Supposedly, some D-21s are Google Earth visible in the boneyard in Arizona. Dunno if they ever flew any operational spy missions as designed.
The on board self defense fighter probably made sense at one time when bombers had enormous range and needed a way to fend off enemy interceptors once near the target. Hard to see the little XF-85 taking on a Mig, but proof of concept is just that. Think it was tried with the B-36 with a larger fighter.
Still a twitchy deal flying near a large aircraft turbulence. heck, ATC even warns of flying near where a large plane was some time before, let alone flying underneath the damn thing!
I know the missions were very different, and the lack of a pilot in D-21 was a huge difference.
My point was that the Air Force was stuck on this idea of an aircraft launched from another aircraft for a lot of years. They spent an enormous amount of resources pursuing it. It never worked out.
I guess in-flight refueling changed the whole game on that idea, and it seemed to have been put to rest.
In-flight refueling must have been a very big deal back when it was developed.
I wonder if one of the reasons the USAF pursued the “parasite” concept so doggedly was institutional rivalry with the Navy. If the Navy can launch airplanes from ships, the Air Force maybe thought “we should be able to launch airplanes from airplanes.”
Supposedly, some D-21s are Google Earth visible in the boneyard in Arizona. Dunno if they ever flew any operational spy missions as designed.
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Wiki says it flew 4 missions over China, launched from B-52’s, and then retired around 1970.
Moonman has it right, IIRC. The D-21 was originally intended to be carryed on the back of the SR-71, but in a test they nearly lost the Blackbird mothership. The USAF went for the B-52 as the carrier/launcher instead. When all this was going on the biggest unknown was Red China’s nuclear testing and ballistic missile range at Lop Nor, deep in western China.
The Taiwanese were running U-2 overflights (and lost several), so the D-21 was chosen to fill the gap.
Supposedly, the Chinese sent the US a panel from a D-21 that departed from it’s original flight plan and was lost.