The Gyrodyne QH-50 DASH (''Drone Anti-Submarine Helicopter'') is a small drone

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

built by

Gyrodyne Company of America Gyrodyne Company of America, Inc. is a real estate investment trust that owns, leases, and manages commercial properties along the Eastern Coast of the United States. Gyrodyne's headquarters are located in Saint James, New York, in Eastern Long ...

for use as a long-range

anti-submarine weapon An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapo ...

on ships that would otherwise be too small to operate a full-sized helicopter. It remained in production until 1969. Several are still used today for various land-based roles.

Design and development

DASH was a major part of the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Fleet Rehabilitation and Modernization The Fleet Rehabilitation and Modernization (FRAM) program of the United States Navy extended the lives of World War II-era destroyers by shifting their mission from a surface attack role to that of a submarine hunter. The FRAM program also cove ...

(FRAM) program of the late 1950s. FRAM was started because the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

was building

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

s faster than the US could build anti-submarine

frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and ...

s. 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 navy could upgrade the sonar on

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

-era destroyers but needed a stand-off weapon to attack at the perimeter of the sonar's range. The old destroyers had little room for add-ons such as a full flight deck. The original DASH concept was a light drone helicopter that could release a nuclear depth charge or torpedoes. The aircraft was considered expendable. The manned Gyrodyne Rotorcycle program of the mid-1950s provided prototype work for the DASH, and ultimately the Rotorcycle was modified to produce the initial drone version, the DSN-1/QH-50A The DSN-1 was powered by a

Porsche Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see #Pronunciation, below), is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany ...

YO-95-6 72 hp

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

and carried one Mark 43 homing

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

. The next developmental version was the DSN-2/QH-50B that was powered by two Porsche YO-95-6 engines and also carried a single Mk 43. Serial production of the DASH began with the third version, the DSN-3/QH-50C, in which a Boeing T50-4

turboshaft A turboshaft engine is a form of gas turbine that is optimized to produce shaftpower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust ...

engine replaced the piston engine and the payload was increased to two

Mark 44 torpedo The Mark 44 torpedo is a now-obsolete air-launched and ship-launched lightweight torpedo manufactured in the United States, and under licence in Canada, France, Italy, Japan and the United Kingdom, with 10,500 being produced for U.S. service. It ...

es. A total of 378 QH-50Cs were produced before production ended in January 1966. A single QH-50A, (DS-1006) was re-activated after contractor testing to verify the tilt-float landing gear. A long cylindrical float was added to each corner of the extended skid framework. Each float could rotate 90° from horizontal, oriented to straight ahead, and incorporated a pad at the end for landing on hard surfaces. For landing on water the floats were rotated to the vertical position and the helicopter settled until the floats were approximately 75% submerged."The Model QH-50A"
''Gyrodyne Helicopter Historical Foundation''. Retrieved: 22 May 2014

Operations

The DASH's control scheme had two controllers: one on the flight deck, and another in the combat information center. The flight-deck controller handled take-off and landing. The controller in the

Combat Information Center A combat information center (CIC) or action information centre (AIC) is a room in a warship or AWACS aircraft that functions as a tactical center and provides processed information for command and control of the near battlespace or area of op ...

(CIC) would fly DASH to the target's location and release weapons using semiautomated controls and radar. The CIC controller could not see the aircraft or its altitude and occasionally lost operational control or situational awareness. Late in the program, there were successful experiments to add a TV camera to the drone. These DASH SNOOPYs were also used as airborne spotters for naval gunfire. A tethered landing system was developed to land and take off in up to Force-6 seas. This system consisted of steel rails that were screwed to the flight deck and a cable system to pull the helicopter out of the hangar bay. The helicopter was attached to the steel rails so that it would not slide off the flight deck in heavy seas. This system was occasionally set up and used aboard ship, but never used in rough seas to launch a helicopter. The DASH came about because Gyrodyne had worked with the

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

to develop a small, experimental co-axial helicopter, the

RON Rotorcycle The Gyrodyne RON Rotorcycle (originally designated HOG) was a tiny, single-seat helicopter designed under contract for the United States Navy. in the mid-1950s. It later was redesigned for a U.S. Marine Corps requirement for a small personal he ...

, for use as a scouting platform. A co-axial helicopter has two contrarotating main rotors to control

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

, unlike the more common main rotor/tail rotor found on most helicopters. Co-axial rotors put more power into lift, allowing shorter rotor blades. Both traits help a helicopter to be as small as possible. On the downside, the blades must be kept very far from each other to avoid colliding, since the blades flex as they rotate. This leads to increased complexity and decreased maneuverability. For a drone, these trade-offs were fine. For the DASH role, the original marine version had a

engine for improved performance and the replacement of the seats and controls with a remote-control system and stowage for two

es. In this form the DASH could be flown up to from the ship, giving a submarine no warning that it was under attack, at least until the torpedo entered the water. Since it was expendable, DASH used off-the-shelf industrial electronics with no back-ups. The controls were multi-channel

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...

FM. Over 80% of operational aircraft losses were traced to single-point failures of the electronics. A total of 10% of the losses were from pilot errors, and only 10% of the losses were from engine or airframe failures. The DASH program was canceled in 1969 and withdrawn from service 1968–1973. DASHes proved unreliable in shipboard service, with over half of the US Navy's 746 drones lost at sea. This was possibly due to inadequate maintenance support, as other services had few difficulties with their DASHes. Although low reliability was the official reason, the manufacturer pointed to the expenses of the

Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...

, and the lack of need for antisubmarine capability in that war. Modified DASH vehicles continued to operate for several more years in the Vietnam War. With attached television cameras, they were used as remote artillery spotters and organic reconnaissance by their ships. Until May 2006, a small number of QH-50D DASH drones were operated by the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

White Sands Missile Range White Sands Missile Range (WSMR) is a United States Army military testing area and firing range located in the US state of New Mexico. The range was originally established as the White Sands Proving Ground on 9July 1945. White Sands National P ...

, where they were used to tow targets and calibrate radars and electronic systems. The

Japanese Maritime Self-Defense Force , abbreviated , also simply known as the Japanese Navy, is the maritime warfare branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. The JMSDF was formed following the dissolution of the Imperial Japanese Navy (IJN) ...

(JMSDF) operated a fleet of 20 QH-50 drones, for use on its ''Takatsuki''-class and ''Minegumo''-class destroyers. 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.

Variants

;DSN-1:U.S. Navy designation for nine pre-production aircraft, redesignated QH-50A in 1962. ;DSN-2:U.S. Navy designation for three pre-production aircraft, redesignated QH-50B in 1962. ;DSN-3:U.S. Navy designation for 373 production aircraft, redesignated QH-50C in 1962. ;QH-50A:DSN-1 redesignated in 1962, nine pre-production aircraft for evaluation, with a 72 hp (54 kW) Porsche flat-four piston engine. ;QH-50B:DSN-2 redesignated in 1962, three pre-production aircraft powered by two 86 hp (64.5 kW) Porsche flat-four piston engines. ;QH-50C:DSN-3 redesignated in 1962, production aircraft powered by a 300 shp (225 kW) Boeing T50-8A turboshaft engine, 373 built. ;QH-50D:production aircraft with a larger Boeing T50-12 turboshaft engine, fibreglass rotor blades and increased fuel capacity, 377 built. ;QH-50DM: There were 10 modified QH-50Ds manufactured (Serial number 150AO- 160AO). The "DM" 550shp was supplied by a modified version of the Boeing T50-12. These were used for military reconnaissance for the

during the Vietnam War. ;YQH-50E: Three QH-50D aircraft modified with

Allison T63 The Allison Model 250, now known as the Rolls-Royce M250, (US military designations T63 and T703) is a highly successful turboshaft engine family, originally developed by the Allison Engine Company in the early 1960s. The Model 250 has been pro ...

-A-5A engines. ;QH-50F: Proposed production version of YQH-50E, not built. ;QH-50H: Proposed twin-engine version of QH-50F with larger fuselage and rotors, not built.

Operators

; *

Japan Maritime Self-Defense Force , abbreviated , also simply known as the Japanese Navy, is the maritime warfare branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. The JMSDF was formed following the dissolution of the Imperial Japanese Navy (IJN) ...

; *

Surviving aircraft

Specifications (QH-50C)

References

Notes

Bibliography

* Apostolo, Giorgio. ''The Illustrated Encyclopedia of Helicopters''. New York: Bonanza Books, 1984. . * . * * Taylor, John W.R. ''Jane's All The World's Aircraft 1969–70''. London: Jane's Yearbooks, 1969. *

External links

QH-50 DASH History on Gyrodyne Helicopters site

QH-50 DASH in U.S. Navy Service

Gyrodyne DNS/QH-50 DASH Production List in helis.com database
{{lone designation, system=

USN The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...

Anti-submarine warfare drones pre-1962, designation=DSN H-50 1950s United States helicopters 1950s United States military utility aircraft Single-turbine helicopters Coaxial rotor helicopters Unmanned aerial vehicles of the United States Unmanned helicopters United States military helicopters Aircraft first flown in 1959