US1124917A - Aeroplane construction. - Google Patents

Description

M. G. KRARUP.

AEROPLANE CONSTRUCTION. APPLICATION FILED JUNE 16, 1910.

2 SHEETS-SHEET 1.

2g N I k I! |l l I WITNESSES: 1 INVENTOR ATTORNEY M. G. KRARUP.

AERQPLANE CONSTRUCTION.

APPLIOATION FILED JUNE 16, 1910.

1,124,917, I PatentedJan.l 2,l9 l' 5.

I 2 SHEETS-SHEET 2.

WITNESSES:

Mnnros c. KrLAnur, or NEW YORK, N. Y.

nnnornann coivsr'noomrom.

. maaerz.

Application filed June 16, 1910. Serial No. 567,163.

To all whom it may concern:

Be it known that I, MARIUS C. KRARUP, a citizen of the United States, and a resident of the borough of Manhattan, in the city, county, and State of New York, United States of America, have invented certain new and useful Improvements in Aeroplane Constructions, of which the following is a specification.

My invention relates to aeroplane constructions and especially to those parts of apparatus of this kind which form air resistance surfaces. I

Its object is'to improve upon aeroplanes by so constructing some of their parts that their efliciency will be increased.

I will describe my invention in the following specification and point out the novel features thereof in the appended claims.

Referring to the drawings, Figure 1 is a side elevation of a well-lmown type of aeroplane constructed in this case to embody my invention. Fig. 2 is a side elevation of the propeller on a somewhat larger scale, showing its front and rear surfaces. In Fig. 3 I have shown in inverted plan view on an enlarged scale, one of the planes or wings of the apparatus which is shown in Fig. 1. Fig. 4 is-a sectional side elevation of the plane shown in Fig. 3, the section being taken on the line 44 of the latter figure. Fig. 5 shows a detail of construction. This figure is a sectional front elevation on'the line 5-5 of Fig. 3, showing one of the ribs of the frame and a manner of afixingcertain parts thereto. Fig. 6 shows in sectional side elevation a modified form of my invention. In Figs. '1 and 8 I have shown in inverted plan view and in sectional end elevation, respectively, a still further modification.

. Like characters of reference designate corresponding parts in all of the figures.

10 designates an aeroplane of a wellknown biplane design. This is shown but diagrammatically in the drawings, and for the sake of clearness some of its parts are omitted as it forms no part of the present invention. 11 is its motor and 12 its propeller. The planes are designated by .13, 13, and 14 are the skids which support it when on the ground.

The planes and some of the other parts of the apparatus are used for applying a thrust against the atmosphere. Heretofore they have been provided with plane or concave surfaces so shaped that the atmosphere in its movement relative to the surfaces met no obstacles or rugosities. These devices have been set at a small angle of incidence with the main extension of their pressure surfaces for the purpose of obtaining a Specification bf Letters Patent. Patentedan, 12, 1915,.

thrust at substantially right-angles to the direction of motion. If thepressure surfaces were plane or nearly plane, and the angle of incidence small, such as from 0 to 15, the thrust was small in proportion to the velocity employed, but the resistance'to motion was also small. If the pressure surfaces were hollow under otherwise similar conditions, the thrust became greater, but

the resistance to motion grew at a much more rapid rate than did the thrust. When the parts which form these surfaces are made according to my invention, a much increased thrust is obtained with only a slightly increased resistance to motion.

Referring now to Fig. 3 I will explain a construction of planes which embodies my invention. In the front of the frame is a substantially rigid spar 20. 21 is a parallel member which forms the rear of the frame. These two parts are connected by a plurality of ribs 22. Thus a light rigid frame is built up over the top of which is stretched curely fastened to the different parts of the frame. Instead of covering the under side of the frame with similar material ll leave it downward from the under surfaces .of the cover 23. Narrow strips or ribbons 24 of thin textile webbing or other suitable material projecting edgewise from the cover 23 are affixed to the front and rear of the frame and secured at intervals to the ribs preferably in such a manner that they cross obliquely to and from one rib to the next. Battens may be used to secure thesestrips to the ribs, or flat wires 25 may be used for open so that the parts of the frame project this purpose; or any other suitable fastening may be used. Their upper edges should also be stitched or'otherwise secured to the cover 232 Thus the under surface ofthe plane or its pressure surface is divided into a plurality of shallow triangular air pockets,

while its upper surface is made smooth as in former practice. These pockets are not necessarily of uniform depth but are preferably made with varying depths as is shown in Fig. 4. Neither are they necessarily in'described have greater consistency in the of equal areas. The strips materially strengthen the structure so that a stronger plane may be built with a given weight than could be made with former constructions. The air pockets thus formed will obviously roduce a greater lifting thrust and ,vwill add but little resistance to the propulsion of the apparatus.

In former constructions the centers of pressure are easily shifted from trivial causes. This is a difficulty which my construction overcomes, as planes made as herea cover or sub-cloth 27 is also used. This is drawn up to the upper cover by some suitable means, such as wires 28, near the front and rear spars, and the sides of the longitudinal ribs 26 and other wires 29 may also be provided intermediate 'the longitudinal members of the frame for a like purpose.

/ In Figs. 7 and 8 T have shown a body 30 formed with intersecting projecting ribs 31. Suitable material may be pressed or molded into some such form in sheets with one or both of its surfaces thus made to form shallow air pockets. Such material may be used for the planes, rudders, propellers, or other parts of the apparatus, or maybe used as a covering over the material already used for the surfaces.

I have shown the propeller 12 with its pressure surfaces 32 constructed with air pockets. These may be formed in the ways which I have already described, or in' any other desired manner. For example, these surfaces may be carved, pressed, or molded into the desired shapes. As the blades of the propellers have a greater rate of movement through the air than do the planes, the pockets may be made shallower than those on the planes. Y

l have illustrated several forms of my invention to show that I do not limit myself to any specific construction or arrangement of parts. I have particularly pointed out certain elements of anaeroplane of wellknown design to illustrate the use of my invention, but obviously it is not limited to such parts or to this specific apparatus as it may be used in many. structures in which the surface is used to produce pressures or thrusts by the action upon it of an elastic medium. On the rudder, blades or other parts of which both sides are used as pressure surfaces, both of their sides may be made with the air pockets.

What T claim is- 1. An aeroplane having only its under surface divided into' a plurality of compartments of substantial. area and depth open downwardly and closed upwardly and laterally to'increase the thrust against the atmosphere relative to the motion of the aeroplane.

2. An aeroplane comprising a frame having transverse ribs, a sheet aflixed to the upper edges of said frame, and ribbon-like members projecting edgewise from the under surface of said sheet and afliXed to the under surface of the sheet and to the sides of the ribs at diagonally opposed points, to thereby divide the under surface of the aeroplane into a plurality of shallow triangular open pockets.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ELLA LUCK, Ennns'r W. MARSHALL.

Images