英語四級聽力只為你量身定制 每天一練(7.14)

Many people have long dreamed of being able to fly around as simply as riding a bicycle. Yet the safety and strength of a flying bike was always a big problem.

Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may available very soon.

The British company Malloy Aeronautics has developed a prototype or model of its flying bicycle. The company says its Hoverbike will be a truly personal flying vehicle.

Grant Stapleton is the marketing sales director of Malloy Aeronautics. He says the Hoverbike is able to get in and out of small spaces very quickly. "It can be moved across continents very quickly because it can be folded and packed," he adds.

Mr. Stapleton says safety was the company's main concern when developing the Hoverbike. He says the designers solved the safety issue by using overlapping rotors to power the vehicle. He says the power comes from adducted propellers, which turn in enclosed spaces.

"With adducted rotors you immediately not only protect people and property if you were to bump into them, but if you ever were to bump into somebody or property, it's going to bring the aircraft out of the air," Mr. Stapleton says.

The company is testing both a one-third scale model and a full-size prototype of the Hoverbike.

Inventors say their Hoverbike will most likely be used first by the military, police and emergency rescue teams.

In New Zealand, the Martin Aircraft Company is also testing a full-scale prototype of its personal flying device, called Jetpack. It can fly for more than 30 minutes, up to 1,000 meters high and reach a speed of 74 kilometers per hour.

Peter Coker is the chief executive officer of Martin Aircraft Company. He said Jetpack "is built around safety from the start." In his words, "reliability is the most important element of it. We have safety built into the actual structure itself, very similar to a Formula One racing car."

Jetpack uses a gasoline-powered engine that produces two powerful jet streams. Mr. Coker says it also has a parachute that can be used should there be an emergency.

"It opens at very low altitude and actually saves both the aircraft and the pilot in an emergency," he adds.

Mr. Coker says Jetpack will be ready for sale to the public by the end of 2016. He adds it will have a price of about $200,000.

I'm Jonathan Evans.

VOA's George Putic reported this story from Washington. Jonathan Evans adapted it for Learning English. George Grow was the editor.

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