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 .
They transported their aircraft in pieces to Kitty Hawk in the autumn of 1903, assembled it, made a few further tests, and on December 14 Orville made the first attempt at powered flight. The engine stalled during take-off and the plane was damaged, and they spent three days repairing it.