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rvuertot Awezázzaze/7 "24-c. 4c. dittozvot y Patented Sept. 19, 1939 2,173,674 UNITED STATES PATENT OFFICE 2,173,674 AERON DEVICE Edward F. Zaparka, Baltimore, Md., assignor to Zap Development Corporation, Baltimore, Md., a. corporation of Delaware Application June 7, 1933, Serial No. 674,729 Renewed January 13, 1937 Claims. (C, 244-90) My invention relates to ailerons, and more wing equipped with the form of aileron shown particularly to ailerons which are balanced so in Figure 1; that it requires gradually increasing control stick Fig. 3 is a graph showing the control stick forces to move them from the neutral position. forces plotted with respect to the angle of at 5 Though I am not to be limited to any par tack of a combined pair of ailerons; 5. ticular location of the ailerons, the ailerons I Fig. 4 is a view in side elevation of an air have shown are of the type illustrated and de plane wing showing another form of my aileron; scribed in my application Serial No. 653,918, filed Fig. 5 is a detail view partly in section show January 27, 1933. ing the form of aileron illustrated in Figure 4, 10 The present application deals with the construc the different positions of the aileron being indi- 10 tion of the aileron per se, and the location of cated by dotted lines; the aileron as specified in Serial No. 653,918 is Fig. 6 is a detail view in side elevation and not restrictive in considering claims in this ap partly in section showing another form of ai plication, except as the language imposes such leron, the different positions being indicated in 15 limitations. dotted lines; Heretofore when a pair of ailerons moved in Fig. 7 is a detail view in side elevation and opposite directions from the neutral position, partly in section showing another form of aileron, there was a "soupy' action at the control stick the different positions being indicated in dotted for the first few degrees of movement of the pair lines; 20 of Zap ailerons from the neutral position. This Fig. 8 is a detail view in side elevation and 20 Soupy action was followed by a very sharp in partly in section showing another form of aileron, Crease in the stick forces necessary to move the the different positions being indicated in dotted pair of Zap ailerons when the change from the lines; vertical angle became great. Fig. 9 is a detail view in side elevation and 25. It is one of the objects of this invention to pro partly in section showing another form of aileron, 25 vide ailerons such that the forces necessary to the different positions being indicated in dotted move the pair of Zap ailerons through increas lines; ing plus and minus angles of attack is consider Fig. 10 is a side elevation of another modifica ably less than for a pair of normal Zap ailerons. tion of my aileron, the different positions being 30. It is a further object of this invention to pro indicated in dotted lines; 30 vide ailerons in which the center of pressure shift Fig. 11 is a rear elevational view of a wing at varying angles of attack creates favorable showing a different form of my aileron in posi hinge moments. - tion above the Wing; A still further object of my invention is to Fig. 12 is a detail view in side elevation of the . 35 provide aileron constructions which are so piv aileron illustrated in Figure 11. 35 oted that the pivot shifts with the angular move Referring to the drawings, in Figures 1 and 2 ment of the .aileron so that the shift in center of I have shown a form of my aileron having a pressure is compensated largely by varying the front slot construction. In Figure 1 I have shown moment arm between the center of pressure and an aileron having a fuselage , a motor 2, pro 40 the point of pivoting. w peller 3 and wings 4. Above the wings 4 and 40 Still another object of my invention is to pro near the trailing edge thereof, as shown in the vide ailerons so constructed that the tendency drawings, I have mounted ailerons 5. The ailerons for the center of pressure to shift on any one 5 are mounted on horns 6; the ailerons being piv designed area of an aileron in one direction is oted at T on the horns 6. The ailerons have 45 compensated for by shift of center of pressure in attached to their upper surface horns 8 to which 45 the opposite direction on another designed area, are pivoted at 9 the aileron control rods O. Em whereby there is a tendency for these opposite pennage surfaces are indicated at 4. shifts in center of pressure on the different de The aileron control rods 0 are pivoted at , 50 signed areas to at least in part neutralize each as diagrammatically illustrated in Figure 1, to a other. control member 2, which is pivoted at 3. The 50 In the drawings: control member 2 is provided with two arms 4 and 5, indicated in dotted lines. The arms 4. Figure 1 is a top plan view of an airplane are connected by a cable 6 and the arms 5 are equipped with one form of my aileron; connected by a cable 7. The cable passes 55 Fig. 2 is a detail view inside elevation of a over pulleys 8 and is attached to a control stick 55. 2,178,674 2 obtained, i.e. stick forces are such that the pilot 9. The aileron control mechanism is of the can control the plane easily; well known type and the details of construction (3) Additionally an increased rolling moment are not given herein. r Spaced from the upper front edge of the aileron is obtained due to the increased lift of the posi 5 is an element 20 which has a curved front sur tive aileron, which is in some instances in the face and is so shaped at its rear as to provide nature of 20 per cent increase in lift of positive a Substantially parallel slot 2 which slopes back aileron, and, therefore, a 10 per cent increase in total rolling moment. - Wardly and upwardly above the upper leading In Figs. 4 and 5 I have shown the aileron 5 pro edge of the aileron 5. The element 20 is sup vided with a supplemental airfoil 23, pivoted at O 10 ported in its spaced relationship to the upper 24 to the trailing edge of the aileron 5. The leading edge of the aileron 5 by means of support supplemental airfoil 23 is provided with a horn elements 22, only one of which is shown. 25 to which is pivoted at 26 a link 27 whose other Referring to Fig. 3, I have shown a graph in end is pivoted at 28 to the supporting horn 6 which the control stick forces in pounds necessary for the aileron 5. 15 5 to accomplish a certain movement of a pair of In Fig. 5 the interior construction of the aileron Zap ailerons in minus or plus directions from the 5 is shown, which is similar to the forms shown neutral position are indicated. The dotted line in Figs. 1 to 8, namely a construction in which . indicates the action of a pair of Zap ailerons there is a front hollow bracing tube 29 having placed as shown in Fig. 2, but without the slot supports 3 pivoted at 7 on the upper tip of the 20 S20 ted front construction just described. The un horn 6. There are provided slots 33 to permit the broken line on the graph indicates the stick forces horns 6 to pass into the interior of the aileron plotted with respect to a pair of Zap ailerons with 5. The position of the aileron 5 with respect leading edge fixed slots. Both lines approxi to the flap or supplemental airfoil 23 in varying mate actual performance. positions is shown in dotted lines in Fig. 5. 25 From an inspection of the dotted line in Fig. 3, Here the supplemental airfoil or flap 23 and it will be seen that for the first few degrees of the linkage indicated causes a phenomenon simi movement of the pair of ailerons from their neu lar to that in the form of aileron shown in Fig. 2, tral position the feel on the control stick is what namely a reduction in the hinge moment of the is known to pilots as “soupy'. The forces neces pair at high plus and minus angles of attack. 30 30 Sary to move the pair of ailerons then become Moreover, the flap increases the rolling moment Sharply greater, and at about ten degrees in the of the pair due to the down aileron. particular graph shown, the force to move an In the form of aileron shown in Fig. 6, the Ordinary pair of Zap ailerons not provided with aileron 5 is provided with a split flap type of con the leading edge fixed slot is about the same as struction in which there is a flap 34 pivoted at 35 35 that to move a pair of Zap ailerons provided with 35 to the lower rear surface of the aileron 5. It the leading edge fixed slot. From ten degrees on is to be noted that the aileron 5 is of the single the forces required to move the pair of ailerons cambered type with a cambered upper surface. to increase minus and plus angles of attack are The flap 34 in its up position forms a continua Very much greater than is the case with the pair tion of the lower surface of the aileron and has 40 40 St. Zap ailerons provided with the leading edge its trailing edge substantially adjacent the trail S.O. ing edge of the aileron. Projecting into the in With the form of aileron just described, I have terior of the aileron 5 is a horn 36 fastened to found that in certain instances lift increase on the upper front surface of the flap 34. Pivoted to the positive aileron is between 18 and 20 per cent, the horn at 37 is a link 38 whose other end is pro 45 and this produces a rolling moment on the vided with a slot construction 39 which fits Over a whole airplane which gives an increase of about pivot 4 provided on the support arm 6. There 10 per cent in total rolling moment over the con is provided a spring 42 attached at 43 to Sozine ventional pair of Zap ailerons. Furthermore, it suitable portion of the interior of the aileron 5 is possible to balance the ailerons considerably at one end, and at the other end attached to farther aft which will permit exceedingly light the horn 36 on the flap 34. Stick forces and, therefore, lighter mechanism. The spring 42 is a tension spring and tends Conversely, Zap ailerons, not equipped with the to hold the flap 34 in the position indicated in flap, when given a pivot point such that there is Fig. 6. When the aileron moves in the up posi a favorable location for balance, so that nega tion (with its trailing edge raised, as indicated in 55 tive hinge moments which might cause flutter are dotted lines) the pivot 4 merely slides in the largely eliminated, have, in certain instances, slot 39 formed in the link 38 and the spring 42 high stick forces. Because of high stick forces, holds the flap 34 in the shut or up position. the rapid control of the airplane is in some in Upon down movement of the aileron 5, however, stances somewhat difficult. the pivot 4f strikes against the end of the slot 39 With the conventional Zap aileron it was found formed in the link 38 and through the linkages that with the point of pivot about 22 to 25 per indicated forces the flap 34 into the open position, cent back from the leading edge, a flutter some as indicated in dotted lines in Fig. 6. This form times occurred at low angles because of negative of construction is peculiarly adapted to a single hinge moments. When the pivot point was moved cambered aileron and tends to decrease the hinge 85 65 up to about 18 per cent, the flutter was eliminated moments of the pair at high plus and minus angles but stick forces tended to become large-because of attack and to increase the rolling moment of of the forward location of the pivot. the pair due to the down aileron. When using the type of aileron with the fixed In Fig. 7 I have shown a construction somewhat leading edge slot construction just described, Similar to that shown in Fig. 6. The aileron 5, 70 O there are numerous advantages. Some of the however, is of the double cambered type and there advantages are that; is provided a flap 44 pivoted at 45 on the upper (1) The pivot point of the aileron can be surface of the aileron 5. The trailing edge of the moved to the rear, preventing fiuttering; flap lies substantially adjacent and just above the (2) Due to relatively great rearward move trailing edge of the aileron. The lower front edge 75 75 ment of the pivot favorable hinge moments are a,178,674 of the flap 44 is provided with a horn 46 to which 3 is pivoted at 47 the link 38 which is identical in 6. This linkage and construction moves the pivot point of the aileron on the horn so that when the 'construction with the link 38 of the construction center of pressure of the aileron is shifted by 5. shown in Fig. 6. A spring 48 is attached to the reason of its angular position, the moment of flaprior ofhorn the 46,aileron and also5. . attached at 49 to the inte force of the pair to the pivots, i.e. the forces nec In the up position of the aileron shown in Fig. essary to move the pair of ailerons, is such that there is no movement of the flap since the slotted for the various angular positions of the ailerons portion 39 of the link 38 slides over the pivot 4, the unbroken line in Fig. 3 approximately repre O and the spring 48 holds the flap shut. In the sents graphically the action which takes place. down movement of the aileron, when the trailing It is to be understood that the graph in Fig. 3 is 10 ledge of the aileron is lowered, however, the pivot .. not intended to represent accurately the action 4 strikes the end of the slot 39 and the flap 44 is which occurs in the case of every aileron pair, but opened against the tension of the spring 48. The is merely indicative of what may be, within reas ls hinge moments at high plus and minus angles of onable limits of error, expected of the ailerons attack are reduced so that the stickforces approx shown in this application. imate those indicated in the unbroken line of the In Figure 10 I have shown the aileron 5 at 5 graph, Fig. 3. . . tached to a support 70 which is relatively long In Fig. 8 I have shown the aileron 5 as single and slopes backward. The support T0 is pivoted 20 cambered with relatively flat lower surface and a at its lower rear end to a pivot 7 formed on a cambered upper surface. The aileron 5 is pro support horn 72 which has a relatively great vided with a flap 5f whose trailing edge lies adja backward angular slope with respect to the up 20 cent and just below the trailing edge of the aileron per surface of the wings 4. The aileron control 5. The flap 5 is provided with an attachment rod 0 is pivoted at 73 to a front part of the sup 25 member 52, which is pivoted on a pivot member port T.O. With this arrangement the aileron is 53 which is also pivoted to the link 38. The pivot pivoted on the horn 72 at a point well below and 53 is adapted to pass through and slide in a slot 54 behind the normal center of pressure of the formed in a bracing rib 55 of the aileron. Pivoted aileron. The different positions of the aileron at 56 to the upper side of the flap 5 is a link 5 with respect to its hinged point is shown in 30 which is also pivoted at its other end 58 to the dotted lines and the construction is such that interior of the aileron construction. the shift in center of pressure on the pair of 30 The link 38 is adapted to pass through an aper ailerons is compensated for by change in the ture 59 formed in the lower surface of the aileron moment arm from the center of pressure to the 5. In up positions of the aileron, as shown in pivots, so that the stick forces necessary to oper 35 Fig. 8, there is a spring 59 attached at 6 to the ate the pair of allerons are within the limits of tolerance, represented by the unbroken line in endinterior to the of thesupport aileron 52 which5 and attachedprevents atthe its flap other 5f - Fig. 3. . . . 35 from Opening...... In Figs. 11 and 12 I have shown an aileron of However, when the aileron is lowered (its trail-". . warped construction. In Figs. 11 and 12 the 40 ing edge lowered) the pin 4f engages the end of trailing edge of the aileron is indicated by the the slot 39 in the link 38 and forces the flap to a line 75. The aileron is warped, as is clearly ap 40 down position with respect to the aileron, as indi parent from these two figures. A line 76 indi cated in dotted lines. The lengths of linkage and cates the trailing edge of the wing 4. This warped points of pivoting are such as to cause the trailing construction is such that when the center of pres 45 edge of the flap to lie substantially in the locus of . sure on one portion of the area shifts in one perpendiculars drawn to the datum lines of the direction, the center of pressure on the other aileron sections which pass through the trailing portion of the aileron shifts in the other direc 45 edge of the aileron. This type of flap is called a tion, and the sum of the center of pressure on "Zap" and I have found it of peculiar utility in the two areas on each aileron in the pair tends 50 connection with the type of aileron shown in to permit the stick forces for the pair to approxi "Figure8. nate the unbroken line shown in the graph, 50 With the form of ailerons depicted in Fig. 8 Fig. 3. there is an increased rolling moment and a reduc claim: tion in hinge moments for the pair at high plus. 1. In an aircraft having a transverse wing ex 55 , and minus angles of attack. . . . . tending on either side of the center line of the . In Figure 9 I have shown an aileron 5 provided craft and roll control mechanism including a with a slot 62 formed in'an interior bracing struc control member, roll producing devices on either ture 63 which is attached to the front. hollow side of the craft and mounted on said wing, Con bracing tube 29. A pivot 64, carried on the upper nections between said control member to said de end of the support horn 6, passes through the slot vices, and means whereby there is a substantially 62 formed in the member 63. . . straight line increase inforces necessary to move 60 Pivoted to the member 63 at 65 is a link. SG the control member as the roll producing devices which is pivoted at 61 on the aileron horn 6. The are moved from their neutral positions. . link 66 passes through an aperture 68 in the lower 2. An aircraft roll control mechanism compris 65 surface of the aileron 5. ing a control member, a roll producing device, op erating connections between the control member 65 It will be understood that in all of these forms and the roll producing device, and means where areof aileron duplicated shown, adjacent the linkages the horns and 6.constructions and that is by there is a substantially straight line increase true of this construction as well. in forces necessary to move the control member 70 In Figure 9 there is shown in dotted lines the as the roll producing device is moved from its movement of the aileron in its up and down posi neutral position. . . O tions. In the up position of the aileron the link 3. In an aircraft having a transverse wing ex age, causes the aileron to move bodily forward on tending on either side of the center line of the craft and roll control mechanism including a con the-horn 6. In the down movement of the ailer trol member, ailerons on either side of the craft is the aileron moves bodily backward on the horn and mounted on said wing, connections between 76 4. 5,178,674 is compensated for by change in the movement said control member to said ailerons, and means arms to the pivots. , whereby there is a substantially straight line in 11. An aleron having a slot therein, a pivot crease in forces necessary to move the control for the aileron mounted in the slot, a support member as the ailerons are moved from their ing horn for the aileron carrying the pivot, a link is . neutral positions. pivoted on the aleron at one end and on the Sup 4. An aircraft roll control mechanism compris porting horn at the other whereby moving the ing a control member, an aileron having a fixed aleron bodily with respect to the pivot is effected slot, operating connections between the control ini moving from the neutral position. member and the aileron, and means whereby 12. An ailefon having a slot therein, a pivot 0 10 there is a substantially straight line increase in for the aileron mounted in the slot, linkage for forces necessary to move the control member as shifting the axis of pivoting of the aileron about - the aileron is moved from its neutral position. the pivot during pivoting. 5. In an aircraft having a transverse wing ex 13. In a pair of slotted ailerons, pivots for the tending on either side of the center line of the aerons mounted in the slots, means for so mov craft. and roll control mechanism including a ing the aleron on the pivots while moving control member, interlinked single cambered al through up and down positions from the neutral lerons having cambered upper surfaces on either as to compensate for shifts in center of pressure side of the craft and mounted on said wing, con by varying the moment arms about the pivots. nections between said control member to said 14. A single cambered aileron comprising a flap 20 allerons, and means including fixed slots located on the lower rear surface of the aileron adapted at the forward edge of each aileron whereby to have its trailing edge in positions of extension there is a substantially straight line increase in and retraction lie substantially within the locus forces necessary to move the control member as of perpendiculars to the datum lines of the air the ailerons are moved from their neutral po foil sections of the aileron and passing through the trailing edge of the aileron, a horn on the 6. In an aircraft having a transverse wing ex flap, a spring within the aileron attached to the tending on either side of the center line of the interior thereof at one end and at its other end craft and roll control mechanism including a to the horn on the flap, and a link pivoted to the control member on either side of the craft and horn at one end and slidably pivoted at its other 30 mounted on said wing and above the upper sur end to a pivot fixed with respect to the aileron. face thereof, connections between said control 15. A single cambered aileron comprising a flap member to said ailerons, and means whereby . on the lower rear surface of the aileron adapted there is a substantially straight line increase in to have its trailing edge in positions of extension. forces necessary to move the control member as and retraction de substantially within the locus E. ailerons are moved from their neutral.posi of perpendiculars to the datum-lines of the air O foil sections of the aileron and passing through 7. Aerons having warped surfaces so that the trailing edge of the aileron, linkages to cause upon movement of the pair to angular positions downward movement of the flap with respect to from the neutral the center of pressure with re the aileron on downward movement of the aileron. 40 Spect to designed areas on each aileron shifts so 16. A double cambered aileron comprising a that the stick forces required to move the pair flap pivoted on the upper rear surface of the of silerons to relatively large plus and minus aileron and having its trailing edge in its re angles from the neutral increase in substantially tracted position adjacent the trailing edge of the direct proportion to the angular movement. aileron, a horn on the flap, a Spring within the 45 8. A pair of warped ailerons whose center of aileron attached to the interior thereof, at one pressure shifts are such in varying positions of end- and at its other end to the horn on the flap, up and down movement of the pair as to permit and a sink pivoted to the horn at One end and the stick forces to increase in substantially slidably pivoted at its other end to a pivot fixed so.straight 9. In aline pair fashion. of ailerons, relatively longw aileron - with respect to the aileron. Supports, backwardly sloping horns, pivots on the 17. A single-cambered aileron comprising a horns on which the supports are pivoted, the sup flap pivoted on the lower rear surface of the, Ports being of such a length and so related to . aileron and having its trailing edge in its re the ailerons and the horns that shift in center of acted position adjacent the trailing edge of the 55 pressure of the pair is compensated for by change, a horn on the flap, a spring within the in the moment arms to the pivots. aleron attached to the interior thereof at one 10. In a pair of ailerons, aileron supports, end and at its other end to the horn on the flap, aileron horns, pivots on the horns on which the and a link pivoted to the horn at one end and supports are pivoted, the supports being of such slidably-pivoted at its other end to a pivot fixed 60 a length and so related to the ailerons and the with respect to the aeron....DWAR) F. ZAPARKA. horns that shift in center of pressure of the pair - , . - -