The Hovering Human

Have you ever ridden a bike? If so, then you have ridden a human-powered vehicle. Some vehicles, like cars or buses, use gas or electricity to move. Human-powered vehicles use the strength of human muscle to move.

Can you think of other human-powered vehicles that move on the ground? How about human-powered vehicles that move in the air?

That second question is harder, isn’t it? Human-powered flight has been a challenge for a long time. For example, the famous scientist Leonardo Da Vinci sketched several human-powered aircraft. That was back in the 15th century!

Did you know?

Engineers who design aircraft are called aeronautical engineers.

For years, many scientists thought that designing a human-powered helicopter was impossible. In 1980, there was a prize announced for anyone who could do this. It is called the Sikorsky Prize. In 2013, a team of engineers from Toronto finally won it!  

Did you know?

The Sikorsky Prize was named after a Russian-American pilot and engineer named Igor I. Sikorsky. He designed and flew the world's first large multi-engine airplane. He also designed the first mass-produced helicopter.

The team was from a company named AeroVelo. Their helicopter is named Atlas.

It’s not easy to design an aircraft that a person must both power and fly! It is even more difficult to keep that aircraft hovering over a fixed spot. It takes some complex engineering and physics to power and maintain flight. 

Did you know?

AeroVelo also created the fastest human-powered vehicle, the Eta Speedbike. It can hit speeds of 144 km/h!

To get off the ground, helicopters need to generate lift. They do this with rotors, which on AeroVelo’s Atlas are turned by pulleys. Rotors are rotating airfoils. 

Bernoulli's Principle explains how shapes on an aircraft help generate lift. Each rotor on a helicopter is an airfoil that has a curved upper surface. When air flows over the curved upper surface, it travels faster than the air flowing underneath the airfoil. This pulls the helicopter upward. 

Rotors with a larger surface area can help provide more lift. AeroVelo’s helicopter had four large rotors. Each rotor was 20.4 metres long.

Any human-powered helicopter has to be light. It needs to have more force lifting it upward than weight pulling it downward. Weight is the force applied on an object from gravity. 

The AeroVelo engineers used strong, lightweight materials to build the helicopter. They mostly used carbon fibre tubes. They also used a lightweight but strong type of wood called balsa wood. 

The entire craft weighed 55 kg. That is about the same weight as a small female Golden Retriever dog. That weight doesn’t include the mass of the pilot, Todd Reichert. Mr. Reichert sat on the seat of a bicycle. As you can imagine, that bicycle was heavily modified!  

Mr. Reichart and the AeroVelo helicopter hovered 3.3 metres above the ground. That’s a little bit higher than a basketball net! The aircraft stayed at this height for just over a minute. To be exact, it hovered for 64.11 seconds. 

Mr. Reichert set a world record for the longest human-powered hovering. What a surprise for those people who said it was impossible!