I just started this thread to see if anyone had any factual info on this drawing and the 851 moniker. In lieu of actual knowledge I'm interested in educated guesses. But it seems like a few replies are from those who view their guesses as cold hard facts. Guesses are fine, just say so, no need to embellish. The only documents or links posted have been by me, but feel free to provide your own supporting documentation.
Participating in this thread is voluntary, no need for egos, we're all good here.
Participating in this thread is voluntary, no need for egos, we're all good here.


















































