Backyard Builders: Do-It-Yourself Aircraft

Three ambitious high school students built this inexpensive human-powered hovercraft; the bill of sale for the craft was under $500. It consists of a 30-inch diameter lift fan with 7.5 inch blades, and a frame made of aluminum, foam and fiberglass. <a href="http://www.youtube.com/watch?v=nqG8qObcXKk&amp;NR=1&amp;feature=fvwp">A video on YouTube</a> details their construction project. (YouTube)

<a href="http://www.steamboatwilly.org">Steam Boat Willy</a> documents a project of the Human Powered Flight Club of the University College London Union, ( UCLU HPFC ). The project’s Web site includes a raft of technical details on the ship’s construction. The club was formed in 1994 and has also built a spool-drive bicycle and the cockpit of a human-powered-aircraft flight simulator. Many organizations exist to support human-powered vehicles, such as the Festival of Human Power and the International Human-Powered Vehicle Association (<a href="http://www.ihpva.org/">IHPVA</a>). (steamboatwilly.com)

A <i>Make</i> magazine intern recently built this <a href="http://blog.makezine.com/archive/2009/09/interns_corner_my_rc_hovercraft.html">radio-controlled hovercraft</a>. He constructed the small craft mainly of birch bass wood supports, with carbon fiber stripping used for security. He powered the craft using a remote control plane engine that he attached to a three-blade propeller—a total vehicle weight of 3.7lbs. The skirt is made out of ripstop nylon and is secured using Velcro. (YouTube)

Not all high-altitude flights are unmanned, and Bob Maddox has a thirst for adventure. The inventor has built a prototype pulse jet -- basically a long tube with a fuel pump, a spark plug and a reed valve. Maddox's jet has a throttle too, meaning he can control the thrust from the "pulse" ignition of air and fuel that occurs about 70 times a second. <a href="http://www.wired.com/autopia/2009/07/bob-maddox-pulse-jet/"><i>Wired</i> profiled the inventor</a>, and his plans to ride a jet powered by four of these rockets into the heavens.  The magazine wrote, "Once he reaches 25,000 feet, a small rocket in his ejector seat will shoot him clear of the pulse jets, and parachutes will bring him -- and the jets -- back to earth. He'll test everything with an unmanned rocket, but Maddox has every intention of making the jump himself at some point." (Bob Maddox)

In the world of homemade aircraft, height is often a goal, and two MIT students recently took the gold medal. The pair launched a digital camera into the stratosphere on a helium balloon, capturing amazing views of Earth from up high. Oliver Yeh, an MIT senior studying computer science and electrical engineering, and Justin Lee, a graduate student in mechanical engineering, lofted the camera Sept. 2 from Sturbridge, Mass. By tracking its location through the GPS readout of a cheap cell phone they launched along with it, the students were able to retrieve the package after it landed in Worcester about 20 miles (32 km) away. <a href="http://www.space.com/scienceastronomy/090923-space-camera.html">The resulting pictures are stunning</a>, revealing the blue glow of Earth with the bright glare of the sun's reflection, contrasting against the blackness of space. Yeh's favorite shot is a frame showing the curve of the Earth, with the shapes of Long Island and Connecticut visible. (Space.com)

<a href="http://www.byu.edu/">Brigham Young University</a> has a lab dedicated to the creation of unmanned vehicles. Students at the BYU MAGICC Lab used laser range-finders and optic flow-sensors to navigate this small unmanned craft through an urban environment safely. The range-finder detects obstacles and changes its preplanned course to avoid the objects. (YouTube)

Building a craft that looks like the vehicle Heene assembled isn’t necessarily the challenge, though his craft looks far more professional than this do-it-yourself UFO project from <a href="http://www.instructables.com/id/a-life-size-U.F.O.">Instructables.com</a>. Clearly, the challenge behind all of these projects is the physics of the project, determining a controlled methodology—be it through helium or human power—for safely getting the craft off the ground.