PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
dropping one rocket in between each lap. The first lap will be flown at 12 lbs, and the last lap
will be flown at 7.5 lbs, with a 1.5 lb rocket being dropped in between each landing and takeoff.
The batteries must be designed for a four lap endurance plus a 30 second power reserve.
6.4 Structures Design-To Specifications
6.4.1 Aircraft Wing Requirements
The aircraft wing is required to sustain a +3.5g load while carrying the centerline store and a -2g
load while carrying the tip stores. The required g loads were determined by including an
additional 1 g of load to the worst case expected scenario for each payload. The worst case wing
loading scenarios were derived from the expected in-flight bank turns the aircraft must make
during each of the missions. The addition of the g loading margin creates a 1.4 safety factor for
the centerline store flight scenario and a safety factor of 2 for the tip store flight scenario. The
safety factor added to the worst expected loading is an added margin for unexpected factors
including in-flight wind gusts and ideal assumptions made for the wing material and
construction.
The aircraft wing is required to fit within the aircraft container while still meeting the wingspan
and payload integration requirements. This requires the wing be foldable or collapsible for incontainer
storage due to the 48” x 24” x 24” dimensions specified by the competition. To
guarantee the aircraft wing does not exceed the maximum container dimensions, the aircraft’s
maximum dimensions on each side shall be 1” shorter than the container’s dimensions. With the
maximum wing dimensions bound to 47” x 23” x 23”, a margin of safety was assured for this
dimension requirement. This margin accounts for the thickness of the walls as well as some free
space on any side of the aircraft in the container.
The wing structure is also required to integrate the wingtip and centerline stores such that they
are securely restrained in the worst case flight loading with some safety factor. The worst case g
loading is expected to be a 2.5g bank turn and 1g of safety factor was added to that loading. A
3.5g loading generates 28 lbs at the centerline store mount and 10.5 lbs at each wingtip store
mount. The additional 1g included in the design wing loading creates a safety factor of 1.4 for
each payload’s mounting point.
6.4.2 Landing Gear Requirements
The aircraft landing gear and supporting aircraft structure is required to survive the impact loads
involved during landing. A successful mission requires that the aircraft survive take-off, flight,
and landings. The landing gear requirement dictates that each gear strut survive a dynamic
loading assumed to be approximately 3 times the heaviest aircraft weight configuration. Landing
the plane on one gear in the heaviest configuration was deemed the worst case landing scenario.
The 3g single gear strut loading includes a safety factor of 1.2 during the heaviest aircraft
configuration and a safety factor of 2.25 in a no payload configuration. An additional 25%
50