern post 1 and the twolower longrons 2 2 of the airplane frame'are joined by a fitting 3, to

the lower end of which is pivoted the usual tail skid 1. The skid is normally held in the position shown, against abufi'er 6 mounted on-the guide-rods 5 5 between which its forward lever-arm swings, by a rubber band or other shock absorber 7 which at one end is attached to the framework and at its other end is connected by thelink 8 to this end of the skid. The skid will, however, rock to the position indicated in dotted lines (Fig. 1) whenever the upward pressure upon its outer lower end is suificient. to fully ex-v tend the shock absorber. I

As illustrated in Figs. 1 and 2, the arresting hook 10, of the usual or of any suitable construction, is pivoted at the end of itsshank 11, to swing laterally,'to ayoke 12 the arms of which'straddle and are pivoted to thefitting 3, above the pivotal mounting of the skid, to swing thereon in a fore and aft vertical plane below and to the rear of the machine. The shank of the arresting hook is yieldingly held in alignment with the yoke bysprings 13 13 which are attached to the two arms of the yoke and bear against the sides of the shank. One arm of the yoke is extended forwardly, parallel to a lower longron, to provide alever arm 14;

- and to this arm isattached the control cord stantially as shown. When about to make a landing, the cord is released and the hook swings down into position, indicated in dotted lines, to pick up a transverse cable on the landing deck, the arms of the yoke straddlin the lower. end of the skid. The drag on the hook, in operative engagement with the cable, swings it upwardly and at the same time both draws the cable up and the tail of the machine down. Such downward movement may carry the tail of the machine So close to the landing deck, indicated by the dotted line a a, as to bring the skid into action, or even to force the ski-d and the hook to the extreme positions indicated in dotted lines, whereupon the tail will rebound but, raising the shank of the hook and thereby increasing the angle of its line of pull, will again be drawn partially back. The. forward movement of the machine will thus be quickly and smoothly arrested with the tail in the position shown with respect to the line of the deck represented by the dash and dot line b b, where the pull of the hook is projected forwardly through the center of'gravity of the machine.

It is evident that the arresting hook can readily be attached to an airplane and as readily removed if its use is not required.

In the modification shown in the remaining figures of the drawings, the arresting hook, the mechanical equivalent of that hereswing vertically upon thefitting 3. Here,

however, the forward extension of one arm of the yoke is omltted, and in place thereof two shapedmembers 17 17 of inverted U- section, are mounted each with its sides straddling an arm of the-yoke, upon the pin with which the yoke is pivoted to thefitting 3 and are braced by securing their forward flattened ends by screws or otherwise to the fittings which join abottom stanchion 2 to the lower longrons. The rear portions of these members, extending backward from the stern-post at a slight upward angle directly above the arms of the yoke, serve as a stop to prevent the shank of the hook from being thrown up high enough to foul the rudder. They, as well as the hook, are readily removable.

After each landing the hook is swung forward, the tail of the machine being raised for the purpose, and releasably secured to the bottom of the machine in any suitable mannerfor example, by pressing its shank between twocurved fingers 18 which, as,

shown, are pivotally mounted upon abottom stanchlon 2*, are yieldingly pressed towards each other by aspring 19 coiled around the pivot, and are provided with di-.

possible untwisting It is to be understood that the invention may be further modified in its various de-.

tails and is not to be limited to either of the two specific embodiments shown and described, except as so expressed in the appended claims.

What I claim as new, and desire to secure by Letters Patent, is-

1. In an airplane, a landing gear comprising a tail skid and an arresting hook which is capable of some lateral movement and the shank of which is pivotally mounted, to swing in a fore and aft vertical plane, upon the frame at the tail of the machine by a fitting adapted to straddle the outer end of the skid.

2. In an airplane, a landing gear comprising a tail skid and an arresting hook which is capable of. some lateral movement and the shank of which is mounted, to swing in a fore and aft vertical plane, by means of a yoke with arms straddling and pivoted to the lower end of the stern post" and of a length to permit of the passage therebetween of the outer end of the skid.

3. In an airplane, an arrestin "gear comprising a hook the shank of Whic is mounted upon a' frame member at the tail of the machine to swing below and to the rear thereof and which is normally but yieldingly held in the vertical plane of the longitudinal axis of the machine.

4. In an airplane, an arresting gear com prising an arresting hook having a pluralpointed head and a stifi metalliccable shank v I a which is mounted upon a frame member of the machine to swing in a foreand aft vertica'l plane below the bottom line of the machine. Y

5. In an airplane, a landing gear comprisprising an arresting hook having a pluralpointed head and a cable shank which is mounted, to swing in a fore and aft vertical plane, by means of a yoke with arms straddling and pivoted to the lower end of the stern post of the machine.

CHARLES WARD HALL.

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