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 .
SINCE that blustery, gray mid-day in December of 1903 on the Outer Banks of North Carolina when The First Flight was accomplished by one of the Wright brothers in a powered, heavier-than-air controllable aeroplane, pretenders and contenders have risen up, each like a mythical Phoenix, to claim the laurels of being the first aviator of powered flight ...