1、NASA TECHNICAL NOTEOSCONASA TN D-7132.F a aI L-SOME LOADING CONDITIONS IMPOSEDBY GROUND TURNING MANEUVERS WITHTHREE JET TRANSPORT AIRPLANESby Albert W. HallLangley Research CenterHampton, Va. 23365NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. DECEMBER 1*72Provided by IHSNot for Res
2、aleNo reproduction or networking permitted without license from IHS-,-,-1. Report No.NASA TN D-71322. Government Accession No. 3. Recipients Catalog No.4. Title and SubtitleSOME LOADING CONDITIONS IMPOSED BY GROUND TURNINGMANEUVERS WITH THREE JET TRANSPORT AIRPLANES5. Report DateDecember 19726. Perf
3、orming Organization Code7. Author(s)Albert W. Hall8. Performing Organization Report No.L-85979. Performing Organization Name and AddressNASA Langley Research CenterHampton, Va. 2336510. Work Unit No.501-38-11-0111. Contract or Grant No.12. Sponsoring Agency Name and AddressNational Aeronautics and S
4、pace AdministrationWashington, D.C. 2054613. Type of Report and Period CoveredTechnical Note14. Sponsoring Agency Code15. Supplementary Notes16. AbstractSome loading conditions imposed during ground turning maneuvers are presented forarrival and departure operations at several airports with C-141A,
5、727, and DC-9 airplanes.The data presented for a total of 809 turns include: ground speed, lateral acceleration, thenumber of turns required during arrival and departure, and the magnitude of the turns.17. Key Words (Suggested by Author(s)AircraftGround loadsFatigue spectrumGround turning maneuvers1
6、8. Distribution StatementUnclassified - Unlimited19. Security Oassif. (of this report)Unclassified20. Security Classif. (of this page)Unclassified21. No. of2922. Price*$3.00For sale by the National Technical Information Service, Springfield, Virginia 22151Provided by IHSNot for ResaleNo reproduction
7、 or networking permitted without license from IHS-,-,-SOME LOADING CONDITIONS IMPOSED BY GROUND TURNING MANEUVERSWITH THREE JET TRANSPORT AIRPLANESBy Albert W. HallLangley Research CenterSUMMARYThis paper presents some data defining ground turning maneuvers for several jettransport aircraft. These d
8、ata were obtained during arrival and departure operationswith a C-141A, 727, and DC-9 airplane at several United States and foreign military andcommercial airports. The data show that on the average, about five ground turns wererequired for each arrival and five turns for each departure. The average
9、 maximum lat-eral acceleration measured during each turn was 0.046, 0.058, and 0.059 g units for theC-141A, 727, and DC-9 airplanes, respectively. The average ground speed for turnswas 5.0, 10.4, and 12.1 knots for the C-141A, 727, and DC-9 airplanes, respectively.INTRODUCTIONPart of the certificati
10、on procedure for transport category aircraft requires a fatigueevaluation of the flight structure and of the landing gear. These fatigue evaluations mustinclude, among other things, the typical loading spectrum to be expected in service. Forthis purpose, the NACA and, subsequently, the NASA have con
11、ducted research programsto define part of the loading spectrum for transport operations. Most of the past workhas been devoted to airborne operations rather than to ground operations. Recently, how-ever, some effort has been made to define sections of the loading spectrum to/be expectedfor ground op
12、erations. Reference 1, for example, has provided data showing center-of-gravity vertical accelerations measured during taxiing, take-off, and landing operationswith transport airplanes. This reference also provides a limited amount of longitudinaldeceleration data measured during the landing rollout
13、. In addition, a program to definethe runway and taxiway roughness environment at typical large commercial airports hasrecently been completed by NASA. An example of these data is given in reference 2.There is little data available to define loading conditions imposed during ground turningmaneuvers.
14、 The purpose of this paper is to present some recent data which can partiallyfill this need.This paper presents some loading conditions imposed“during ground turning maneu-vers with three jet transport airplanes. Data were obtained during arrivals and departuresProvided by IHSNot for ResaleNo reprod
15、uction or networking permitted without license from IHS-,-,-at several United States and foreign military and commercial airports which were partic-ipating in a joint USAF/NASA runway traction program utilizing a C-141A airplane (ref. 3)and a joint USAF/FAA/NASA runway research program utilizing a 7
16、27 and a DC-9 air-plane. The data presented herein include: airplane ground speed and lateral accelera-tion during ground turns, number of turns performed during arrival or departure, andthe magnitude of the ground turns. At this time, there appears to be no similar dataavailable for general referen
17、ce.SYMBOLSay lateral acceleration measured at airplane center of gravity, g unitsf observed frequency of occurrence for an event in a given class intervalg acceleration due to gravityN total observed frequency for one sample of data6n , nose-wheel steering anglej/ relative airplane headingDesignatio
18、ns:Cl,C2,etc. United States commercial airportsFl,F2,etc. foreign airports (military or commercial)Ml,M2,etc. United States military airportsFAA Federal Aviation AdministrationNACA National Advisory Committee for AeronauticsNASA National Aeronautics and Space AdministrationUSAF U.S. Air ForceProvide
19、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EQUIPMENT AND PROCEDUREAircraft and InstrumentationThe NASA has recently participated in several runway research programs relatedprimarily to the stopping performance of aircraft. The aircraft utilized in thes
20、e pro-grams were an Air Force C-141A, an FAA 727, and an FAA DC-9. The NASA-installedinstrumentation was very extensive for each airplane and similar to that which isdescribed in reference 3 for the C-141A airplane. Only the instrumentation requiredto measure and record the magnitude of ground turns
21、, lateral acceleration, and airplaneground speed was utilized for the data presented in this paper.The magnitude of the ground-turn maneuvers for the C-141A airplane was indicatedby the nose-wheel steering angle. The nose wheel of this airplane could be deflected fromthe center position to a maximum
22、 steering angle of 80 in each direction. Turn maneu-vers were defined in this manner rather than by the change in airplane heading becausethe combat traction program (ref. 3) required a sensitive heading measurement relativeto the initial heading; consequently, the heading time history was off scale
23、 during mostof the ground-turn maneuvers.A low sensitivity recording of relative heading was available for the programsinvolving the 727 and DC-9 airplanes. Therefore, the magnitude of the ground turns wasindicated by the heading change for the 727 and DC-9 airplanes.The lateral acceleration values
24、were obtained by means of accelerometers locatedat the airplane center of gravity for all three airplanes and also in the cockpit for the727 airplane. These accelerometers were alined to sense the acceleration normal tothe plane of symmetry and the lateral acceleration data presented herein are unco
25、rrectedfor the effect of airplane roll attitude. This correction to remove the component of accel-eration due to gravity would be equal to the sine of the roll attitude.The ground speed was obtained from measurements of wheel angular velocities. Theground-speed data were measured by the nose-wheel s
26、ensors for the 727 and DC-9 and bythe left-rear-inboard main-wheel sensor for the C-141A.Resolution of DataThe data were reduced and tabulated with the following resolution:Nose-wheel steering angle Nearest 0.8 (0.01 full scale)Relative heading Nearest 5.0Lateral acceleration Nearest 0.01 g unitGrou
27、nd speed Nearest 1.0 knotProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TestsAs previously indicated, these airplanes were made available by the USAF and FAAand were instrumented by NASA for runway research programs related primarily to trac-tion or
28、 stopping distance. The data for this paper were obtained on a noninterferencebasis during arrival and departure at the various airports which were participating in thebasic runway research program. Arrival data were recorded from the time just priorto touchdown to the time when the airplane was fin
29、ally parked. Departure data wererecorded from the time the airplane left the parking ramp to the time the airplane wasairborne.RESULTS AND DISCUSSIONScope of DataIt is believed that these data are the largest quantity that have ever been assembledto describe ground-turn maneuvers. Therefore, the dat
30、a are expected to be useful indescribing average operating conditions for jet transports similar to the C-141A, 727,and DC-9 airplanes. Certain limitations should be considered in the interpretation ofthese data which were obtained while in transit to various test sites for runway researchprograms.
31、For example, it is probable that some of the arrivals and departures werenot treated as routine operations by ground control personnel. It could also be arguedthat some of the operations at military airports do not accurately represent commercialoperations. Furthermore, these data only represent the
32、 operational techniques of a smallsample of pilots.Description of Ground-Turn ManeuversFor the C-141A, all nose-wheel steering deflections 6n having both a duration ofat least 5 seconds before returning to the center position and a magnitude of at least 0.11of the maximum steering angle were assumed
33、 to indicate a deliberate turn maneuver.Time histories of lateral acceleration measured at the center of gravity ay, relativeheading i/, and nose-wheel steering angle 6n for five typical turn maneuvers for theC-141A are shown in figure 1. Figure l(a) illustrates two turns, each having a shortduratio
34、n and a small heading change. For each turn, the ground speed, which was mea-sured at the time of maximum 6n, was 3 knots; and the maximum lateral accelerationfor each turn was 0.02g. Figure l(b) illustrates a turn of longer duration than that shownin figure l(a). This turn is more typical of the tu
35、rns represented by these data and itoccurred as the airplane turned from the runway following a landing rollout. For thisturn, the nose wheel was deflected for about 25 seconds, the ground speed was 6 knots,and the maximum lateral acceleration was 0.05g. Figure l(c) illustrates a somewhatunusual man
36、euver which is probably a U-turn on the runway following a landing rollout.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The maneuver consisted of two continuous turns - first, a small swing to the right andthen a large long duration turn to the le
37、ft. The ground speed was 13 knots during the firstturn and dropped to 2 knots during the last turn whereas the maximum lateral accelera-tion during each turn was 0.04g and 0.09g, respectively.Turn maneuvers for the 727 and DC-9 were defined by the recorded time history ofrelative heading. Time histo
38、ries of ay at the center of gravity and i/ showing fourtypical turn maneuvers for the 727 and DC-9 are shown in figure 2. These turns showsome similarity to those given in figure 1 for the C-141A. The 180 turn following land-ing rollout shown for the 727 in figure 2(a) is about the same duration as
39、the turn followinglanding rollout shown for the C-141A in figure l(c) which was also probably a 180 turn.The ground speed for the turn shown in figure 2(a) was 26 knots at the beginning anddropped to 8 knots at the completion of the turn. The two successive turns shown in fig-ure 2(b) represent a ma
40、neuver that occurred occasionally with each airplane; that is, asmall turn in one direction followed immediately by a larger turn in the opposite direc-tion. The 90 right turn from the runway shown for the DC-9 in figure 2(c) is similarin duration to that shown for the C-141A in figure l(b).Number o
41、f Turns Performed During Ground OperationsThe number of ground turns performed during arrival and departure is given intable I for each airport and airplane. These data represent arrival and/or departureoperations at 31 United States military, 8 United States commercial, and 13 foreign mil-itary or
42、commercial airports. Generally, these data were obtained during one arrivaland departure from each airport. There are some variations from this pattern, for exam-ple, the C-141A had 10 operations at airport M2. Table I also shows that data were notobtained for every arrival or departure. These missi
43、ng data were usually the result ofpriorities on personnel or on the data recording system related to the primary researchprogram. A total of 635, 96, and 78 turns were performed by the C-141A, 727, andDC-9 airplanes, respectively. Of the 809 turns performed by all three airplanes duringarrival and d
44、eparture operations, 420 were to the left and 389 were to the right. Becauseof better visibility, the pilot would generally prefer to make a left turn if he has a choiceof direction such as for a 180 turn. However, all the turn data in this paper are summa-rized without regard to algebraic signs rel
45、ating to the direction of turn.The number of ground-turn maneuvers required during arrival or departure at anairport should be essentially determined by the airport geometry, runway in use, groundtraffic pattern, and airplane parking position. Particular airplane characteristics, suchas the ability
46、to make exit taxiways short of the runway end, and other factors could pos-sibly affect the number of turns required at some airports. These effects are consideredsecondary and beyond the scope of the present data. Therefore, the data for the numberof turns required for arrival or departure are grou
47、ped together for all three airplanes5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-and are summarized at the bottom of table I. Based on 80 arrivals and 79 departures,these data show that, on the average, about five ground-turn maneuvers are requir
48、ed foreach arrival and about five turns for each departure; thus, a total of 10 ground turns perflight are required.The frequency distribution of the number of turns performed during each arrivaland each departure is given in table H and figure 3. These data show that although thenumber of turns per
49、 arrival or departure operation ranged from 1 to 12, the frequencyof occurrence was low for these extreme values. The relative frequency f/N wasgreater than 0.1 only for three, four, five, and six turns per operation.Magnitude of Ground-Turn ManeuverBecause of instrumentation restrictions, the magnitude of the ground-turn maneuverfor the O141A can only be indicated indirectly by
