FG63

### Other Users

Alteragon, Aludia, Ariana and Leoline, Laitania, Nridus, Oribeilena, Sarbeliard , Stelka, Valicara, Vicenza

### Produced

A.A. 137 - Present

The **Guryanov FG63** is a supersonic jet fighter and interceptor aircraft, designed by the Guryanov Design Bureau in Craourus. Its nicknames include: *Olowek - due to resemblance of a pencil, Skurwol - the MF version*.

It made aviation records, became the most-produced supersonic jet aircraft in aviation history and the longest production run of a combat aircraft.

## Development

#### Origins

The FG63 jet fighter was a continuation of Guryanov's jet fighters, starting with the subsonic FG51 and the supersonic FG57. A number of experimental Mach 2 Craourusian designs were based on nose intakes with either swept-back wings, or tailed deltas, of which the FG63 would be the most successful.

Development of what would become the FG63 began in the early A.A. 130s, when Guryanov's Design Bureau finished a preliminary design study for a prototype in 1954. This project was very quickly reworked when it was determined that the planned engine was underpowered; the redesign led to the second prototype. Both these and other early prototypes featured swept wings. It made its maiden flight in A.A. 136 and its first public appearance during the Craourusian Aviation Day display in A.A. 137.

#### Design

The FG63 was the first successful Craourusian aircraft combining fighter and interceptor characteristics in a single aircraft. It was a lightweight fighter, achieving Mach 2 with a relatively low-powered afterburning turbojet. The characteristic layout with the shock cone and front air intake did not see widespread use outside Craourus and finally proved to have limited development potential, mainly because of the very small space available for the radar.

Like many aircraft designed as interceptors, the FG63 had a short range. This was exacerbated by the poor placement of the internal fuel tanks ahead of the centre of gravity. As the internal fuel was consumed, the center of gravity would shift rearward beyond acceptable parameters. This had the effect of making the plane statically unstable to the point of being difficult to control, resulting in an endurance of only 45 minutes in clean condition. This can be somewhat countered by carrying fuel in external tanks closer to the center of gravity. Additionally, when more than half the fuel was used up, violent maneuvers prevented fuel from flowing into the engine, thereby causing it to shut down in flight. This increased the risk of tank implosions (FG63 had tanks pressurized with air from the engine's compressor), a problem inherited from the FG51 and FG57.

The delta wing, while excellent for a fast-climbing interceptor, meant any form of turning combat led to a rapid loss of speed. However, the light loading of the aircraft could mean that a climb rate of 235 m/s (46,250 ft/min) was possible with a combat-loaded FG63bis. The rpm of the engine would increase by 2.5% and compression ratio would thus increase, with a rise in exhaust temperature. The use of WEP thrust was limited to 2 minutes to reduce stress on the engines' 750 (250+250+250) flight hours lifetime, since every second of super-afterburner counted as several minutes of regular power run due to extreme thermal stress. The Craourusians gave the emergency-power setting its "diamond regime" name. Given a skilled pilot and capable missiles, it could give a good account of itself against contemporary fighters. Its G-limits were increased from +7Gs in initial variants to +8.5Gs in the latest variants. However, not until the FG72 would Craourus ultimately replace the FG63 as a maneuvering dogfighter to counter new foreign air superiority types.

The FG63 was exported widely and remains in use. The aircraft's simple controls, engine, weapons, and avionics were much appreciated by importing nations. The use of a tail with the delta wing aids stability and control at the extremes of the flight envelope, enhancing safety for lower-skilled pilots; this in turn enhanced its marketability in exports to developing countries with limited training programs and restricted pilot pools. While technologically inferior to the more advanced fighters it often faced, low production and maintenance costs made it a favorite of nations buying Craourusian military hardware.

The FG63 has a delta wing. The sweep angle on the leading edge is 57°. The angle of incidence is 0° while the dihedral angle is −2°. On the trailing edge there are ailerons with an area of 1.18 m², and flaps with an area of 1.87 m². In front of the ailerons there are small wing fences.

The fuselage is semi-monocoque with an elliptical profile and a maximum width of 1.24 m (4 ft 1 in). The air flow to the engine is regulated by an inlet cone in the air intake. On early model FG63s, the cone has three positions. For speeds up to Mach 1.5 the cone is fully retracted to the maximum aft position. For speeds between Mach 1.5 and Mach 1.9 the cone moves to the middle position. For speeds higher than Mach 1.9 the cone moves to the maximum forward position. On the later models, the intake cone moves to a position based on the actual speed. On both sides of the nose there are gills to supply the engine with more air while on the ground and during takeoff. In the first variant of the FG63, the pitot tube is attached to the bottom of the nose.

The cabin is pressurized and air conditioned. The minimum height for ejection **in level flight** was 110 m.

On the under side of the aircraft there are three air brakes, two at the front and one at the rear. The front air brakes have an area of 0.76 m², and a deflection angle of 35°. The rear air brake has an area of 0.46 m² and a deflection angle of 40°. The rear air brake is blocked if the airplane carries an external fuel tank. Behind the air brakes are the bays for the main landing gear.

The empennage of the FG63 consists of a vertical stabilizer, a stabilator and a small fin on the bottom of the tail to improve yaw control. The vertical stabilizer has a sweep angle of 60° and an area of 5.32 m² (on earlier version 3.8 m²) and a rudder. The stabilator has a sweep angle of 57°, an area of 3.94 m² and a span of 2.6 m.

The FG63 uses a tricycle type undercarriage. On most variants the main landing gear uses tires that are 800 mm in diameter and 200 mm in width. Only the early variants use tires with the size 660×200 mm. The wheels of the main landing gear retract into the fuselage after rotating 87° and the shock absorbers retract into the wing. The nose gear retracts forward into the fuselage under the radar. The nose wheel can be lowered manually by simply unlocking its hatch from inside the cockpit. Thus, landing with undercarriage locked in the up position due to an internal failure was not a major issue, with a number of such successful landings on the nosewheel and ventral fuel tank or the airbrake.

## Variants

### Craourus-build Variants

##### FG63 *Olowek*

Designed and build by the Kingdom of Craourus. Short-range day fighter; the FG63 *Olowek* was the first FG63 model to be produced in large numbers. The FG63 had only one NR-30 cannon on the starboard side, with only 60 rounds; however, it added the capability to use the K-13 missile system, of which two could be carried on underwing hardpoints. On early-production FG63s the launch rails were of the APU-28 type; later models had these replaced by APU-13 rails. The launch rails were removable, allowing the FG63 to carry two UB-16-57 unguided rocket launchers, two S-24 rockets on PU-12-40 launch rails or two FAB-100/250/500 bombs or ZB-360 napalm tanks. The *Olowek* had further upgrades: an improved ASP-5ND optical gunsight and an upgraded SRD-5ND ranging radar, instead of the older ASP-5NV-U1 and SRD-5MN *Baza-6* radar rangefinder from its Prototype. Powered by a R11F-300 giving the plane a thrust of 5740 kgf of thrust.

##### FG63RM *Skurwol*

Modern and upgraded version of the FG63. Entire new airframe was made with a long saddle tank on it's spine and nose intake was enlarged. Single 30mm gun was replaced with a double barrel 23mm cannon with 200 rounds. Two more pylons where added on its wing to carry more bombs and rockets. Next to K-13 missile, it can carry 4x R-60 Air-to-air missiles. New RP-22 Radar and powered by a R13-300 turbojet with a thurst of 6495 kgf.

### Foreign-built variants

#### Alteragon

##### FG63RMP *Fulgrim*

Long-range single seat fighter/interceptor based of the FG63RM. Reinforced wings allowing it to carry 4x R-3R long range semi-active radar homing missile, build by Alteragon and very similar to AIM-7 *Sparrow.* Bigger saddle tank on its back to increase fuel capacity.

##### FG63TO *Logar*

Ultimate FG63 based of the FG63RM. Fitted with a R25-300 turbojet engine. Reinforced wings giving it a great variety and increase amount of missiles, rockets and bombs. 6x R-60, each 2x mounted on a twin rail on each wing. Improved K-13, K-13M as well carrying R-3R. Flares added to the belly of the Plane for increased protection against infrared homing missiles. Ammo capacity for its 23mm was increased to 250.

#### Oribeilena

##### TXF-13 *Kajikia*

For more information, check the TXF-13.

Oribeilena licensed build FG63 based of the Craourusian FG63RM *Skurwol.*

#### Stelka

##### FG63DMP *Sup*

Stelkan produced FG63 based of the FG63 *Olowek*. All-weather interceptor. These were powered by the R11F2-300 turbojet and fitted with the RP-21M radar. Further, the weapons control system was modified from that of the *Olowek* to allow use of the IR-seeking K-13. Single 30mm cannon was replaced by a double barrel 23mm cannon with 200 rounds of ammo. Later test proved that the DMP can carry Kh-66 air-to-surface missile.