Yakovlev Yak-1 & others

https://en.wikipedia.org/wiki/Yakovlev_Yak-1

The Yakovlev Yak-1 (Russian: ??????? ??-1) was a World War II Soviet fighter
aircraft. Production began in early 1940. It was a single-seat monoplane with a
composite structure and wooden wings.

The Yak-1 was a manoeuvrable, fast and competitive aircraft. The
composite-wooden structure made it easy to maintain, and the engine proved to be
reliable. It formed an essential basis for subsequent developments from the
Yakovlev bureau. It was the founder of a family of aircraft, with some 37,000
being built. As a reward, designer Alexander Yakovlev was awarded the Order of
Lenin (Orden Lenina) - the highest decoration bestowed by the Soviet Union - a
100,000 ruble prize, plus a Zis motor car.

Prior to World War II, Yakovlev was best known for building light sports
aircraft. His Yak-4 light bomber impressed the Soviet government enough to order
the OKB to design a new fighter with a Klimov M-106 V-12 liquid-cooled engine.
Formal specifications, which were released on 29 July 1939, called for two
prototypes - I-26-1 with a top speed of 620 km/h (385 mph) at 6,000 m (16,685
ft), combat range of 600 km (375 mi), a climb to 10,000 m (32,808 ft) of under
11 minutes, and armament of 2 × 7.62 mm ShKAS machine guns and 1 × 12.7 mm (0.5
in) Berezin BS heavy machine gun, and I-26-2 with a turbocharged M-106 engine
with a top speed of 650 km/h (404 mph) at 10,000 m (32,808 ft) and armament of 2
× 7.62 mm (.3 in) ShKAS machine guns. The design took full advantage of Yakovlev
OKB's experience with sports aircraft and promised agility as well as high top
speed. Since the M-106 was delayed, the design was changed to incorporate the
Klimov M-105P V-12 engine, with a 20 mm (.8 in) ShVAK cannon in the "vee" of the
engine block, in a motornaya pushka mount.

I-26-I first flew on 13 January 1940. The prototype suffered from oil
overheating problems which were never completely resolved, resulting in 15
emergency landings during early testing. Then, on 27 April 1940, I-26-1 crashed,
killing its test pilot Yu.I. Piontkovskiy. The investigation of the crash found
that the pilot had performed two consecutive barrel rolls at low altitude, which
was in violation of the test flight plan. It was believed that during the first
roll, the main landing gear became unlocked, causing it to crash through the
wing during the second roll. It has been hypothesized that Piontkovskiy's
deviation from the flight plan was caused by frustration that his aircraft was
being used for engine testing while I-26-2, built with the lessons of I-26-1 in
mind, was already performing aerobatics.

Troublesome and slow testing and development concerned Soviet officials, since
I-26 was ordered into production under the name "Yak-1" on 19 February 1940, a
mere month after I-26-1 made its maiden flight. The goal of this gamble was to
reduce the lag time between the prototype and production aircraft. As backups,
the I-200 and I-301 were also ordered into production. Although the Yak-1 was
slower than the I-200 and less heavily armed than the I-301, it enjoyed the
advantage of having been started earlier, which gave it a consistent lead in
testing and development over its competitors. Due to the Axis invasion of the
Soviet Union on 22 June 1941, development and implementation of several other
upcoming promising designs, like the Polikarpov I-185, proved unfeasible.
Yakovlev might have been Joseph Stalin's personal favorite, which may have been
in the Yak-1's favor.

Simultaneous manufacturing and testing of a design that required as many
improvements as I-26 wreaked havoc on the production lines. Almost 8,000 changes
were made to the aircraft's blueprints by 1941, with an additional 7,000
implemented the following year, and 5,000 more changes coming in 1942.
Production was further slowed by shortages of engines, propellers, radiators,
wheels and cannons. Shortages of quality materials resulted in plywood being
torn off the wings on several aircraft. To make matters worse, Factory No.292
which was the main manufacturer of Yak-1s was bombed on 23 June 1943 and burned
to the ground. Amazingly, production resumed amid the ruins on 29 June. Due to
loose tolerances, each aircraft was essentially unique, with workers performing
the final assembly having the unenviable task of mating what often proved to be
somewhat dissimilar components. For example, the left and right main landing
gear could be of different lengths and different angles relative to the
aircraft, which required adjusting their attachments to ensure an even stance
for the completed aircraft. Parts were often not interchangeable between
aircraft. Production of the Yak-1 ended in July 1944, with somewhere around
8,700 built.


Role
Fighter

Manufacturer
Yakovlev OKB

First flight
13 January 1940

Introduction
1940

Retired
1950

Primary user
Soviet Air Force

Produced
1940-1944

Number built
8,700

Variants
Yakovlev Yak-3
Yakovlev Yak-7
Yakovlev Yak-9
Yakovlev Yak-15

At the time of the German invasion of Soviet Union on 22 June 1941, 425 Yak-1s
had been built, although many were en route or still disassembled. 92 machines
were fully operational in the Western Military Districts, but most were lost in
the very first days of the war. The Yak-1 was designed with the goal of
providing direct coverage of the Il-2 attack planes from enemy fighters. Thus,
most of the air combat took place below 4,000 m (13,123 ft), at low altitudes
where the Yak-1 performed the best. The Yak-1 proved to have a significant
advantage over its Soviet competitors. A full circle turn took just 17 seconds
in the Yak-1M. The MiG-3, which had the best high-altitude performance, did
poorly at low and medium altitudes, and its light armament made it unsuitable
even for ground attack. The LaGG-3 experienced a significant degradation in
performance (as much as 100 km/h/62 mph on some aircraft) compared to its
prototypes due to the manufacturer's inexperience with its special wooden
construction, which suffered from warping and rotting when exposed to the
elements. The Yak-1's plywood covering also suffered from the weather, but the
steel frame kept the aircraft largely intact.

The aircraft's major problem early in deployment was fuel leaks caused by
failure of spot-welded fuel tanks from vibration. Also troublesome was the fact
that the canopy could not be opened under certain conditions in earlier models,
potentially trapping the pilot in a falling aircraft. As a result, some pilots
had the sliding portion of the canopy removed altogether. The first 1,000 Yak-1s
had no radios. Installation of radio equipment became common by spring 1942 and
obligatory by August 1942. But Soviet radios were notoriously unreliable and
short-ranged, so they were frequently removed to save weight.

Soviet naming conventions obscure the fact that the Yak-1 and its successors —
the Yak-7, Yak-9 and Yak-3 — are essentially the same design, comparable to the
numerous Spitfire or Bf 109 variants. Were the Yaks considered as one type, the
37,000 built would constitute the most produced fighter in history. That total
would also make the Yak one of the most prolific aircraft in history, roughly
equal to the best known Soviet ground attack type of World War II, the IL-2
Shturmovik. But losses were proportionally high, in fact the highest of all
fighter types in service in the USSR: from 1941 to 1945, VVS KA lost 3,336
Yak-1s: 325 in 1941, 1,301 the following year, 1,056 in 1943, 575 in 1944 and 79
in 1945.

Specifications (Yak-1b)

General characteristics
Crew: One
Length: 8.5 m (27 ft 11 in)
Wingspan: 10.0 m (32 ft 10 in)
Height: 2.64 m (8ft 6in)
Wing area: 17.2 m2 (185.1 ft2)
Empty weight: 2,394 kg (5,267 lb)
Loaded weight: 2,883 kg (6,343 lb)
Max. takeoff weight: kg (lb)
Powerplant: 1 × Klimov M-105PF V-12 liquid-cooled engine, 880 kW (1,180 hp)

Performance
Maximum speed: 592 km/h at altitude (368 mph)
Range: 700 km (435 mi)
Service ceiling: 10,050 m (32,972 ft)
Rate of climb: 15.4 m/s (3,038 ft/min)
Wing loading: 168 kg/m2 (34 lb/ft2)
Power/mass: 0.31 kW/kg (0.19 hp/lb)

Armament

1 × 20 mm (0.8 in) ShVAK cannon, 1 × 12.7 mm (0.5 in) Berezin UBS machine gun.
One-second salvo weight of fire 2 kg (4.4 lb) with both the cannon and the
machine gun using high-explosive ammunition