A few weeks ago I flew down to NASA Dryden to attend a scramjet talk (Allan Paul came over from Australia to talk about his recent successes). We had some time to burn before the talk and the civil servant who was our host asked if we wanted to look at the SR-71s. Naturally we said "yes" with enthusiasm. None of the SR-71s at NASA Dryden are operational (they're too expensive to fly). They're all waiting to be gutted of classified hardware and then sent off to museums. While I was kicking the bald rotten tires of one of these magnificient airplanes, I was told the operational speed was in fact only a little bit above Mach 3. The SR-71 could fly faster but didn't for reasons of safety. While looking at the SR-71, we were asked if we'd be interested in seeing the D-21s. The immediated response was "Is the Pope Polish? What a silly question. Of course we want to see the D-21s!"

We were driven out to an obscure part of NASA Dryden where they had four D-21s. Three of them were still mothballed, but one was open for inspection. The D-21 is a ramjet powered supersonic drone that was designed to ride piggyback on the SR-71's ancestor (A-11?). The one and only attempt to launch a D-21 from an SR-71 type aircraft ended up wrecking both vehicles and killing some people. From then on the D-21s were launched from B-52s and used rockets to propel them to their operating point. The D-21 is a ***very cool*** design. It has a titanium exterior and uses the same basic inlet as the SR-71. The D-21 has an afterburner/combuster based upon a single titanium(?) nozzle (no spring loaded turkey feathers aft of the afterburner like the SR-71). The ramjet is just a straight pipe as one would expect. I believe the D-21 power plant was made by Marquat (sp?). I asked what was being planned concerning the D-21 and was told there were asbestos issues that prevented work on it. I then expressed some opinions using four-letter words about the intelligence of people preventing use of the D-21 simply because it had some asbestos on it.

Gary