Gyrodyne QH-50 DASH

https://en.wikipedia.org/wiki/Gyrodyne_QH-50_DASH

The Gyrodyne QH-50 DASH (Drone Anti-Submarine Helicopter) is a small drone
helicopter built by Gyrodyne Company of America for use as a long-range
anti-submarine weapon 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's Fleet Rehabilitation and
Modernization (FRAM) program of the late 1950s. FRAM was started because the
Soviet Union was building submarines faster than the US could build
anti-submarine frigates. 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-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 YO-95-6 72 hp
piston engine and carried one Mark 43 homing torpedo. 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 255 hp (190 kW) Boeing T50-4 turboshaft
engine replaced the piston engine and the payload was increased to two Mark 44
torpedoes. A total of 378 QH-50Cs were produced before production ended in
January 1966.


Role
ASW drone

National origin
United States

Manufacturer
Gyrodyne Company of America

First flight
1959

Introduction
1963

Status
In service as target tug

Primary users
United States Navy
United States Army
Japanese Maritime Self-Defense Force

Produced
1962–1969

Number built
755

Developed from
Gyrodyne RON Rotorcycle


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 (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 to develop a small, experimental co-axial helicopter, the RON Rotorcycle,
for use as a scouting platform. A co-axial helicopter has two contrarotating
main rotors to control torque, 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 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.

Since it was expendable, DASH used off-the-shelf industrial electronics with no
back-ups. The controls were multi-channel 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.

Specifications (QH-50C)

General characteristics
Length: 12 ft 11 in (3.94 m)
Rotor diameter: 20 ft 0 in (6.10 m)
Height: 9 ft 8½ in (2.96 m)
Disc area: 314.2 ft² (29.2 m2)
Empty weight: 1,154 lb (524 kg)
Max. takeoff weight: 2,285 lb (1,036 kg)
Powerplant: 1 × Boeing T50-BO-8A turboshaft, 300 hp (224 kW)

Performance
Maximum speed: 80 knots (92 mph, 148 km/h)
Cruise speed: 50 knots (58 mph, 93 km/h)
Range: 71 nmi (82 mi, 132 km)
Service ceiling: 16,400 ft (5,000 m)
Rate of climb: 1,880 ft/min (9.6 m/s)

Armament
2 Mk.44 or Mk.46 torpedoes



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