1st Design Report
No Flight Score
“The Aero Design competition is intended to provide undergraduate and graduate engineering students with a real-life engineering challenge. The competition has been designed to provide exposure to the kinds of situations that engineers face in their real-life work environment. First and foremost a design competition, students will find themselves performing trade studies and making compromises to arrive at a design solution that will optimally meet the mission requirements while still conforming to the configuration limitations.”
AMAT went into the 2014 season determined to build on our success in 2013. We applied and improved our precise manufacturing techniques to build the 2014 aircraft, Aura. Named for the Greco-Roman divine personification of the breeze, we designed Aura’s aerodynamics from the ground-up to meet the difficult design objectives of the advanced class. With a record number of active members, we structured the team into sections to allow for efficient design and manufacturing. In addition, this structure created new leadership roles on the team and improved the educational experience for our members.
Fall quarter was spent primarily acclimated our new members to AMAT practices and teaching critical skills like composite manufacturing and CAD design. The aerodynamic design was completed by iterating in the custom AMAT design codes. This was combined with structural concepts from each team section to create an initial design of the aircraft system. This core design remained throughout the process and was refined using further aerodynamic analysis, CFD, structural prototypes, and CG confirmation.
Coming into winter quarter, Aura’s primary CAD model was finished and we proceeded into final build. Carbon fiber composite structures were used extensively to create stiff, durable, and lightweight structures. We employed CNC machining, laser cutting, and 3D printing to create high precision components. This allowed us to use thin margins of safety in designing the aircraft system for the optimal empty weight of 8lb and fully loaded flight weight of 26lb. Aura entered flight testing in March and completed 10 flights. Two of these flights ended in crashes which were repairable but impacted the weight of the competition weight of the aircraft. We were able to validate that the aerodynamic design performed as expected and troubleshot numerous procedural, electronic, and structural issues. This amount of flight testing was unprecedented in AMAT history and allowed us to refine Aura into competition shape.
The competition fell at the end of the UC spring break. Because of this we decided to start our trip to Texas early with a visit to NASA Johnson Space Center (JSC) in Houston. We saw historic locations, examined amazing feats of engineering, and talked to numerous brilliant people from astronauts to engineers and technicians about the centers work past, present, and future. We then traveled from Houston to Fort Worth for the SAE Aero Design competition. On Friday Aura sailed through technical inspection and the captains gave their 10 minute technical presentation to a panel of engineers from event sponsor Lockheed Martin. At the end of the day, AMAT’s scores on the previously submitted design report and Friday’s presentation put us in 1st place overall with 1st in design report and 4th in presentation.
Flight rounds began bright and early on Saturday. We struggled with engine trouble as our 0.46 tuned nitro engine either refused to start or produce the thrust it had provided back in Davis. In addition to the engine, a faulty telemetry receiver disabled the data acquisition system (DAS). We were fortunately able to borrow a receiver from a member of the host flying club, the Thunderbirds, putting the DAS back in operation. Aura took to the sky during the second flight round of the day but after losing the headwind when it turned into the right hand pattern, it did not have enough airspeed to remain airborne due to the reduced thrust from the engine and crashed spectacularly. Undeterred by the pile of scraps before them, the team set to rebuilding the utterly destroyed aircraft. Repairs were made to the tail, the fuselage was pieced back into one piece, and the spare wing was readied. It took nearly 24 hours of continuous work but Aura, now Frankenstein’s Aura, was ready to fly again. Unfortunately 25+ mph winds and skewed aerodynamic surfaces from the crash led the flight to an abrupt end with a tree in the flight path.
While AMAT was unable to register a flight score, only one of the advanced class teams did and it wasn’t enough to overcome our high design and presentation scores. The end result was UC Davis taking top marks with 1st in design report, 1st overall, and best crash in the 2014 SAE Aero Design West Advanced Class.
Hwang Rak (Daniel) Choi
Julio de Haro