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Aviation History
1933
1933 - 0200.PDF
44 SUPPLEMENT TO FLIGHT THE AIRCRAFT ENGINEER JULY 27, 1938 "S -co* - OOI nnn A I k CO& VO / T -/ / // r / / / / 7 7^ s / / z* -• -/ ) / / / / ?c /> o r T -T T i 1 i I *•/ -rss*ss*£t /t»/i£Atr ce£f*/£/ewr&/K„)— />a*vr z^*/.* or £*****' Vi. *f*&i or trrr*rc/r(a.)* s»r nurtsj/s r*d*r* I 1 X rzs?r> r.*: ^> Ejrr>^sws£4'i#*' S£mt^ _ c* 1 ry£?4+fe-& r/?er> 4>s>r/i— Cf JI/.J9.C.& - T.A/&2Z. V1 fr > _ fa ,, ?t £i _. ,p »j r^"^ ,pW p£3 oP f H£- ?2£i it,l& /A/J HinjA nh^. f -9// k*0' -»5« _^i^ e /s »*«»< « Lid <£-£<! *3*> e I 1*1 Is 1 ^ —I 1 1 1 1 1 1 p—, /"' 7-CAtsAt*. r>en£/*T tfatFr-^/t/^Ai r.T ITC*?"**. . coef-stce/vr sr^. _i 1 1 I I I I I I r-*t«A 6^ /V.IC./r.-T./v.'fZl -AV^,. 3 S *">• J r ? i N J 1 <: _.ot>o& ^£JL£l -g" ,eeo 1 J_- "\ PI* *»• ! 1 1 1 i 1 1 ! /B/r4At//t>4k At*J9£Jvr,£-0£*f*£*&/vr&ftrml ftac&7~ 2S ff OFC*t6&£> V3.£3#**?4 _ li ill 3D '/ /^i^/P^ rsr*/ji/M£ £pq.£ y>£J?^/?n£v &/?*•£•* *£"*•&* e^eTt v/^/p '.tH.»K i I * a f .*.- T. sv +22 i I ja» *r£&jm \ \ /* A «•>• -^ S f ^J •/•• k -/*« '"**, •rs' &#f B^" "*/" •• / *o* r/.Mr' y *%s '»• i-^-ro ^.v^" t JMUW MMM t**r#**r nw 9* .« i^>-* • r* . t \\ i—» to* »- 1 tZ S/4, J £? Figs. 3D to F give pitching moment coefficients for an airfoil, while in Figs. 4 and 4A the pitching moments of a conventional Zap-equipped monoplane are shown. The net result is that the balance and stability is undis turbed and increases in tail area or abnormal stabiliser adjustments are not necessary. Our next point of interest, stimulated by the flight? of the Aristocrat, was the extremely low operating forces necessary to move the flap down. With a simple flap of the type used on the Breguet observation aeroplanes in France as early as 1917, the forces necessary to get the flap down were excessive, so much so that the flap could only be deflected approximately 30 deg. when usabit? operating forces and time to operate are taken into con sideration. Even if it were deflected to greater angle- the lift coefficients would still be below that of the Zap. (Reference NACA Technical Report No. 422 from which curves on Fig. 5 are interpolated.) With the straight type of split flap, such as tie Wright, where the leading edge of the flap is a fixe;'. hinge, the operating forces are compelled to work against the full aerodynamic load. If the mechanise is of cantilever construction the forces are prohibitive. If it is of a toggle arrangement, which would have to be some modification of the Zap toggle, without ti e beneficial effect of the sliding front edge, there aga^i the forces are extremely high and particularly excessr.c at small angles of flap opening. These forces diminiii after the flap has caused sufficient drag to slow tne plane a great amount. (See Fig. 6 showing relative loads of Zaps versus straight flap for same angles.) I'J*- hypothetical aeroplane we used in arriving at these figures had a wing area of 309 sq. ft.; 48 ft. 8 in. spa' 83 in. chord, Clark Y airfoil; gross weight, 4,600 lb-: wing loading, 14.8 lb.; power loading, 10.8 lb.; maxi mum speed of 150 miles per hr. The flap area for hot;; the Zap and simple flap was 30 per cent, of the total area and the flap chord 30 per cent, of the wing cborc 754 rf
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