An electric motor allows the impeller pack to sit close to Salzmann’s body without being too noisy or dirty. Sustainable energy is important to Salzmann as well, making the electric motor the perfect fit.
The twin 5-inch-wide carbon-fiber impellers took three years to develop after Salzmann and one of his basejumping mentors thought of an extra motor as a means to prolong a jump. Each impeller spins at roughly 25,000 rpm and has an output of 15 kilowatts. The pack is powered by a 50-volt lithium battery and the whole pack weighs roughly 26 lbs. The structure of the pack is made of aluminum and carbon fiber to keep it as light and comfortable as possible in flight.
Various pack prototypes were tested in wind tunnels—including one on Sweden capable of testing wingsuit flight—before Salzmann’s first flight as well. There, they discovered that the suit itself needed to have some additional air inlets in order to feed the impeller enough air.
To test it out, Salzmann originally planned to jump over a set of three skyscrapers in South Korea, falling down to the lower skyscrapers’ height and then soaring up and over the tallest skyscraper of the three using the impellers.