, Thank you Cliff. It is a pugnacious but not unpleasant looking aircraft and from all accounts they flew well. There were about 300 of them (the production I-4) in service from about 1927 to 1937 and they were all metal at a time when most "advanced" western nations were still playing around with wood wire and cheese cloth aircraft types. The production types had three different wing planforms, this one, another with a smaller lower wing and one with no lower wing at all as used in Professor Vakhmistrov's Zveno (link) experiments in which a TB-3 bomber was modified to carry up to five smaller aircraft, one on top of each wing and one below each wing, and one either on top of or below the fuselage.
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Ross.