The Mammoth Book of Space Exploration and Disasters

In the days of the research airplane program, things were somewhat different than the bureaucracy that we find ourselves in today. For instance, there could be a day where I would do an X-1 launch early in the morning, fly the X-4 over lunch hour, and do a D-558-II launch in the afternoon. That was not a typical day, but there were days of that type. We were very versatile in our operation in those days.

Crossfield gave his impression of the different handling characteristics of the X-1 and the D-558-II:

Well, I flew both the X-1 and the D-558-II. They were quite different in their flying characteristics even though they were both pretty good flying airplanes. [They were not]… necessarily as good as we would like to see because they were experimental.

I am often asked what goes through your mind when you are flying these airplanes? The answer has to be that you do not have time to [ponder] philosophical considerations of what is in your mind. You are concentrating all of your capabilities on the job at hand.

The basic shape of the X-1 came from the .50 calibre bullet. Crossfield:

When they were designing the X-1, we did not have the capability to do wind tunnel testing transonically. So they made a very good… decision. They made the forebody of the X-1 shaped like a 50 caliber bullet which was a well-known supersonic projector at the time.

It was [that kind of] judgmental design characteristic that was essential at that time; but we had no way to test [it]. And that is the sole reason for the research airplane program. We had the capabilities with engines to speeds and altitudes; [but] we had no capability to test. We did not know how to analyze, so flight test was the only way.

Crossfield described the development of the X-15, including discussions with Walt Williams:

Well, as I remember the genesis of the X-15, one time coming home from a fishing trip with Walt Williams (who was my boss at NACA)… We heard on the radio that a 75,000 pound thrust Viking rocket engine was successfully fired at Santa Suzanna. Of course nothing would do but I got a piece of paper out of his glove compartment and we decided what we could do to man a plane with a 75,000 thrust rocket. That became the X-15. We gave that idea to Hilbert Drake who developed it in 1955. In that year the X-15 went under contract.

Crossfield described what they were trying to achieve at that stage of X-plane development and how it contributed to the drive toward space and eventually hypersonic travel:

The research airplane program’s primary goal was to develop technology that we could put to useful purpose – supersonic high-speed aerodynamics… We had plans to take us [all the way] into space. That was part of the long-range goal for the research airplane program. Unfortunately, that got diverted by many other circumstances.

The productivity of an airplane is gauged by its speed times its payload, divided by its fuel consumption. The way to get that productivity is to go fast. And the way to go fast is to go high. With the engines that we were developing in those days, we were trying to find out what it took to go high so that we could go fast and get the productivity that we needed for the air transport as we saw it at that time – and the way we see it today.

Unfortunately, we took a moratorium on that development for some years; but we are back on track today with the National Aerospace Plane, which is nothing more than an extension of the very successful research airplane program.

On his third flight on the X-15 Crossfield ran into longitudinal instability with pitch oscillation. Crossfield described his actions in the cockpit and how he responded to the problems with the aircraft:

Well, the checkout in the X-15 was rather abrupt in that, on our first flight, we flew it as a glider alone. That gave me three minutes and fifty-eight seconds to learn how to fly the airplane and bring it in for a landing.