A projected modification of the I-1 for ground attack duties.

AG-1 - Wing .30 cal ShKAS machine guns
AG-2 - Oblique .30 cal UltraShKAS machine guns

History:
An attack aircraft armed with machine guns. Originally it was designed to use 10 ShKAS machine guns, but later, from the opinions of the weapons builders Mozharovski and Venevidov, the weaponry was replaced by a pair of UltraShKAS machine guns with a rate of 10,000 shots per minute (!) located on the lower deck of the rear fuselage and covering in a salvo a strip of land of about 25 meters.
- https://www.ecured.cu/Boljovitinov_S

In a drawing of four I-1 variants, the I-1Sh can be seen as the second one from the top. Drawing can be found here - http://survincity.com/2010/12/i-1-2hm-107-far-fighter-the-project-bolkhovitinov/