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 .
The plaque reads: THE ORIGINAL WRIGHT BROTHERS AEROPLANE: The world's first power-driven, heavier-than-air machine in which man made free, controlled and sustained flight, invented and built by Wilbur and Orville Wright flown by them at Kitty Hawk, North Carolina December 17, 1903.