Sunday, September 16, 2012

First X-15 Powered Flight 53 Years Ago Today


I've always been in love with the X-15, the most successful Research Aircraft of all time. As a little boy of 10 years old, I built *every* model of it I could find. I built just the X-15, and the kit that was the NB-52 Carrier Aircraft, with a little 4" removable X-15 that you could pop off the pylon and "fly" away while your other buddies played "Chase-1" and "Chase-2" with models of the F-100 Super Sabre and F-104 Starfighter, leaving your 4th buddy to lumber around "flying" the now lonely NB-52 back to your "base".

September 17th will mark the fifty-third anniversary of the X-15's first powered flight.

There were a total of 3 aircraft built, known by their tail numbers of 66670, 66671, and 66672.

At first the aircraft were powered by a pair of XLR11 rocket engines, which were the same engines used in the Bell X-1 due to the much more powerful XLR99 engine being behind schedule.

It was the first aircraft to routinely exceed  100,000 feet, and towards the end of the program, it routinely flew at 200,000~250,000 feet.

The record altitude for the X-15 was 354,200 feet, a record that stood for FORTY ONE years, until Brian Binnie in SpaceShipOne exceeded in 2004 by achieving and altitude of 367,441 feet.

In terms of speed, the X-15 was the first aircraft to exceed Mach 4, Mach 5, and Mach 6, with its fastest flight being Mach 6.72, or 4520 MPH.

The Mach 6.72 flight was flown by the X-15A-2, a modified version of the #2 aircraft, shown above, wearing it's ablative coating.

This is 6630 feet-per-second, nearly THREE times as "Fast as a speeding bullet". The aircraft was damaged by local heating, suffering several burnt-through areas on its lower (ventral) stabilizer. Although North American rebuilt the aircraft, it never flew again, and the program was terminated after 199 flights.

A typical flight would have the X-15 carried aloft by the NB-52 to 45,000 feet and Mach .85, and then released. The pilot would light the engine, and then fly a very precise profile for either a high-speed, or high-altitude flight. High-altitude flights typically released the X-15 in the vicinity of Wendover, Utah, while high-speed flights would release the X-15 in Northern Nevada. The ground track was 300~400 nautical miles, depending on flight profile, and the aircraft landed, dead-stick, approximately 8 to 12 minutes after release.

That's right, only eight to twelve minutes for the entire flight, from release to landing!

And the landing was unpowered, "Dead Stick", with a descent rate of 12,000 feet-per-minute, and a glide angle of 12*~20*, at 200~300 knots, depending on where the aircraft was in the landing pattern.

Ten men flew the X-15, and one gave his life exploring the unknown realm of high-speed, high-altitude flight in this aircraft.

They were:
Mike Adams, USAF
Neil Armstrong, NASA
Scott Crossfield, North American Aviation
Bill Dana, NASA
Joe Engle, USAF
Pete Knight, USAF
Jack McKay, NASA
Forrest Petersen, USN
Bob Rushworth, USAF
Milt Thompson, NASA
Joe Walker, NASA
Bob White, USAF

These were very brave men, pushing forward the frontiers of flight. I'm honored to have known, and worked with, Pete Knight.

While the "Mercury Seven" were getting all the 'good press', benefits, and public adoration, the men who flew the X-15 were basically unknown, although several  of them would go on to other programs, and one into the history books.

The X-15 was really America's first operational spaceship, and collected much needed data about hypersonic  and high-altitude flight. Much of this information helped solve problems with the Space Shuttle, and validated or corrected, theoretical data from earlier wind tunnel research.

I find it amazing that this aircraft was flying 50 years ago, and data collected during the program are still useful.

And I find it even more amazing that we no longer have any programs of this sort operating.

The follow-on/concurrent program to the X-15 was to be the X-20 Dyna-Soar, but interagency politics )USAF vs NASA) and Robert Macnamara killed that one.

If the X-20 program had come to fruition, we would have had a fully functional, reusable, spaceplane flying ten to fifteen years before the Space Shuttle.

But that's a story for another day.....



  1. I built lots of models as a boy, and the X-15 was one of the first. First time we saw an SR-71, it looked very familiar ... said to my sailor buddies, "I know where THAT one came from."

  2. yep, I built my share of SR-71 models, too!
    I spent something like EIGHT MONTHS building up that large one that Testor's made.
    Revell or Monogram, or somebody made a very large (24" long?) X-15 that I always wanted to build, but I can't seem to find who made the kit.
    Oh,'s not like I need ANOTHER hobby or anything....;-)


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