Pashinin I-21

Would you like to see this in-game?
  • Yes
  • No
0 voters


Brief Summary:
The I-21 was intended to replace the I-16. It performed quite well when compared to contemporaries from the larger bureaus of Yakovlev and Lavochkin.



The I-21’s story begins with its designer Mikhail Mikhailovich Pashinin (1902-1973) who, after graduating from the Moscow Aviation Institute, worked at Moscow Aircraft Plant No.1, where he held several positions. One of these positions included being a lead designer. In 1938 he would be transferred to aircraft plant No. 21, Gorky (Nizhny Novgorod) as the deputy chief designer for N.N. Polikarpov. He would be appointed the chief designer for aircraft plant No. 21 not long after and would be involved in introducing modifications to the I-16.

In the second half of 1939, he would begin the development of the I-21, which he proposed could replace the I-16. The I-21 at this point was proposed as a cannon fighter with the M-105P engine and was considered by the NKAP expert commission in November 1939.


Based upon previous work on the I-16, the fuselage in the nose was a spatial welded truss made of chromansil pipes covered with duralumin while the rear was made of wood. The wings were designed with rounded tips, and flaps were installed on the rear edge of the centre section. The keel and stabilizer were made of solid wood whilst the rudders were made from aluminium and covered with canvas.

The wheels (600x180mm) were retractable with racks rotating 90°. The flight performance of the aircraft was to be a flight weight of 2400kg, service ceiling of 10400m and a maximum speed of 613km/h with an armament of one nose mounted 20mm ShVAK cannon and two 7.62mm ShKAS LMGs.

Because the initial design had many shortcomings, several options were considered, such as the replacement of the 20mm with a 23mm and an M-107P engine, until May 1940. A full sized mock-up of the design was built in March 1940 with the intention of using the originally proposed design.

Construction of the first prototype was completed in June 1940, being almost identical to the proposed design from November 1939 with the 28% alignment of the MAR. The plane’s first flight was at the airfield of aircraft factory No. 21, lasting 18 minutes on July 11th 1940. The machine was flown by test pilot P.V. Fokin until August, by which time it had completed 33 flights with a total of 16 hours of flight time. Starting from August 3, Fokin would perform several flights to perform aerobatic manoeuvres. According to the test pilot’s reviews, the I-21 obeyed the rudders well, was stable during a dive, and landing and take-off were rated as being simpler compared to the I 16. He also stated the directional and lateral stability were good, though the longitudinal stability required further research.

The aircraft would be flown in Moscow at Tushino Airfield during August 18 1940’s dedicated aviation day with the plane spending some time at the Central Airfield in Moscow. Pilots of the Air Force Research Institute would test the plane and noted the tendency of the vehicle to stall on the wings when landing at high angles of attack, for which Pashin offered to equip the second prototype with automatic slats on the detachable parts of the wing, as the second prototype had already been built at this point.

The second prototype, completed on the 18th of August 1940, had been designated No. 21A213 – a presumed typo on the aircraft’s documentation which designated it as the 3rd copy of the 21st type aircraft plant 21.

The second prototype had an alignment value of 23-25% of the MAR to improve on the longitudinal stability performance. It also had a more swept winged design compared to its predecessor to approach the longitudinal stability issues.


Fokin would take his first flight with the aircraft on the 8th of October 1940, lasting 17 minutes. The aircraft would unfortunately have a few issues, the first of which being the left magneto failed on the first flight, and the second being the engine was revealed to be substandard and had to be replaced due to metal shavings being found in the oil filter. On the 17th, Bolshakov would perform a familiarization flight in order to continue with test flights to test out the speed and aerobatics at an altitude of 5000m on the 20th and 24th of October and the 1st and 2nd of November. Both test pilots concluded the prototype behaved steadily in air.

The second prototype was fitted with a 23mm PTB cannon with a total capacity of 81 shells (9 clips of 8 shells each); the reloading was pneumatic. Ground testing for the aircraft’s armament had 536 shells in total fired from the 23mm and 2350 rounds from each of the two ShKAS LMGs. 76 shots were fired in the air until the aircraft was ordered to be sent to Moscow by the head of the Main Directorate of the Red Army Air Force, Lieutenant General of Aviation Rychagov.

On the 21st of November 1940, the second prototype arrived at Chkalovskaya airfield near Moscow and on the 27th it was accepted for state testing. Experienced test pilots Stefanovsky and Suprun were appointed as the leading pilots for the state testing. A number of shortcoming were revealed with the aircraft and the testing was accelerated during the time until the testing was stopped on the 4th of December 1940.


A third prototype was built and completed in December 1940 with Bolshakov testing the aircraft by December 14, 1940. This aircraft was noticeably different from it’s two earlier prototypes with a larger vertical tail surface increased by 0.21m², a retractable crutch wheel and the water radiator protrusion reduced by 60mm. The oil coolers were removed from the wings and the wingtips became rectangular. A horseshoe-shaped oil radiator was installed under the front of the engine hood (which was already present on the Yak-1 and LaGG-3). The engine intake pipes were placed in the root of the fuselage and the exhaust pipes were grouped into two exhaust manifolds on each side of the engine. The flight alignment of the aircraft, according to the factory design bureau, was between the range of 19.5-24% of the MAC.

The aircraft would be tested from the 1st of March to the 26th of May 1941 and would conclude with no transference for state testing on the 6th of June 1941. The aircraft was used in the defence of Moscow although it is unknown if the aircraft performed any combat missions. This would conclude the history of the aircraft but Pashinin would work on other vehicles aiding in the development of them even if his own project in the I-21 was unsuccessful.

Due to other contemporary Soviet aircraft already being produced in numbers and having an easier landing time compared to the I-21, the project would be cancelled. But the aircraft could perform similarly to its contemporaries – the LaGG-3 and Yak-1 – although with the those larger bureaus developing much faster, the I-21 would have been left behind in the end.




Based on the 3rd prototype:
Crew: 1
Length: 8.29m (27’2 feet)
Wingspan: 9.4m (30’8 feet)
Height: 4.3m (14’1 feet)
Wing Area: 15.46 m² (166.41 square feet)
Empty Weight: 1210kg (2668lb)
Take-off Weight: 2670kg (5886lb)
Engine: Klimov M-105P V12 1050hp engine
Service limit: 10600m (34776 feet) (6.59mi)
Maximum range: 760km (472.2mi)
Maximum Speed (High altitude): 573km/h (356mph)
Maximum Speed (Low altitude): 488km/h (303.2mph)
Rate of climb: 12.6m/s (2480.3feet/m) (certain sources state a 16.6m/s or 21m/s)
Armaments: 1x 23mm BT-23 nose mounted cannon, 2x7.62mm ShKAS LMGs
Hardpoints: None

Additional Images:






From what I’ve been able to find, BT-23 is another name for the PTB-23 cannon that’s already in WT on the I-301. So the gun’s performance is already a known quantity.

At any rate, always room for more WW2 fighters.


Glad I could help on this one, and it gets full approval from me! +1

1 Like