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 .
Wilbur and Orville Wright are credited with the creation of the first self-powered and piloted airplane. The two brothers tested numerous aircraft designs before they successfully built and flew their airplane in 1903. The first plane used a propeller to maintain movement and flight.