DASH was a major part of the United States Navy's Fleet Rehabilitation and Modernization (FRAM) program of the late 1950s.
Instead of building frigates, the FRAM upgrade series allowed the US to rapidly update by converting older ships that were less useful in modern naval combat.
The original DASH concept was a light drone helicopter that could release a nuclear depth charge or torpedoes.
Each float could rotate 90° from horizontal, oriented to straight ahead, and incorporated a pad at the end for landing on hard surfaces.
The DASH came about because Gyrodyne had worked with the United States Marine Corps to develop a small, experimental co-axial helicopter, the RON Rotorcycle, for use as a scouting platform.
For the DASH role, the original marine version had a turboshaft engine for improved performance and the replacement of the seats and controls with a remote-control system and stowage for two Mark 44 torpedoes.
In this form the DASH could be flown up to 22 miles (35 km) from the ship, giving a submarine no warning that it was under attack, at least until the torpedo entered the water.
Until May 2006, a small number of QH-50D DASH drones were operated by the United States Army at White Sands Missile Range, where they were used to tow targets and calibrate radars and electronic systems.
Because the JMSDF regarded the DASH operation as highly prestigious and the aircraft were flown and serviced regularly, they suffered a much lower loss rate than the US Navy.
However, with the difficulty of maintaining DASH operations after the termination of the U.S. program, the drones and associated equipment were removed from JMSDF service in 1977.