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.

Specifications

General characteristics Performance