Powered Flight – Micro Class Plane

On the 18-20th of March 2013, the Powered Flight division has participated in the SAE Aero Design East held in Fort Worth, Texas.

One of the aircrafts built by the team, the Pizza Box II, entered as the Micro Class entry, which has the mission of having an empty weight as low as possible while being able to carry a huge amount of payload. The design entries of Micro Class also has to satisfy the size constraint of 24” by 18” by 8”.

The design of the Pizza Box II began in September 2012, where members came together to decide on the selection of airfoil, planform, powerplant, and the construction materials. Pizza Box II is a second revision of the first Pizza Box designed by the team back in year 2011. The team has decided to retain most configurations of the original Pizza Box, as it is extremely simple to build, has a low empty weight, and performs well at low Reynolds number. Research by Reid shows that a Bezier thin airfoil has a better performance for micro-aerial vehicles. As such, a Bezier thin airfoil of 8% camber at 25% chord and a 1% reflex at 85% chord is selected for its high lift-to-drag ratio and high coefficient of lift. The planform of the Pizza Box II has changed from Drenalyn to Plaster2 in favour of the higher lift-to-drag ratio.

fort_worth_SAE

The construction material of the Pizza Box II is mainly foam. A variety of foam such as extruded polystyrene (XPS), expanded polypropylene (EPP), and Depron foam. EPP is chosen for the fuselage for its durability, while 3mm Depron foam is chosen for the wing for its stiffness. The prototype of the Pizza Box II has been put to several flight tests to verify its design and performance. Its empty weight stands at 0.24 pound, and it is capable of lifting a payload up to 1.12 pound, which is nearly 4.7 times its empty weight!

 

SAE_MicroClass

During the competition at Fort Worth, Texas, Pizza Box II didn’t have too much luck and experienced some difficulties such as loosen battery connectors and strong winds that resulted in plane crash. Out of 6 flight rounds, Pizza Box II managed to complete one flight round with a payload of 0.96 pounds, which placed the team at 4th in the highest payload fraction and 4th in the highest overall flight score. The team also scored the 2nd in the design presentation of Pizza Box II.