The task was to build a flying object that transforms itself by means of an Arduino controller and accelerates independently on a ramp and glides without further propulsion. Criteria were the object has to be developed as a lightweight vehicle with initial dimensions of 20x20x20cm. The ramp must have a length of 1.80m and a height of 120mm.

The first problem we encountered when looking at the ramp was the low gradient and the low starting height before the free flight. In order to get enough thrust within the given short starting distance, it was first important to find out which type of drivetrain could guarantee this. After many test runs with velocity prototypes laser-cutted of acrylic glass, a brushless motor controlled by an ESC control unit and powered by 2-4S batteries proved to be the most suitable combination. A further feed factor was the span of the propellers, their pitch and number of blades.

The second challenge we faced in this project was gliding. The requirement was that all powering systems had to be switched off after leaving the ramp. Relevant factors for achieving a large gliding distance are on the one hand the wingspan in relation to the total weight, shape and finish of the wing profile, positioning of the centre of gravity and on the other hand the attachment of a tail fin for stabilisation. The gaps in the wing profile visible in the pictures are the result of initial thoughts about possible transformation points.

Measurements: 74x50x20cm

The transformation contains several actions that are linked together in a chain reaction. The connection of the individual transformations (linear expansion, folding out of the tailplane and tensioning of the wings) has the advantage of saving material and reducing the complexity of the structure.

1) The heart of the transformation is a carriage that travels over a threaded rod, which in turn is rotated by a geared motor. This driving movement transports the carriage, which is guided over two carbon fibre profiles, towards the rear.
2) This movement causes the tail element to extend to the rear and tension the pulling rope and therefore spanning the wings and tail. The connection of the individual wing elements is ensured by narrow rod joints. These joints are limited in their range to prevent overstress of the wings.

Since the goal was to achieve the lowest possible weight, it was necessary to use materials that are both light and durable. Balsa wood was used for the wing struts and airfoil for the wing surface. The mounting brackets and the frame joints are made of laser-cut acrylic. The frame elements, on the other hand, are made of carbon fiber profiles.

Purchased brass parts were used for the pulleys and eyelets. The wheels were turned from aluminum.