JBirdAV8r From United States of America, joined Jun 2001, 4500 posts, RR: 19
Reply 1, posted (12 years 9 months 5 days 22 hours ago) and read 3570 times:
Whenever Boeing dreams up a new airplane design, they assign a letter as the middle value. When the project is finalized, a numerical value is assigned. The 7N7, 7X7, etc. were all predecessors to today's designs.
Someone in here is probably better suited to answer the question more in-depth, but I think that's the jist of it!
NDSchu777 From United States of America, joined Oct 2001, 419 posts, RR: 3
Reply 2, posted (12 years 9 months 5 days 21 hours ago) and read 3554 times:
My guess is that once the airplane is given the final go-ahead and there are real orders for the plane, it will be re-named the Boeing 787. I believe the 777 was the 7J7 at one point and Airbus even has a similar system. The A380 was the A3XX during its conceptual phase.
Areopagus From United States of America, joined Sep 2001, 1379 posts, RR: 1
Reply 3, posted (12 years 9 months 5 days 16 hours ago) and read 3418 times:
7N7 became 757
7X7 became 767
7J7 was a ~150-passenger propfan proposal abandoned in 1987 due to lack
of customer interest
7S7 was a proposed design, but I don't remember particulars and Google doesn't help much