The Polikarpov I-16 Rata, Mosca

U.S.S.R.
U.S.S.R.

side viewfront viewunder view

In the beginning of the 1930's the Soviets were reassessing their air fleet. The threat of monowing bombers was much greater than that of biplane bombers, because of their payload and performance numbers. Already a number of monowing bombers entered service with the Soviet Airforce, the VVS (Voenno-vozdushniye Sily). To have a weapon available that was able to intercept these bombers a monowing fighter had to be designed.
However, it was realised that the monowing fighter would offer greater performance, but lacked agility compared to it's biplane counterparts. Therefor it was suggested to create a fighter force of mixed combination: biplanes as well as monowing fighters. This was the reason why design progressed simultaneously on the I-15 and I-16, the first a biplane fighter, the second a cantilever monowing fighter.
Already another design team was working on a fighter like the I-16, Sukhoi's I-14, but Polikarpov asked and received permission to build a rivalling desing. The design team started work in March 1933 and worked with enormous dedication to complete the design of the TsKB-12 as an extremely dumpy type with close-coupled flying surfaces and a fuselage tailored to the diameter of the selected engine, namely the M-25 radial piston engine that was the Soviet license-built version of an American engine, the Wright R-1820 Cyclone. Despite its appearance of great modernity, the TsKB-12 was of mixed rather than all-metal construction, mainly because of the absence of readily available light-alloy industry, and the abundant availability of good quality wood.
The TsKB-12 had a semi-monocoque fuselage with a skin of shpon (birch veneers molded into shape before being bonded into a multi-layer veneer) over pine longerons and half-frames. Flying surfaces were basically of metal. The cantilever tail unit was a Dural construction covered with fabric. The wing, which was tapered in thickness and chord, was based on two steel spars with Dural ribs. Skinning of the wing was Dural as far back as the front spar and with fabric to the rear of this line. Long-span slotted ailerons were made of Dural, and covered with fabric, and were designed to droop through 15° as semi-flaps during landing. The airframe was completed by the tailskid landing gear, which included wide-track main units that could be retracted inward by a hand-cranked system requiring 44 turns for full retraction or extension. The enclosed cockpit had an aluminum-framed canopy (complete with integral Vee-type windscreen) that could be slid forward for access to the cockpit, and bungee chords assisted opening of the canopy in flight to counter the pressure of the slipstream.
The intended engine was the M-25, a license built version of the Wright R-1820 Cyclone, but negotiations were slow and painstaking, and were delayed considerably, so the TsKB-12 prototype that made its first flight on December 31 1933 was powered by the same engine as used for the I-5 and I-15 fighters, namely the M-22 radial, rated at 480 hp (358 kW) at optimum altitude. This engine drove a two-blade Dural propeller with ground-adjustable blades, although in this application the engine was enclosed in a long-chord cowling with an optimized cooling-air slot at its rear.

Version list:

Further pictures:

A Polikarpov I-16 Rata being prepared by ground crew.
A Polikarpov I-16 Rata being prepared by ground crew.

A Polikarpov I-16 Rata taking off from a hiding place amongst the trees. Maybe during summer 1941?
A Polikarpov I-16 Rata taking off from a hiding place amongst the trees. Maybe during summer 1941?

 

Technical data on the Polikarpov I-16 Type 10
Powerplant 1 × Shvetsov M-25V radial, rated at 750 hp (559.12 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • (Ground) Attack Fighter
  • Close Support Attack Fighter
  • Fighter-bomber
Length 19 ft 2.5 inch Height 8 ft 5 inch
Empty weight 2945 lb Operational weight 3805 lb typical
Wing Span 29 ft 6.33 inch Wing Aspect ratio 5.57
Wing Area 156.51 sq ft Service ceiling 27000 ft
Maximum speed 278 mph at 10400 ft Cruising speed unknown
Initial climb rate Climb to 16,405 ft in 8 min 12 sec Range unknown
Fuel capacity internal unknown Fuel capacity external unknown
Machine guns
  • 2 × 0.3 inch ShKAS fixed forward-firing in the upper nose, 650 rounds each
  • 2 × 0.3 inch ShKAS fixed forward-firing, 900 rounds each
Cannons -
Bomb load unknown Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) 31 December 1933 Operational Service 1935 - late 1940's
Manufacturer Polikarpov Design Bureau Number produced 9.004+ total, unknown out of 7.364+ this version
Metric system
Length 5.85 m Height 2.57 m
Empty weight 1336 kg Operational weight 1726 kg typical
Wing Span 9 m Wing Aspect ratio 5.57
Wing Area 14.54 m² Service ceiling 8230 m
Maximum speed 447 km/h at 3170 m Cruising speed unknown
Initial climb rate Climb to 5.000 m in 8 min 12 sec Range unknown
Fuel capacity internal unknown Fuel capacity external unknown
Machine guns
  • 2 × 7,62 mm ShKAS fixed forward-firing in the upper nose, 650 rounds each
  • 2 × 7,62 mm ShKAS fixed forward-firing, 900 rounds each
Cannons -
Bomb load unknown Torpedoes/rockets -

Technical data on the Polikarpov I-16 Type 24
Powerplant 1 × Shvetsov M-63 radial, rated at 1100 hp (820.04 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • (Ground) Attack Fighter
  • Close Support Attack Fighter
  • Fighter-bomber
Length 20 ft 1.33 inch Height 8 ft 5 inch
Empty weight 3285 lb Operational weight 4215 lb typical,
4619 lb max
Wing Span 29 ft 6.33 inch Wing Aspect ratio 5.57
Wing Area 156.51 sq ft Service ceiling 35500 ft
Maximum speed 304 mph at 13125 ft Cruising speed 185 mph at optimum altitude
Initial climb rate Climb to 16,405 ft in 4 min 0 sec Range 435 miles typical
Fuel capacity internal 56 Imp gal (67 US gal) Fuel capacity external Up to 112 Imp gal (134 US gal) in two 56 Imp gal (67 US gal) drop tanks
Machine guns
  • 2 × 0.3 inch ShKAS fixed forward-firing in the upper nose, 650 rounds each
  • 2 × 0.3 inch ShKAS fixed forward-firing, 900 rounds each
  • 1 × 0.50 inch Beresin BS fixed forward-firing in the middle of the upper nose, 300 rounds. This gun was not used in combination with the 20 mm Cannon
Cannons
  • 2 × 20 mm ShVAK fixed forward-firing in the wing leading edges, 180 rounds each, as an alternative to the two 0.3 inch ShKAS guns in the wing. The 20 mm Cannon were not used in combination with the 0.50 inch guns
Bomb load Up to 1,102 lb of disposable stores carried on two underwing hardpoints rated at 551 lb each. General disposables load consisted of:
  • 2 × 551 lb FAB-250 bombs
Torpedoes/rockets
  • 6 × 3.2 inch RS-82 unguided air-to-air or air-to-surface rockets
Crew 1Naval or ground based Ground
First flight (prototype) 31 December 1933 Operational Service 1935 - late 1940's
Manufacturer Polikarpov Design Bureau Number produced 9.004+ total, unknown out of 7.364+ this version
Metric system
Length 6.13 m Height 2.57 m
Empty weight 1490 kg Operational weight 1912 kg typical,
2095 kg max
Wing Span 9 m Wing Aspect ratio 5.57
Wing Area 14.54 m² Service ceiling 10820 m
Maximum speed 489 km/h at 4000 m Cruising speed 298 km/h at optimum altitude
Initial climb rate Climb to 5.000 m in 4 min 0 sec Range 700 km typical
Fuel capacity internal 255 liters Fuel capacity external Up to 508 liters in two 254 liters drop tanks
Machine guns
  • 2 × 7,62 mm ShKAS fixed forward-firing in the upper nose, 650 rounds each
  • 2 × 7,62 mm ShKAS fixed forward-firing, 900 rounds each
  • 1 × 12,7 mm Beresin BS fixed forward-firing in the middle of the upper nose, 300 rounds. This gun was not used in combination with the 20 mm Cannon
Cannons
  • 2 × 20 mm ShVAK fixed forward-firing in the wing leading edges, 180 rounds each, as an alternative to the two 7,62 mm ShKAS guns in the wing. The 20 mm Cannon were not used in combination with the 12,7 mm guns
Bomb load Up to 500 kg of disposable stores carried on two underwing hardpoints rated at 250 kg each. General disposables load consisted of:
  • 2 × 250 kg FAB-250 bombs
Torpedoes/rockets
  • 6 × 82 mm RS-82 unguided air-to-air or air-to-surface rockets

Here is a quick overview of all different versions, without the full technical specifications:

Different versions of the Polikarpov I-16  Rata, Mosca
TsKB-12 This designation was given to the initial Polikarpov I-16's, and stuck with the prototype. The first TsKB-12 was powered by 1 × M-22 radial, rated at 480 hp (358 kW). The second prototype was powered by 1 × Wright R-1820-F-2 Cyclone radial, rated at 600 hp (447 kW). The second one was further refined while the first was was used for service trials.
The second one soon was powered by 1 × Wright R-1820-F-3 Cyclone, rated at 640 hp (477 kW). Not only it meant an increase in speed, but the operating ceiling increased from 4,300 ft (1.300 m) to 10,000 ft (3.000 m) because of the better high altitude capabilities. The second prototype also received the very distinctive tunnel-type engine cowling with its trailing edge flush with the fuselage, and provision for nine exhaust stacks. This cowling was used on almost all versions, except the Type 4 and UTI-2 versions.
Other modifications on the second prototype were a propeller spinner, and duralumin skinning on all wing upper surfaces. The landing gear was strengthened and retraction/extension of the gear was changed as well. This second prototype was sometimes also called TsKB-12bis.
Number built: 2
Polikarpov I-16 Type 1 I'm unsure, but it looks like that this version was the pre-production batch of the I-16. Otherwise it is possible that it was another designation for the prototypes.
Number built: unknown out of 7.364+
Polikarpov I-16 M-22 Type 4 This version was the first definitive production version, and was mainly based on the second prototype, also called TsKB-12bis. It differed in some area's from the original to solve a number of problems and weaknesses. For one thing: it possessed hinged lower portions on the landing gear fairings to cover the wheels when retracted. Also the last of these aircraft was fitted with an armored back to the pilot's seat.
However, it was a s yet powered by 1 × Shvetsov M-22, rated at 480 hp (358 kW), since no other engines were available yet.
One I-16 Type 4 aircraft was used for extensive spin trials. The revolutionary new design (first unbraced monowing fighter, with retractable gear of the world) mad a lot of military officials doubt that the I-16 could be handled well, especially during spins. In September 1935 test pilot Peotr Stefanovsky succesfully performed and recovered from 90 spins, proving theories at the time about spinning to be wrong, and showing that the I-16 could be handled well.
Number built: unknown out of 7.364+
Polikarpov I-16 M-25 Type 5 The Polikarpov I-16 M-25 Type 5 was more like the second prototype, it inherrited the engine as well and was thus powered by 1 × Shvetsov M-25 radial, rated at 640 hp (477 kW). Other changes were a strengthened new landing gear operating mechanism, a starter and an oxygen system. These modifications increased the weight of the aircraft from 3,305 lb (1.520 kg) to 3,505 lb (1.590 kg). Climb rate deteriorated, and the ceiling was a little lower. Horizontal max level speed however increased. It had a two-blade AV-1 Dural propeller, and two underwing hardpoints rated at 220 lb (100 kg) each to carry a FAB-100 bomb.
Service pilots still doubted the I-16's ability to recover from spins, and 5 test pilots conducted more than 3.000 spin recoveries and other aerobatic aneuvers to end it once and for all.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 6 this version was the standard 1936 production model, whose airframe incorporated local strengthening here and there worth 110 lb (50 kg). It was powered by 1 × Shvetsov M-25A radial.
Number built: unknown out of 7.364+
Polikarpov I-16 M-25V Type 10 In 1937 the next major version was developed. Initialy it was powered by 1 × Svhetsov M-25A, but soon it was powered by a Shvetsov M-25V for high altitude. Apart from the engine also armament was enhanced. Two 0.3 inch (7,62 mm) ShKAS guns were already in the wings, but two more were additionally placed in the nose above the engine. Some aircraft also received a Cannon in the nose to augment the I-16's armament. Flaps were added to reduce landing speed and run, and for the first time a retractable landing ski was used as well.
This and the strengthening of the airframe in some places added weight, and it rose to more than 3,747 lb (1.700 kg). Nevertheless performance was more or less equal to the I-16 Type 5.
Number built: unknown out of 7.364+
Polikarpov I-16P Type 12 The I-16P was a 'gunship' version, where 'P' stands for Pushhyechnyi, or Cannon. it was based on the I-16 Type 5, but was fitted with 2 × 20 mm Cannon in the centre wing section with provision to fire through the propeller arc. These cannon were fitted in place of the two 0.3 inch (7,62 mm) ShKAS guns. it was some 220 lb (100 kg) heavier than the I-16 Type 5.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 17 Another 'gunship' version, the I-16 Type 17 was based on the I-16 Type 10. the Type 17 had in stead of the two wing mounted 0.3 inch (7,62 mm) ShKAS guns two 20 mm ShVAK cannon. these were placed more outward in the wing, beyond the propeller arc. Weight increased, and performance sufferd slightly, but the increase in firepower was tripled.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 18 The standard production model in 1939, the Type 18 was based on the Type 10, powered by 1 × Shvetsov M-62 radial, rated at 920 hp (686 kW). The exhaust arrangement was modified in which alternating single and twin pipes emerged through three holes on each side. The propeller first was an AV-1 two-blade, but later a VISh-6A. The fuel tank was protected from now on. It had an empty weight of 3,148 lb (1.428 kg), a max take-off weight of 4,034 lb (1.830 kg), and a max level speed of 288 mph (464 km/h) at 16,405 ft (5.000 m).
Number built: unknown out of 7.364+
Polikarpov I-16 Type 20 Since the Shvetsov M-62 consumed more fuel, and the fuel capacity remained the same, operational range decreased. Type 20 was designed to have two jettisonable fuel tanks to set that straight.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 24 This version was powered by 1× Shvetsov M-63 radial, rated at 1,100 hp (820 kW). This version reached the peek of performance of the whole I-16 family: 273 mph (440 km/h) at sea level, and 303 mph (489 km/h) at 15,750 gt (4.800 m). it became the standard production model of 1940, and had besides the engine also plywood skinning of the upper wings, a radio and a gun camera. the tailskid was replaced by a wheel, and two fuel tanks with the capacity of 154 lb (70 kg) each were mounted under the wings. last but not least, the surface finish was improved.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 27 Combine the modifications of the Type 20, and the armament of the Type 17, and you get the Type 27. Powered by 1 × Shvetsov M-62, it packed a pretty punch with 2 × 20 mm ShVAK and 2 × 0.3 inch (7,62 mm) ShKAS guns.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 28 When mated with a Shvetsov M-63, the Type 27 became the Type 28. Gunships had existed before, but the main opponent then was the nakajima Ki-27, which was lightly armored and thus didn't need the heavy firepower of 20 mm cannon. Since the 20 mm Cannon had a negative effect on maneuverability, interrest in 'Gunships' had subsided ever since the Khalkhin-Gol conflict. It was not until the Soviets broke off their attacks on the determined Fins that the need for heavy firepower once more rised. Although in words it seems only a small change, in design the new 'Gunship' version needed a lot of redrawing and retooling.
Number built: unknown out of 7.364+
Polikarpov I-16 Type 29 The Type 24, although the fastest of it's breeding didn't improve as much as was anticipated. Mainly this was caused by the wrong choice of propeller, while overcooling of the cylinderheads in a glide, exhaust pipe breakages and cracking of the engine cowling were hardly helpful. In the Type 28 a lot of problems were already overcome, and this final production version was based on the Type 28, and armed with 2 × 0.3 inch (7,62 mm) ShKAS guns and 1 × 0.50 inch (12,7 mm) UBS, all mounted in the upper nose. Under the wing six racks for 82 mm Rockets were mounted. A radio mast for communications was thrown in as well.
All the extras added weight, increasing the empty to 4,662 lb (2.115 kg). Thsi in combination with the extra drag caused by all other and new external features decreased the max level speed to 266 mph (429 km/h) at 13,600 ft (4.150 m).
Number built: unknown out of 7.364+
Polikarpov UTI-2 The I-16 was pretty revolutionary for it's time. Therefore it needed a conversion trainer, and what other aircraft to fulfill that role than the... I-16!
The UTI-2 was an unarmed version based on the I-16 Type 4, powered by 1 × M-22 radial. It was manufactured in 1935 - 1936.
Number built: about 100 out of 1.895+
Polikarpov UTI-4 (Type 15) This trainer versio was similar to the I-16 Type 5 and I-16 Type 15. it had no armament, radio, an oxygen equipment. During trials it was concluded that the (manual) gear retraction was seldomly used, and consequently the UTI-4's all had fixed undercarriages.
Number built: about 1.795 out of 1.895+
I-16/M-22 Other designation for the first prototype
Redesignated aircraft
Polikarpov I-16Sh Sh stands for Shturmovic, meaning Attacker. This version was a single I-16 Type 1 conversion for the ground attack role, armed with 4 × 0.3 inch (7,62 mm) ShKAS or PV-1 fixed forward-firing guns, two in the upper nose and two in the wing. It had underwing racks for 220 lb (100 kg) of bombs, additional armor in front of the pilot and an armored bucket seat with provision for a seat -pack parachute.
Number built: 1
Polikarpov TsKB-18 Other designation for the I-16Sh
Redesignated aircraft
Polikarpov SPB SPB stands for Skorostnoi Pikiruyushchnyi Bombardirovshchik, Fast Dive-Bomber. It was a single conversion from the I16 type 5 with a pneumatically operated system for the actuation of the main landing gear and dive brakes that replaced the inboard ailerons sections. The wing was restressed to carry 2 × 551 lb (250 kg) FAB-250 bombs, and was armed with 2 × 20 mm ShVAK cannon fixed forward-firing in the wing leading edges.Although no series production followed, some I-16's were nevertheless converted in the field in August 1941. 12 conversions were made, and were carried in pairs under the wings of six Tupolev TB-3 bombers. The bombers took the I-16's up and afield, where at some point they were launched for an attack on the rail-bridge over the river Danube at Chernovod in Rumania.
Number built: 1 plus12 converted.
I-16UTI Redesignation of the UTI-4
Redesignated aircraft

Operational remarks:

The I-16 was first used during the Spanish Civil War (1936 - 1939). It was there that it received it's nickname 'Rata' (Rat) or 'Mosca' (Fly). Of course, there is almost no culture or people on Earth that considers the name 'Rat' to be nice. So why the two names, one not nice, the other neutral? In order to explain this we have to look at the political situation in Spain during the Civil War. Nationalists (more or less Right wing extremists like the Nazi's) were fighting against the Republicans (Left wing supporters, or Communists). Both camps were supported by foreign armies, the Republicans by the Soviets, and the Nationalists by the Nazi's from Germany. Of course the Republicans liked the I-16, since it was fighting for them, and dubbed it 'Mosca'. the Nationalists however considered the I-16 to be a threat, and dubbed it 'Rata'. In that theatre the I-16's opponents were mainly the German Heinkel He 51, and the Italian Fiat CR.32 biplanes. Although it was slightly less maneuverable, the I-16 Type 5 was superior in speed and climb.
the I-16 Type 10 was improved on the I-16 Type 5, and serviced the Soviet Union in the wars in Spain and China, and Khalkin-Gol. In the latter Theatre its main opponent was the Japanese Army Type 97 Nakajima Ki-27. The Ki-27 was fast and maneuverable, and was more stable than the I-16. The I-16 however could endure more damage, and had better armament. This was even more increased when a 20 mm Cannon was added to the already superior weaponry.
During the Second Sino-Japanese War (1937-1945) the I-16 was exported to China. At the time the I-16 was about equal to the mitsubishi A5M, but the A6M reisen made the I-16 look decidedly inferior.
The main war where the I-16 fought, however was the Great patriotic War (1941 - 1945) when Germany and the Soviet Union clashed. By 1941 the I-16 was obsolete, and great numbers were lost on the ground and in the air. At the beginning almost 40% of all fighter units near the Soviet border had the I-16 as their mount, but after the first weeks of 'Operation Barbarossa', as the German attack on the Soviet Union was called, this number declined rapidly.
Rests m eto say that some I-16's were captured by the Fins and Germans, where the Fins used the majority against the former owners. 8 aircraft survived the War in Finish hands.

Strengths:

Weaknesses:

 

Got any comments?
Do you want to discuss this with someone else?
Post a message at the World War 2 Warbirds messageboard!!

 

© by Frans Bonné, 2000
Last revision: 9/23/01