Complex sentence: Nineteen R engines were assembled in a limited production run between 1929 and 1931, and valuable experience was gained by Rolls-Royce and Supermarine designers for use in the development of the Rolls-Royce Merlin engine and the Spitfire.
Split into simpler sentences: Nineteen R engines were assembled in a limited production run between 1929 and 1931. The experience gained by Rolls-Royce and Supermarine designers was invaluable in the subsequent development of the Rolls-Royce Merlin engine and the Spitfire.