1、I . ., NASA TECHNICAL MEMOANDUM NASA TM X- 72805 Lt) o co N “ I 100 20 X 103 80 1f) 60 12 40 8 20 4 o a 20 40 60 80 100 120 Ground speed, knots Figure 2.- Va.ria.tion of tire vertical ground load with ground speed. (Unpublished data obtained from flight tests.) ,D rl “t1 til 0 rl “t1 0 , bO rl ro tJ
2、 rl + “ 41 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, . ! F THft .) )1 ! c .-u . II. 0 L. tI :u . o Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 1-t . I “ .I. .v l 1 . Provided by IHSNot fo
3、r ResaleNo reproduction or networking permitted without license from IHS-,-,-Drag-load beam , . FORWARD Drag-load beam Vertical, drag, and side accelerometers Wheel angular velocity and angular displacement indicators Verlical-1oad beam Side-load beam , yTire I I / I I , , I / / -“ torque links Figu
4、re 5.- Schematic of amometer used in tests. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-:; “ 0-0 “ “-co U . c:t! QJ 0 C:.i!: “ -= g QJ -QJ “ .c :;. :;: QO -, ,; “, - 45 . .9 .9 0 :.1“ co . 0 c 0 90 . -“ -“ -“ ,; ,; 45 .2 .9 -; “ w w t t “ QJ “0 :
5、;,. 0 40 -e :.: “,- “,-t .9 .!? ?O QJ “- :;2 0 v a 80 20 -3 x 103 40 “ v; a 15 0-:E “, 2 “, . :J :J ., ., 10 “ - . “ ., “ 0-I) 0-“ “ . “ . . “ 5 - co co Ol- 0 _L_J 80 f 14 -10 )( 103 : z , . ;t: ,1 “, “, :J :J c:r E“ 5 40 . -_. .s .s “ . . . “ . co co _L . .-J 0 0 O x 103 1.0 10 IltJ .5 n LL_.J 1 2r
6、l -x 103 1.0 -. J“- -v- II) s .5 f _ l. L.L_J 0 3 llO I. 0 0 i .-0-,5 -“ I “ “ .c -C:=-: _ J L I_ . -L _ J _ . L_L _L_ 0 .4 .0 _8 1.0 0 .2 d .0 Time, sec Time, sec tiure 6. Typical lime histories of various parameters recorded and computed for lesl run brake cycles_ Yaw dngle 00 It): qround speed 51
7、 knots; r1r concrete surface. -;!I -. : _ -1 J , L.l .J (1 I I _.L.-_J . J 1.0 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.8 .6 d .4 .2 a .8 .s s .4 .2 a _-v .2 .4 .6 Wheel slip ratio V-Spin-down l Spin-up .1 L.a Figure 7.- Variation of computed
8、 friction coefficients with whepl slip ratio during a brake cycle on dry concrete surfac. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flrj I S .“4 .5 an. .6 I / .4 .2 o - _ -L _ _ _ _ .r; .4 . o .4 .6 .8 1.0 Wheel llP ratio (;1) l;round speed :-:
9、 ;0 knots l“jlU, (l,.- !:lri:llinn of lr:i;-f)r(e frlrtion (o,ffici(nt. IIrj r,nr! (ornlrinffnrffi“j0nt)j with wW(J 31il rat.io for 1.e!31. tire at :. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, .6 “,-. / “ ( I “-jJ (1 .2 o (1, ) (r( Jlln! , t-
10、1 :.“, rlr(l -Yaw n.nr: e 0 12 ;r , ) . . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-)J S .6 .4 I .2 I , I A!f!i- -fiiY6i-*- !“lg.- - filL.“._ o .Ii , I “ -o _ _ _ _ _ / .0 o .? .6 .8 l.0 Wheel slip ratio (c) Ground speed : 100 knots. “jllltf
11、11.- Cr)nc1ud.,d. r-f I J Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.6 ,.- 1/ :- -.2 / _ -: _ =- =-= =-= / - -/ .-;-:-L o _ _ _ _ _ _ _-o .2 .4 .6 .8 1.0 Wheel slip ratio ( a) Ground speed : 50 knots. 1“ igure 9.- Variation of drag-force fricti
12、on coefficient lld and cornering force friction coefficient II with wheel slip ratio fOT test tire at s various ground speeds and yaw angles on a wet concrete surace. Average water dep+.h = 0.0.5 to 0.08 cm (0.02 to 0.03 in.). Provided by IHSNot for ResaleNo reproduction or networking permitted with
13、out license from IHS-,-,-.6 .2 - -=-o _ _ _ _ _ - .6 Yaw angle -0 .4 -_3 _ o -9 u 12 s .2 o .2 .4 .6 .8 1.0 Wheel slip ratio (b) Groll.1d speed : 75 knots. Figure 9.- Continued. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.4 I d .2 - - knots. Pi(
14、pur, 10.- C(mtinued. Yay angle -_0 _ -3 _ ._ ;o - 9 -Llo .8 1,0 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.6 . . 2 _ =-_ “:I. - _ _ _ - . -. - - - -.:=o -. .-. - - - - - -“.-OL-_ _ _L _ _ _ _ .6 .4 .2 o wbeel slir rnio (e) Ground speed = 100 kn
15、ots. Figure 10.- Concluded. ,- -Yaw angle - _ 0 - 3 _ 60 _ 91“1 _ 12 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-11“1IIIffIlI!H“III“I“.IH“, , ,.“ . “RHIiIIIIKjjI1llJIIIIIIIIIIIIIII!II:“IIItI_HRII“,“, _ ,IW IIIMIIIIIIIII AI. _. !,“-“ ,F , .8 Dry W
16、et o_ _ -o-_o .6 l.n “cI. max. 4 .2 L o “ _ - _ _ .4 . ud skid .2 OI _ _ -L _ _ _ . 6 it- .:-0- -. _-_-=-=f“.=-:=()Q-:-.4 US, mal( 0- -_. _ . .0 _ 0-0 ,2 r.l rd ti o 2IJ 40 w 80 100 o 20 40 Ground speed, knots Ground speed, nots .i!t“.“. -.=, “B 80 100 fI 20 40 F :;tl to:! “t t;l . 1 . “ 2.0. C. tlt
17、: t-4 I“ “,d ,I“ “d , t:. “ IiJ CI t-,l :i ffW “*“t t:j I -.J V.angle dig - 0 0 - 0 3 - 6 -A 9 D 12 60 80 100 Ground specJd. knots Figure II. - Valiation of maximum drag-flrce friction coefficient i.id . skidding drag-force friction coefficient:Jd kd and maximum cornering-force fridl,on . max , 5 I
18、coeffic:ent J-.: f . :X with ground speed at various yaw angles on dry. wet, and flooded surfaces. (Closed symbols denote rubber congminated surfacet Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.8 .6 JJd max .4 . 2 o .4 _ JJd skid . 2 0 .0 _ Dry
19、o , . I t - -0-0 I -0 - .4r “s.max.2 “ / 0 3 6 9 12 Yaw angle, deg Wet Ground speed, kt o 5 - - 0 50 - 0 75 - A 100 , . . “L. “ _,.II o -o . -A _ _ -=-=-9-_ _ D- =2=- -0 - -.: # I I i I o 3 6 9 . 12 Yaw angle, deg ,.,;P: Flooded G-0 g_ =:g -6- -0-:. =-I:l.- _ - -li - - -D. 0 0 0 0 !-=- -g- I dD-O-0-
20、_ -0- -/:-A- 6 9 12 0 3 Ya . .lngle, deg Figure 12. - Pfect Of yaw angle on maximum drag-force friction coefficient!d skidding drag-force coefficient ;d kd and maximum cornering-force max , s I fl :.:tlon coeiticient Ils, max at various ground speeds on dry, wet, and flooded surfaces. (Closed symbols denote rubber contaminab!d surface.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
