Five mechanical engineering students from ETH Zurich recently returned from an unusual trip that offered them a unique chance to showcase the prototype of their flying film reel “Reely” at the American entertainment group Disney in California. The students’ project leader, Valentin Gresch, is still raving about the week-long sojourn: “We spent a year preparing for this big moment and sacrificed a lot of our free time”, he says.

Apart from visiting labs at Disney, the ETH Zurich students were also given an opportunity to test their film reel at the two Disney theme parks near Los Angeles. “We flew the film reel in different sections of the park to find out which theme it might be best suited for”, says Gresch. “Reely” went, for instance, on a test flight through Main Street, a shopping street at Disneyland.

The powerful at Disney found their idea “totally cool”, Gresch explains. After all, Disney hardly has any flying objects like “Reely” at its theme parks. All the same, he was unable to say whether the film reel would actually have a place or a role to play at one of the theme parks. “The project has to go through a number of authorities before it can be integrated into a domain”, he says.

The project all started when Disney asked ETH Zurich professor Roland Siegwart from the Institute of Robotics and Intelligent Systems whether his students could “develop an aircraft that combines technology and entertainment”. In a focus project, which budding mechanical engineers can do in their 5^th and 6^th semesters, five ETH Zurich students and two electrical engineering students from ZHAW took it upon themselves to do precisely that.

From Tinker Bell to flying television

The students’ original ideas ranged from “Tinker Bell”, the fairy from Peter Pan, who was to fly through Disneyland beating her wings, to a flying television. The latter soon became the favourite, but a screen meant that too many surfaces would have been exposed to the wind. Then, during a coffee break, the team finally came up with the idea of making a film reel that plays movies as it hovers in the air.

After an extremely intensive year of development, the result is ready to be unveiled: “Reely” has taken off – literally. The students fixed six 4.3-inch screens where the film is usually wound. A minicomputer is installed behind each of the screens, obtaining its data from 4-gigabyte memory cards. Still images can be seen on twelve further frames. According to Gresch, you can't watch a whole movie like this, of course; it's more about the effect.

Based on quadrotor

The film reel flies because it is basically a helicopter with four rotors arranged crosswise. The flight direction is controlled by changing the rotational speed of the individual rotors, which are 25 centimeters in diameter. Each of the four electric motors draws 250 watts of power from a central power supply, a lithium-polymer battery that supplies both the onboard electronics and the minicomputer. “Reely” measures 80 centimeters in diameter and only weighs 1.46 kilograms thanks to a sandwich structure made of composite materials. The majority of the weight is taken up by the batteries, rotors and displays. The film reel itself only weighs 400 grams.

The film reel is currently controlled by radio remote control. Originally, it was supposed to fly on its own, but the onboard computer currently lacks the necessary computational power and the control software would still have to be tested and improved if need be. A GPS sensor has already been prepared, however, and only needs to be connected to the control system.

Incidentally, the Americans will not be the first to have the pleasure of seeing “Reely” fly publicly, but rather the Swiss public: on September 25, the film reel will be hovering above the lakeside of Zurich during the Researcher's Night – cinema by the lake in an extraordinary form.