This hulking great thing was developed in
1950 in response to a US Navy requirement for an
Anti-Submarine Warfare helicopter. This is the only tandem rotor
design produced by Bell.
In the event the award
went to Sikorsky with its HSS-1. Turns out the HSL-1 was so noisy
sonar operator couldn't hear the bleeps. Not only that but it
wouldn't fit on the elev-
most of the fleet carriers operating at the time. Three XHSL-1
prototypes were built
follow-on HSL-1s had already found their way into the Navy inventory
before its full
operational problems had been discovered. Several of these
were modified for mine sweep-
duties, whilst others became trainers.