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 .
In a startling announcement a few days ago, Jane's All the World's Aircraft has named an August 1901 flight by Connecticut aviation pioneer Gustave Whitehead as the first successful powered flight in history, beating the Wright Brothers by more than two years.