Originally Posted by
treadigraph
Got a source for that Euan? Most pages I looked at suggest 22 February '75 as the first flight date for T8-1, design and mock up had been completed in 1972 and prototype completed in late 1974. Concept dates back to 1968.
Sorry, Treadi, my books are all in storage, so I cannot tell you exactly, but IIRC it was one of the Yefim Gordon books on the type. If I am wrong on the dates, then I will of course retract that portion of my post!
However, if the various sources agree that the design and mockup was complete by 1972, and that the T8 design (1968) served as the basis for it, then the historical facts still strongly argue against the suggestion that the Su-25 was a copy of someone else's design.