Skybolt (missile)

Skybolt
A Skybolt at the Glasic Air Force Museum, Avoca
Type	Medium-range, Semi-Active Homing air-to-air missile
Place of origin	Tír Glas
Service history
In service	1972 – present
Used by	See operators
Production history
Manufacturer	• XYZ: 1968–94 • GAIA: 1994–present
Produced	1968-1991
Variants	Skybolt I, IA, II, III, IIIA, Skybolt 90
Specifications
Weight	510 lb (230 kg)
Length	12 ft (3.7 m)
Diameter	8 in (200 mm)
Warhead	High explosive blast-fragmentation • Skybolt I, 66 pounds (30 kg) • Skybolt IA, 86 pounds (39 kg) • Skybolt III, 88 pounds (40 kg)
Detonation mechanism	Proximity/impact Fuze
Engine	Solid-fuel rocket motor
Wingspan	42 in (1,100 mm) Skybolt I and II
Operational range	• Skybolt I: 45 km (24 nmi) • Skybolt II: 60 km (32 nmi) • Skybolt III: 75 km (>38 nmi)
Speed	Mach 4 (4,900 km/h; 3,045 mph)
Guidance system	• Skybolt I Semi-active radar homing • Skybolt II and III Inertial guidance Mid-course update Active radar homing

The Skybolt is a medium-range air to air missile derived from the Dayanese Sparrow missile. In use since the 1970s little of the basic design remains in the variants still fielded.

Skybolt was initially simply to replace the seeker for the Sparrow with a Brennan-Brown semi-active monopulse seeker, this soon developed into a more involved set of changes including the substitution of Dayanese avionics with systems from Collins and the replacement of the fuzing system with a Foley-designed radar-fuze. Monopulse seekers are more accurate, less susceptible to jamming and better able to discriminate targets from ground clutter at lower altitudes. The BB seeker offered significantly better performance than the original seeker allowing XYZ initially to dispense with warhead improvements carried out by Dayashina to address a lack of accuracy.

Skybolt was tested in Dayashina against domestically produced monopulse-equipped Sparrows, In the end the Dayanese elected to use a different seeker than Skybolt for their later marques of Sparrow. Skybolt would go through a variety of upgrades before in the 1990s being supplanted by the lighter but more capable Black Spear also designed by XYZ.

History and development

Skybolt came about from a Glasic plan to fit an inverse monopulse seeker to the Red Top missile in the abortive Blue Dolphin which left a requirement still to be fulfilled. Various options were studied with the Dayanese Sparrow being the preferred choice and by 1968 test firings of the missile were taking place. Major differences between Sparrow and Skybolt were the addition of the monopulse seeker, improved electronics and avionics, improved control surfaces an active-radar fuze and modified rocket motor essentially making the Skybolt a new missile.

Test firings showed that the Skybolt could function properly in a high-ECM environment at both high and low altitude, it could be launched from as low as 100m to attack higher-altitude targets or from higher altitude at targets as low as 75m. The missile entered ARTG and CRTG service in 1972, by this time featuring a dual-pulse motor and larger 39kg warhead.

By 1985 Skybolt II was about to enter service which provided a step change in capability from previous iterations of the missile in that it featured solid-state electronics throughout, an active-homing seeker with inertial mid-course guidance a tapered boat-tail fuselage, thinner control surfaces with electronic actuation and a larger rocket motor. Events would overtake Skybolt II with Skybolt III taking its place. This had all the aforementioned improvements afforded by Skybolt II but also included the deletion of the mid-body fins, further improvements to the electronics and avionics as well as slightly a slightly larger warhead and rocket motor made possible by the deletion of the mid-body fins and shrunken electronics package. This would be the penultimate Skybolt in service with an improved Skybolt III adding thrust-vectoring, an mmW seeker and better ECCM capabilities to the missile. Skybolt 90 would have improved on this further with a dual-seeker and further ECM hardening but development shifted toward a new missile which would become Black Spear.

In 2002 the ARTG announced the launch of the Capability Upgrade and Sustainment Programme or CUSP which replaced obsolete and out-of-production subsystems of Skybolt with those from Black Spear essentially providing the missile with a life-extension into the 2010s.

Variants

	Skybolt I	Skybolt IA	Skybolt II	Skybolt IIA	Skybolt III	Skybolt 90
Length	3.7 m (12.1ft)	3.68 m (12ft)	3.66 m (12ft)
Wingspan	1.02 m (3.3ft)				-
Finspan	0.77 m (1.9ft)
Diameter	0.210 m (8.2in)
Weight	200kg (441lbs)		230kg (507lbs)		225kg (496lbs)
Speed	Mach 4				Mach 4.5
Range	30km (16.1 nmi)	45km (24.2 nmi)	60km (32.3 nmi)		70km (37.8 nmi)
Propulsion	HAJ Swift boost-glide motor	HAJ Swallow dual-pulse motor			HAJ Skylark multi-pulse motor
Warhead	30kg (66lbs) Continuous Rod	39kg (86lbs) Fragmentation			40kg (88lbs) Fragmentation

Foreign developments

Socialist Republic of Menghe

In 1992, Tír Glas issued Menghe a production license for a composite Skybolt design. This export model had solid-state electronics in the guidance system, but retained the SARH seeker head and heavier fins of the Skybolt IA. As on the Skybolt IA, it had a 45-kilometer range and a 39 kg fragmentation warhead.

Within Menghe, this missile was designated YGG-6 (6식 공대공 유도탄 / 六式空對空誘導彈, ryuk-sik gongdaegong yudotan, "Type 6 air-to-air missile"). On entering service, it was integrated with the DS-5M and SR-7G1 fighters, and it was later integrated onto the SR-8, SR-9, and DS-10. Though less capable than contemporary Skybolt models, it was a generational leap over the preceding YGG-3, and was well-received by Menghean pilots.

The YGG-6 served as the basis for the development of the YGG-7 Hwasal, which incorporated an active radar seeker, a dual-pulse motor, and a mid-course datalink. Despite initial rumors that the Hwasal used Skybolt II's seeker head, the seeker and control surfaces were of domestic Menghean design.

Operators

Current Operators

Tír Glas

• Royal Glasic Air Force (ARTG)
• Royal Glasic Navy (CRTG)

Tír Tairngire

• Royal Tairngiric Air Force (ARTT)

Former Operators

Tír an crainn

• Royal Crainnic Navy (CRTC)

Tír Ealga

• Royal Ealgan Air Force (ARTE)
• Royal Ealgan Navy (CRTE)

Tír Tairngire

• Royal Tairngiric Navy (CRTT)

Socialist Republic of Menghe