![The Lockheed D-21, a Mach 3.3 Drone intended for launch from the SR-71 Blackbird : r/EngineeringPorn The Lockheed D-21, a Mach 3.3 Drone intended for launch from the SR-71 Blackbird : r/EngineeringPorn](https://preview.redd.it/saw-this-next-to-an-sr-71-and-it-looked-like-this-had-no-v0-szgmfb1vegx91.jpg?auto=webp&s=893e016a56891195c5b08062841eb412e12b8c7a)
The Lockheed D-21, a Mach 3.3 Drone intended for launch from the SR-71 Blackbird : r/EngineeringPorn
![Flying Atop SR-71 Blackbird, Meet US' Top Secret Spy Drone That No One Knew Existed Until It Was Abandoned Flying Atop SR-71 Blackbird, Meet US' Top Secret Spy Drone That No One Knew Existed Until It Was Abandoned](https://eurasiantimes.com/wp-content/uploads/2022/06/US-Supersonic-Ramjet-Powered-Spy-Drone-D-21.jpg)
Flying Atop SR-71 Blackbird, Meet US' Top Secret Spy Drone That No One Knew Existed Until It Was Abandoned
![Gerry Doyle on Twitter: "did you know: much as the u.s. tried to build a mach 3 reconnaissance drone, the d-21, around the sr-71's mighty j58 engines, the soviet union built the Gerry Doyle on Twitter: "did you know: much as the u.s. tried to build a mach 3 reconnaissance drone, the d-21, around the sr-71's mighty j58 engines, the soviet union built the](https://pbs.twimg.com/media/DpxJepYUcAAjmxK.jpg:large)
Gerry Doyle on Twitter: "did you know: much as the u.s. tried to build a mach 3 reconnaissance drone, the d-21, around the sr-71's mighty j58 engines, the soviet union built the
![Flying Atop SR-71 Blackbird, Meet US' Top Secret Spy Drone That No One Knew Existed Until It Was Abandoned Flying Atop SR-71 Blackbird, Meet US' Top Secret Spy Drone That No One Knew Existed Until It Was Abandoned](https://eurasiantimes.com/wp-content/uploads/2022/03/Sr71_Blackbird-e1655034642232.jpg)