Polikarpov I-16 - origins and development

As far as I understand, there is no existing topic here. So I decided to create one - after Apophenia here mentioned online references about "I-16 Type 1", which (by some of these references) was ostensibly powered by M-32 engine! While M-32 was actually liquid-cooled V16! (For correctness, I must note that Apophenia also considered it a misprint - probably they meant M-22).

There was my answer at that topic, so you can recognize that Type 1 never existed, and Type 4 was actually the first I-16 production version. But I think the Little Donkey deserves its own topic.

Of course I-16 never was projected with M-32, or any other inline engine. It was radial-engined, very compact aircraft from the beginning. The very first draft of what became I-16 (dated 1932) looked like this (see attachment).

From the very beginning, Polikarpov planned to use Wright SGR-1820 F-3/F-5 Cyclone engine for it. But in 1933 we already didn't have a license for its production. Therefore the VVS chief Yakov Alxnis proposed Polikarpov to design a version with M-22 engine, much less powerful but available in sufficient number. With M-22, the calculated maximum speed was 345 km/h at sea level and 300 km/h at 5000 m altitude; climbing to 5000 m - 10-11 minutes, service ceiling 6700 m. Of course the performance with Cyclone was much better: maximum speed 375 km/h (sea level), 415 km/h (3000 m altitude), climbing to 5000 m - 6-6.5 minutes, ceiling 9200 m.

In June 1933 the preliminary design was revised, taking the form we know. In August, intensive tunnel model tests began; they definitely confirmed advantages of NACA-type cowling over Townend ring, and allowed to choose the most proper parameters of it. On September 20, Semen L. Margolin, the Zavod 39 director, wrote in his official report: "During the designing of I-16 (TsKB-12) aircraft, the 2nd TsKB brigade made some alternative calculations for different engines. These calculations clarified that in case of Wright Cyclone F-5 engine install, we'll get such high flight/tactical performances of this aircraft that it would be, certainly, a first class fighter much superior over all known European or American models".

Due to very promising characteristics of the new fighter, the USSR Council of Labour and Defence made a decision to put it into production already on November 22, 1933 - even before its maiden flight! On December 30, 1933 Valery Chkalov flew first time with first TsKB-12 prototype (M-22 powered). Shortly after this, in early January 1934, the second TsKB-12bis with Wright Cyclone was also flown.

Sources:
1. Ivanov V. The unknown I-16 / Krylia Rodiny magazine, No.12/1993, p.20-21.
2. Maslov M. The King of Fighters: Polikarpov's warplanes. - Moscow, 2009 (ISBN 978-5-699-30998-6). - P.288-290.

Some less known I-16 prototype versions:
I-161 (I) was designed at Zavod No.21. It was Type 4 derivative, but with four wing-mounted ShKAS machine guns instead of two. Also it was planned to add crunches for four 20-kg bombs. This aircraft was undergoing the official tests at NII VVS on July 22-26, 1935; it was clarified that additional ShKASes reduce their shooting temp after aerobatic figures from 1800 to 1200 RPM, or even totally didn’t shoot. The UVVS (VVS administration) demanded to remedy these defects and to present the aircraft for retesting in September 1935, but it wasn’t done.

I-161 (II) was a 1937 project of “unweighted” I-16 version, planned for production in 1938. There were also some calculations for M-88 engine, but the works didn’t progress more.

I-163-1 was etalon model for year 1937, unweighted (1600 kg takeoff weight). It featured with redesigned landing gear, empennage and with mast antenna. Also it was the first I-16 with flaps. Starting from April 1937, this aircraft made about 1000 flights before the New Year. It carried out its task, but the innovations weren’t introduced on the production Type 5. The flaps appeared in series only on Type 10.

I-163-2 was a version with larger flaps and hydropneumatic system of landing gear retraction (instead of hand drive). It wasn’t flown.

I-164-1 or I-16s was long-range escort fighter with M-25V engine, with two additional fuel tanks mounted in wings. It passed through the factory tests in February 1938, with test pilot Thomas Suzi (he dead in I-180-2 crash on September 5, 1939). With total 500 kg of fuel, I-164-1 reached 2000 km flight range.

I-165 or I-16bis – an improved version with so-called “high-speed” wing (with stressed skin instead of fabric), refined aerodynamics of fuselage and engine cowling, with “oil-pneumatic undercarriage legs” (I don’t know if this term means retraction system or just a shock-absorber). Like I-164, I-165 had also additional fuel tanks. Two prototypes were built, both with M-62 engines.

I-166 was designed under TsAGI task. It was unweighted (only 1383 kg takeoff weight), but its main distinctive feature was NACA cowling with common exhaust-gas receiver (instead of individual stubs) and with cooling flaps around its back. Annular oil radiator was also applied. The aircraft was tested by Thomas Suzi.

Source: http://i16fighter.narod.ru/mods/exp.htm (based on Mikhail Maslov's research).

About attack I-16 versions (Type 9 and TsKB-18) see here: http://www.secretprojects.co.uk/forum/index.php/topic,10038.msg94095.html#msg94095

To be continued...

Hi,

also here is some Polikarpov I-16 variants.

Thanks Hesham, but these sketches are very rough and incorrect. For example, they show Type 18 with tail wheel and Type 24 with tail skid, although the opposite is true. Also propeller spinners of Type 18/27 and Type 24/29 are shown as the same, which isn't correct.

For more proper illustrations of production versions differences, look here: http://vvs.hobbyvista.com/Modeling/Polikarpov/I-16/Kit_Comparison/index.php.

Let's define some symbol plane I-16. Since the production of the plant was planned at the Gorky avizavode № 21, I-16 poluchiz industrial designation of I-16 Type 4. Before the plane I-16 at the plant № 21 were built or intended to build:
I-5 type 1
HAI-1 type 2
I-14 type 3, (only planned to build)
I-16 Type 4
A small digression first 50 cars built plant № 39, and then to plant № 21.

igor-mich said:

I-5 type 1
HAI-1 type 2
I-14 type 3

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The KhAI-1 of Zavod 21 production which was send to Kiev Zavod 43 as etalon model, had serial number 3211 (http://www.airwar.ru/enc/cw1/hai1.html). In these numbers, the first digit is type number. This means that KhAI-1 was Type 3, and Type 2 was planned for I-14.

Точно известно, что был ХАИ-1 № 3211 (его как эталон отправили в Киев вместе с оснасткой и чертежами, когда переносили туда производство). Известно также, что первая цифра номера означает номер типа. Значит, ХАИ-1 - тип 3, а И-14 - тип 2.

High-altitude versions (I-16TK, I-16V).

As an attempt to increase aircraft flight altitudes, the Central Institute of Aviation Motors development (TsIAM / ЦИАМ) since 1935 experimented with turbochargers (rus. турбокомпрессоры – ТК). The first versions were for Mikulin AM-34 engine; they were tested on different aircraft (R-Z, BOK-1, TB-3, DB-A) during 1935-38. In 1938, the TK-1 turbocharger was adapted for M-25 radial engine.

In middle 1938 these turbochargers first time were mounted on fighter aircraft. It was I-16 type 5, serial number 521A250. It was first high-altitude fighter in Soviet Union. The details of its tests are unknown, but next year another prototype was built. This time it was Type 10, serial number 1021582, with M-25V engine and AV-1 variable pitch propeller. It was first flown on August 4, 1939. The tests were carried out with participation of 8th “high-altitude” TsAGI department. Until October 3, 30 flights were done by test pilot Yuri Stankevich. Maximum speed was reached at 8600 m altitude – 494 km/h.

Later the same aircraft was reengined with M-62 and the tests continued. With new engine speed exceeded 500 km/h; some sources specify even 520 km/h at 10 000 m altitude. If it’s true, it was the fastest I-16 ever.

Despite encouraging results, turbochargers weren’t more used on I-16. In 1939 it was considered that new, more advanced and specialized aircraft would be used for high altitudes. Several design teams already got orders for such designs. Also, it was totally impossible to implant pressurized cockpit into Little Donkey. Even if it would weigh only 30 kg (minimum possible weight), the aircraft CG would be 35 % of MAC – absolutely inadmissible.

Sources:
1. M.Maslov. King of the Fighters: Polikarpov’s warplanes. Moscow, 2009 (ISBN 978-5-699-30998-6). – P.354-356.
2. http://i16fighter.narod.ru/mods/exp.htm

Side view is by Yuri Guglya, from his monograph in Ukrainian Aerohobby magazine (today it is called Aviatsiya i Vremya / Aviation & Time), No.1/1994.

"Heavy-armed" prototype versions.

Another way to increase I-16 capabilities was to improve its weapon. Among other things, installation of synchronized armament allowed to concentrate masses near center of gravity and make the aircraft more manoeuvrable. In December 1938, two I-16 fighters were taken from operational air brigade based at Lyubertsy and transferred to Polikarpov OKB for experiments.

One of them, a Type 10 No.1021332, was fitted with two synchronized 12.7-mm Berezin TKB-150 machine guns. They were mounted along fuselage sides ahead of the cockpit, slightly below the longitudinal axis. To place them and their ammunition load (440 rounds), significant reduction of fuselage fuel tank was necessary. Therefore center wing tanks were enlarged, and wing-mounted ShKAS machine guns with ammunition boxes removed.

This version was designated I-16SO (И-16СО, for Синхронный, опытный – synchronized, prototype). Its empty weight (without fuel, oil, and pilot but with full ammunition load) was 1535 kg, takeoff weight 1835 kg; CG was 31.5% of MAC. On March 4-14, 1939 the I-16SO passed through armament trials at shooting gallery, and from March 23 to April 9 it underwent polygon tests.

The second aircraft was older Type 5, No. 521570. It obtained even more powerful weapon – two synchronized ShVAK cannons, mounted straightly through pilot’s cockpit. For their maintenance, small access doors were made in fuselage sides. Ammunition was supplied from two magazine cases, each for 175 rounds. This version named I-16PS (И-16ПС; Пушечный синхронный – cannon-armed, synchronized) was tested from February 10 to April 4, 1939.

Both I-16SO and I-16PS had the same problem: when firing, expanding gases hit the cockpit and engine carburettor. This problem was more critical on the PS version; therefore, fuselage-mounted cannons didn’t appear more on the I-16. But it wasn’t in vain: Polikarpov team used experience they gained with I-16PS when working on I-185. In contrast, SO version was rated successful; some sources claim it was even recommended for serial production. But for some reasons it wasn’t actually produced. Finally, synchronized Berezin machine gun appeared on the production Type 29 – but only one.

I-16SO continued to fly after tests, and one of its flights finished with a little disaster: on May 20, 1939 pilot Belozerov was landing in cross wind conditions and the landing gear unexpectedly “folded”. A photo of this disaster is published in Maslov’s book, and it is the only I-16SO photo I have. So, I attach it here.

These versions were Polikarpov OKB creations; they were born in Moscow, at Zavod No.156 (former ZOK TsAGI) which was Polikarpov base that time. But the I-16 mass production factory, Zavod No.21 in Gorky city, also created its own “heavy-armed” I-16 version. On January 21, 1939, by the order of chief engineer Kupriyanov and chief designer Pashinin it obtained its name – I-16 type 16. It featured with synchronized 12.7-mm ShVAK machine guns (referred as “cannons” in the documentation); this 12.7-mm ShVAK, basically enlarged ShKAS, was a precursor of well-known 20-mm “true” ShVAK cannon. Three prototypes were built: No.16211 to 16213. After “shrinked” program of factory tests they were sent to NII VVS for service trials. Sorry no more info.

Sources:
1. M.Maslov. King of the Fighters: Polikarpov’s warplanes. Moscow, 2009 (ISBN 978-5-699-30998-6). – P.341, 352-354.
2. http://i16fighter.narod.ru/mods/exp.htm

Another drawings of turbocharged versions (now both of them!). This time by Mikhail Maslov, from his I-16 monograph published in 1996 in "Armada" series.

And the attack Type 9 (known for its movable guns) from the same source, incorrectly signed "Type 11" . Probably a misprint.

But what about the principle of the plant rooms because type 11 serial number # 9211, means must be Type 9

Of course Type 9! And I wrote - the drawing incorrectly signed as "Type 11", probably a misprint. Or maybe Maslov's mistake - he is only a human, too.

Unfortunately I don't have the whole Armada book (only xerocopies of the drawings), so I can't say how is it named in the text. In "King of the Fighters" (pages 317-318) Maslov mentions it only as "No.9211".

redstar72 I scanned a page from the ANT-32 can read.

Sincerely, Igor-mich

igor-mich said:

redstar72 I scanned a page from the ANT-32 can read.

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Yes, I have seen. Thank you for the scans! There is some new info for me.

I'll write the answer a bit later. I don't use Google translator, and my English isn't actually so perfect - and it takes me enough time to write detailed answer in English.

According to my data type 11 wearing a training version of the I-16 (УТИ-3) serial number 11211.

igor-mich said:

According to my data type 11 wearing a training version of the I-16 (УТИ-3) serial number 11211.

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Certainly!
So, today's update - unusual I-16 trainer versions.

We all know two I-16 trainer versions: the main one – UTI-4 (Type 15) and the previous – UTI-2 (Type 14), which was distinctive by M-22 engine under NACA cowling (like I-16 type 4 from which it originated) and, usually, by fixed landing gear (although some of them had normal retractable). But this form of UTI-2 actually wasn’t first!

The first I-16 trainer appeared in May 1935. Its serial number was 8211, so it was Type 8 in Zavod 21 classification. It looked even more advanced than any of its descendants, because it had enclosed cockpits – both were covered by common clear canopy! The landing gear also was standard, i.e. retractable. Interesting detail: the sources mention this version under designation UT-2, instead of “UTI-2”! (Of course UT-2 is usually related to light monoplane designed by Yakovlev, but it appeared later…)

Then there are some ambiguities. According to Maslov, “UT-2” No.8211 was presented for tests in May 1935, but was tested since July 1 until August 16. What did it wait for during two months, isn’t clear. Or maybe Maslov means the official trials? Anyway, the trainer with M-22 engine reached 349 km/h maximum speed at sea level; landing speed was 127 km/h. Its empty weight was 970.3 kg, takeoff weight 1370.5 kg; CG was 31.3 % of MAC. It was proposed to improve the aircraft and then retrain pilots for I-16 on it. Before the New 1936 Year, 22 I-16 trainers were produced; but only 3 of them (including No.8211) were built as Type 8. The rest were already simplified Type 14 – UTI-2 as we know it, with open cockpits and fixed landing gear. Another 27 examples of UTI-2 were built in 1936, and then UTI-4 came.

By the way, UTI-4 was the most numerous I-16 version at all – more than 3600 were built.

But there was also another prototype trainer version – the UTI-3 (Type 11) mentioned by igor-mich. Its main distinctiveness was its engine – 690-hp M-58, designed in Zaporozhye by Arkady Nazarov as further development of M-22 (some sources mention its alternative designation – M-22U). The single UTI-3 prototype (No.11211) was also tested in 1935, and also is counted in the number of 22 trainers produced that year. It was tested by Valery Chkalov, who rated it very good – much better than M-22-powered Type 8. But UTI-3 wasn’t produced in series, because its engine wasn’t.

Sources:
1. M.Maslov. King of the Fighters. P.300-301.
2. http://i16fighter.narod.ru/mods/exp.htm

From; Козырев - Авиация Красной Армии (Москва, 2011)

a two strange concepts to I-16 ?.

The first picture is the projected I-16SPB-BRAB-500, a 1940 variant of the I-16 Zveno dive-bomber carried under a TB-3 four-engined bomber. Operational SPBs were armed with two 250-kg bombs carried under the wings outboard of the undercarriage attachments. The navy wanted a variant capable of carrying a single BRAB-500 armor-piercing, antiship bomb. (Les chasseurs Polikarpov, Herber Leonard, Docavia, 2004)

The second picture looks like a rigid-towed glider for pulling a torpedo. It uses the I-16 Type 24 rather than the Type 5, so I'd guess that it is a naval project from a later period in the war. But I have no actual information on this one.

Many thanks to you Iverson.

The answer here: (including the post of Hesham))
http://www.secretprojects.co.uk/forum/index.php/topic,11520.60.html
http://www.secretprojects.co.uk/forum/index.php/topic,4869.msg39216.html#msg39216

An a bit of American inspiration

Justo Miranda said:

An a bit of American inspiration

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Thank you my dear Justo,

but are some of them real ?.

Polikarpov`s sketch of two-seat turret-fighter

Nice find Stenda,

and what ais your source ?.

hesham said:

and what ais your source ?.

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Here in comments