61 years ago today, on May 11, 1964 (March 30, 1964 in the lunar calendar), the B-70 bomber with three times the speed of sound made its maiden voyage. The B-70 bomber that cost $1.34 billion On May 11, 1964, the B-70 bomber flying at a speed of 3,200 kilometers per hour officially appeared at the Northern American Aircraft Factory in Palmerdal, California, and the research work before the aircraft took off was not known. In the $1.34 billion Air Force project, only one more such aircraft can be produced as planned. The aircraft is designed to fly 6,000 miles over 20,000 meters, which sets a new standard for aircraft performance. But critics argue its technology is outdated. Supporters of the aircraft countered that the B-70 set a precedent for the use of light metal titanium, of which 6 tons were used in the predecessor of the aircraft body. It is believed that the B-70, which weighs 275 tons, is the heaviest aircraft ever built. It is powered by six jet engines, and the air inlet is large enough for a person 1.8 cm tall to stand upright in it. The B-70 will fly this summer, and the data obtained from the test flight will be used to design a commercial transport aircraft, which will fly at three times the speed of sound.