Thank you Carsinamerica,
and for this later design,I never heard about it,look great,do you have a drawing to it ?.
The only interpretation I've ever seen was this sketch, which has been published in several books on the 747. It turns out I had the wrong numbers, though: the stretched double-decker carried 732 passengers on long-range service.
What I would dearly love to know about any of these four proposals is this: did Boeing intend to use the same wing on these stretches? The drawing seems to imply that the wingbox stayed the same, but I cannot imagine how, for example, the 50-foot
stretch variant could possibly use the same wing and engines as the 747-200B, not if they wanted it to fly appreciable distances.
These drawing still boggle my mind. That first stretch proposal is even larger than the 1996 747-600X, nearly three feet longer! It's the largest 747 proposal I know of.