PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
aircraft. Finally the assembly time was estimated based on the numbers of steps required for
assembly.
The comparison between aircraft configurations began by defining the effects the additional
surfaces have on the aircraft. The lift required by the wing and tail must equal the weight of the
aircraft. The tail lift force from similar sized DBF aircraft is approximately 0.73 pounds 4 . For
the canard, the surface provides positive lift while the conventional tail provides negative lift.
The weight of the aircraft was estimated using 6 pounds for wing and avionics weight, 8 pounds
for payload weight and 0.75 pounds for tail boom construction weight. The wing area was
calculated by the lift required by the wing. Since the canard and conventional both required
bigger wing areas than the flying wing and because the flying wing’s weight was only wing
weight (no tail), it was decided that the canard and conventional aircraft weights needed to be
increased. The weights of these configurations were increased and new wing areas were
computed. This process was iterated until the weights and wing surface areas converged.
Based on a minimum wing span of 5 feet, the aspect ratio was calculated. The aspect ratio is
inversely proportional to the aircraft’s drag. Therefore, the flying wing and canard were both
predicted to have similar drag characteristics while the conventional has the most drag.
The assembly time of the aircraft was determined from the number of motions required to move
the aircraft from the aircraft container to a flight ready condition. Since each aircraft must have a
minimum wing span of 5 feet and the maximum box dimension is 4 feet, the wing cannot be a
single piece. Three options are present: two separate wing halves joined by a spar, two wing
halves folded by a hinge on the centerline, or folding wingtips. The folding wingtip design
presents the best option due to the importance of the structural integrity of the aircraft’s center.
Each configuration must have the folding wing tips, but the canard and conventional also have
the large tail structure. This would also require some sort of attachment or folding mechanism.
Additionally, servo connections to the control surfaces would introduce complexity which would
increase the assembly time. The canard and conventional would therefore have similar assembly
times, while the flying wing would have a lower assembly time due to its absence of a tail.
The initial calculations performed for this design selection showed that the flying wing was the
best suited configuration to optimize the overall competition score as seen in Table 3.
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