1059:
381:
For conventional fixed-wing aircraft with moderate aspect ratio and sweep, Oswald efficiency number with wing flaps retracted is typically between 0.7 and 0.85. At supersonic speeds, Oswald efficiency number decreases substantially. For example, at Mach 1.2 Oswald efficiency number is likely to be
589:
147:
884:
807:
927:
675:
634:
230:
960:
337:
268:
185:
299:
739:
450:
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27:, is a correction factor that represents the change in drag with lift of a three-dimensional wing or airplane, as compared with an ideal wing having the same
1096:
458:
52:
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1038:
1024:
304:
1115:
1089:
1120:
425:, which is certainly not true in general. Assuming that the profile drag itself has a constant+quadratic dependence on
1125:
235:
390:
It is frequently assumed that Oswald efficiency number is the same as the span efficiency factor which appears in
1082:
758:
892:
976:
391:
371:
28:
645:
604:
398:
is typically used for both. But this assumes that the profile drag coefficient is independent of
200:
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1109:
584:{\displaystyle C_{D}=c_{d_{0}}+c_{d_{2}}(C_{L})^{2}+{\frac {(C_{L})^{2}}{\pi eAR}}}
706:
is the span efficiency factor from inviscid theory, such as lifting-line theory
1058:
741:
expressions gives the relation between the Oswald efficiency number
43:
of the wing or airplane has a constant+quadratic dependence on the
142:{\displaystyle C_{D}=C_{D_{0}}+{\frac {(C_{L})^{2}}{\pi e_{0}AR}}}
879:{\displaystyle {\frac {1}{e_{0}}}={\frac {1}{e}}+\pi ARc_{d_{2}}}
39:
The Oswald efficiency is defined for the cases where the overall
16:
Correlation factor comparing drag coefficient with an ideal wing
452:, an alternative drag coefficient breakdown can be given by
1045:
http://calteches.library.caltech.edu/3961/1/Obituaries.pdf
1070:
679:
is the quadratic part of the profile drag coefficient,
638:
is the constant part of the profile drag coefficient,
935:
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816:
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648:
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404:
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286:
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165:
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921:
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733:
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628:
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417:
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293:
262:
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179:
141:
1090:
8:
1097:
1083:
1019:, Fourth edition. AIAA Education Series.
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988:
1065:This engineering-related article is a
1017:Aircraft Design: A Conceptual Approach
1000:Aircraft Design: A Conceptual Approach
386:Comparison with span efficiency factor
748:and the lifting-line span efficiency
31:and an elliptical lift distribution.
7:
1055:
1053:
802:{\displaystyle C_{D_{0}}=c_{d_{0}}}
1069:. You can help Knowledge (XXG) by
14:
1057:
1002:, Section 12.6 (Fourth edition)
341:is the Oswald efficiency number
305:circumference-to-diameter ratio
1033:, Sixth edition. McGraw Hill.
922:{\displaystyle c_{d_{2}}>0}
555:
541:
526:
512:
394:, and in fact the same symbol
106:
92:
1:
1043:PhD. William Bailey Oswald,
1015:Raymer, Daniel P. (2006).
670:{\displaystyle c_{d_{2}}\;}
629:{\displaystyle c_{d_{0}}\;}
598:
225:{\displaystyle C_{D_{0}}\;}
156:
1142:
1052:
1029:Anderson, John D. (2008).
955:{\displaystyle e_{0}<e}
889:For the typical situation
236:zero-lift drag coefficient
274:aircraft lift coefficient
45:aircraft lift coefficient
332:{\displaystyle e_{0}\;}
263:{\displaystyle C_{L}\;}
180:{\displaystyle C_{D}\;}
1031:Introduction to Flight
956:
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671:
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419:
362:
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295:
294:{\displaystyle \pi \;}
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143:
1116:Aerospace engineering
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924:
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736:
734:{\displaystyle C_{D}}
699:
672:
631:
586:
447:
445:{\displaystyle C_{L}}
420:
418:{\displaystyle C_{L}}
382:between 0.3 and 0.5.
363:
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144:
1121:Aircraft wing design
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998:Raymer, Daniel P.,
977:Lifting-line theory
697:{\displaystyle e\;}
392:lifting-line theory
41:coefficient of drag
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361:{\displaystyle AR}
358:
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1126:Engineering stubs
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972:Lift-induced drag
845:
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714:Equating the two
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137:
23:, similar to the
21:Oswald efficiency
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191:drag coefficient
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25:span efficiency
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15:
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10:
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4:
3:
2:
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1080:
1074:
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1068:
1063:
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1056:
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1046:
1042:
1040:
1039:0-07-126318-7
1036:
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1028:
1026:
1025:1-56347-829-3
1022:
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989:
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978:
975:
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916:
913:
906:
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897:
869:
865:
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842:
839:
834:
827:
823:
819:
810:
792:
788:
783:
779:
772:
768:
763:
755:
754:
753:
751:
747:
726:
722:
705:
690:
683:
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678:
659:
655:
650:
642:
641:
637:
618:
614:
609:
601:
600:
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572:
569:
566:
559:
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463:
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437:
433:
410:
406:
397:
393:
385:
383:
373:
369:
355:
352:
345:
344:
340:
323:
319:
311:
310:
307:of a circle,
306:
302:
287:
280:
279:
275:
271:
254:
250:
242:
241:
237:
233:
214:
210:
205:
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192:
188:
171:
167:
159:
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153:
133:
130:
125:
121:
117:
110:
100:
96:
86:
79:
75:
70:
66:
61:
57:
49:
48:
47:
46:
42:
34:
32:
30:
26:
22:
1071:expanding it
1064:
1049:
1030:
1016:
999:
888:
749:
742:
713:
593:
395:
389:
380:
372:aspect ratio
151:
38:
29:aspect ratio
24:
20:
18:
1110:Categories
1010:References
929:, we have
35:Definition
851:π
567:π
288:π
118:π
966:See also
370:is the
303:is the
272:is the
234:is the
1037:
1023:
594:where
152:where
983:Notes
1067:stub
1035:ISBN
1021:ISBN
947:<
914:>
19:The
1112::
991:^
962:.
752:.
276:,
238:,
193:,
1098:e
1091:t
1084:v
1073:.
950:e
942:0
938:e
917:0
907:2
903:d
898:c
870:2
866:d
861:c
857:R
854:A
848:+
843:e
840:1
835:=
828:0
824:e
820:1
793:0
789:d
784:c
780:=
773:0
769:D
764:C
750:e
745:0
743:e
727:D
723:C
691:e
660:2
656:d
651:c
619:0
615:d
610:c
576:R
573:A
570:e
560:2
556:)
550:L
546:C
542:(
536:+
531:2
527:)
521:L
517:C
513:(
506:2
502:d
497:c
493:+
486:0
482:d
477:c
473:=
468:D
464:C
438:L
434:C
411:L
407:C
396:e
356:R
353:A
324:0
320:e
255:L
251:C
215:0
211:D
206:C
172:D
168:C
134:R
131:A
126:0
122:e
111:2
107:)
101:L
97:C
93:(
87:+
80:0
76:D
71:C
67:=
62:D
58:C
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