- Can better helmets make football safer?
- Why do submarines move more like torpedoes than fish?
- What are the technological obstacles to colonizing another planet?
- Why can’t I use a dimmer switch with a compact fluorescent bulb?
- Can we build a time machine?
- Can seawalls prevent beaches from eroding?
- Why is a bicycle easier to control when it’s moving?
- Can we control machines using only our thoughts?
- How can we make hearing aids work better?
- How does a particle accelerator work, and why are such large structures necessary?
Can humans fly like birds?
It all depends on what you mean by “fly like birds”…By Leda Zimmerman
Humans will never fly by flapping our arms with wings attached, says Mark Drela, Terry J. Kohler Professor of Fluid Dynamics in the Department of Aeronautics and Astronautics. The arms and chest of a human do not have anywhere near enough muscle mass to provide the necessary power.
And it’s unlikely that we will achieve flight by flapping wings powered by our legs, Drela says. In theory, human legs do have enough strength to do this, but only if the wings’ span is large enough — at least 80 feet or so — and if they also weigh significantly less than the human. This large-size/low-weight combination is extremely difficult to achieve with current mechanical technology, and no one has yet succeeded or even come close to realizing it, although many have tried.
But, says Drela, we have achieved one type of human-powered flight: using an aircraft with a fixed wing and propellers driven by leg pedaling. Because the wing is fixed, it can be built both long enough and light enough to permit flight. Around 100 airplanes like this have been flown to date. One notable example of this design is the Daedalus aircraft, the result of a multi-year MIT project involving Drela, as well as other MIT faculty, and students. Named for the mythological Greek inventor, Daedalus has a wing spanning 112-feet and weighs just 52 lbs. The craft as a whole tips the scale at a mere 68 pounds.
On April 23, 1988, Daedalus took off from the Greek island of Crete, piloted by 160-lb Olympic cyclist Kanellos Kanellopoulos. Three hours, four minutes, and 59 seconds later, Daedalus came down in the surf just off Santorini’s black sand beaches, after facing gusty winds that damaged the craft’s tail boom. Kanellopoulos swam ashore, and the Daedalus, having flown 72.4 miles, smashed the world’s record for human-powered flight. While never aloft again, this human-powered aircraft continues to inspire in its current home: Terminal B at Dulles Airport.
Posted: November 30, 2010