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airplane design 5 - component weight estimation - part 4

Mục tiêu học tập • Phần 1 Bối cảnh Công nghiệp • Phần 2 sân bay Kế hoạch • • • • • Hệ thống sân bay Mỹ • Cải thiện sân bay Capitol Kinh phí sân bay Quy hoạch sân bay Gió bố trí kế hoạch Rose Phân tích Chỉ Runway (Bài tập về nhà vấn đề) • Phần 3 Thiết kế Hướng dẫn • Phần 4 Xây dựng | 8 Baggage and cargo handling Eqn. 7.4 8 9 Operational items See Section 7.10. 10 Paint See Section 7.15. Step 6i The following list itemizes all required input data for estimating the weight items listed in steps 2 and 5. WT0 127 000 lbs nult 2.5 s 1 296 ft2 vc 295 kts VD - 369 kts nult 3.75 A 10 X 0.32 -A 1 4 35 deg. A 2- 33. 5 deg Mn 0. 85 n t c ra 0.13 b 113.8 ft fcr 2.26 ft sh 254 ft2 b. 35.6 ft n trh 1.30 ft c 12.5 ft lh 32.5 ft sv 200 ft2 zh bv - 0 v - 35.8 ft s _ S r V 0.45 s - 0.32 A 1 . 8 - 1 4 45 đeg. If 124.3 ft Wf hf 26.4 ft qD 461 psf WT 7 505 lbs n 14. 1 4.0 d 13.2 ft Jj Ulu X X p 20 psi 1 11.7 ft A. 28.3 ft 2 2 c n ini Dinl - 6- ft Notes 1 The value for n . follows from the v-n diagram of Figure 4.5. 2 Most data were obtained from Ourania data listed in Part II. The reader is reminded that a detailed geometric definition may be found in Part II as Table 13.2 a Class I weight statement as Table 10.5. Detailed definitions of layouts of fuselage powerplant wing high lift system empennage and landing gear may be found in Chapters 4 5 6 7 8 and 9 respectively. Step 7 Tables 4.2a - 4.2c list all weights computed as part of the Class II weight estimation process. Part V Chapter 4 Page 54 step 8 The Class II empty weight of the Ourania is 72 622 lbs. This compares with 68 450 lbs for the Class I weight estimate. This represents a difference of 4 172 lbs which is 6.1 percent of the Class I empty weight. Several comments are in order 1. an iteration through the equations of step 7 should be performed to determine the convergence empty weight. 2. several weight savings can be made in the Ourania a the empennage can be manufactured from composites which would yield a weight saving of about 15 percent or 359 lbs. b the nacelles can be manufactured partially from composites which would yield a weight saving of about 10 percent or 264 lbs. c by manufacturing the low stress areas of the wing and fuselage from composites a weight saving of about 5 percent should be .