Aigios Seiren
| Aigios Seiren | |
|---|---|
| |
| Role | Airborne early warning and control |
| Designer | Aigios Defence |
| First flight | 15 June 1963 |
| Introduction | 22 December 1965 |
| Status | In service |
| Primary user | Republic Navy See Operators |
The Aigios Seiren is a carrier-capable airborne early warning aircraft in service with the Republic Navy. The aircraft was designed and developed by Aigios Defence who had presented several different prototypes along with the Seiren to the Navy whilst they were looking for a new airborne early warning platform for usage with their carriers.
Replacing the older Warthog aircraft, the Seiren entered service in 1965 aboard the Akhilleus-class carriers of the fleet to conduct air and ground detection, early warning and for coordinating airborne efforts away from the carrier. Over the years the aircraft has been subject to several updates which has allowed it to maintain it's ability to operate in the modern environment.
Design and development
At the time of the request for a new EAW aircraft, the Republic Navy was heavily relying upon the Warthog, an aircraft that was both modified from an anti-submarine aircraft and suffering from being rapidly outdated by a world experiencing constant radar improvements. It was eventually decided that a purpose-built aircraft for early warning would be sought. The admiralty requested that the aircraft be able to be updated while still in service to newer radar technologies, be compatible with the fleet communication and relay network and for it to be capable of operating over long periods of time with minimal maintenance in a war-time environment if needed. Aigios Defence, which had been manufacturing aircraft for the Navy already, submitted the proposal for the Seiren at the same time as two other models.
When the Seiren was requested, it had only flown two test flights for the Navy. One as a aerodynamic testbed and a second with full equipment. Design constraints on the airframe due to the possibility of it having to serve on older aircraft carriers meant that it had some negative flight characteristics early into it's life. Despite this request, the aircraft carriers in question were put out of service five years after the Seiren's entry into service without any having served aboard one.
The EAW.2, released in 1972, increased the size of the airframe to it's original design size and introduced several measures to help raise it's potential. The previous air frame had suffered from sea corrosion and improper ventilation of it's avionics compartment when in flight, something that led to maintenance nightmares over the first seven years of the design's service life. The major update to the airplane occurred following an extensive testing period and resulted in the older model being rendered obselete as soon as they could be replaced with the newer model.
The update to the airplane introduced an improved radar complex with heightened modularity to allow for the installation of new components easily and for components to be removed for maintenance with ease. The radar internals were completed modernised, the on-board computers were updated to early-era multi-function displays and the pilot controls were revamped to replace the interial system with a far superior laser gyroscope. A rapid beam data-link was introduced to allow the aircraft to help vector aircraft into position to engage threats without being jammed and finally a modernised central computer hub was installed in place of old servo systems to improve crash survivability of carried equipment.
Five years later in 1977 the EAW.2/B was introduced, refitting the main command center and cockpit drastically. Glass displays were added with a GPS/INS-approach ability, a strengthened underbelly was added along with an update to the radar which prompted the update. An improved air cooling system was also added to replace the previous rapidly outdated system.
The EAW.2/C was developed in 1998 to revamp the engines of the aircraft to modern standard. An eight-blade propeller was installed to an engine with improved fuel conservation abilities. The blades were capable of being removed easily for maintenance and were constructed out of a sturdier material with easily replaced leading-edge inserts. The holding frame for the engine was exchanged for a newer, vibration-absorbing design and also introduced a de-icing heater to aid flight preparations in cold climates.
Considerations for replacing the aircraft in 2004 were abandoned when Aigios Defense presented an updated EAW.3 design. The update featured an entirely new avionics suite with an advanced active electronically scanned array (AESA) radar, an improved passive listening system to detect enemy radars and better link itself with modern fighter planes. An entirely new glass touch-screen display system was introduced and a refuelling point at the front of the aircraft for in-flight refuelling was also added to increase it's endurance. The touch-screen displays in the cockpit allow the co-pilot to act as another radar operator if required. The new AESA radar is believed to be capable of detecting fighter-sized stealth aircraft with it's UHF-band active array as opposed to the previous generations high and normal bands. The radar system has an advanced electronic scanning system to 'cleanse' targets for positive identification and a fully modernised computer system board for rapid electronical functions.
The aircraft is a high-wing airplane, carrying two turboprop engines both of which have a landing gear installed to it to function along with the gear mounted on the front under-carriage. The airplane was designed with carrier operations as a main feature, with a strengthened under-carriage, tail hook and front-gear latch for take off and recovery aboard carriers. The aircraft's main electronics and radar are mounted in a rotating radar dome mounted above the aircraft and is capable of being readily serviced while aboard ship. The wings of the aircraft fold just after the engines to stow facing backwards along the length of the airplane to keep them from hitting the radar dome. The design intention of the radar is for the usage of advanced electronic sensors to detect enemy aircraft, enemy ships and airborne missiles in order to control and vector in the carrier's air wing to destroy the threats or to prepare defences as necessary.
Shortly after the EAW.2's introduction the plane was developed to allow for service as a carrier-capable transport, better known as Carrier onboard delivery (COD). The COD.1 was developed to provide critical logistics support to carriers at sea by delivering high-priority cargo, mail and passengers and has the load capacity to also load spare parts for aircraft, such as jet engines or entire sections if needed.
The COD.1 altered it's airframe from it's EAW.2 sibling. The radar dome was gone, the tail was raised to allow for a cargo hatch and the bottom of the aircraft was levelled out to allow for wide cargo to be loaded. The internal compartments for the crew was swapped out for cargo or bolt-attach passenger chairs as appropriate. The reduced standard weight meant that the COD.1 could carry up to 4,500 kg of cargo easily. The cargo systems and bolt accessories were rated as capable of surviving harsh carrier landings repeatedly over a long period of time without failing. An aft cargo door and port-starboard doors were added to expedite cargo and crew movement to allow for a quick turnaround when aboard the busy environment of a flight deck. The cargo ramp allows the COD.1 to provide an airdrop ability for supplies and personnel. A COD.2 update was made in order to introduce EAW.3 updates to the aircraft. Glass architecture for the cockpit, improved survivability and a redesign of the cargo-hold allowed the Seiren COD.2 to perform as a capable carrier cargo aircraft into the future.
Variants
- Seiren EAW.1
- First production variant of the aircraft. Served for seven years before the new update rendered it obselete.
- Seiren EAW.2
- Introduced in 1972 to update the initial production model and to fix deficiencies found in service.
- Seiren EAW.2/B
- Glass display update that revamped the interior drastically. Underbelly underwent updates for landing survival.
- Seiren EAW.2/C
- Introduced in 1998 to completely modernise the engine system.
- Seiren EAW.3
- 2004 update. Completely replaced avionics suite with AESA radar, improved listening system and data-links for modern aircraft. Glass touch-screen architecture and an extending refuelling nozzle for endurance increase while in flight.
- Seiren COD.1
- Based off of the EAW.2 and released at the same time in 1972, provides carrier delivery of 4,500 kg. Tail raised to allow for stern ramp ability.
- Seiren COD.2
- Revamped design to introduce updates of EAW.2/B and /C.
- Seiren COD.2/B
- Introduced in 2004 to introduce glass touch-screen architecture and in-flight refuelling system.
Operators
Specifications
General characteristics
- Crew: EAW.3: 5 (Pilot, Co-Pilot, Radar Officer, Air control officer, information control officer), COD.2/B: 4 (Pilot, Co-Pilot, 2 load masters.)
- Capacity: 26 passengers, 12 litter patients
- wikipedia:Payload: 4,550 kg (10,030 lb) ()
- Length: 17.80 m (58.4 ft) ()
- Wingspan: 24.70 m (81.0 ft) ()
- Height: 5.60 m (18.4 ft) (EAW.3)
4.90 m (16.1 ft) (COD.2/B) () - Empty weight: 15,310 kg (33,750 lb) ()
- Loaded weight: 22,405 kg (49,395 lb) ()
- Max. takeoff weight: 24,655 kg (54,355 lb) ()
- Powerplant: 2 × Aigios EROS-22 turboprop, () each
Performance
- Maximum speed: 394 mph (634 km/h)
- Range: 1,496 mi (2,408 km) ()
- Service ceiling: 33,500 ft (10,200 m) ()