SF-4 Viper

* MK.I
* MK.II
* MK.II Export Variant
* MK.III

The ***SF-4 Viper*** is a interceptor starfighter designed for the Terran Systems Alliance in the early 1990s. The original *MK.1* variant only saw rudimentary tests on the four models produced, however the *MK.2* Viper would prove itself to be a equal or superior to almost any starfighter that had been made up to that point. With a combination of repulsorlift technology and traditional reaction control systems, which allowed the fighter to effectively change its trajectory on a dime, the Viper was very maneuverable. This was only limited by the endurance of the airframe and the pilot themselves, on which the stress was reduced due to the aforementioned anti-gravity systems. The fighter could also land and launch from practically any location large enough to hold it.

## Mark II History

**Development**

A joint project between Lockheed Martin and the Incom Corporation, the SF-4 Viper was intended to act as an Interceptor Starfighter for fleet defense and fighter and bomber interception.

First ordered by the United States Air Force in late 1987, the first four prototypes would come off the production line at Air Force Plant 4 in early 1989. After its first flight test, it was decided to test the fighters limits in air-to-air combat. To that end, a pair of Vipers would be put up against a pair of F-15C Eagles.

In a series of three full day long tests over the course of several months, the F-15’s would win every single engagement with the Vipers despite some close calls.

Several weaknesses the new fighters design would be discovered, including limited pitch and yaw at speeds exceeding 900 Knots with the repulsor system unable to compensate. Another flaw would be lack of sufficient missile capacity with only four internal and two external hard points.

The only advantage the Viper had was its much greater gun range and ammo count for its two 30mm cannons.

Following these tests, the Viper would return to the drawing boards. During this redesign process, the decision to add RCS thrusters across the frame was made, along with the addition of more powerful engines to power its three thrusters, and more precisely designed flaps and ailerons. In terms of internal systems a full overhaul was needed. With this overhaul a much smaller yet more effective computer system was installed, freeing up space for an additional four missile hard points. This would bring the total up to ten.

These changes, alongside a more aerodynamic air-frame, provided the fighter with the speed to match its atmospheric counterparts, while affording it extreme maneuverability in both a planets atmosphere and the vacuum of space.

This new design would be labeled as the SF-4 Viper MK. II, with the former design retroactively labeled the MK. I, and would prove itself extremely capable during tests against the F-15, F-16, and even former Russian Mig-29s.

After proving itself during these exercises, a full production run of one-hundred aircraft was ordered, for both the USAF and the newly formed Terran Systems Alliance Navy.

**Clone Wars**

However, by the time of the Separatist assault on the Sol System, only roughly four-dozen had been received. During the battle over Earth, the Vipers of the 12th Fighter-Interceptor Wing proved the craft’s effectiveness when a formation of only fourteen Vipers successfully saved the *Dreadnaught-class* heavy crusier *TSS Kongō* from a swarm of thirty Vulture droid fighters and twelve Hyena droid bombers, while only taking three casualties.

Over the course of the next two years of the Clone Wars, over 8,000 MK.2 Vipers would be built and see combat in almost every battle the TSA would participate alongside the SF-6 Banshee multi-role fighter. During the last year of the war, Mark II’s would be equipped with a hyperdrive, which allowed them to escort bomber formations and starships through hyperspace. These craft would be witness to the Fall of the Republic, via Order 66 and the creation of the Galactic Empire. After this all Terran units returned to the Alliance space.

**Post-Clone Wars**

During the almost twenty year period of time between the end of the Clone Wars and the official start of the Galactic Civil War, many upgrades such as more efficient RCS thrusters and hyperdrive, would be retrofitted to nearly all surviving MK.2’s to keep them combat capable in a rapidly changing galactic situation. However MK.2 production would officially cease in 2005, with a number of advanced atmospheric fighters being designed and built with the now available funding, such as the F-22 Raptor and F-35 Lightning. However, almost 1,000 more of the fighters would be secretly built on the Terran Star Forge upon its completion in 2008, with a majority of the fighters being sold to various militia groups whom needed assistance against piracy, and also be ‘stolen’ for use by the nascent Alliance to Restore the Republic. These craft would have their Terran weapons removed and replaced with laser cannons and concussion missile launchers.

**Galactic Civil War**

By the beginning of the Galactic Civil War, MK. II’s had been assigned to virtually every Terran ship and installation large enough to carry them, along with the fighters sold to various militia groups and secretly given to the numerous rebel cells under the guise of being stolen from various outlying storage facilities. During the battles of Earth, Endor, Jakku, and Coruscant, these fighters proved themselves vastly superior to the Galactic Empire’s T.I.E fighters in every aspect, only being realistically challenged by the later T.I.E Interceptor, Phantom, and Defender models.

## Mark II Export Variant History

During the post-Clone Wars era, many militia groups found themselves lacking in sufficient protection from pirates and rogue CIS remnants. Given the lack of response from the Galactic Empire in terms of arming various groups in areas it could not reach (revolving around its policy of central control of military assets), if fell to the TSA to pick up the slack in arming these groups.

This redesign of the Mark II Viper, colloquially know as the Mark 2.5, modified the frame for easier manufacturing and maintenance. Alongside this, the armament was completely revised, going from two 30mm cannons and 8 internal and 2 external hard-points, to two laser cannons and a concussion missile launcher with a total of 12 missiles.

The craft would be introduced in 2001, and see action with over two dozen militant’s across the Outer Rim. Several dozen of the craft would eventually fall into the hands of the Alliance to Restore the Republic, whom would then begin to manufacture their own.

The fighter would gain a reputation as a vicious dogfighter and see action in Rebel service is many major engagements including the Battles of Scarif, Yavin, Hoth, Earth, and Endor.

Even in TSA service its legacy would continue in the Mark III Viper, which would take many design elements from the 2.5 during its development.

## Mark III History

The Mark III began development shortly after the Clone Wars, when the Mark II proved itself a very capable fighter. Improvements included more powerful engines, a built in hyperdrive, and a third 30mm cannon mounted on the fighters spine above the cockpit. However it’s most important upgrade was that of a stealth coating, allowing the fighter to be almost completely undetectable from great distances. First flown in 2007 and entering service in 2009, it would initially only see limited production, with only 200 being built from 2009 to 2012, but orders for the craft began to increase rapidly with rising rebel and terrorist activity across the galaxy.

Its true era of combat began with the beginning of Terran involvement in the Galactic Civil War, where the Mark III proved itself superior to all T.I.E variants, save for the later Phantom and Defender models. Post-war, the Viper MK.2 would be fully retired and work would begin on a complement to the Viper MK.3s and replace the SF-6 Banshee, the SF-14 Fulcrum multi-role fighter.

## Gallery

MK. II and MK. III Vipers in formationMK.II Export Vipers in formation over Earth
## Trivia

* Based on the *Viper Starfighters* from 'Battlestar Galactica'.

## Appearances

* *Not So Far Away, Not So Long Ago* (first appearance)
* *Book One: An Uplifting War*
* *Book Two: Deception and Darkness*
* *Book Three: Return of Legends*