(We've already watched a landing party from USS Juneau trying to blow up a tunnel on the coastal rail route from Vladivostok-Sonbon route.)
The crash investigators found that the number two propeller was indeed feathered. The cause of the problem was improper adjustment during maintenance on 22 July 1950, when all four propellers were changed. A problem was detected with number two during a test flight, and the ground crew was instructed to install new contactors. There was no paperwork indicating that this was done, and the entire maintenance crew was killed in the crash. The number three engine and propeller were not found. The generators were found to be working, so there was sufficient electrical power to retract the landing gear. No crew members recalled hearing the landing gear motors. The switches could not be checked due to the degree of destruction of the aircraft, but the fuse was intact. It was noted that there were only six seat belts for the ten men in the forward compartment.
Their report made four recommendations:
- That procedures regarding propellers be reviewed and improved so as to identify malfunctions on the ground;
- That more emphasis be placed on training pilots and flight engineers in procedures for handling propeller problems;
- That there should be better follow-up of maintenance problems; and
- That escape exits and tunnels should be kept clear of baggage.USAF B-29 operating procedures were changed as a result of the investigation; aircraft with the same type of propellers as 44-87651 were required to be test-flown after corrective maintenance, and the number of persons permitted aboard an operational flight was reduced to 16, as it was felt that overloading and an inadequate number of safety belts in the accident aircraft contributed to the high loss of life.
The idea that America had a "small" atom bomb in its arsenal in 1950 makes intuitive sense, but is, in fact quite wrong. A lump of fissile material will only achieve "prompt criticality" if the mean free path of a neutron through the lump is less than the dimensions of the said lump. In other words, the neutron has to pass through a volume occupied by plutonium/highly enriched uranium/other exotic material for sufficiently long as to encounter the neutron cross section of the relevant isotope. This will also depend on the density of the lump. This is kept low in the W 33/48, and, we assume, W 54, by separating the fission mass into one or more lumps and then combining them with an explosive. The W33/48 was a gun-type warhead designed for some degree of earth penetration in order to make craters in front of advancing Red tank armies. The W48, on the other hand, was a "hybrid gun-assembly/implosion design" based on a cylindrical "primary" originally developed for two-stage hydrogen bombs. Cylindrical designs are popular because it is easy to inject tritium axially, boosting
Finally, and of some interest here, is the development of a driving plate, which sounds to me like a tamper plate but isn't. An arrangement of metal plates ensures an instantaneous linear detonation and the best-shaped convergent high explosive jets. The W54, because it was so very small, was by far the greatest challenge for the weaponeers yet, since the time between reaching prompt criticality and disassembly had to be so small. So, at least on the technical side, congratulations on that!