Operational Use
In 1947, an entirely new 346 prototype was constructed, incorporating refinements suggested by the tests. This was designated 346-P ("P" for planer - "glider"). No provision was made for a powerplant, but ballast was added to simulate the weight of an engine and fuel. This was carried to altitude by a B-29 Superfortress captured in Vladivostok and successfully flown by Wolfgang Zeise in a series of tests. This led to the construction of three more prototypes, intended to lead to powered flight of the type.
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