PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
apparatus to both protect the device as well as maintain the integrity and shape of the wing. A
small balsa plate was glued into the servo cavity which allows the servo to be screwed into place.
Wiring for the rudder, aileron, and release mechanisms was placed in the hole created for it, and
enough run through the wingtip to attach the vertical, aileron, and wingtip to the main wing. The
balsa spar and hinge system was then glued into place on the wingtip. Great care was taken to
ensure that the balsa spar and hinge were properly placed and aligned within the wingtip such
that no twist or different angles of attack are introduced to the final aircraft.
Once the spar, wiring, and release mechanisms were installed, the release mechanisms were tied
to the servo with Kevlar string and paper was taped over all hollows to prevent glue from
spreading into the hollows. The wingtips were then sheeted with balsa in the same manner as the
verticals. The wiring and release mechanisms were tested after sheeting to ensure no glue spread
to the system. Rubber sections were then cut to fit the airfoil shape at the wingtip folding edge
(this provided some degree of pre-stress for the hinge system). Balsa sheets were first fitted to
the wingtip edge, and the thin rubber airfoil shapes glues to the wingtip. The location where the
wingtip stores connect to the aircraft via magnets was then hollowed out to allow the rocket
magnet to directly contact the installed metal. Next, a small hollow was created for the aileron
control servo and the servo installed. Like holes were then drilled into the trailing edge which
matches those created for the aileron. The aileron hinges were glued into place, servo linkages
were attached to the aileron, and the control surfaces tested.
12.4 Main Wing Sub-Assembly
Figure 109: Main Joined Wing Assembly
Once the cut along the aircraft fold location was made, the main wing could be built in tandem
with the wingtips. The elevators were removed first using a bandsaw, and the elevators sheeted
and sanded. These control surfaces were then monokoted and holes drilled along the leading
edge. Small hinges similar to the ones used in the rudder and aileron were then installed, and the
elevator was then set aside until later. In the wing, sections where the motors are placed were
removed from the wing and balsa mounts integrated. The mounts were made by shaping blocks
carefully to maintain wing shape and tightly hold the metal motor mounts which directly house
the motors. Once these were glued into place, the wing halves were sheeted. While the wings
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