休斯XH-17最大旋翼直升機，70年前美國黑科技跟蘇聯有得一拼

在Culver City, California, the Air Force's XH-17, the world's biggest helicopter. With rotor blades extending more than 130 feet, the experimental heavy cargo copter can carry loads of more than 10 tons. This trailer van is the largest object yet lifted by helicopter. She's capable of carrying tanks, bridge sections, howitzers. In civilian use, she can carry heavy loads without ever worrying about traffic. This helicopter with muscles. Howard Hughes, noted aircraft producer, unveils his monster helicopter to the public and Air Force officers at Culver City, California. Powered by turbojet motors, the huge copter is designed primarily to lift great weights. It is the largest aircraft of its kind known. And when perfected, it is expected to take off and carry the load of a small freight car. And in passenger models, upwards of 100 persons. The copter itself weighs 40,000 pounds, and its rotating blades measure 125 feet from tip to tip. The 30-foot high craft is just another glimpse into the future of flight in all its varied and promising phases.