PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
7.2.2 Avionics
Should the pilot, while operating an in-flight aircraft, lose radio communication to the vehicle
due to Radio Frequency Interference (RFI) the aircraft will crash. However, this probability is
low because of the transmitter selection. Because the operating frequency is 2.4 GHz, no other
radios can operate on the same channel and interfere with the communication with the Buff-2
Bomber. Also the selected transmitter has a programmable failsafe. If for some reason the
communication with the vehicle fails, the receiver will automatically cut throttle and deflect the
control surfaces to bring the aircraft down.
7.2.3 Propulsion
The propulsion sub-team must be most worried about whether or not their selected motor and
battery configuration can propel the aircraft far enough to complete each mission. If the total
range is insufficient to complete four laps at maximum weight, the consequence is no score and
ultimately no chance of winning the competition. Fortunately this is a lower level probability as
much analysis and testing has been done to accurately calculate the actual thrust provided from
the motors. Further mitigation will involve dynamic testing of the entire propulsion system.
7.2.4 Structures
The wingtip hinge design is necessary for the aircraft to fit into the storage container. However,
“breaking” the wing along the span increases the possibility of a catastrophic failure during flight
that results in competition failure and possible endangerment of bystanders. Because of the
mechanical complexity, the wingtip hinge presents the most probable and dangerous risk the
aircraft faces. However, much of the risks associated with this design aspect can and will be
mitigated with extensive ground testing. The overall strength of the hinge system and its ability
to restrict free-play will be optimized before the system is tested in flight.
7.2.5 Missions
Tasked with designing the release mechanism of the wing mounted stores, the missions sub-team
was able to determine their most significant risk to mission success is the possibility of the
release mechanism jamming or failing during the mission. This possibility is mid-to low range
simply because extensive testing will be done on the prototype and final design to ensure that the
mechanism can release the stores with a 95% success rate. Another primary risk is if the rules,
which undergo constant upgrades and explanations, may soon not allow magnetic mechanisms to
hold the payloads to the wing. Although a low risk, this will be mitigated by not abandoning the
mechanical design system and holding it as a backup to the magnetic system.
7.2.6 Microcontroller
Implementing the microcontroller creates additional risks to the overall avionics subsystem. The
microcontroller is only enabled when the pilot gives the appropriate input on the transmitter;
however, it is possible that the microcontroller receives a false reading and activates while the
plane is in flight. The probability of this situation occurring will be fairly low as safety features
58