propfan md i read that during a period of unusually high fuel costs md built one with propfan engines these look like turbofans but with a propellor attached to the rear they are known for their effeicency after some initial hype no orders came and the model i believe it was a one off more of a demonstrator than anything else was scrapped there has been intermitent talk of using propfans on civil aircraft since then but it has not come to anyhting