The Mammoth Book of Space Exploration and Disasters

A second orange streak shot out, Carder saw it and said close into the mike, “Two is good.” The blast from the rockets jolted the moving cars and the plane was still eating up the lakebed, far ahead of us now. Another quarter of a mile and the Skyrocket began to shed the ground; hanging heavily over the desert she reluctantly rolled a bit, the gear went up. I tensed with the pilot in the ship; if anything went wrong at this moment – that would be all! The seconds went by and she gathered speed, rocked obediently over and began the steady climb up. The sky held, only for a few more seconds, the two bright spots with the chase pilot diving to catch up… and then the planes were absorbed into the distance.

Scott Crossfield’s engine explodes

The US government’s research program into rocket-propelled aircraft made its tests at Edwards Air Force Base (formerly Muroc Army Air Force Base). Between 1950 and 1955 Scott Crossfield flew nearly all of the experimental aircraft under test at Edwards. These included the X-1, XF-92, X-4, X-5, D-558-I and the Douglas D-558-II Skyrocket. On 20 November 1953, he became the first man to fly at twice the speed of sound.

NACA was primarily concerned with research and did not usually try to break records, although in the case of Mach 2 it was allowed to make an exception to gather the research data.

In 1988 Crossfield described many of his experiences, including the value of the experimental aircraft program:

The research airplane program was probably the most successful government research program on record. It involved about 30 airplanes for 30 years, running from 1945 to 1975, and probably produced almost all of the information that has been essential to our transonic and supersonic flights, our transonic transports, and our space program.

Crossfield described the purpose of the X-1 program:

The X-1 was the first of the research airplane series – post-war research series. Its primary purpose – or its sole purpose – was to see if we could, in fact, exceed the speed of sound with a manned aircraft. There were a lot of people who said that we could not. And a lot of reputable opinions that said that we could.

It was very simply designed. It was an airplane that incidentally was patented by Bob Wood in 1945. It used an RMILL4 engine which was the beginning of our successful rocket era [and was] developed by the Navy and Bob Truax. The all-point simplicity and design – and the objectivity and design – made it very successful. It did accomplish its end of flying supersonically in 1947, of course, [we all know] with Captain Charlie Yeager at the controls.

The design of the D-558-II Skyrocket became the standard model for swept-wing aircraft. Crossfield commented:

The D-558-II was one of the research airplanes funded by the Navy. That is the reason that it did not have the “X” designation.

It was primarily the review to look at what the transonic effects of the swept-wing would be. With it we flew some several hundred flights and wrote the book on how we could design and build modern swept-wing airplanes. It proved many of the things that we have learned since then.

The D-558-II was a very productive airplane. Almost every airplane in the air today has a little bit of the D558-II basic information – or what we learned from it – in it.

Crossfield gave a specific example of this:

It has been well known for many years that a characteristic of swept-wing aircraft is instability at high angles of attack. With the D-558-II, we learned many many ways to relieve that instability so that we could get the handling qualities that pilots need to fly airplanes in a commercial environment. Handling qualities… engineering ease for controllability… [are all] desirable characteristics.

Test pilots, like Crossfield, often had to fly several different experimental aircraft during a single day. Crossfield described such a day: