posted 11-29-2015 07:52 AM               

Space Cover #345: The X-2 Lights Its Fire

Sixty years ago this month, the oft-troubled X-2 rocket plane finally lit its engine in flight. The cover above was carried on this first powered flight on November 18, 1955, as annotated by the pilot, Frank K. "Pete" Everest. Everest placed this cover into the mail after the flight and it was postmarked at Edwards, CA on November 21, 1955. It is listed in the Ellington-Zwisler Rocket Mail Catalog Volume 2 as United States #74.

The X-2 rocket plane program started in 1945 as a higher-speed, swept-wing followon to the X-1 rocket plane (itself still in formulation). The X-2 was envisioned as a Mach 3 (three times the speed-of-sound) aircraft that could fly over 100,000 feet in altitude. These two performance goals called for major advances over the X-1 in rocket engine technology and airframe construction. Two X-2's were built, and were designed to be dropped from an Air Force EB-50 bomber.

The first X-2 performed its first glide flight on June 27, 1952 with the unpowered X-2 sliding all over the Edwards dry lakebed during landing. Two more glide flights were successful. Then on May 12, 1953 the X-2 was carried aloft in the EB-50 to test propellant handling in flight. The X-2 suffered an explosion and was destroyed, killing test pilot Jean Ziegler and EB-50 crewman Frank Wolko.

The second X-2 was delivered to Edwards AFB in July 1954. It performed three unpowered glide flights, each of which ended with hair-raising slides and ground loops upon landing. The X-2 was returned for fixes to its landing gear and to install the final fix to the earlier explosion problem. The Air Force, exasperated at the slow pace of the X-2 development, set December 31, 1955 as the deadline for a successful powered flight or they would cancel the program.

An attempt was made on October 25, 1955, but problems prevented the engine from starting. However, the X-2 landed without slides or ground loops. At least the landing gear problems had been fixed!

Finally on November 18, 1955, Everest lit the X-2's engine in flight. As he approached Mach 1, his chase pilot noted buffeting in the horizontal stabilizer (rear wing), and Everest stopped the engine to slow down. He restarted the engine, accelerated, and buffet was noted again near Mach 1. In an effort to troubleshoot the buffet, Everest stopped the engine again and tried for another restart. This time the engine failed to restart. Everest had to dump his remaining rocket propellant and land. Inspection after landing showed that there had been a fire in the engine compartment that severely scorched the aircraft. Lit fire part deux...

Despite the Air Force's deadline, the X-2 lived on into 1956. Space Cover of the Week #122 describes a bit of the X-2's history during 1956. We'll also devote a few more columns to the X-2 over the next year as the 60th anniversaries pass us by.