F-28 Viper

Layartebian Defense Corporation F-28 Viper
(Artwork by Mist)
Role	Multirole fighter
National origin	Layarteb
Manufacturer	Layartebian Defense Corporation
First flight	17 June 1994 (1994-06-17)
Introduction	1 April 2002 (2002-04-01)
Status	In-Service
Primary users	Imperial Layartebian Air Force Imperial Layartebian Navy
Produced	2004 - Present

The Layartebian Defense Corporation F-28 Viper is a twin-engine supersonic multirole fighter aircraft originally designed for the Imperial Layartebian Military. More Vipers have been produced than any other supersonic, Layartebian, jet fighter. The Viper is an all-weather, 4.5 generation aircraft similar to the Dassault Rafale and the Eurofighter Typhoon.

The Viper's key features include a frameless, bubble canopy for superior visibility, a side-mounted control stick and throttle, dual engines, and a large, delta wing. The aircraft makes heavy use of fly-by-wire systems, making it a highly agile aircraft, especially when combined with thrust vectoring engines. The fighter has an internal cannon and 14 hardpoints for air-to-air and air-to-ground ordnance.

The Viper is the most numerous fighter in Layartebian service and it is the most exported Layartebian fighter aircraft of all time. The Viper forms the backbone of several foreign air forces and navies.

Development

Origins

The origin of the F-28 Viper stems from the 1980s when the F-16 Fighting Falcon was introduced to service. Originally planned to be a lightweight fighter for air superiority, the aircraft ballooned into a multirole workhorse for the Imperial Layartebian Air Force. However, the design had some flaws and teething problems with the first variants did not sit well with brass. Wire chafing caused several prominent crashes, killing multiple pilots in the 1980s and though these problems were largely rectified by the 1990s, especially with the F-16C/D variants, the initial troubles left a sore memory of the aircraft. As if these initial problems weren't enough, limitations on range and payload for the Falcon ultimately doomed the nimble, agile fighter in the eyes of the brass.

In the early 1990s, the Ministry of Defense began a new fighter program dubbed the Joint Multirole Fighter Program or JMF Program. At the time, the British Aerospace EAP, the Mirage 4000, and the Dassault Rafale had all taken to the skies with technological demonstrators. The EAP would eventually become the Typhoon, while the Mirage 4000 was canceled in favor of the Rafale. It was from these aircraft, along with others, that the JMF Program would take its influence.

Early on in the JMF Program, designers conceded that a delta wing would be necessary for the type of ordnance, range, and agility requirements placed on the JMF. In addition, the debut of stealth aircraft such as the F-117 Nighthawk and the B-2 Spirit guaranteed that some attention would need to be paid to stealth, albeit the JMF Program was never required to procure a stealth fighter, that was left for other programs. The aircraft had to have a top speed in excess of Mach 2 at altitude and in excess of Mach 1.1 at sea level and it had to have two engines, which was a major distinction from the Falcon, which was a single-engine aircraft. Some in the Ministry of Defense believed that the single-engine of the Falcon contributed to its high accident rate and, for the aircraft to be accepted by the navy, it had to have two engines.

What resulted was the YF-28, which first flew on June 17, 1994. The aircraft bore a rather unique design while having the same, general appearance as its contemporary, soon-to-be 4.5 generation fighters. On its first test flight, the fighter was taken up to transonic speed and flown through several maneuvers not typically done for a first test flight. Handling was superb and performance issues were nonexistent. On the third test flight, the aircraft exceeded supersonic flight and on its seventeenth test flight, it reached a top speed of Mach 2.05 at an altitude of 36,500 feet (11,125 meters).

Fifteen prototype YF-28s were constructed from 1994 to 1996 and put through rigorous testing. Ten were single-seat variants and five were two-seat variants. The two-seat variants were used primarily for naval testing. The JMF was in direct competition with the F-18 Super Hornet to replace the F-18 Hornet and the A-7 Corsair II on aircraft carriers. The Corsair II had already been replaced with the air force by the Falcon but several A-7E Corsair IIs still flew with the navy into the early 2000s.

The YF-28 was officially dubbed the "Viper" on July 10, 2000 when low-rate initial production was authorized. The first operational squadron of F-28A Vipers would reach initial operational capability on April 1, 2002 with the air force and on January 11, 2004 with the navy.

Production

Low-rate initial production began in July 2000 and in FY00, eight aircraft were produced with a further sixteen in FY01. By FY05, there were over one hundred and twenty-five aircraft produced per year, with this number exceeding two hundred and fifty in FY10. From 2000 to 2003, Vipers were only produced on one line by this was expanded to two lines in 2004, three lines in 2005, and five lines in 2008. As of 2019, Viper production continues on all five lines with an astonishing rate of some four hundred and fifty aircraft per year.

Manufacture of the Viper is purely domestic, despite requests from large, export partners to secure their own production lines. The aircraft is produced at facilities in New York, Pennsylvania, Alabama, Venezuela, and Guyana. There were plans to open a facility in Quebec but these were shelved by the Layartebian Defense Corporation to produce other aircraft.

Upgrades

Initial versions of the F-28 Viper were of the Block 1 variant. The Block 1 variant offered very limited air-to-air and air-to-ground capabilities. These aircraft were largely to be used as trainers for pilots transitioning into the first squadrons. Only forty-eight such aircraft were produced on the Block 1 standard. These aircraft could only carry AIM-9M Sidewinder air-to-air missiles and unguided, iron bombs of the Mark 80 series.

Production quickly switched to the Block 5 variant, which integrated full air-to-air capabilities, allowing the employment of the AIM-7 Sparrow, the AIM-120 AMRAAM, and the newer variants of the AIM-9 Sidewinder. A total of one hundred and forty-four aircraft were produced before production switched to the Block 10 variant.

The Block 10 variant offered integration of precision-guided munitions for air-to-ground missions. This included the use of GPS-guided JDAM bombs and laser-guided Paveway bombs as well as guided missiles such as the AGM-65 Maverick and the AGM-88 HARM. Unguided rockets as well as other air-to-ground missiles were integrated into the aircraft's software. Over five hundred Block 10 aircraft were produced.

The Block 15 variant, however, was to be the penultimate variant produced. Eventually, all Block 5 and Block 10 aircraft were upgraded to the Block 15 variant. The Block 15 variant included full ordnance capabilities as well as newer weapon systems that were not available when the initial Block 1, 5, and 10 variants were produced. It also increased the capacity for chaff and flare dispensers as well as provided the ability to carry standoff jamming pods.

The current variant is the Block 20, which has upgraded the aircraft's radar and countermeasures systems with new software updates and provided the ability to conduct electronic jamming missions in two-seat variants. There are currently no plans to update Block 15 aircraft to the Block 20 standard due to the high cost.

A future Block 25 variant is planned, which would focus primarily on the propulsion systems of the aircraft. Designers are evaluating engine upgrades that would allow for slightly less fuel consumption at cruising power, increasing the aircraft's range by as much as 10%. There may be other changes as well to the aircraft's fly-by-wire systems and its avionics; however, this variant is not planned to begin production or conversion until 2022.

Design

Overview

The Viper is a twin-engine, highly maneuverable, supersonic, multi-role, tactical fighter aircraft. The aircraft itself is much larger than the F-16 Falcon but comparable to other delta-wing, Western, 4.5-generation fighter aircraft. It utilizes a fly-by-wire flight control system that enables the aircraft to perform highly agile maneuvers, which is significantly aided by the thrust-vectoring engine controls. The Viper is capable of 9-g maneuvers and it can reach over Mach 2 in level-flight at altitude. A frameless, bubble canopy affords the pilots superb visibility in dogfights and significant innovations were taken in the cockpit to help pilots reduce the effects of g-force during maneuvers. These innovations included side-mounted controls and a reclined seat. The aircraft has a thrust-to-weight ratio greater than one, providing significant power in acceleration and turning.

The Viper is armed with a 27-millimeter internal cannon, the GAU-20/A Impulse Revolver Cannon in the starboard wing root. The aircraft has fourteen hardpoints for the mounting of a number of air-to-air, air-to-ground, and miscellaneous stores to complete its mission. Due to it being a 4.5-generation fighter, considerable measures were taken to reduce the overall radar cross section of the aircraft. This enables a delay in detection from search and fire control radars, perhaps giving the Viper an edge against an enemy. Much of the aircraft's construction is from lightweight composites, which help aid in this reduced RCS.

General Configuration

The Viper is designed to be highly agile in all speed regimes, whether slow or supersonic. This is largely achieved through a relaxed stability design, which means that the aircraft is aerodynamically unstable. Without its fly-by-wire system, it would be very difficult to fly and for that reason, all fly-by-wire systems have quadruple redundancy to ensure survivability in battle.

The airframe, largely made out of lightweight composites, has an estimated lifespan of 8,000 hours and it can withstand -4g to +11g; however, maneuvers over +10.5g will deform and damage the wings, requiring replacement. A G-limiter onboard the aircraft prevents maneuvers in excess of +9g, primarily to prevent G-LOC or G-force induced loss of consciousness. Because G-LOC at low altitude is almost always fatal, the Viper is equipped with an auto-GCAS system that prevents a ground collision. The auto-GCAS system automatically corrects for diving maneuvers and automatically returns the aircraft to level or climbing flight to prevent collisions with the ground. This system was credited with preventing two crashes during the prototype and evaluation phase of the aircraft's development.

The Viper's design includes not only a delta wing but also active clouse-coupled canards to maximize maneuverability and enhance low-speed, low-altitude performance. Thanks to those canards, the landing speed of the Viper is around 115 knots (132 mph or 213 km/h), which is especially useful for carrier landings. Coupled with its thrust-vectoring engines, the Viper is capable of aggressive maneuvers, even at low-speed.

While all variants of the Viper come equipped with arrestor hooks, it is only the carrier-capable variants that have a reinforced undercarriage system, which is needed because of the high impacts of carrier landings and the stresses of catapult launches. These variants are also equipped with an automated landing system, which means that the aircraft could land itself without input from the pilot. Carrier-capable aircraft also have folding wingtips to reduce storage requirements in the confines of carrier decks. The downside to this is the increase in empty weight for carrier-capable aircraft.

Cockpit

The Viper is fully equipped with a glass cockpit meaning that it incorporates a number of multi-function displays. These allow the pilots to choose from any number of displays allowing for robust aircraft control. The principles of data fusion are highly present in the cockpit, which aims to reduce the workload on the pilot, especially in single-seat aircraft.

The Vipers controls are fully HOTAS or Hands on Throttle and Stick, with the flight control stick on the right and the throttle on the left. This is done chiefly to aid in control during high G-force maneuvers but also to provide additional room in front of the pilot, especially with regards to the display screens. Both the pilot and the RIO/WSO sit on ACES II zero-zero ejection seats, reclined to 30° to aid in high G-force maneuvers. The reliability of the ACES II makes it the primary ejection seat in Layartebian aircraft.

The pilot has access to four LCD multi-function displays or MFDs. Directly centerline with the pilot is the primary display, which measures 8 inches (20 cm) square. Two secondary displays right and left of this display measure 6.25 inches (15.88 cm) square. A tertiary display sits underneath the primary display, in between the pilot's legs. This display is also 6.25 inches (15.88 cm) square. The RIO/WSO has the same configuration but he also has two additional 3 inch x 4 inch (7.62 cm x 10.16 cm) displays. Despite this highly digital layout, the critical systems of the aircraft such as its artificial horizon, fuel gauge, compass, speedometer, altimeter, and AOA meter are entirely analog to ensure proper functionality in electrical blackout conditions that might negate the ability to use the MFDs. The RIO/WSO cannot control the aircraft but he has these systems as well due to redundancy. All MFDs have a resolution of 1024 pixels x 1024 pixels.

The canopy of the Viper is coated with a layer of indium tin oxide (ITO), which not only gives the canopy a gold tint but also helps reduce the radar cross section of the aircraft. The canopy itself is made of polycarbonate material and it is designed to flex during bird strikes to ensure survivability.

The head-up display or HUD of the Viper is a wide-angle design. It offers high performance and low latency to ensure that it is always function. It, like all systems within the cockpit, is compatible with night-vision goggles. In addition, the aircraft's systems are also compatible with helmet-mounted display or HMD systems.

Climate control systems in the cockpit provide for air conditioning and heating systems and the aircraft's cockpit is equipped with a redundant backup life-support system to counteract potential hypoxia-related issues.

One novel feature on the Viper, which is only seen in a handful of aircraft, is a direct voice input (DVI) system. This allows the pilot to utilize specific words to control non-critical systems in the aircraft. However, the DVI system requires a significant amount of training and it is largely speaker-dependent meaning that every pilot in a squadron would need to have his voice recorded into each aircraft. Because of this, Layartebian aircraft have the DVI system deactivated.

Avionics

It is the avionics of the Viper that truly set it apart from other aircraft in its class. Special attention was paid in the design and the development of the Viper to ensure that the avionics could not only provide enhanced situational awareness on the battlefield but also be compatible with future upgrades. It is for that reason that the avionics are something of a modular design.

For basic functionality, the Viper is equipped with a GPS and an inertial navigation system. The aircraft can utilize Instrument Landing System or ILS for landing in poor weather or other conditions. The aircraft has a ground proximity warning system and Link 16 capabilities, which can be expanded to new standards. All aircraft feature these systems but domestic and export aircraft have different advanced systems such as radar and ECM.

Detection Systems

Vipers in service with the Imperial Layartebian Military are equipped with the AN/APG-91 solid-state, active electronically scanned array (AESA) radar. The radar is composed of 1,600 transmit/receive modules, which provide near-instantaneous beam steering and frequency hopping capabilities. This makes the radar an LPIR radar. The radar has a diameter of 26.38 inches (670 mm) and a weight of 529 lb. (240 kg). It has a peak power output of approximately 24 kilowatts but an average pulse significantly less. Each T/R module is 4.4 inches (112 mm) long by 1.18 inches (30 mm) width by 0.47 inches (12 mm) thick. They weigh only 2.82 oz (80 g) each but can handle 15 watts of maximum power.

The AN/APG-91(V)-1 in the F-28 Viper is capable of both air-to-air and air-to-ground modes. It is capable of tracking 32 aircraft at once, of which 8 can be engaged simultaneously. Air-to-air modes include: range while scan (RWS), track while scan (TWS), single-target track (STT), and dogfight. Because the radar is a synthetic aperture radar, it can provide high-resolution mapping. In air-to-ground modes, the AN/APG-91(V)-1 can engage both stationary and moving targets as well as seaborne targets. The radar also has terrain-following capabilities. The AN/APG-91(V)-1 operates on X band. Export Vipers are equipped with the AN/APG-80 radar instead.

The use of the radar, despite its LPI capabilities, means that the Viper is still actively transmitting emissions. To counter this, the Viper is equipped with the AN/AAS-48 IRST. Mounted on the nose just forward of the canopy, the AN/AAS-48(V)-1 IRST provides passive detection via infrared capabilities. It has a range of 50 miles (80 km) head-on and 90 miles (145 km) for the rear with limited air-to-ground capabilities. Against supersonic targets, these ranges increase. The system is entirely passive and functions on two IR bands, 3 - 5 µm and 8 - 11 µm. It has a field of view of 180° x 75° and can simultaneously track up to 500 targets. The IRST is a weather-dependent system however and it is not useful against ground targets. In a dogfight, the IRST is also equipped with a ranging laser, which aids the cannon. Export Vipers are equipped with the OSF IRST system.

For ground-attack missions, the Viper would carry an AN/AAQ-33 Sniper targeting pod. The Sniper can be mounted on chin pylon, where it provides downward-focused FLIR and laser-designation. It can be used for nap-of-the-earth flying without utilizing the terrain-following capabilities of the Viper's radar. The Sniper pod provides high-resolution imagery and laser-designation up to 50,000 feet (15,250 m). All versions of the Viper would require the Sniper for laser-designation or ground-targeting FLIR.

Self-Defense Systems

To defend against threats, the Viper is equipped with the AN/ASQ-238 Electronic Countermeasures Suite. The version specifically deployed on the Viper is the AN/ASQ-238(V)-1 system. It provides an assortment of jamming and warning systems. This includes the AN/ALR-94 Radar Warning Receiver, which provides 360° detection for radar-based threats out to as far away as 300 mi (480 km). To provide warning in case of laser-designation, the ECS equips the AN/AVR-4 Laser Warning Receiver, which is a short-range system solely for the detection of laser-designation.

While the AN/ALR-94 provides warning against radar-based threats, the Viper has the AN/AAR-52 Missile Warning System for non-radar threats, primarily infrared-guided missiles. The AN/AAR-52 is a dual-mode system that utilizes infrared and ultraviolent detection to warn the pilot of approaching missiles. The use of both systems is done to help counter the advantages and disadvantages of each. Infrared-based alert systems detect the hot rocket motor of incoming missiles but they are not all-weather systems, which UV-based systems are. IR-based systems are highly effective against air-to-air missiles while UV-based systems are better against surface-to-air missiles. The AN/AAR-52 utilizes these systems thus to warn the pilot of approaching missiles that might escape the AN/ALR-94.

Beyond warning the pilot of approaching threats, the ECS can also jam them. Against radio frequency (RF) threats, the system employs the AN/ALQ-229 for jamming. The AN/ALQ-229 provides not only full spectrum jamming of a wide area but also directional jamming for focused lethality. The AN/ALQ-229 is also effective against monopulse seekers such as the AIM-120 AMRAAM. Against these missiles, the AN/ALQ-229 utilizes "Cross-eye techniques." To achieve this, there are transmitters placed on each wing of the aircraft with a 180° phase shift. This angle-deception technique forces the seeker of the incoming missile to realign its antenna and in doing so gives the missile incorrect tracking data causing the missile to miss entirely. However, the system is not effective against two separate seekers coming from different bearings. The AN/ALQ-229 is supplemented by the AN/ALQ-230, which is used for IR jamming. The AN/ALQ-230 utilizes pulses of infrared energy to confuse and disrupt incoming infrared-guided missiles and it is effective against both air-to-air and surface-to-air missiles.

All of these systems are linked together so that they can function automatically without input from the pilot - or manually if the pilot would prefer. Electronic warfare variants of the Viper add the AN/ALQ-232, which is a multiband, standoff jammer with a higher power output to disrupt tracking radars for surface-to-air missiles and communications bands via noise jamming. The electronic warfare variants also mount the Next Generation Jammer pods for enhanced protection against low, mid, and high radio bands. Export Vipers carry the AN/ALR-67 Radar Warning Receiver, the AN/AAR-56 Missile Approach Warner, and the AN/ALQ-214 RF Jammer. Export electronic warfare Vipers utilizes the AN/ALQ-99 jamming pod.

Beyond radars, IRSTs, and ECM systems, the Viper is also equipped with a number of physical countermeasures in the form of chaff, flare, and decoys. All Vipers are equipped with AN/ALE-47 dispensers for chaff and flares. Each dispenser can hold up to 30 chaff bundles or flares and there can be up to five configurations for chaff and flare loads. The Viper mounts eight on the fuselage with two in the front and six in the rear of the aircraft. On Block 15 aircraft however, these were supplemented by the ability to carry additional dispensers in their weapons pylons, adding six additional dispensers for a total of fourteen dispensers. These pylons are carried on stations 2 and 11.

In addition, the Viper mounts two AN/ALE-58 high-capacity dispensers on stations 1 and 12. These high-capacity dispensers can hold up to 160 chaff or flare cartridges; however, they are typically loaded with chaff so that the under-fuselage dispensers can be loaded with flares. All told, a Block 15 Viper will normally carry 320 cartridges in its AN/ALE-58 dispensers, 180 chaff cartridges in its pylon dispensers, and 120 medium or 240 small flare cartridges in its AN/ALE-47 dispensers. The F-28 Viper is, in its basic configuration, able to act as a chaff bomber, laying out long corridors of chaff to confuse enemy radars and missiles, maximizing its ability to carry as many as 740 chaff cartridges without external pods. For pods, the Viper can carry the AN/ALE-37A Chaff Pod, the AN/ALE-41 Chaff Pod, or the AN/ALE-43 Chaff Pod, of which eight of each - except for the AN/ALE-43 - can be carried. Because of the weight of the AN/ALE-43, there can only be seven carried. The AN/ALE-37A weighs 277 lb (126 kg) and it can carry up to two, 120-round payload modules for a total of 240 rounds of chaff, flares, or decoys. The AN/ALE-41 weighs 360 lb (163 kg) and the AN/ALE-43 weighs 626 lb (284 kg) and both utilize rolls of chaff to create long corridors.

Beyond chaff and flare dispensers, the Viper is also equipped with two decoy systems. On wing stations 3 and 10, the Viper mounts a single AN/ALE-55(V)-2 towed decoy dispenser. Each dispenser holds 3, towed decoys, which are trailed on a long, fiber-optic wire behind the aircraft. The decoy is normally towed significantly behind the aircraft to ensure that the blast radius of a surface-to-air missile is well away from the aircraft. Complementing these are two AN/ALE-57 decoy dispensers, each of which carry 6 decoys with a diameter of 2.16 (55 mm) each. These can include radio-frequency or infrared-frequency jammers or chaff/flare packets. Normally, they carry expendable jammers that are designed to operate for 10 - 20 seconds after they are ejected, providing effective jamming to missiles in their terminal phase. The infrared-frequency jammer is intended to spoof imaging-infrared missiles, which are not spoofed by flares. These are carried on stations 5 and 9. Only certain export customers receive these two decoy dispensers while the chaff and flare dispensers are standard on all Vipers.

To say that the Viper is not well-protected is simply a lie given its ability to carry a large array of countermeasures, decoys, and electronic warfare systems.

Specifications

General characteristics Performance