PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
8.4.9 Motor Mount
The motor and propulsion systems were designed to attach to the foam wing. A mounting
system that integrates into the wing was designed in order to accomplish this. This mounting
system consists of four major components. The motor is the first component and attaches
directly into the motor pylon, the second component, as shown in Figure 71. Simple M2.6
machine screws and aluminum strap are used to secure the main motor body to the pylon. A
motor pylon was required in order to maintain necessary propeller clearance on a swept wing.
The motor pylon is to be made from 0.02 inch 2024 aluminum sheet formed such that it was 6.5
inches long and 1.2 inches in width.
Figure 71: Motor and Motor Pylon System
The motor and pylon assembly then integrates into the third component which is a balsa hard
mount that is installed into the wing structure. The wing itself makes the fourth and final
component of the motor mounting system. In addition to accommodating the motor, the
aluminum pylon in the airflow also acts as an effective heat sink for both the attached motor and
speed controller. The integration of the motor pylon into the balsa hard mount and into the wing
itself is shown in Figure 72. This balsa insert was designed to distribute the propulsion system’s
load into a large surface area of the wing foam-core and balsa skin. The motor pylon requires a
hard point to bolt onto because the foam does not provide adequate structural support. The pylon
and balsa insert are bolted together using four light ¼ inch nylon bolts through the holes seen in
Figure 72. Lastly, the balsa insert is glued into a slot cut from the wing before the wing is
sheeted with the balsa skin. Wire access to the motor is provided by a tunnel bored through the
foam and balsa to the pylon.
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