Original sentence: After a series of modifications, by May, the engine was placed in the classic position, at the lower end of the rocket, to simplify the plumbing.By September 1931, his rockets had a classic aerodynamic appearance of a smooth casing and tail fins.It was a misuse of Goddard's talent, but some of the ideas he developed found their way into the Bell X-1 and Bell X-2 rocket planes, the Navy's Viking sounding rocket and the Navy's Vanguard rocket that put the second US satellite into orbit
Edited sentence: After a series of modifications, by May, the engine was placed in the now classic position, at the lower end of the rocket, to simplify the plumbing.By September 1931, his rockets had the know familiar appearance of a smooth casing and tail fins