A B-50 bomber did the first part of the climb. Shortly after daybreak on Sept. 27, 1956, it carried the rocket-powered Bell X-2 aloft and released it at 31,800 feet. Capt. Milburn G. “Mel” Apt then went to full power and flew the X-2 to 2,094 miles per hour, or Mach 3.196.
That made Apt the first person to fly more than three times the speed of sound. Before he could bring it home, the X-2 departed controlled flight, and Apt did not survive. The Air Force and NASA record both the speed and the loss.
The account comes from an Edwards Air Force Base history article by Peter W. Merlin of the NASA Dryden History Office. It says Apt “became the first man to fly more than three times the speed of sound,” reaching “a speed of 2,094 miles per hour.” The page carries no publication date.
A rocket plane that rode to altitude
The X-2 did not take off from a runway. A carrier aircraft lifted it to launch altitude first. NASA’s fact sheet on the aircraft says “A Boeing B-50A bomber was modified to carry the X-2 to launch altitudes around 30,000 feet.” The first B-50A was later lost, and a modified B-50D took over the job, the fact sheet says.
Power came from a Curtiss-Wright XLR25-CW-1, a two-chamber, liquid-fueled rocket engine. The NASA Dryden fact sheet on the “Bell X-2 Starbuster” gives it “a variable thrust rating from 2,500 to 15,000 pounds.” The airframe was built of stainless steel and K-Monel, a copper-nickel alloy, according to the same sheet.
Those materials were the point. NASA describes the X-2 as “designed to investigate the structural effects of aerodynamic heating,” the heat that builds on an airframe at high speed. The Edwards article says Bell built the X-2 to study aerodynamic heating along with stability and control “at high speeds and altitudes.” Bell built two X-2 aircraft, serial numbers 46-674 and 46-675, per the Edwards article.
Mach 1 at 44,000 feet, Mach 3 above it
After the drop, Apt went to full power and climbed. He “exceeded Mach 1 at 44,000 feet,” the Edwards article says, and the X-2 carried on to about 72,200 feet. On that run the aircraft reached Mach 3.196.
Apt had flown chase for the X-2 before he was offered the chance to fly it himself in September 1956, the Edwards history says. According to the article, he had been told to “make no effort to obtain maximum speed” and to stay within the limits of earlier flights while refining the flight profile.
The X-2 already held an altitude mark by then. NASA’s fact sheet says Capt. Iven Kincheloe flew it to 126,200 feet on Sept. 7, 1956, “a record that stood until the advent of the X-15 program.”
Inertial coupling and the escape capsule
With the Mach 3 run complete, Apt “began an abrupt turn back toward Rogers Dry Lake,” the Edwards article says. The X-2 went into diverging rolls and tumbled. NASA’s fact sheet names the problem: “a control divergence known as inertial coupling.”
The X-2 had a way out. NASA says “the entire nose assembly would jettison and deploy a stabilizing parachute,” a capsule meant only to slow and steady the pilot until he could bail out at a safe altitude. Apt separated the capsule, but “was unable to extract himself before it struck the ground,” per NASA. The Edwards article says the capsule came down on the Edwards range, and the rest of the aircraft fell about five miles away.
The X-2 had been scheduled to go to the National Advisory Committee for Aeronautics for research flying once the Air Force finished its test program, the Edwards article says. The crash on Sept. 27, 1956, ended that plan. The speed Apt reached that morning, 2,094 mph, is recorded by both Edwards and NASA as the first time a person flew faster than three times the speed of sound.
Top image: Bell X-2 No. 1 (46-674) landing on its skids, 1954. Image Credit: NASA — Public domain / Wikimedia Commons
This article was produced with the assistance of AI and reviewed by Combat Rated editors prior to publication.