Friday, May 22, 2009

Joe Engle and the X-15

I had the pleasure of attending Joe Engle's lecture at the National Air and Space Museum last night. Engle spoke on the X-15's role in expanding our understanding of hypersonic and high-altitude flight.

I was fascinated by the X-15 when I was a kid and the program was in full swing in the early 1960's. For my money, there was never another aircraft or spacecraft that embodied pure speed. Sure, it was technically an aircraft, but let's face it - this was a rocket with wings!

As a kid, I focused on the X-15's altitude and speed records. What I was not aware of was how important a role the X-15 played in the evolution of the Space Shuttle in unpowered flight. Engle put up a chart that showed how similarly the X-15 and the Space Shuttle behaved in their approach and landing characteristics, without engine power. One of the key lessons from the X-15 program was energy management - how to bleed off speed while the aircraft drops like a rock, set up an approach, and make a precision landing at about 200 mph.

Engle had some great stories, too. My favorite was his discussion about how the cockpit windows would occasionally "glaze" - the expansion of the airframe from frictional heating would sometimes shatter one of the two windows. In such a situation, the pilot would set up an approach where he would look out the other window. If both windows were to glaze, the planned procedure was that the chase plane would talk the pilot down to a safe altitude, at which time he would jettison the canopy. Engle said he lived in hope of this happening to him on one of the flights. He even carried a silk scarf in his pocket to tie around his neck. He thought it would be great to come back from a hypersonic flight in an open cockpit, wearing his silver space suit with a scarf blowing in the wind!

Engle graciously signed autographs after the lecture. I was able to complete my crew signatures on the 2TV-1 Beta cloth patch shown in the previous post about Vance Brand. I can't imagine a starker contrast than what Engle must have felt between the short hypersonic X-15 flights and being Earthbound for 8 days sealed in a vacuum chamber!

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