Hi all!
Some corrections from me. The
ANT-12 (I-5) fighter was projected from late 1927 to 1929, not in 1930. It was a counterpart of Polikarpov I-6 prototype. By the order, September 1929 was appointed as its rollout date, but the project wasn't completed. The works were abandoned, and the task was transferred to TsKB-39 NKVD special design bureau (where Polikarpov and Grigorovich created their well-known I-5, first flown at April 29, 1930). But it wasn't the end for ANT-12 project: engineer V. Rodionov suggested to continue project at free time, as a community work. Almost all TsAGI engineers undertook a commitment to work 70 hours free on this project, and it became known at TsAGI as
Obschestvennyi Samolet - "community plane" or "volunteer plane". It wasn't scheduled into official plan of prototype aircraft production, but at December, 1929 the UVVS issued a specification for it. Since then, the aircraft was classified as interceptor fighter and obtained a new official index -
I-8 (ANT-13)! So, ANT-12 and -13 are actually two stages of the same project!
The volunteer work resulted in
real prototype which was first flown at December 12, 1930 by Mikhail Gromov. The I-8 was tested until April 1932, but wasn't delivered to the official state tests because its performance was worse than required by the specification. Another reason was that I-8 was powered by foreign engine (Curtiss Conqueror).
Now about the
ANT-24: it was projected as a bigger version of TB-4 (ANT-16) with four (unrealized) powerful M-44 engines, 2000 hp each, instead of six 830-hp M-34. It was a precursor of giant ANT-26 (TB-6). The TB-4 specification was issued at March 1930, and the first flight was at July 3, 1933. And in March 1932 the production of ANT-26 prototype beginned - it means that design works were already completed. The ANT-24 was only a preliminary design, and I think it could be from early 1931.
ANT-30 (SK-1) was 4-seat "flying cruiser", further development of R-6 (ANT-7) and ANT-21 (MI-3); also a bomber version was projected.
ANT-46 (DI-8) was also twin-engined heavy fighter / cruiser, derived from SB (ANT-40), and it was
3-seat; only one prototype was built. See more about both these aircraft at
http://www.secretprojects.co.uk/forum/index.php/topic,7951.0/all.html.