AIR CORPS INFORMATION CIRCULAR

Transcription

1 , f,,.j 8 '1-1( ( ),. 6, 6 7 File D SupplSept AR CORPS NFORMATON CRCULAR <AVATON > PUBLSHED BY THE CHEF OF AR CORPS, WASHNGTON, D. C. Vol. V September 1, 1926 No. 567 WND TUNNEL TEST FOR ELEVATOR HNGE MOMENT COEFFCENTS ON THE HORZONTAL TAL SURFACE NO. 5 WTH BALANCED ELEVATOR (Supplementary to Serial Report 2463, A S. nformation Circular, Vol. V, No. 5 1 ) ( ARPLANE SECTON REPORT ) Prepared by P. M. Lyons Engineering Diision, Air Corps McCook Field, Dayton, Ohio May 20, 1926 Ralph Brown Oi2iuk;,1 LBRARY MAY 2 9 Z013 Non Oepoitory Auburn Uniersity WASHNGTON GOVERNMENT PRNTNG OFFCE 1926

2 CERTTFCA'l'E: By di rection of the Secretary of War the matter contained herein is published as administratie information and is required for the proper transaction of the public business. (n )

3 WND TUNNEL TEST FOR ELEV A TOR HNGE COEFFCENTS ON THE HORZONTAL TAL NO. 5 WTH A BALANCED ELEV A TOR. MOMENT SURFACE (Supplementary to Serial Report 2463, A. S. nformation Circular, Vol. V, No. 511) OBJECT T he object of this test was to determine the eleator moments about the hinge line on t his balanced tail surface. DESCRPTON OF MODEL The stabilizer of this horizontal tail surface i the same as was tested before (see Test o. 111, ),* but the eleator has been altered by adding a balanced portion as shown in an accompanying sketch. The airfoil section is the U. S. A.-47, the chord 3 inches, and the oer-all span 11.2 inches. The two eleator hinges are of the cone piot type offering ery little friction. DESCRPTON OF TEST The balanced eleator was tested in the same manner as the unbalanced eleator t ested J uly 22, T he stabilizer was mounted horizontally on a spindle attached to the. P. L. balance. A small wire was See Serial R eport 2463, A. S. nformation Circular, Vol. V, No. 5ll. fastened to the eleator at a point near t he trailing edge and 1.25 inches from t he hinge line. T he wire was passed up through a 7'2-inch tube to a -pound Toledo scale located on top of the tunnel. The tube extended down from the tunnel wall to within about 3 inches of the model. A turnbuckle was used in the wire to obtain desired eleator angles which were determined by a special telescope at the side of the tunnel. RESULTS OF TEST Between the time of the original test and this test the method of air straightening in the tunnel has been modified. T h is change, howeer, is belieed not to hae any appreciable effect upon t he comparison of the two eleators. The coefficients for the balanced eleator, due to small net forces, are not as consistent as those for the unbalance-ct eleator. Comparing the cures (fig. 2) it will be obser ed that the balanced eleator hinge moment coefficients are of about onethird the magnitude of those for the unbalanced eleator Right half of horizontal tail surface No. 5-balanced and unbalanced eleator. rota! stabilizer area=.110 square feet. 'l'otal eleator area (balauced)=.105 square feet. Total eleator area (unbalanced)=.075 square feet. Airfoil Section U. S.A.-47. FG. 1 (1)

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5 ELEVATOR HNGE MOMENTS Balanced Eleator Horizontal tail surface o. 5. Air Speed: As noted. Standard Air. Au thority: McCook Field (5 ft.) Wind Tunnel Test No D ate T ested : January 28, Stabilizer at 0. Eleator: As noted. Eleator angle (degrees) o ]Q _ o JO Net force (pounds) Moment Cosine of (lb. in.) eleator forcex F irst Second Aer- angle l.25x run run age Cos. 40M. P. H SO M. P. H " Mc ()j) ELEV.A.TOR HNGE MOMENTS Unbalanced Eleator Horizontal Tall Surface No. 5. Air Speed: 40 M. P. H. Standard Air. Authority: M ccook Field (5 ft.) Wind Tunnel T est No D ate Tested : July 23, Stabilizer at 0. E leator: As noted Eleator angle (degrees) Net force (pounds) Cosine Moment (lb. in.) force x l.25x Cos. M c., L _ M M c 12XA XCXV' M Au=Eleator area=.075 square feet C =Eleator cbord=.107 feet V =Air speed =40 miles per hour o M Mc 12X.A.n XCXV' 40 M. P.H. Mc M 80 M. P. H. Mc.= M An=Total eleator area=.105 square feet C = Eleator chord=.107 feet V =Air speed- as noted. 0

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