Fuselage Closure Angle
The closure angle is the aft fuselage closure seen in a plan view of the three-view drawing and it varies among designs. The higher the closure angle, the greater the pressure drag component offered by the fuselage. In rear-loading aircraft, the fuselage closes at a blunt angle; combined with a large upsweep, this leads to a high degree of separation and, hence, increased pressure drag.
1.23.4 Front Fuselage Closure Length, Lf
This is the length of the front fuselage from the tip of the nose cone to the start of the constant cross-section barrel of the mid-fuselage (Figure 3.49a). It encloses the pilot cockpit/flight deck and the windscreen – most of which is associated with a kink in the mould lines to allow for a better vision polar (see Section 4.7.4) and to enable the use of flat windscreens to reduce cost. In general, it includes the front door and passenger amenities, and may have a row or two of passenger seating.
Figure 3.50. Fuselage cross-section geometrical parameters