Mach, and not so Mach

Flight Journal, Feb 2000 by Gudaitis, Frank

Shortly after the end of WW II, the USAF, the U.S. Navy and the National Advisory Committee on Aeronautics (NACA) joined forces to investigate the problems of supersonic flight and compressibility. The result was the construction of three X-1 research "rocket" planes that differed only slightly from one another.

When the test series on the first X- Is had been completed, a second generation came into being. The X-1A was powered by a Reaction Motors bi-fuel rocket motor that developed a maximum static thrust of 6,000 pounds. It differed from the X-1 in that it was fitted with turbo-driven fuel pumps, had a greater fuel capacity and a longer (by five feet) fuselage. These changes increased the flight endurance under power from 2.5 minutes to approximately 4.2 minutes. Fully loaded, it weighed 16,000 pounds and about half that when empty.

It was carried aloft under a B-29 to an altitude of around 70,000 feet. On December 12, 1953, Maj. Charles Yeager (who also made the first supersonic flight in the X-1) flew the X-1A at more than 1,600mph; by contrast, its gliding landing speed was only 155mph.

By comparison, the U.S. Navy's Goodyear "K" airships-crewed usually by three officers and six others-floated along. They were 251 feet long, 62 feet wide, 79 feet high, contained 456,000 cubic feet of helium and had a useful load of 11,000 pounds. At a gross weight of 29,000 pounds, they could carry up to 1,200 pounds of bombs or depth charges.

Powered by two R-1340 Pratt & Whitney Wasp radial engines, their top speed was 80mph, but their range exceeded 2,000 miles and they were widely used during the War. A tribute from the Navy stated, "Not one of the thousands of transports and supply vessels that were escorted by these non-rigid airships was ever lost to submarine attack."

The X-1A no longer exists, but the research behind it led to the development of many great aircraft and spacecraft. The airships (blimps), however, are still with us, and you can see them floating over a sporting event near you.

-Frank Gudaitis