ESA Document - Emits - ESA

s
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 339 of 422
between half and three-quarter of the length from the bottom. Thus the centre of pressure shall be
after this point, so the IBD shape should be long enough to fulfil this requirement.
4.4.2.3 Baseline design
The baseline for the design is an IBD shape with a 60˚ half cone angle, with a reference diameter
of 25m (reference surface of 490m 2 ). This shape was a good compromise between aerodynamic
coefficients (drag, lift and L/D) and centre of pressure for the stability.
Cd, Cl
1.4
1.2
1
0.8
0.6
0.4
0.2
Figure 4-79: 60 degrees half cone angle, 25 m Base diameter
0
0
0 2 4 6 8 10 12 14
Mach number
Figure 4-80: Aerodynamic coefficients vs Mach number
CD
CL
L/D
0.7
0.6
0.5
0.4
0.3
0.2
0.1
L/D