Yakovlev Yak-7

Yakovlev Yak-7

Company type	Fighter aircraft
Industry	Aerospace
Founded	1939
Founder	Alexander Sergeevich Yakovlev
Headquarters	Soviet Union
Products	Military aircraft

The Yakovlev Yak-7 (Russian: Яковлев Як-7; NATO reporting name: Mark) originated as a derivative of the earlier Yakovlev Yak-1 fighter, initially conceived as a trainer before being adapted into a combat fighter. Throughout its service, it demonstrated versatility by fulfilling both training and frontline combat roles, earning high regard from pilots. Compared to the Yak-1, the Yak-7 was generally more robust, simpler in design, and superior in performance.

Design and development

In 1939, Alexander Sergeevich Yakovlev created an advanced tandem-seat trainer originally named "I-27," later redesignated "UTI-26," which was proposed alongside the I-26 design that evolved into the Yak-1. The "UTI" (Uchebno Trenirovochnyi Istrebitel, meaning Training Fighter) aimed to familiarize trainee pilots with high-performance aircraft prior to transitioning to frontline fighters. Development began in 1940, and the UTI-26 featured a larger wingspan positioned further aft for improved balance, dual cockpits equipped with duplicate controls, and a basic communication system. Its armament consisted of a single 7.62 mm (0.30 in) ShKAS machine gun mounted in the cowling, primarily for training purposes; however, Yakovlev envisioned its use extending to courier and light transport missions near the front lines.

The initial production models, designated Yak-7UTI, retained retractable main landing gear. However, starting summer 1941, a fixed landing gear variant called the Yak-7V (Vyvozoni meaning Familiarization) was introduced to simplify manufacturing, with the trade-off of reduced performance deemed acceptable for a trainer role. Both the Yak-7UTI and Yak-7V were outfitted with skis for operations in winter conditions.

A dedicated team from Factory No. 301 led by K.A. Sinelshchikov was assigned from the Yakovlev OKB to oversee Yak-7UTI production. One particular aircraft (serial number 04-11) was modified to include an armored backrest plate for the rear cockpit position, self-sealing fuel tanks filled with inert gas upon depletion, three "RO" rocket launchers under each wing carrying RS-82 rockets, a centrally mounted 20 mm (0.79 in) ShVAK cannon firing through the propeller spinner with 120 rounds of ammunition, and two additional 7.62 mm ShKAS machine guns under the cowling each loaded with 750 rounds. The rear cockpit remained intact and could be configured either with a second seat lacking controls for rapid courier or transport roles or replaced by an auxiliary fuel tank to extend range; alternatively, it could carry bombs or other equipment. Powered by an M-105P engine, this version was designated Yak-7/M-105P.

Sinelshchikov implemented these modifications without informing Yakovlev initially; upon learning of them, Yakovlev expressed doubts regarding their necessity. Nevertheless, factory trials revealed that this variant outperformed the single-seat Yak-1 due to improvements applied during UTI development as well as enhancements such as larger tires and wheels on the revised landing gear, improved brakes, and modified elevators among other refinements. Following submission to authorities, the Yak-7 received immediate approval. Armament testing at the scientific trials Polygon for aircraft armament (NIPAV) confirmed that weaponry did not adversely affect flight behavior or overall performance. Moreover, its stability as a firing platform surpassed that of contemporaries like the Lavochkin-Gorbunov-Gudkov LaGG-3 and Mikoyan-Gurevich MiG-3.

In August 1941, decrees from both the GKO and NKAP authorized production of the Yak-7 at Factories No. 301 and No. 153; however, due to evacuation of Factory No. 301 to Novosibirsk, it merged operations with Factory No. 153. Consequently, only 62 units were manufactured during 1941: 51 between September and October at Factory No. 301 and 11 in December at Factory No. 153. Test pilot A.N. Lazarev praised its favorable flight characteristics including ease of spin recovery and stable behavior during dives—qualities he regarded as safer than those of the Yak-1—though he identified issues related to M-105P engine piping, landing gear locking mechanisms, tires, and tail wheel. The first batch of approximately sixty aircraft entered operational service by late 1941.

A significant subsequent variant was the Yak-7/M-105PA model which replaced the two ShKAS machine guns on the cowling with twin 12.7 mm (0.50 in) UBS machine guns carrying respectively 260 rounds on the left and 160 on the right side. This version employed an M-105PA engine coupled with an axial ShVAK cannon armed with 120 rounds. Oil and glycol radiators were enlarged and slightly tilted downward for enhanced cooling efficiency; airframe insulation was improved; tail wheel became fully retractable; jointing and skin panels were executed with greater precision; engine cowling panels fitted more tightly; propeller reduction gear functioned more reliably; electro-pneumatic reloading systems were installed; and canopy frames were strengthened accordingly. The Yak-7B underwent twenty-seven test flights during January and February of 1942 with reports highlighting that although it was comparable in performance to LaGG-3s and MiG-3s as well as foreign fighters operating within USSR service at that time, it exhibited superior stability and flight characteristics overall. Subsequently, GKO approved production at Factory No. 153 beginning April 1942 replacing earlier Yak-7A models; approximately 261 units were completed by July that year. After May 20th production runs included a 68 L (18 US gal) fuel tank positioned behind the pilot’s seat; however pilots engaged in combat over Stalingrad and Kuban often removed this tank due to lack of protection and negative impact on handling characteristics. Generally regarded favorably by pilots who found it easy to fly across all altitudes with stable handling and straightforward maintenance requirements, it nonetheless lagged behind in climb rate compared to the Messerschmitt Bf 109, while matching its maneuverability and speed except vertically. Criticisms included excessive drag from radiators, poor quality canopy glass, insufficient pilot protection, overly long takeoff and landing distances, and notably inadequate power output.

Yakovlev proposed engine improvements to Klimov resulting in an upgraded M-105PF powerplant delivering an additional 130 horsepower (97 kW) output increase. Equipped with this engine upgrade, the Yak-7B achieved a maximum speed of 599 kilometres per hour (372 mph), exhibited significantly enhanced climb rates up to 5,000 metres (16,000 ft), and demonstrated improved maneuverability both horizontally and vertically. However, removal of the rear fuel tank reduced operational range while shifting center of gravity forward excessively; persistent issues remained related to cooling system overheating and oil leaks inherent in M-105 engines.

One notable armament configuration was the Yak-7-37, which mounted a 37 millimetres (1.457 in) MPSh-37 cannon (motornaya pushka Shpital'novo, meaning engine-mounted Shpital'nyy cannon) positioned between engine cylinder banks firing through the propeller spinner.

Operational history

The Yak-7 demonstrated strong capabilities as a close support fighter; however, the initial two-seat models were criticized for being front-heavy. To address this, the manufacturer added a fuel tank behind the cockpit. Pilots raised concerns about the tank’s lack of armor protection, often opting to remove it during field operations. Combat experience led to continuous design adjustments, culminating in the widely produced single-seat version known as the Yak-7B.

Following World War II, several Yak-7V trainer aircraft were supplied to Polish forces, and one Yak-7V was delivered to Hungary to assist with pilot training for the Yak-9 fighter.

In trials conducted between April and May 1942, a limited run of 22 Yak-7-37 aircraft was approved. These were assigned exclusively to the 42nd Fighter Aviation Regiment (IAP) on the North-Western front, where they achieved notable success in both aerial engagements and ground attack missions.

Variants

File:LET C-11.Yak-7 outline.Lakeland FL 18.04.07R.jpg

LET C-11 modified to Yak-7 outline, Lakeland, Florida, in April 2007

Ya-27

two-seat prototype derived from a pre-production I-26

Yak-7UTI

initial two-seat trainer and communication model; 186 units produced in 1941

Yak-7V

(vyvoznoy) two-seat trainer variant; 510 built between 1942 and 1943 plus 87 conversions from Yak-7B

Yak-7

single-seat fighter variant based on the Yak-7UTI, featuring added armor and enhanced armament; limited production during 1941–42

Yak-7-37

authorized after April–May 1942 trials with a batch of 22 units equipped with a MPSh-37 37 mm (1.457 in) cannon (MPSh stands for motornaya pushka Shpital'novo, an engine-mounted Shpital'nyy cannon) firing through the propeller spinner. Additionally armed with two 12.7 mm (0.500 in) UBS machine guns mounted above the engine in the forward fuselage.

Yak-7A

enhanced version of the Yak-7, approximately 300 manufactured in early 1942

Yak-7B

further refined iteration of the Yak-7A featuring reduced wingspan, simplified landing gear, and improved equipment; production totaled around 5,000 units

Yak-7D

long-range prototype serving as the foundation for the Yak-7DI/Yak-9

Yak-7K courier

VIP transport adaptation converted from Yak-7B in 1944

Yak-7U Mark

Yak-7PVRD

experimental model fitted with two DM-4 ramjet engines mounted under the wings, achieving a top speed of 800 km/h (500 mph); only two constructed

Yak-7DI

long-range fighter variant later redesignated as Yak-9

Yak-7 M-82

version powered by a new M-82 engine, tested in 1941

Yak-7R

jet-powered project featuring one liquid-fueled jet engine alongside two ramjets developed in 1942

Yak-7R

alleged jet variant equipped with a Jumo 004 engine reportedly built in Tbilisi for a Red Square parade flight in 1947

Yak-7R

Yak-3 derivative powered by a Jumo 004 turbojet, with development initiated by no later than 1945 and likely first flight occurring in 1946

Yak-7T

two aircraft created specifically to test heavy cannons mounted on the engine—NS-37 and NS-45 models with calibers of 37 mm (1.457 in) and 45 mm (1.772 in), respectively

Operators

Template:Country data Albania

• The Albanian Air Force introduced 20 Yak-7V two-seat trainers in 1945, alongside 30 Yak-7A single-seat fighters, an enhanced version of the Yak-7. In total, 50 units were deployed.

France

• The Normandie-Niemen squadron of the Free French Air Force operated a number of these aircraft.

Bulgaria

• The Bulgarian Air Force utilized three Yak-7V aircraft.

Hungary

• For training purposes related to the Yak-9 fighter, the Hungarian Air Force operated one Yak-7V.

Template:Country data Mongolia

• The Mongolian People's Air Force employed several Yak-7s as training aircraft.

Template:POL

• Within the Polish Air Force in the Soviet Union, a limited number of Yak-7Bs served training roles in the 1st Fighter Regiment "Warszawa". Additionally, several Yak-7Vs were assigned for training and courier missions. The Polish Air Force operated Yak-7 models from September 1943 until September 23, 1946.

Template:USSR

• Soviet Air Force

Template:YUG

• The SFR Yugoslav Air Force operated two Yak-7V aircraft.

Specifications (Yak-7A M-105PA)

File:Yakovlev Yak-7UTI and Yak-7B side-view silhouettes.png

See also

Bibliography

• Gordon, Yefim and Dmitri Khazanov. Soviet Combat Aircraft of the Second World War, Volume One: Single-Engined Fighters. Earl Shilton, Leicester, UK: Midland Publishing Ltd., 1998. ISBN 1-85780-083-4.
• Green, William. Warplanes of the Second World War, Volume Three: Fighters. London: Macdonald & Co. (Publishers) Ltd., 1961 (seventh impression 1973). ISBN 0-356-01447-9.
• Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: Soviet Air Force Fighters, Part 2. London: Macdonald and Jane's Publishers Ltd., 1978. ISBN 0-354-01088-3.
• Kopenhagen, W., ed. Das große Flugzeug-Typenbuch. Stuggart, Germany: Transpress, 1987. ISBN 3-344-00162-0.
• Leonard, Herbert. Encyclopaedia of Soviet Fighters 1939-1951. Paris: Histoire & Collections, 2005. ISBN 2-915239-60-6.
• Liss, Witold. The Yak 9 Series (Aircraft in Profile number 185). Leatherhead, Surrey, UK: Profile Publications Ltd., 1967.
• Mellinger, George. Yakovlev Aces of World War 2. Botley, UK: Osprey Publishing Ltd., 2005. ISBN 1-84176-845-6.
• Morgan, Hugh. Soviet Aces of World War 2. London: Reed International Books Ltd., 1997. ISBN 1-85532-632-9.
• Шавров В.Б. История конструкций самолетов в СССР 1938-1950 гг. (3 изд.). Kniga: Машиностроение, 1994(Shavrov, V.B. Istoriia konstruktskii samoletov v SSSR, 1938-1950 gg., 3rd ed. (History of Aircraft Design in USSR: 1938-1950). Kniga, Russia: Mashinostroenie, 1994. ISBN 5-217-00477-0.
• Stapfer, Hans-Heiri. Yak Fighters in Action (Aircraft number 78). Carrollton, Texas: Squadron/Signal Publications, Inc., 1986. ISBN 0-89747-187-3.
• Taylor, Michael J.H. Fighters and Bombers of World War II in Colour. London: Bison Books, 1985. ISBN 0-86124-224-6.
• Winchester, Jim. "Yak Fighters." Fighters: The World's Finest Combat Aircraft- 1914 to the Present Day. Bath, UK: Parragon Publishing, 2003. ISBN 1-4054-3843-6.

External links

• Detailed overview of the Yakovlev Yak-7 at aviation.ru
• Information on Yakovlev fighter aircraft