Aigios Viper
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| Aigios Viper | |
|---|---|
| <imgur w="350">VaU0hsb.png</imgur> | |
| Role | Interceptor, air superiority and multirole combat aircraft |
| Designer | Aigios Defence |
| First flight | 20 June 1971 |
| Introduction | 12 February 1974 |
| Status | In service |
| Primary user | Republic Air Force Republic Navy See Operators |
The Aigios Viper is a Belfrasian supersonic, two-seater Variable-sweep wing fighter aircraft in service with the Republic Air Force and Republic Navy along with various foreign export partners. The Viper was developed to replace the Continental Reaper for the Republic Navy after five years of service, and until 2014 in the Republic Guard.
Design and development
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In regards to the development of the Viper, it was more straight-forward than most others. The two primary customers would be the Republic Navy and the Republic Air Force. The former wanted a super-sonic interceptor capable of filling the roles of escort attack in 'spearing' attacks into enemy air convoys to destroy hostile bombers or to perform a loitering fleet defence role for prolonged periods of time. The latter, the Air Force, wanted a fighter capable of conducting a two-stage interception role; Where it would move to an assigned area and loiter until assigned to intercept specific targets as part of the country's strategic defence initiative. The resulting Viper FG.1 was capable of filling all of these roles and also provided modular installation in the Radar Intercept Officer (RIO's) console, allowing the plane to fill the roles of a bomber aircraft with the installation of guidance systems as appropriate.
The Viper was originally equipped with twin Sentennei CH-24 engines that were capable of accelerating the aircraft at full load to Mach 2.34 and manage a near-vertical ascent to 20,000 ft from take-off. The engines also had a decent economy setting to allow the aircraft to loiter as per one of it's design requests without burning unneeded fuel on things such as APU management, something which is instead operated by dynamo-generation from the main fans. The forward air intakes have movable ramps and bleed doors which manage airflow requirements of the engines. Despite these features, the CH-24 engines were almost dangerously misdesigned, leading to several engine failures during operations, including one infamous incident in which an Viper entered an unrecoverable flat-spin that resulted in the deaths of it's crew - LT George Winters and LTJG Frederik Garros during the 1976 Thessalonian Air Show.
As a result of deaths of Winters and Garros a major redesign of the engines took place, grounding the entire Viper fleet in the meanwhile - Something that caused major controversy in the military council as it presented an exposure in the country's strategic security. The Viper's design for the Air Force was to allow it to engage enemy bombers with long-range missiles in the event of a hostile invasion, and without the Vipers on duty the job fell to less-able airframes. Tests of the engine showed that, during missile launch, the plume of the missile often entered the intake and increased the chance of an in-flight failure by almost 35 percent. A bleed system and a cross-spark system was introduced, to filter out unnecessary intake with the former and to forcibly re-start a failed engines with the latter until a new engine design could be implemented. Despite the 'heath robinson' solution to the issue, no further incidents were reported until the FG.2 entered service.
The FG.2 variant entered service in 1982, primarily introducing the new Augment GTX-500 engines. These new engines features stronger turbine blades which also boasted an 'oscillation-friendly design', allowing the airframe to undergo harsher manoeuvres without risking damage. This also inadvertently allowed the engine to 'bounce-off' the exhaust from missile launches without causing a compressor stall, as a purpose-built bleeder system filtered air flow over the engine's designed limit out the side automatically. A feed-switching system allowed air flow to be diverted between engines, an improved version of the cross-spark system. While this was designed to restart a failed engine if conventional means failed, it also allowed the engines to maintain equal airflow during high-G manoeuvres that typically reduces airflow to at least one of the engines in particular. The drawback on the engine design was it's reduction in reheat efficiency which has been corrected in-service with updated fuel regulation hardware.
The most distinguishing feature of the aircraft is it's variable-geometry wings, called 'swing-wings' by Viper pilots. These wings allow the fighter to achieve impressive results. When fully swept back it reduces it's drag, allowing it to fly significantly faster than if it had static-geometry wings. The Navy store their aircraft with swept wings to reduce space. When the wings are brought fully forward it allows the plane to fly at much slower speeds, appropriate for landings and take-off. Typically an on-board computer, upgraded over the years, automatically alters the geometry of the wings to provide optimum lift-to-drag ratios as the aircraft speeds up and slows down, although this can be manually controlled by the pilot to significant risk during manoeuvres. Each wing features a singular pylon for weapons, mounted just before the variable-geometry wing begins.
Continuing a design to support increased performance over it's predecessor, the Viper's fuselage has also been produced to this end. A twin-tail arrangement above each engine nacelle offers increased stability when turning at speed and brought back an internally-carried 20mm Gatling cannon, something that the Republic Navy was missing for roughly ten years before it was brought into service. Each engine is held in the nacelles, which are spaced apart to provide a 'flat bally', which the Viper holds the majority of it's ordnance. The nature of the design provides nearly 60 percent of the Viper's aerodynamic lift, independent of the wings' current geometry.
The most potent feature of the Viper is its sensors. The Model 9 was one of the most potent fire control radars of its era and remains very competitive to this day. Its installation was enabled by the large size of the airframe and thus generous space for the radome. It is able to track up to 24 aerial targets simultaneously, and engage six with long-range air-to-air missiles. The later Model 21 radar is able to cue air-to-surface or anti-ship weapons, enabling the Viper to function in the strike role. In the FG.3, the SABR-E AESA radar is installed, enabling it to track up to 30 aerial targets at a range of up to 3-400km, depending on the size of their radar returns, and engage eight of them.
The Viper is also the first aircraft in Belfrasian service to possess an Infra-red search and track system. In the FG.3, this is replaced by an improved multi-spectral electro-optical sensor, which enables the Viper to track hostile air targets in either visual or infra-red wavelengths.
The Viper's countermeasures system includes chaff and flare dispensers, as well as electronic defensive aides such as a radar-warning receiver and self-defence jammer. In the latest models, the chaff dispensers have been upgraded with the BriteCloud DRFM jammer/decoy system, which can be released from standard 55mm chaff tubes.
Variants
Despite being a 43-year old design, the Viper has only seen three major updates thanks to it's already highly modular design.
- FG.1
- Test
- FG.2
- Test
- FG.2/A
- Test1
- FG.3
- Test
Operators
Specifications
General characteristics
- Crew: 2 (Pilot and Radar Intercept Officer)
- Length: 19.1 m (63 ft) ()
- Wingspan: 19.55 m (64.1 ft) (Spread)
11.58 m (38.0 ft) (Swept) () - Height: 4.88 m (16.0 ft) ()
- Empty weight: 19,838 kg (43,735 lb) ()
- Loaded weight: 27,700 kg (61,100 lb) ()
- Max. takeoff weight: 33,720 kg (74,340 lb) ()
- Powerplant: 2 × Augment GTX-500 afterburning turbofans
Performance
- Maximum speed: 1,544 mph (2,485 km/h) (Mach 2.34)
- Combat radius: 575 mi (925 km) ()
- Ferry range: 1,840 mi (2,960 km) ()
- Service ceiling: 50,000+ ft (15,000+ m)
Armament
- Guns: 1× 20mm rotary cannon mounted in nose. (670 rnds)
- Hardpoints: 10 total: 6× under-fuselage, 2× under nacelles and 2× on wing mounts with a capacity of 6,900 kg of ordnance and fuel tanks
- Missiles:
- Air-to-Air missiles:
- Air-to-ground missiles:
- Anti-Ship Missiles:
Avionics
- SABR-E Scaleable Multi-Function AESA Radar
- ISR-22 Decoy Deployment System
- Thunderbolt Combat Interface
- Attached Targeting pods