The Sinaljanah S-630 Alzawjiu Heavy Fighter Aircraft was an aircraft built by Sinaljanah Aircraft Industries, in use with the Air Corps of the Armies of the Five Deserts from 1938 to 1959. It was occasionally used on Eanqa-class Aircraft Carriers of the Sultan's Navy.
The quest for a heavy fighter for the Army Air Command began in 1935, when the concept of a heavy fighter, its combination of range and firepower being alluring, the lack in agility being seen as an acceptable drawback.
Designed as a bomber destroyer and escort fighter, with ground attack not even factoring into it, the first drafts were massive, under-powered single-engine fighters, which were quickly abandoned - soon, Sinaljanah proposed a two-engine, two-seat fighter. The first mock-up was finished in late 1936, the first prototype being finished a few months later and having a first flight in early 1937. Its main competitors were the Kyrenaian Aircraft Factories KAF-109 Tayrih Fighter of the RKN and the Taebith T-112 Sahm Fighter of the RKA.
The major issue was of this prototype was, that the engines were prone to failure and underpowered, which led to Sinaljanah installing the same engines as on the Sinaljanah S-57 Passenger Airliner and later the Falawatis F-1 Reconnaissance Floatplane, the Sinaljanah SM-13 Engine. Capable and proven, this engine proved to be the salvation from some of the problems plaguing the S-630A.
The RKA was satisfied and gave the order to produce the aircraft in 1938 as the Sinaljanah S-630NAI-1 Alzawjiu Heavy Fighter Aircraft.
In 1942, when it became more and more apparent, that the S-630NAI-1 was not agile enough to face smaller, single-engine fighters in an equal footing, the S-630 was relegated to reconnaissance, ground attack and maritime patrol duties.
The Alzawjiu was produced in several variants during its production run from 1937 to 1948.
S-630A was the pre-production model, fifteen aircraft built, test-wise equipped with two Alqatat Gunsmiths 20mm Aircraft Guns (20x82 Series) and a light machine gun for a reargunner.
S-630NAI-1 was the first production model, added two hardpoints under the wings, for up to three hundred kilograms of bombs. In field modifications starting weeks after its introduction, the NAI-1 was enabled to carry rockets, up to six under each wing.
S-630NAI-2 was the version with an upgraded engine, the Sinaljanah SM-25 Engine with 1,150 horse power of power output. It also changed quite a bit about the armament, exchanging the 20mm guns for the advanced version of the 20x110mm Series and adding two 40mm cannons with autoloaders having a thirty round clips under the wings, omitting the hardpoints. As Gunbird, the S-630NAI-2 was well-liked with the ground forces supported by it, but utterly hated by the pilots.
S-630NAI-3 worked out the last mechanical kinks, added a serialized radar and moved autocannons from the nose to the wings, which was a change, which the pilots did not like. Only a handful of S-630NAI-3s were produced.
AA-1 and AA-2 were S-630NAI-2s with small air search radars, production starting in 1943 and 1945 respectively.
After the first flight in early 1937, the Army Air Corps ordered fifteen pre-production models, S-630A, to test
The first combat test was during the Aintalaq-Uprising in 1939, when a formation of Alzawjius of the 38th Long-Range Fighter Wing engaged rebel positions with autocannon fire and was attacked by a formation of fighterplanes, Cellule Repubblicane CR-15 Gabbiano Fighter-Bombers, which they routed with two planes lost to their six lost biplanes. Later analysis emphasized, that it was not the agility or firepower of the Alzawjius, which brought them victory in that fight, but the armour, which the light machine guns on the CR-15s was unable to penetrate.
By 1942, faced with more modern fighters like the Braccio B-26 Interceptor and the Sciathán Léachtóir Fighter, it became apparent, that the S-630NAI-1 was fighting an uphill battle on a hill, which got higher and steeper by the month. The Army Air Command tasked Sinaljanah Aircraft Industries with developing the S-630 into a ground-attack and reconnaissance aircraft, possibly with a second use as a maritime patrol aircraft.
S-630NAI-2 rolled out later that year, with new engines and armament, AA-1, the first night fighter in service with the Kyrenaian Armed Forces followed based on that version in 1943, equipped with a radar set. AA-2 was added in 1945.
As a heavy ground-attack aircraft and reconnaissance plane, as well as for maritime patrol, the Alzawjiu proved itself very capable, more capable then the contemporary Sinaljanah S-65 Einaq Ground Attack Aircraft – however, the Einaq was lighter, cheaper to acquire and operate. They were far more numerous then the Alzawjiu. In 1947, S-630NAI-3 was added to the list, but enjoyed only a short production run.
In 1948, the production of the Alzawjiu ended. From 1950 onwards, the Alzawjiu was mostly used as a trainer for new pilots and as a target tug for AA-gunnery practice. In 1959, the Army put the last Alzawjius out of service, handing them over to the Coast Guard, where they served in a maritime patrol role until 1979. The last remaining Alzawjius were handed to private collectors or museums.