PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
using 1/32 in diameter copper BBs and the longitudinal CG of the rocket was aligned with that of
the aircraft. Competition rockets employed 1/8 in aluminum fins to ensure that they did not
break on store drops.
The two connection points on each store were located as far apart from one another as possible
on the underside of the wing which effectively reduced the moment holding the store in place.
This meant that the inboard stores experienced a smaller load on the front metal tab and rear
pylon than the outboard stores due to the greater chord length of the wing. This also meant that
each store was unique due to inboard/outboard and left wing/right wing combination
considerations. Each store pylon location was located ½ in from the trailing edge of the aircraft
and remained clear of aileron movement.
8.2.2 Centerline Store
The centerline store utilized two Tru-Fire triggers located on the front and aft sides of the store.
An HS-77BB servo actuator was placed between the two mechanisms and connected to the
release mechanisms with Kevlar string. The servo, string length, and mechanisms were
calibrated to ensure that they release at the same instant, reducing the chance of a jamming
scenario.
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Figure 49: Left: Store-Fixed Metal Tab; Right: Tru-Fire Trigger Assembly
Each Tru-Fire trigger was mounted to the centerline joiner plate using ½ in aluminum L-wedges
and bolts. 1¼” metal tabs with a hole for the trigger were secured to the store with aluminum
hose clamps wrapped and tightened about the circumference of the bottle. To release, the
centerline servo will rotated counter-clockwise until both triggers released their tabs
simultaneously. Figure 50 shows the centerline release design.
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