It was aviation history in the making. In a muddy field west of Ottawa last week electronics technologist Gerald Bower wrestled with the controls of a radio transmitter for five minutes, manoeuvring a pilotless plane into position. Three hundred feet above him, the balsam wood craft with a 15-foot wingspan soared and dipped, responding to the transmitted commands. Then, as the plane’s onboard batteries were about to go dead, Bower switched them off—and watched as the electrically powered propeller plane continued its flight for another three minutes. Before about 100 fascinated observers from across Canada, the United States and from as far away as Japan, the plane was flying under power—but without using any fuel. Instead, its electric motor drew its power from microwaves beamed up from a ground antenna. Declared Robert Bearcaw, a U.S. National Aeronautical and Space Administration flight expert: “It’s one of those things nobody believes until he sees it.”
That official launching on Oct. 6 capped a five-year $2-million project by a five-member team from the federal ministry of communications. But in fact, it was the sixth time that the delicate plane had flown without an onboard fuel supply. In one previous test, the SHARP 5 (for Stationary High Altitude Relay Platform) flew for an hour
on microwave power. Still, it was only a first step for the Canadian researchers and others in the United States working on similar projects. Their ultimate goal: a full-sized, unmanned plane that can stay aloft for months at a time, performing such tasks as relaying radio and television transmissions or monitoring pollution. For a number of reasons—including the fact that it does not have to return to the ground for fuel—such a craft could operate at a fraction of the cost of the aircraft and satellites that now do those jobs.
For the flight, a dish-shaped ground antenna beamed 10,000 watts of microwave energy to copper receptors on the underside of the aircraft. Those receptors then converted that energy into 150 watts of direct current—enough to drive the craft’s electric motor, which in turn powered the propeller.
There was a quick reward for the success: federal Communications Minister Flora MacDonald, who was at the official launch, announced that Ottawa would continue financing the microwave flight project. With that assistance, said the researchers, by 1992 a $30-million microwave-powered aircraft—with a wingspan seven times the size of the prototype—could be soaring through the skies.
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