In the CF we called it "Beta". It was sometime ago but I don't think we had to go as far as 20 degrees. I think it was in the order of 12-14 degrees on the Twin Otter. Very easy to get. First idle power then a twist of the throttle grips and pull the power levers back and "Hey Presto" you have Beta.
Very good for STOL landings, IF you get it right. If wrong you would get Beta in the air (about 3-4 feet AGL) and the result was a very heavy landing
