The Robinson R22 is a reference in civilian helicopters. It is a two-bladed helicopter that can carry only one passenger in addition to the pilot. Its low-power engine makes it a fairly hard helicopter to fly for a pilot who is still in his early stages of learning. But it has low operating costs, which makes it popular with flight schools.
In a sense, it is the little brother of the famous Robinson R44, bigger, more spacious, and more powerful too. It's one of the most popular helicopters in UK flying clubs and on Wingly.