How has the helicopter changed since it was invented?

Why did Tecumseh decide to join the british? What were the goals of the radical reconstruction program? What was the Battle of Truk during World War 2? What did soldiers in the US Civil War live in? Prior to 1930 what group of people was eligible to vote but not afterwards due to discrimination? How did the Russian withdrawal help the Germans? Why do children go to war? Why did Pontiac stage an uprising in 1763? What started started World War 2? How did the locations of Hawaii and Midway make them important islands to Japan and the US in World War 2? What were the army of the north called in US Civil War? Which theather of Wolrd War 2 was associated with the invasion of Sicily? What was the nickname given to ypres during World War 1? What country had the biggest influence in World War 2? Why did Mary seacole help people in the war? What was a major of weakness the British military early in World War 2? Why did the boar war start? What impression of American soldiers does the narrator tell about the beginning of the story in we Filipinos are mild drinkers? How did hilter died? Who was the General that came up with the Idea of Convoys?