US3141637A

US3141637A - Airplane wing flaps

Info

Publication number: US3141637A
Application number: US151515A
Authority: US
Inventors: Dornier Silvius; Schrenk Oskar
Original assignee: Dornier Werke GmbH
Current assignee: Dornier Werke GmbH
Priority date: 1960-11-12
Filing date: 1961-11-10
Publication date: 1964-07-21
Anticipated expiration: 1981-07-21

Description

July 21, 1964 DORNIER ETAL AIRPLANE WING FLAPS Filed NOV. 10, 1961 INVENTORS. 5/1. w as DOE/V152 ATIOEWZK United States Patent 3,141,637 ALANE WING FLAPS Silvius Dornier, Friedrichshafen, and Oslrar Schrenk, Friedrichshafen-Manzell, Germany, assignors to Dornier-Werire G.m.b.H., Friedrichshafen, Germany, a German firm Filed Nov. 10, 1961, Ser. No. 151,515 Claims priority, application Germany Nov. 12, 1960 1 Claim. (Cl. 244-42) The invention relates to airplane wings having flaps at their trailing edges, and more particularly to means for increasing the effect of the wing flaps, i.e., the diversion of the propeller slip stream for producing lift.

In the patent application of Silvius Dornier et al., Serial No. 130,785, filed August 11, 1961, now Patent No. 3,129,907, it is proposed to increase the lifting effect of the propeller slip stream when the fiap or flaps on the trailing edge of the airplane wing is or are extended by making the underside of the flap or of the rearmost flap, in case there are several flaps behind each other, deeply concave whereby the angle at which the upper surface is placed relative to the bottom surface at the trailing edge of the flap becomes very small. It has been found that this configuration of the second flap of a two-flap system makes this system as effective as a system having three or more flaps arranged behind each other at the trailing edge of an airplane wing.

It is an object of the present invention to provide a structure or" an airplane wing flap which substantially increases the diversion of the propeller slip stream without unduly increasing the weight of the flap. This object is obtained by making the underside of the fiap vaulted and by swingably connecting an auxiliary substantially plane or platelike airfoil to the underside of the flap and within the vault or cavity formed thereby. The auxiliary airfoil, when protracted or extended, moves away from the trailing edge of the flap and enlarges the cavity at the underside of the flap wherein the air is diverted, upon extension of the main fiap. The auxiliary airfoil is adjacent to the rear portion of the underside of the flap when the latter is in retracted position.

In a modification of the invention the auxiliary airfoil is swung forward and closes a substantial portion of the cavity at the underside of the flap when the latter is in retracted position. The forward edge of the airfoil abuts against the leading edge of the flap when in retracted position.

In a further modification of the invention the auxiliary airfoil is replaced by the rear portion of the flap which rear portion is hinged to the forward portion of the flap. During normal flight, when the flap is in retracted position, the rear portion of the flap is in line with the forward portion of the flap. When the flap is extended, the rear portion thereof is at an angle with respect to the forward portion and enlarges the cavity formed in the underside of the forward portion of the flap.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawing wherein:

FIG. 1 is a diagrammatic cross sectional illustration of an airplane wing flap structure according to the invention.

3,141,637 Patented July 21, 1964 "ice FIG. 2 is a diagrammatic illustration of a modification of the structure shown in FIG. 1.

FIG. 3 is a diagrammatic cross sectional illustration of a further modification of an airplane wing flap according to the invention.

FIG. 4 is a diagrammatic large scale illustration of an actuating mechanism forming part of the structure shown in FIG. 3.

Referring more particularly to FIG. 1 of the drawing, numeral 1 designates the rear portion of an airplane wing. A flap 2 is connected to the wing 1 in the conventional manner, not shown. The underside of the flap 2, particularly the forward portion thereof, is vaulted and forms a cavity 3. Due to this configuration of the underside of the flap the angle formed by the underside and the top side of the flap at the trailing edge thereof is very Small. An auxiliary rigid platelike airfoil 4 is placed in the cavity 3 and hinged at 5 to the underside of the flap 2. FIG. 1 shows the device in protracted or extended position. When the fiap is in retracted position the airfoil 4 is in the position indicated by a dotted line 4' which is codirectional with the underside of the flap. The airfoil is adjacent to the rear portion of the underside of the flap whereas in the protracted position the airfoil is away from the trailing edge of the flap 2. In the protracted position the airfoil 4 forms a considerable enlargement of the cavity in the underside of the fiap- 2 and increases the diverting effect of the flap on the propeller slip stream.

Aside from the hinge 5 the airfoil 4 is connected to the flap 2 by a toggle

joint including levers

101 and 102, lever 101 being pivotally connected at 103 to the flap 2 and lever 102 being pivotally connected at 104 to the airfoil 4.

In the modification shown in FIG. 2 of the device according to FIG. 1 the airfoil 4 is swung forward upon retraction of the flap 2, until the forward edge of the airfoil 4 contacts the leading edge of the flap 2 and the airfoil 4 covers the cavity 3, preventing disturbing currents at the underside of the flap during normal forward flight. When the flap 2 is protracted the airfoil 4 is swung away from the leading edge of the flap toward the trailing edge thereof to the position indicated by a dotted line 4' in FIG. 2. This movement is limited by a lever mechanism similar to that shown in FIG. 1.

In lieu of the provision of an auxiliary airfoil as shown in FIGS. 1 and 2 the entire rear portion 105 of the flap 2 may be swingably connected by means of a hinge 5' to the forward portion of the flap 2 as shown in FIG. 3. When the flap is in retracted position the rear portion 105 is codirectional with the underside of the flap and forms a smooth continuation of the forward portion as shown in solid lines in FIG. 3. When the flap is protracted or extended the rear portion 105 is moved into the position 105' shown in dotted lines in FIG. 3.

FIG. 4 shows a mechanism for swinging the rear portion 105 of the flap 2 relative to the forward portion of the flap. This mechanism comprises a pinion 106 mounted on the pin of the hinge 5. A rack 107 cooperates with the pinion 106 for swinging the rear portion 105 into the desired position. The rack 107 may be hydraulically operated in a conventional manner. In lieu of a rack and pinion a worm gear may be provided. It is also possible to effect the desired relative position of the forward portion and of the rear portion of the flap 2 by lever mechanisms similar to those shown in FIGS. 1 and 2.

3 We claim: by the concavely shaped underside of the flap upon re- In an airplane wing having at least one fiap at the traction of said flap. trailing edge, said flap having a trailing edge and a leading edge, and an underside having at least a forward por- References Cited in the file Of this Patenl tion concavely shaped and forming a deep cavity, an 5 UNITED STATES PATENTS auxiliary airfoil swingably connected to the underside of the flap for swinging said auxiliary airfoil away from the 2136845 Fenton 1938 leading edge and from the trailing edge of the flap and FOREIGN PATENTS forming an enlarged substantially concavely shaped sur- 727,432 France 29, 1932 face at the underside ofthe flap upon extension of the 10 846 421 France June 5 1939 flap, and for swinging said auxiliary airfoil to abut against 71627 4 Jan 1942 the leading edge of the flap for closing the cavity formed