Fuselage Group Mass

Consider a 5% weight reduction due to composite usage in nonload-bearing struc­tures (e. g., floorboards). Use Equation 8.15:

L = 15.24 m, Dave = 1.75 m, VD = 380KEAS = 703.76 kmph = 195.5 m/s and Cfus = 0.04, ke = 1.04, kp = 1.09, kuc = 1.06, and kmat = (0.9 + 0.9 x 0.1) = 0.99

		Semi-empirical	Mass		Graphical
	Component	(kg)		fraction %	solution – lb (kg)
1.	Fuselage group	930		10		^2,050 (932)
2.	Wing group	864		9.2		^2,100 (94б)
3.	H-tail group	124		1.32		H-Tail+V-Tail^460 (209)
4.	V-tail group	63		0.67
5.	Undercarriage group	380		4		^900 (409)
6.	Nacelle + pylon group	212		2.245		^410 (18б)
7.	Miscellaneous Structures group total		2,591		27.56
8.	Power plant group	1,060		11.28
9.	Systems group	1,045		11.12
10.	Furnishing group	618		6.57
11.	Contingencies MEM	143	5,457	0.7	58.05
12.	Crew	180		1.92
13.	Consumables OEM	^ 119	5,800	1.73	61.7
13.	Payload (as positioned)	1,100		11.7
14.	Fuel (as positioned) MTOM	2,500	9,400	26.6	100
	MRM		9,450		100.53

Table 8.5. Bizjet mass (weight) summary

fuselage

horizonta tail

Then:

MFcivil = cfus X ke X kp X kuc X kdoor X; (MTOM X nult) X (2 X L X Dave X

For civil aircraft, (MTOM x nult)x = 1; therefore:

M-Fcivii = 0.04 X 1.04 X 1.09 X 1.06 x 1 x 1 x (2 x 15.24 x 1.75 x 195.50’5)1’5 = 0.048 x (2 x 15.24 x 1.75 x 195.50’5)1’5 = 0.048 x (53.35 x 13.98)15 = 0.048 x (745.95)15 = 0.048 x 20,373.3 = 978 kg

There is a 5% reduction of mass due to the use of composites:

MFcivil = °.95 MFcivil-all metal ^ 930 kg

This is checked using Torenbeek’s method (Equation 8.13); refer to Chap­ters 6 and 9 for dimensions:

WFcivil = 0.021 Kf {VdLht/ (W + D)}05 (f s-gross _area )

Kf = 1.08, L = 50 ft, W = 5.68 ft, D = 5.83 ft, Lht = 25 ft, Vd = 380 KEAS,

Sfus „gross – area = 687 ft

Therefore,

WFcivil = 0.021 X 1.08 X 1.07 X {380 x 25/(5.68 + 5.83)}0 5 x (687)12

= 0.0243 x (825.4)0 5 x 2,537.2 = 0.0243 x 28.73 x 2,537.2 = 1,770 lb (805 kg)

The higher value of the two (i. e., 930 kg) is retained, which gives a safer approach initially.