Topic's name was changed to include all non-standard and strange designations from Lockheed.
Please note that the L- designations have nothing to do with the early L- series which became the CL- series.
BLACKBIRD prototypes, early studies and related programs
A-1 ARCHANGEL II development of U-3 project
A-2
A-3 CHERUB I
? CHERUB 2
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-11
A-12 CYGNUS, also dubbed the "TITANIUM GOOSE" (Project OXCART)
AF-12 "THE THING" two-seat air defense interceptor variant; officially designated as YF-12A (Project KEDLOCK)
RB-12 proposed bomber derivative of A-12
M-12 "MOTHER GOOSE", redesignated as M-21 and used as a carrier aircraft for D-12 > D-21 (MD-21 combination)
R-12 UNIVERSAL, initial project for a reconnaissance version of M-12
RS-12 reconnaissance/strike version of M-12 which led to the RS-71, itself redesignated as SR-71
D-12 "LITTLE WHIZZER" drone, initially called Q-12; ; redesignated as D-21 as part of the MD-21 combination (TAGBOARD program)
Q-12 early designation of D-12
Other projects of the same period were the B-2, GUSTO I, RAMJET KITE and "PETERBILT" tow plane project.