The only jet plane to successfully hover and take off vertically is the British-built Harrier Jump Jet. According to the Global Security website, the Rolls-Royce company developed the Harrier jet plane.
According to the Technology Student website, the Royal Navy ordered the Harrier Jump Jet during a period of cutbacks. The plane was designed for use on smaller naval ships, rather than large aircraft carriers.
Although the Harrier has only one engine, it differs from other jets in that it has four exhaust nozzles instead of one. Technology Student reports these four nozzles are the critical factor in the jet's ability to achieve vertical takeoff and hover.
Technology Student explains the four exhaust nozzles can be moved to face the ground, allowing vertical takeoff and hovering. By pushing the thrust of its engine downwards, the Harrier can hover and maneuver at low speeds.
According to Technology Student, the act of hovering requires a large amount of power for only 90 seconds of hovering time. While hovering for 90 seconds, the Harrier uses about 150 gallons of water to cool the engine.
While the Harrier hovers, vents on the end of each wing allow it to move, according to Global Security. This is because the usual form of movement airplanes use won't work at the low speed of hovering.
