my father would often give me little things around the house to keep me busy, like accronyms to figure out. One day, he asked me to look up and tell him what the TLAR
bombsight was. Well, after countless hours of looking in Janes aircraft, and half a library later with no sucess, i finally gave in and asked him what it was.
Holding out his fist, he extended the thumb up and said " This is a TLAR bombsight" Some pilots actually used it in korea and viet nam: what they would do is hold their arm out, with their thumb up and level with the face, and when the target lined up with the top of the thumb, the range was just about there and the pilot would release his weapons. And that was the origin of the T
Incidently, according to him, clipped nails could throw you off a whole bunch....