General Information
Type I-28, Yak-5
Function Experimental fighter
Year 1940
Crew 1
Powerplant
Type M-105PD
Power see table
Size
Length 8.48m
Height 2.42m
Wingspan 9.74m
Wing area 17.15m2
Weights and loads
Empty 2450kg
Takeoff 2928kg
Wing Load (kg/m2) 171
Power load (kg/hp) 2.52
Speed
at 0m 515km/h
at 9000m 650km/h
Landing 133km/h
Maneuverability
Turn time 17.6sec
Roll
Landing ?m
Takeoff ?m
Range
Practical ?km
Ceiling
Ceiling 12000m
Climb
5000m 5.2min
One Turn 800m
Payload
Fuel+Oil 310+30kg
Gun Type (Position)Ammo
20mm ShVAK (engine) 1*120
7.62mm ShKAS (engine) 2*750
Salvo (kg/sec) 1.73

I-28 (Yak-5 1940) fighter by A.S.Yakovlev

I-28 (Yak-5)
51k I-28 from "Soviet Combat Aircraft of the Second World War" by Yefim Gordon and Dmitri Khazanov, Vol.1
Courtesy of Thomas Heinz

High altitude fighter-interceptor of the I-26 family. Major difference - experimental M-105PD engine, equipped with 2-stage turbocharger E-100 designed by V.A.Dollezhal (so 'D' in the engine designation). I-28 was designed specially for service with PVO forces. In addition to the Yak-5 designation, I-28 also appears in documents as 'samoliot N°28', I-28-N, I-28-V and I-26V (here 'N' stays for 'nagnetatel'/compressor, 'V' for 'vysotnyj/high altitude).

Engine M-105P M-105PD
Sea Level 1020hp 1020hp
1st altitude 2000m 2350m
1100hp 1160hp
2nd altitude 4000m 6650m
1000hp 1000hp

Since the I-28 was just 100kg heavier than series Yak-1, it had a sensible advantage not only high altitude interceptor, but also as a mid-altitude (2500 to 5000m) front-line fighter.

Factory trial results of the new engine were promising, with substantially higher output than standard M-105P and much higher altitude capability. It was planned to install automatic supercharger control for hydraulically-operated turbine, but reliable solution was not found in time. Here troubles of the I-28 began. Manual supercharger control placed additional stress on the pilot, distracting his attention. Since pilot could not constantly adjust the supercharger, nominal engine power was never achieved in flight.

I-28 was designed and built within 3.5 months: July 10 to October 29, 1940. Its layout was similar to the I-26, but fuselage and tail surfaces were of all-metal construction. Wooden wing was ow slightly smaller span and less rounded tips, and was fitted with wide-span automatic leading edge slats. Landing gear - identical to one of UTI-26-2 (improved design). Tailplane and elevators were same as on UTI-26-2, what provided I-28 with better handling during landing approach than I-26. Engine cradle and fuel system of the I-26 were changed to accommodate modified engine. I-28 carried RSI-3 radiostation.

Aircraft (single airframe) was assembled on October 29, 1940 and arrived to the OKB testing ground. Ground trials continued until the end of November by senior pilot P.Ya.Fedrovi, senior engineer V.V.Barsukov, mechanic M.M.Schipanov.

First flight (December 1, 1940) lasted only 20min. Engine 'behaved' - smoke, vibration, misfiring forced pilot to shot it down and go for emergency landing. Aircraft was not damaged. The cause was prosaic: tube supplying oil to the engine was ruptured.


I-28 (Yak-5)
50k I-28 (appears to be photographed right after another engine failure) from "Soviet Combat Aircraft of the Second World War" by Yefim Gordon and Dmitri Khazanov, Vol.1

Courtesy of Thomas Heinz

According to V.B.Shavrov, factory trials continued until April 16, 1941. During this period three engines were changed and nine forced landing were performed...

After installation of new M-105PD I-28 was transferred to LII for engine tuning and flight evaluation. Persisting engine 'issues' stretched the tuning process well into late 1942, providing no positive outcome.

Later A.S.Yakovlev continued efforts to built high altitude interceptor. In 1942 he used Yak-7 airframe, and in 1944 Yak-9PD and Yak-9PV were built.

Predecessor(s)Modifications, Developments

I-26

UTI-26-2

I-30
Yak-7M
ReferencesLinks
  • "Yak fighters of the Great Patriotic War period" by A.T.Stepanets
  • "History of aircraft construction in the USSR", Vol.2 pp.195-196
  • TsGASA, f.NII VVS, op2, ed.hp.446
  • Yak-5, Yakovlev

  • Created March 07, 1999
    Modified March 17, 1999
    and Thomas Heinz
    Back to
    Main Gate