In parallel with the
I-26 (or Y-26), the Yakovlev design bureau developed a two seat version
under the designation Y-27. One pre-production I-26 was completed to
this configuration. It was intended to not only serve as a dual control
fighter trainer but also as a liason and unit support aircraft.
Compared with the I-26, the Ya-27 was simplified and reduced in weight,
the tandem cockpits being enclosed by an extended glazed canopy. The
resulting Yak-7 aircraft entered production in May 1941 and was soon
found to have better flying qualities than that of the series Yak-1
aircraft. This performance, combined with the urgent need for for more
fighters, led to production of a single seat version of which the first
was flown in June 1941. In the following month the fighter was
officially designated the Yak-7A and the two seater Yak-7V. By the end
of 1941, a new single seater, the Yak-7B had replaced the Yak-7A. Total
delivery of all versions of the Yak-7 was 6,399 aircraft with
production ending in early 1943. Of this number, some 1,500 were
series version of a
single seat fighter with the 1,050 hp (783 kw) M-105P engine. The rear
cockpit was deleted and faired over and a new pointed wing with a span
of 33 ft 7 3/4 in (10.00 m) was introduced.
for the two seater which by July 1941 was in large scale production
with the same wingspan as the Yak-7A. Some Yak-7Vs had fixed landing
gear that could operate with wheels or skis.
Wingspan was reduced to
32 ft 9 3/4 in (10.00 m) but still the same wing area as the Yak-7A and
Yak-7V. Landing gear was simplified and equipment was improved. This
version proved to be a very important type in the V-VS inventory that
performed well against enemy fighters. Over 5,000 of this type were
with wooden wings and metal spars and increased fuel capacity.
A version with a
redesigned fuselage to mount the M-82 radial engine and armed with one
fuselage mounted 12.7 mm (0.50 in) UBS machine gun and two 20 mm ShVAK
cannon. Was tested in 1941.
Two aircraft tested
with engine mounted heavy cannon for anti-tank duties. One had the 37
mm NS-37 cannon and the other the 45 mm NS-45 cannon.
A field conversion of
1944 for use as a VIP transport with a very comfortable rear cockpit.
Several examples were modified to this version.
Two series aircraft
tested with two DM-4C ramjets on pylons under wings. Maximum speed was
increased by 56 mph (90 km/h).
Type: Two Seat
Tandem Trainer & Liason
Aleksandr Sergeyevich Yakolev
1,050 hp (783 kw) M-105P 12-cylinder Vee engine.
Maximum speed 407 mph (655 km/h) at 10,170 ft (3100 m); service ceiling
35,105 ft (10700 m).
Range: 559 miles
(900 km) on internal fuel.
equipped 4,641 lbs (2105 kg) with a maximum take-off weight of 5,864
lbs (2660 kg).
33 ft 7 1/2 in (10.25 m); length 27 ft 10 1/4 in (8.49 m); height 7 ft
11 1/4 in (2.42 m); wing area 159.53 sq ft
(14.83 sq m).
engine mounted 20 mm ShVAK cannon with 140 rounds and two synchronised
12.7 mm (0.50 in) UBS machine guns with 348 rounds each.
(prototype), Yak-7 (initial designation for the two seat liason/trainer
and also for the first single seat conversion), Yak-7A, Yak-7V
(official designation for the two seat trainer), Yak-7B (shorter
winspan of (10.00 m) 32 ft 9 3/4 in), Yak-7D (experimental) Yak-7/M-82
(M-82 radial engine), Yak-7T (anti-tank), Yak-7K (VIP transport),
Yak-7PVRD (ramjets under wings).