I know this has been asked a thousand times but I can't find it in the archives. Can anyone email me or post ALL BT Flat Model designations with acknowledged production numbers for each year. Does someone have a simple chart on one single piece of paper? Yea I know U, UL, UH and ULH but also UA and I have seen somewhere 2 or 3 other designations (UM?) Is there a registery for our motors? Thanks.