PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
clearance is available with the wing-tips folded: This was determined using the code provided in
Appendix D
Figure 32: Assembly Feasibility
The wing area was determined to be 7.14 ft 2 from the performance sizing. Using an upper bound
of 25° leading edge wing sweep, and a nominal taper ratio of 0.5, the leading edge of the wing at
the fold is 19 in behind the nose. This means the aircraft will be 23 in long when folded in the
box. This was the upper bound because ½ in thickness for the walls of the box was assumed. It is
also important to note that even with a 14 in propeller (the largest under consideration for the
project), the propellers can still be mounted on the front of the aircraft with adequate clearance
from the wing, and still remain behind the nose of the aircraft. Based upon this information, it is
entirely feasible to fit the flying wing inside a 2’ x 2’ x 4’ box by only folding the wingtips.
7.2 Risk Assessment
The largest risks involved with designing the Buff-2 Bomber are enough to warrant concern and
additional analysis in order to alleviate as much danger of total aircraft failure. The major risks
from each subsystem were further analyzed to determine the overall importance, probability, and
mitigation.
7.2.1 Aerodynamics
Insufficient stability of the aircraft would result in a loss of pilot control and erratic flight.
Included in this risk is the possibility of aircraft damage during takeoff and landing if the
unstable nature of the aircraft prompts the plane to pitch or roll when operating at low velocities.
Should the aircraft be unstable, the control surfaces would be unable to compensate and a crash
is imminent. This was mitigated through extensive analysis and research into airfoils and design
of flying wings. Even with the amount of time devoted to aerodynamic design, the probability of
instabilities is still at a medium level. However, because the consequences are so great, that this
aerodynamic risk possibilities are still undergoing continuous analysis.
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