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Developed in 1937 from the I-15 at the Moscow Aircraft Plant No 1, the I-15bis( bis meaning Mk 2) or the I-152 as it was known, never fully satisfied the Soviet air force's requirements, however it did prove to be an extremely robust aircraft which made ideally suited for the testing of Merkulov's new auxiliary ram jet engines. In December 1939 test pilot P. Loginov started testing a I-15bis biplane fitted with two Merkulov DM-2 ramjets fitted under the lower wings. This aircraft was a flying laboratory for Soviet ramjet development, in which, at the time it lead the world. The first five flights of the I-152DM (Dopolnityelnyi Motor) perfected the start up techniques for the ramjets and during the subsequent flights the speed increment was measured with the ramjets operating at around 20 km/h. Improvements aimed at reducing starting time, enhancing combustion and cutting the excessvie fuel consumption were investigated in the aircraft's 54 flights, which were performed with out damage to the I-15bis |
