The "swing-tail" (hinged) tail section concept was successfully utilized by the Flying Tiger Line some years back, when they used the Canadair CL-44 turboprop, based upon the Bristol Brittania aircraft, to carry cargo. Unlike the "Ultimate Guppy", the tail section opened hydraulically and was not dependent upon ground-based equipment to move the tail section. (see Google/Wikipedia for additional details.)
There are a few "alive and healthy" R-2800s around! :-) The 2800s were used on the C-54/DC-4s, and the Berlin Airlift Historical Foundation has one in great shape. (They have a web site.They fly to various air shows throughout the year, etc.) I agree. The sound of that smooth 2800 was music!
Yeh. I remember the first time they landed a newly-bought empty 990 into FMY, longest runway 5000'. They got it stopped, but barely. Over the fence for that bird was about 165-170 kts., equivalent to a fighter. Gulf American paid for putting an additional 1000' there at Page, but even that didn't help. Density Altitudes in FL go UP on warm days, and they could not carry more than a very light load. So, they wound up flying the 990s into TPA. ---This was in 1967, I think. Fade out, fade in. I wound up working for Flying Tigers at ORD in 1974, and what did I see resting by one of the alert hangars alongside The Naked City's Comet? One of the 990s.And it sat there for several more years. :-)
Boy, were both of these airplanes noisy! I worked in ATL at the old airport when UA flew them on the other side of the concourse (from NW), and they were sometimes painful to hear unless one was insulated in some manner from their compressor whines.