allow each blade to move forward and aft and relieve in-plane stresses, generated as a byproduct of the flapping motion. This development led to the Cierva C.8, which, on 18September 1928, made the first rotorcraft crossing of the English Channel followed by a tour of Europe.

United States industrialist Harold Frederick Pitcairn, on learning of the successful flights of the autogyro, visited de la Cierva in Spain. In 1928, he visited him again,