Vetrov-Kazakov VeK-7

Vetrov-Kazakov VeK-7
A VeK-7 of the 84th Aviation Squadron, 209th Guards Aviation Fighter Regiment.
General information
Type	Fighter-bomber, Interceptor, fighter
Manufacturer	VeK Design Bureau
Status	Retired
History
Manufactured	1942-1947
Introduction date	12 January 1943
Retired	25 June 1950

The Vetrov-Kazakov VeK-7 was a single-engine single-seat fighter-interceptor and fighter-bomber aircraft of the Stasnovan Revolutionary Air Force during the Second Great War. It was designed by the Vetrov-Kazakov Aircraft Design Bureau and built in large numbers to replace the earlier MiG-3s in the high altitude interceptor role. However as the war progressed and more variants were built, the VeK-7 found itself serving multiple roles, including ground attack.

Design and development

As soon as the MiG-3 entered service in the Stasnovan Revolutionary Air Force, plans immedeately began to develop a successor. The rival Vetrov-Kazakov Design Bureau already had a concept for a high-altitude fighter-interceptor in the works from 1935, which was created as a response to the Bf 109. A few prototypes were built but rejected by the VVS. However, the multiple teething of the MiG-3 brought the VeK prototype into the forefront once again. The final nail in the coffin was the TBD Incident, when three VVS MiG-3s crashed after entering flat spins during an interception mission against Elesarian recon aircraft. The Commissariat of Defence and the VVS both approved the improved design offered by VeK, and work began on a production version of the aircraft.

The prototype, named I-24, was similar to the MiG-3 is some aspects, such as the wing shape, but overall the aircraft was larger and heavier. The I-17 was originally powered by a Krasna AD-20 liquid-cooled V12 engine producing 1,400 hp, and had a top speed of 642/h at high altitude, just 2 km/h over the MiG-3. The engine was deemed insufficient during testing, and the Krasna OKB was tasked to create a more powerful engine. The start of the Second Great War with the Axis invasion of the Internationale states hampered the process of new aircraft designs in the USRS, as much funding was diverted to other branches and the production of already existing designs.

However, as the MiG-3s were proved insufficient in taking on Axis aircraft such as Elesarian Bf 109s and Granzerian Vertegas at high altitude, funding was again re-alocated to the I-24 project. The new powerplant, the 1,500 hp Krasna AD-42A, was ready by early 1942, and gave the aircraft a top speed of 672 km/h at 7,800 metres. The larger engine required the aircraft to be lengthened to fit it, and some aspects of the airframe were reworked for overall better balance. The new prototype, named I-27, flew on February 12t 1942, with satisfying results, and after some further modification, the design was approved for mass production as the VeK-7.

The VeK-7 was armed with three 20mm ShVAK cannons, one engine mounted and two in the upper engine cowling (each with 250 rounds per gun). This armament was uncharacterstically heavy for Stasnovan aircraft, but fit the VeK-7s role as a high altitude interceptor that would be required to engage heavy bombers. Stasnovan pilots generally liked the armament and the tight grouping on the nose, but complaints were made about the recoil generated by the cannons. Another problem was the large muzzle flash that would obscure the pilot's view, especially during night-time fighting. Pilots thusly used to fire only in short and disciplined bursts, so as to not loose speed or their target. Later variants had different armament loadouts, for example the VeK-7M, introduced in 1944 replaced the engine mounted ShVAK with a NS-23 23mm, while the VeK-7U wtih a NS-37 37mm. The ShVAKs in the engine cowl were gradually improved with recoil compensators, while measures were taken to reduce the muzzle flash as well. Provisions were also included for mounting underwing onrdnance and gun pods.

While the AD-42A engine proved sufficient in the baseline VeK-7 variant, the later, more heavily armed versions, required a better engine to compensate. A more powerful engine was alreaday in the works for the navalised variant, the VeK-7K, and it was decided that it would power the improved ground based versions as well, so as to streamline production. The new engine was the Krasna AD-45M, producing 1,650 hp. While not increasing the top speed by a large margin (only and additional 15 km/h on the VeK-7U), it was similarly sized, and was able to compensate for the heavier armament and improved avionics of the later versions, while it was also found more reliable to maintain than the AD-42.

The VeK-7K navalised variant of the VeK-7 is a curious case of an naval aircraft built solely to equip a single ship, and one of the few specialised exceptions in the efficiency and quantity-minded Stasnovan wartime industry. The old TBD fighters that formed the Combat Air Patrol of the Noyabrskaya Revolyutsiya, the sole Stasnovan aircraft carrier during Great War II, were heavily outclassed by Axis aircraft. As such, the decision was taken to create a navalised fighter of an already existing land based design to replace them. Despite being larger than the generally small Stasnovan fighters (like the Yak-9s or La-5s), the high-altitude performance of the VeK-7 was deemed critial in dealing with level-bombing attacks by high-flyig bombers against naval targets. The new VeK-7K had wider, folding wings, the more powerful AD-45M engine and a reinforced fuselage to withstand that extreme stress of carrier landings. A total of 104 airframes were built, 30 to equip the 279th Shipborne Fighter Aviation Regiment onboard the Revolyutsiya, another 60 for the reserve/trainning 280th and 281st Shipborne Fighter Aviation Regiments, and 14 spares.

Variants

• VeK-7: Baseline variant introduced in 1942. 3x20mm ShVAK armament (250 rpg) and the AD-42A engine. Used widely in high altitude missions.
• VeK-7K: Carrier-borne variant introduced in 1943. Same weaponry as the baseline version, but with the more powerful and improved AD-45M powerplant. Also features provisions for underwing ordnance.
• VeK-7M: Improved version introduced in 1944. Engine-mounted 20mm replaced by a NS-23 23mm cannon with (90 rpg), with improved radio set and avionics, and can also carry underwing ordnance.
• VeK-7U: Fighter-Bomber version introducedd in 1945. Features an engine-mounted NS-37 37mmm gun (27 rpg), as well as the AD-45 engine. Used in both interception and ground attack roles, as the centrally mounted 37mm could take on both heavy bombers and the lightly armoured top armour of AFVs, with the right ammunition.

Specifications (VeK-7)

General characteristics

• Crew: 1
• Length: 9.85 m (32 ft 5 in)
• Wingspan: 11.80 m (38 feet 8 in)
• Height: 3.30 m (10 ft 9⅞ in)
• Wing area: 17.44 m² (188 ft²)
• Empty weight: 2,899 kg (5,965 lb)
• Loaded weight: 3,855 kg (7,415 lb)
• Powerplant: 1 × Krasna AD-42A liquid-cooled V12 engine, 1,120 kW (1,500 hp)

Performance

• Maximum speed: 672 km/h (417 mph) at 7,800 altitude
• Combat range: 1,000 km with drop tanks (621 mi; 539 nmi)
• Service ceiling: 12,000 m (39,400 ft)
• Wing loading: 155 kg/m² (39.3 lb/ft²)

Armament
VeK-7:

• 3 × 20 mm ShVAK cannon, one engine-mounted (250 rpg), two in upper engine cowling (250 rpg)
• Optional 2 x 12.7 mm Berezhin UBK gun pods under the wings (350 rpg)

VeK-7M:

• 2 × 20 mm ShVAK cannon in upper engine cowling (250 rpg)
• 1 × 23 mm Nudelman-Suranov NS-23, engine-mounted (90 rpg)
• Optional 2 x 12.7 mm Berezhin UBK MG pods (350 rpg) or 2 x 20 mm Berezin B-20 cannon pods (150 rpg) under the wings
• Provisions for 4 x FAB-100 (100 kg) bombs, 2 x FAB-250 (250 kg) bombs, or 8 x RS-82 or RBS-82 rockets under the wings

VeK-7U:

• 2 × 20 mm ShVAK cannon in upper engine cowling (250 rpg)
• 1 × 37 mm Nudelman-Suranov NS-37 (later Nudelman N-37), engine-mounted (27 rpg)
• Optional 2 x 12.7 mm Berezhin UBK MG pods (350 rpg) or 2 x 20 mm Berezin B-20 cannon pods (150 rpg) under the wings
• Provisions for 4 x FAB-100 (100 kg) bombs, 2 x FAB-250 (250 kg) bombs, or 8 x RS-82 or RBS-82 rockets under the wings