Those magnificent men
Even if NASA has taken much of the glory from lone inventors today, it is still possible for such inventors to make substantial steps in aviation. This was the original impetus behind the EAA, and the spirit is still alive. One such innovator is Attila Melkuti, who is chasing the elusive goal of vertical take-off and landing (VTOL).
Helicopters, of course, take off and land vertically. But because the main direction of their thrust is upward, even the most sophisticated choppers have limited range and forward speed. That is why engineers have been trying for decades to design aircraft that can push (or pull) themselves forward as well as up and down.
So far, the successes have been outnumbered by the failures. Helicopters aside, the Harrier jump-jet, a British military aircraft, is the only real winner. But it is noisy and expensive to operate, and so has no applications beyond the role for which it was originally designed. If a cheap, quiet VTOL aircraft could be made, it would have many civilian applications. Indeed, such a craft would have the potential to transform aviation, shrinking the size of regional airports by allowing runways to be replaced with landing pads.
That is a long way off. Indeed, Mr Melkuti's prototype has not yet flown. It is scheduled to have its first test flight in the next few weeks. But Mr Melkuti has eliminated one of the main elements that have plagued previous VTOL aircraft—the need to swivel the engines (or the thrust-producing exhaust from them) so that they go from providing lift to providing forward thrust. It was a failure to manage this transition that nearly ended America's V-22 Osprey programme, which is designed to produce a transport VTOL whose wing propellers will rotate through 90°.
Mr Melkuti has solved the problem by having the whole aircraft turn instead. He does this by using a propulsion system called a ducted fan. This is a propeller with five blades that is encircled by a band made of a light, composite material. That makes the aircraft both safer (because there are no stray propeller blades around) and quieter (because the sound is deadened by the encircling band).
What is novel about Mr Melkuti's design, though, is that the aircraft's wings are placed at an angle to the fan. And besides the wings, the fuselage itself provides aerodynamic lift. The craft takes off with the fan perfectly horizontal, blowing straight down. As the craft then rotates, the wings start providing lift, and the fan starts blowing towards the back. To land, you simply reverse the process.
Many observers at the meeting were concerned about the stability of Mr Melkuti's craft. He claims to have solved the stability problem with a system of louvres that guide the fan's exhaust. He also says that the craft should be able to glide to a landing if the power fails.
If he himself fails, it would not be the first time that VTOL prototypes fell short of their promise. If he succeeds, he could become a very rich man. Either way, he embodies the spirit of innovation in aviation that suffuses this Wisconsin prairie.
From The Economist 08/03
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