02 Aerodyamics, Prototypes and Manufacturing

Shane Hills, Jae Hwan Choi and Jean-claude Angles

As was mentioned in the introduction section, the aircraft went through only two design iterations over the course of the ten week quarter, namely Spaero 1 and Spaero 2. This is due to the fact that Spaero 2 proved to be a highly maneuverable and effective aircraft that was able to carry sufficient water ballast for fighting fires; the final choice of ballast for the missions was 21 drops. To this end, no design changes were made to Spaero 2 since the completion of Problem Set 3. As a result, all flight characteristics and design and flight characteristics have largely remained unchanged, and can be found in Problem Set 3, Task 4, including aircraft dimensions and weights, aerodynamic capabilities, and design conceptualizations.

One of the main advantages of moving to a more sophisticated manufacturing approach that emphasized laser cut balsa components and carbon reinforcement was that new components could be quickly built in the event of failure. The manufacturing team continually worked in parallel with the rest of the Spaero group in order to consistently provide the controls and mission planning team with a working aircraft capable of testing mission strategies. As a result, spare parts, including a new fuselage, main wing, and tail were produced proactively in order to provide a quick turn around in the event of a fatal crash or unexpected delay. Fortunately however, no such incident occurred. Despite this, during the competition the manufacturing team was continually on-call in the event that a new aircraft was needed to continue flying missions.

During the competition flight week, Spaero 2 sustained multiple minor structural failures, including a broken wing attachment, a motor mount failure, and a more serious loss of a portion of the horizontal tail. However, due to our structuring of team responsibilities, a member of the manufacturing team was on hand to quickly and effectively mend the failed component, and in most cases the team was able to get back to flying again within hours or minutes

The design iterations in both model and picture form can be seen below.

Above left: Spaero 1 CAD model. Above right: Spaero 2 CAD model. Notice that the wings and tail have not been modelled as their true rib and spar designs, as this was handled in DevWing. Below left: Spaero 1 construction. Below right: Spaero 2 construction.

One of the most remarkable aspects of the design iteration process is the huge leap that was made from Spaero 1 to Spaero 2, while the underlying design methodology is evident in the evolution of the concept.

Previous: 01_Introduction

Next: 03_Controls