It would be interesting to know how some of these drawings were used at the time - were they presented to airlines or just floated in the press? Assuming that the proportions are depicted accurately, some of the 473 layouts are so ridiculous that it's hard to believe Boeing was seriously considering them. The engines on the 473-3x drawings are so far outboard that, according to my uncalibrated eyeball, the airplane would be uncontrollable after an engine loss. The vertical tails don't seem unusually large to compensate. Combined with the fact that the pairing into pods makes a total loss of thrust on one wing more likely, the engine arrangement alone makes these configurations suspect.
The high-wing layout without visible landing gear fairings on the fuselage implies the use of bicycle landing gear (I've seen this depicted elsewhere) with all it's weight, volume and handling penalties. Only the East Germans went this route and even they probably knew better.
My guess is that these drawings were feints designed not to fly but to reassure Convair, Lockheed and especially Douglas that Boeing wasn't serious about a jetliner or was pursuing a low-investment, low-risk compromised approach rather than a game-changer. I wouldn't be surprised to see tanker versions depicted since that would make the feint more believable - or maybe that would have invited ridicule by the USAF. Everyone in the industry seemed to accept that jets were coming someday, but Douglas and Lockheed (the industry leaders) had recently launched the last generation of piston-engined airliners (DC-7C and L1649) and hoped to recover their investment before launching into new development programs of unprecedented scale. Both would probably have, at most, preferred to offer low-risk, low-investment turboprop developments of these airframes.
If they were feints, they worked since Boeing gained a first-mover advantage which they never really lost (at least in the American industry). Douglas was caught flat-footed peddling the DC-7D and had to break the bank to develop the DC-8. Convair was compelled to pioneer a non-viable niche (smaller, faster and shorter-ranged) and Lockheed missed out on the first generation.
Boeing, with it's big jet bomber experience and weak position but long history in airliner business, was the obvious candidate for a game-changing jetliner. I'd bet that these drawings were intended to lull the competition into complacency.
Boeing B-47 development as airliner.JPG
