1 Discard any hammer with mushroomed or chipped face or with cracks in the claw or eye sections. 2  Wear safety glasses or goggles, or a face shield (with safety glasses or goggles).  Strike a hammer blow squarely with the striking face parallel to the surface being struck.
The first jet airplane was the Heinkel He 178 made in Germany in 1939, right before the outbreak of World War II .
T he first successful rotorcraft was a gyroplane, designed by Sr. Juan de La Cierva in Spain and flown on 17th of January, 1923. His success created much interest world wide and led to the development of the first successful helicopter, the Focke-Wulf, Fw 61 which was first flown in June of 1936 in Germany.In 1933, the Focke-Wulf Co. built Cierva C.19 and C.30 gyroplanes under license.is success created much interest world wide and led to the development of the first successful helicopter, the Focke-Wulf, Fw 61 which was first flown in June of 1936 in Germany.