1、NASA Contractor Report 3295 Selected Advanced Aerodynamics and Active Controls Technology Concepts Development on a Derivative B-747 Aircraft Summary Report Staff of Boeing Commercial Airplane Company CONTRACT NASI-14741 JUNE 1980 MSA FOR EARLY DOMESTIC DISSEMINATION Because of its significant early
2、 commercial potential, this information, which has been developed under a U.S. Gov- ernment program, is being disseminated ,within the United States in advance of general publication. This information may be duplicated and used by the recipient with the ex- press limitation that it not be published.
3、 Release of this information to other domestic parties by the recipient shall be made subject to these limitations. Foreign release may be made only with prior NASA ap- proval and appropriate export licenses. This legend shall be marked on any reproduction of this information in whole or in part. Da
4、te for general release June 1982 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TECH LIBRARY KAFB, NM NASA Contractor Report 3295 Selected Advanced Aerodynamics and Active Controls Technology Concepts Development on a Derivative B-747 Aircraft Summa
5、ry Report Staff of Boeing Commercial Airplane Company The Boeing Commercial Airplane Company Seattle, Washingtorl Prepared for Langley Research Center under Contract NASl-14741 National Aeronautics and Space Administration Scientific and Technical Information Office 1980 Provided by IHSNot for Resal
6、eNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-FOREWORD This document constitutes the summary report of work conducted under NASA Contract NASl-14741 during the period May 1977 th
7、rough May 1979. The contract was managed by the NASA Energy Efficient Transport Office (EETPO) headed by Mr. W. J. Alford - a part of the Aircraft Energy Efficiency (ACEE) Program organization at the Langley Research Center. Mr. D. B. Middleton of the EETPO was the Technical Monitor for the contract
8、. The work was performed within the Product Development organization of the Boeing Commercial Airplane Company, 747 Division. Key Contractor management personnel responsible for the contract work were: G. W. Hanks R. L. Allison M. A. Booth R. H. Weiland A. H. Eldridge D. E. Chichester J. R. Fuller B
9、. R. Perkin D. W. Abrams Program Manager Project Manager 747 Technology 747 Design Aerodynamics Technology Flight Controls Technology Structures Technology Structures Technology Weights Technology Principal measurements and calculations used during these studies were in customary units. . . . 111 Pr
10、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CONTENTS SUMMARY. PROGRAM OBJECTIVE . PROGRAM SCOPE . WING TIP EXTENSIONS . WING TIP WINGLETS WING LOAD AL
11、LEVIATION . WING STRUCTURE MODIFICATIONS . WEIGHT IMPACT. . FINAL EVALUATION REFERENCE . PaRe 1 4 6 8 12 20 28 32 34 46 V Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SUMMARY Under the NASA EET Program Phase I contract, wing tip extensions, wing t
12、ip winglets, and the use of active outboard ailerons for wing load alleviation were studied as possible ways to improve fuel efficiency for the Boeing 747. The general approach was. to improve the cruise lift to drag ratio (L/D) by means of wing tip modifications while using a wing load alleviation
13、system to minimize the associated structural weight increase. Details of the work conducted under the contract are contained in NASA CR-3164 (ref. 1). Wing Tip Modifications-Two wing tip extension designs, 1.83m (6 ft) and 3.66m (12 ft), were evaluated. Previous testing has shown the wing with eithe
14、r tip extension to be flutter free. Aerodynamic design and high speed wind tunnel testing were accomplished for five winglet configurations. One of the winglet designs showed 96% of the potential drag improvement predicted by subsonic flow theory. A 3.2% increase in full-scale, maximum trimmed L/D w
15、as estimated. Flutter testing of the winglet disclosed a symmetric flutter mode and a wing tip flutter mode, due primarily to aerodynamic rather than mass effects. A significant flutter weight penalty resulted. Winglets achieve slightly more L/D improvement than a tip extension having the same panel
16、, but result in less increase in wing semispan (gate clearance) and lower bending moments on the inboard portions of the wing. Wing Load Alleviation-Effectiveness of the outboard low-speed ailerons as wing load alleviation surfaces was determined by means of high-speed wind tunnel model (0.03 scale)
17、 testing and aeroelastic analyses. These ailerons introduce wing torsion loads but are effective in reducing wing bending moments. A balance tab on the aileron was evaluated as a means of reducing wing torsion, but the present untabbed aileron proved to be the best overall approach and was selected.
18、 A net airplane operating empty weight (OEW) reduction equivalent to 2% of the wing structural box weight could be achieved by resizing the wing structure to take advantage of maneuver load alleviation capability. A further 0.5% reduction could be achieved through gust load alleviation. The improvem
19、ent in fuel efficiency attributable to maneuver load alleviation, was estimated to be 0.2%. Wing acceleration was the only feedback parameter retained in the final control law and which provided elastic mode suppression of the first wing bending mode. A fail-operational mechanization concept was sel
20、ected that included redundancy to yield estimated reliability approaching that of a dual yaw damper system. Structural safety margins, though reduced, are adequate with the system failed. Wing Tip Modifications Combined With Wing Load Alleviation-A 1.83m (6-ft) wing tip extension and the best wingle
21、t were analyzed in combination with symmetrically deflected out board ailerons. With aeroelastic effects included, maneuver load alleviation capability was greater for the winglet than for the tip extension. However, requirements for increased flutter material were found to offset the apparent advan
22、tage in ultimate load sizing. A flutter mode control system (of no benefit with tip extensions) would be beneficial with winglets, but would require an extensive development and test program. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Fuel Savin
23、gs-Block fuel savings data were computed as a function of range with fixed payload. The fuel savings attributable to the individual concepts (fig. 1) indicate the winglet is the most attractive from the standpoint of fuel use reduction. Further reduction due to addition of wing load alleviation is c
24、onsiderably less than that for the tip modifications. Economic Comparisons-Tip extension or winglet retrofit appears impractical with or without wing load alleviation. With amortization of development and engineering flight test program costs excluded, winglet production costs are about three times
25、that of a 1.83-m (6-ft) tip extension due to the larger size and increased complexity. Wing load alleviation system cost, if installed in combination with a tip modification, is about one- third that of a 1.83-m (6-ft) tip extension. Return on investment comparisons, as a function of market base for
26、 a typical 1978 fuel price, are shown in Figure 2. Escalation of fuel prices relative to the general inflation rate did not alter the selection of the best configuration. The most economically attractive study configuration was a 1.83-m (6-ft) tip extension, without a wing load alleviation system. T
27、he return for the wing load alleviation system could be more favorable for other specific 747 applications, or for airplanes designed for outboard aileron actuation at high speeds. Conclusions and Phase II Recommendations-The winglet has excellent potential for fuel savings, particularly in combinat
28、ion with a wing load alleviation and flutter mode control system, but it appears doubtful that recurring production costs for the winglet could be reduced sufficiently to become economically competitive with a simple wing tip extension for the Model 747. Although the 1.83m (6-ft) tip extension offer
29、ed only approximately 60% of the fuel reduction potential shown by the winglet, the tip extension was the only candidate concept offering operating economics that would provide an acceptable return to the airlines. The tip extension continued to show this advantage at relatively high fuel prices, an
30、d was judged a viable candidate for incorporation during normal growth of the Model 747. Flight testing of maneuver and gust load alleviation concepts has been accomplished on the 747 as part of a separate Boeing-funded IR their application to add pitch damping for GLA also was considered. -4- Provi
31、ded by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-747-2006 baseline WLA system Wing load alleviation (WLA) using active outboard aileron input to elevator Configurations 1. Wing tip extensions only 2. Winglets only 3. Wing load alleivation only 4. Wing load
32、 alleviation and: a) Wing tip extensions b) Winglets Figure 3. Study Configurations -5- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-PROGRAMSCOPE Figure 4 illustrates the scope of the Phase I program. The 2-year study program consisted of analyses
33、 and wind tunnel tests. No flight testing was conducted and, apart from wind tunnel model parts, no hardware was developed. Emphasis was on those factors that would affect the economic trades (e.g., lift to drag ratio (L/D), structural weight, system reliability, and general design complexity), rath
34、er than on detailed structural design or control system development, which were to be planned for Phase II. The two high-speed wind tunnel tests were accomplished in the Boeing Transonic Wind Tunnel (BTWT) to obtain force and pressure data for winglets and for symmetrically deflected outboard ailero
35、ns. Low-speed configuration (flaps down) testing was deferred to Phase II. Flutter testing of winglets was accomplished in the University of Washington Aeronautical Laboratory (UWAL) and the Convair Aeronautical Laboratory (CVAL) using a low-speed flutter model dynamically scaled to represent high-s
36、peed conditions. Engineering analyses were conducted to determine loads, structural sizing (including flutter stiffness requirements), weights, L/D performance, and stability and control effects for the various concepts. Preliminary engineering design studies were accomp- lished to the extent necess
37、ary to develop conceptual layouts and work statements for pricing and to support the analytical effort. Production costs were estimated. Price curves based on these costs were used in addition to performance estimates to determine airline return on investment. Technical and economics data were consi
38、dered in making the Phase II recommendations. -6- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Byear program Analyses complete May 79 l Wind tunnel testing BTWT UWAL A CVAL l Studies 0 Wing load alleviation (WLA) Final configuration WTE/WTW + W LA
39、 I- V Recommendation Wind Tunnels costs vs BTWT: Boeing Transonic Wind Tunnel (force and pressure tests) benefits UWAL: University of Washington Aeronautical Laboratory (flutter tests) CVAL: Convair Aeronautical Laboratory (flutter tests) Figure 4. Program Outline -7- Provided by IHSNot for ResaleNo
40、 reproduction or networking permitted without license from IHS-,-,-WING TIP EXTENSIONS CANDIDATE DESIGNS Two wing tip extensions (WTE) were anlayzed in detail. One was a 1.83-m (6-ft) WTE previously tested in a Boeing High-Speed Wind Tunnel test. The second was a 3.66-m (12-ft) WTE selected for anal
41、ysis on the basis of preliminary (quick-look) trend studies that considered flutter and the effects of increased aeroelastic washout on lift to drag ratio (L/D). Although L/D continues to increase for semispan increases to 3.66 m (12 ft,) the maximum studied, the detailed analyses showed net fuel ef
42、ficiency to be little better for the 3.66-m (12-ft) WTE than for the 1.83-m (6-ft) WTE when structural weight effects also were included. Based on results of the trend studies and subsequent detailed analyses, a 2.74-m (9-f-t) WTE was selected as the optimum semispan increase for a WTE without wing
43、load alleviation (WLA). A longer tip extension could be optimum with WLA, depending upon the extent to which the WLA system negates the added weight penalty. However, concerns regarding flutter, the need for leading-edge flaps, and gate/maintenance hangar access increase with the length of the WTE.
44、PRELIMINARY TREND STUDIES The study plan called for detailed analyses of a 1.83-m (6-ft) WTE and an alternate WTE to determine net fuel efficiency improvement considering both L/D and weight effects. The purpose of the preliminary trend studies was to provide guidance in selecting the alternate conf
45、iguration. Prior studies had shown that aeroelastic washout negated much of the potential L/D benefit of a WTE. Hence, elastic wing twist was computed for 1.83-m (6-ft) and 3.66-m ( 12-f t) extensions. Baseline wing stiffness was assumed; i.e., no structural resizing for the twist calculation nor fo
46、r the preliminary flutter trend analyses. The configurations analyzed for the trend study are shown on Figures 5 and 6. The 1.83-m (6-ft) tip extension has a constant chord, thickness, and jig twist that are the same as the existing 747 wing section at wing buttock line (WBL) 1169. The 3.66-m (12- f
47、t) tip extension has a constant thickness/chord ratio and jig twist that are the same as the existing wing section at WBL 1169, but has a tapered chord. Aerodynamically, differences due to a tapered planform versus constant chord planform were found to be negligible for the 1.83-m (6-ft) tip. -8- Pr
48、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-w46.1 .Wing buttock line 1 Change in aeroelastic twist due to WTE Figure 6. 1.83-m (S-ft) Wing Tip Extension Geometry 0 0 Z -2 E %,-, : t -b / Wing buttock line 400 600 -600 1000 1200 1400 Existing cruise twist (model W46) Change in aeroelastic twist due to WTE Figure 6. 3.66-m (12-ft) Wing Tip Extension Geometry -9- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-WI
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