Yak-7B M-105PA fighter by A.S.Yakovlev

Color scheme from lost source. Air intakes, gun fairing, covered rear cockpit, enlarged chin oil cooler - but Yak-7A-style tailwheel.

Development of the series Yak-7A, the Yak-7B was better armed and featured number of other improvements. Rifle-caliber ShKAS machineguns were replaced by far more capable pair of 12.7mm synchronized UBS (left with 260 rounds, right with 140). To accommodate those machineguns, Yak-7B had distinctive fairings on the engine cowling. As an option, six RS-82 rockets could be replaced by two bombs (from 25 to 100kg each).

On the Yak-7B full package of airdynamic TsAGI recommendations was implemented:

• Engine air intakes was made flush with wing surface, enlarged and turned slightly downwards
• Protecting mesh was tilted and moved deeper into intake
• Intake channels were carefully sealed
• Tailwheel was completely retractable and covered with two side doors (like on the UTI-26)
• Wheel doors, access hatches, engine cowling were better fitted
• Surface finishing quality was improved

Takeoff engine rate and propeller regime were modified in order to improve takeoff performance. Oil and water cooler channels and shutters were revised, allowing continuous operation with maximum engine power. Externally those changes may be identified by turned downwards outlet of the oil cooler ('beard'). Some efforts were made to overcome oil leakage problem of the M-105 engine, but with little success. Emergency pneumatic system was extended to wheel brakes and landing flap, increasing aircraft reliability. Emergency air bottle was relocated under cabin floor. Cockpit also was revised:

• Control stick R-1 similar to one of the Bf-109 was installed
• Sliding section of the canopy was strengthened

Modification of the electric system included:

• Lowered voltage on the control panel light, improving their reliability
• Single-wire system with adequate grounding and shielding
• As a result, range and quality of radio communication finally matched VVS demands
• Electro-pneumatic weapons control
• Parking grounding introduced

All Yak-7B were equipped with radio receiver RSI-4 'Malutka' and had provision for the RSI-3 'Oriol' transmitter. Nonetheless, shortage of transmitters forced factory to fit only fraction of fighters with full set of radio equipment. For example, only 10% Yak-7B of the 22th batch carried transmitters.

Despite Yak-7B was heavier than its predecessors, carried antenna mast and fairings on the engine cowling, its performance was (finally!) identical with the UTI-26-2, what was a 'milestone' in the Yak-7 evolution. With new weapons, Yak-7B salvo was superior to all domestic single-engine fighters and most of the enemy aircraft (Bf-109F and Bf-109G-2).

The first series Yak-7B ('golovnoj') N°14-13 passed combined State and Factory Trials between January 28 and February 5 1942 at the Novosibirsk Factory N°153 airfield. Trials brigade included pilots A.G.Kochetkov (NII VVS) and N.S.Rybko (LII), leading engineers V.N.Saginov (LII), A.T.Stepanets (NII VVS) and A.P.Rybchenkov (Factory N°153), weapon specialists A.G.Aronov (NII VVS) and G.I.Goudimenko (A.S.Yakovlev OKB). Trials were quite short: 27 flights, totalling just 17h. The only revealed shortcoming was and increased tendency to noseover.

It was clear that aircraft is a success, and the GKO immediately ordered Factory N°153 to cease production of the Yak-7A in favour of new 'family member'.

Yak-7B M-105PA was built in April-July 1942, with total 261 aircraft assembled. Little new changes were introduced during this period. Since May 10 the RS-82 launchers were deleted, because larger firepower improved efficiency of Yak-7B attacks against bombers and ground targets. Increasing production of the specialized Il-2 attackers allowed to use Yak-7B in its major role - air-to-air combat.

Another change was an installation (May 20) of additional 80l fuel tank in the rear cockpit. This tank was intended to counterweight increased weapons weight, but at the same time it increased the weight and vulnerability (it was unprotected!). Naturally, it was disliked by pilots, and was often removed by field mechanics. This 'field modification' was approved (post-factum) by the GKO at the end of October 1942.

Special weapons trial was carried out in June 1942, when series Yak-7B N°22-03 performed 25 flights (7h57min), firing its guns from under variety of conditions.

Yak-7B M-105PA were used during Kuban` and Stalingrad battles. Pilots and commanders agreed that its combat performance is superior to all domestic fighters (LaGG-3 and MiG-3 especially). It is also superior to Bf-109 in horizontal combat and almost even in vertical maneuvers (depending on the Bf-109 model). List of shortcomings included:

• Heavy, insufficient engine power, slow acceleration
• Large drag induced by oil and water coolers
• Poor rear view
• Poor quality of canopy glazing (plexiglas), forcing pilots to fly with open cockpit
• Demanding to airstrip length and quality

Predecessors	Modifications/Variants
Yak-7A	Yak-7R M-105PA plus 2*DM-4	Yak-7-37	Yak-7B M-105PF

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Created January 19, 2001

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