Tupolev SB in Soviet Service. Part Two.

 

The first combat usage of the Tupolev SB under VVS's (Soviet Air Force) Red Star was in the Battle of Lake Khasan. This battle was part of the many Soviet-Japanese border clashes in the eastern sector of the Sino-Soviet Manchurian region which took place between 29th July and 11th August 1938. One Tupolev SB was lost to Japanese fire. 

Tensions escalated in the region and fighting broke out again in the Khalkin Gol, eastern Mongolia, close to the border with China, in May 1939. At first there were two SBAP (Russian acronym for 'Fast Bomber Regiment') units present; 150 and 38 SBAP. 

In this battle, which lasted until 16th September and caused Soviet forces heavy losses, the SBs were not involved at first. However, due to the increasing Soviet casualties, two regiments of SB bombers were deployed in June, flying their first mission of the 26th. The SBs were employed thoroughly when the Japanese launched an attack in early July. 

Both 150 and 38 SBAPs were composed of a mixture of old and new models of the SB, so the differing speeds between bombers proved to be a serious problem when maintaining formation, specially when the Japanese Nakajima Ki-27 fighter attacked and the poor defensive arrangement of the SB could do little to defend, as the radio operator had to man both dorsal and ventral turrets. In order to minimise casualties against Japanese fighters, Soviets changed their tactics, so the SBs had to fly in altitudes over 6.100 m (20.000 ft), where it was difficult for the Japanese to intercept. In August a new regiment, 49 SBAP arrived in the battlefield and the SBs were employed in aerial raids against Japanese forces until Soviet and Mongolian forces lead by Georgy Zhukov carried out an offensive which ended with the cease-fire in 16th September 1939.

The SB was also employed by the VVS in the Soviet Invasion of Poland. At 6:00 am, on 17th September 1939 approximately 310.000 Soviet troops crossed the Polish border from the east and the SB was the backbone of the VVS during this campaign. Both Belarussian and Ukrainian fronts had a total of 637 SB 2M-100As available when the Polish-Soviet War broke out. They were assigned to 10th, 16th, 18th and 70th SBAPs. 

During the first days of the invasion, most of their missions were against strategical railroad stations and communication hubs, including the Stanislawow and Buczacz marshalling yards, as well as Polish airfields of Kowel, Dubno and Luzk, where they encountered resistance and Polish P-11 fighters shot down two SBs that day.

On 19th September, some of the remaining P-11s tried to attack a formation of SBs without any success at all. 

The SBs also raided one of the last Polish strongholds near Kamien Koszyrski on 22nd September. By that date the Polish Air Force had already collapsed and the VVS only flew some sporadic sorties over Poland. On 29th September a formation of various SB 2M-100As bombed the town of Nujno. 

VVS's bombing operations over Poland were limited until 6th October 1939, when the Polish campaign ended. This was because of the lack of suitable targets and only a handful of SBs were lost in the 20 days this campaign lasted.

The Tupolev PS-40 was a civilian transport variant, which we will cover in a future post. 

The Tupolev MMN was an version which featured several aerodynamical improvements. It was made on the basis of the SB 2M-103 and was powered by two 1.100 hp Klimov M-105 engines. Each engine, housed in an aerodynamically modified cowling was equipped with a centrifugal two-speed twin-stage supercharger driving a three-bladed propeller. 

The wingspan was reduced and the tail was redesigned and reduced in size. Nose section was also modified in order to have clearer portions. Armament consisted on two 7,62 mm ShKAS machine guns placed in a dorsal turret and a single ShKAS machine gun in the nose section. This reduced the defensive armament of the regular SB as they normally had two ShKAS in the nose.

The MMN also featured additional wing fuel tanks and a second landing light. It was also lighter than the SB 2M-013. 

It was accepted for state trials in September 1939 and achieved a top speed of 458 km/h (285 mph) flying at 4.200 m (13.780 ft). This was only 8 km/h (5 mph) faster than the standard SB 2M-103. As it had smaller wings, it also had smaller wing area, resulting in a faster landing speed of 160 km/h (99 mph), making it more dangerous. The MMN did not pass state trials because of its nimble defensive armament, its marginal faster speed and its high landing speed over the SB 2M-103. The only prototype was assigned to Aeroflot where it received the nickname of Shchuka (Pike).

Sources:

1st https://en.wikipedia.org/wiki/Tupolev_SB

2nd https://en.wikipedia.org/wiki/Battle_of_Lake_Khasan

3rd https://en.wikipedia.org/wiki/Battles_of_Khalkhin_Gol

4th https://j-aircraft.com/research/George_Mellinger/sovietorderofbattle.htm

5th Signal Squadron - Aircraft In action 194 - Tupolev SB in Action

6th https://en.wikipedia.org/wiki/Soviet_invasion_of_Poland

7th http://www.airvectors.net/avtu2.html

Tupolev SB in Soviet service. Part one.

 

The Tupolev SB (development TsAGI-40), was a Soviet high-speed bomber, twin-engined, three-seat monoplane bomber which flew for the first time in 1934. 

Its inception can be traced to the Tupolev ANT-40, studies of which began in early 1930s with speed given very high priority, as it was considered the best defence against fighters. 

In 1933 UVVS (Soviet Air Ministry) issued a requirement. In January 1934, TsAGI (Central Aerodynamic Institute) had gathered enough information to make that project real. 

The SB was developed at Tupolev KB (design bureau) by a team led by Aleksandr Arkhangelski. 

There were two versions planned, one powered by the Wright-Cyclone radial engine (called ANT-40RT) and another powered by the Hispano-Suiza 12Y liquid-cooled V-12 engine (called ANT-40IS). The experience gained with the design of the ANT-21 heavy fighter was put into practice.

The first prototype, ANT-40.1RT (Wright powered) made its first flight on 7th October 1934, while the second one ANT-40.2IS (Hispano-Suiza powered) flew on 30th December 1934 and showed superior performance. The Hispano-Suiza variant was actually a Klimov M-100, which was the Soviet copy of the Hispano-Suiza 12Y engine.

The ANT-40.2 was considered for production thanks to its good performance numbers for the time. However, it had consistent teething problems which lead to unhappy personnel to cover it with placards, listing its defects before the visit of Sergo Ordzhonikidze (Soviet commissar for heavy industry). When seeing those placards, Ordzhonikidze summoned Tupolev to a meeting at the Kremlin to discuss those shortfalls. In that meeting, Tupolev stated that those defects were trivial, to which Stalin answered:

"There are no trivialities in aviation; everything is serious and any uncorrected 'triviality' could lead to the loss of an aircraft and its crew.".

The first production aircraft was completed before the end of 1935 (when the ANT-40.2 was still under testing) and it entered full production in 1936. It was manufactured in two plants. Plant No 22 at Moscow and plant No 125 at Irkutsk (Siberia) from 1937 until 1941. 

As stated, there was a second prototype of the ANT-40IS, called ANT-40IS 2. It featured various improvements such as enlarged tail unit, engine nacelles moved slightly forward and a trim tab added to the right aileron. This prototype was tested with a fixed ski landing gear and defensive armament installed (a 7.62 mm ShKAS machine gun in the rear cockpit). After testing of this second prototype was completed, it was sent to plant No 22 to incorporate such improvements into production aircraft.

The ANT-46 was a heavy-fighter variant, directly derived from the ANT-40.1RT but powered by two French Gnome-Rhône 14K radial engines rated at 800 hp each. It was armed with two 76 mm APK-4 recoilless guns placed in the outer wings. It was also equipped with two fixed rearward-firing 7.62 mm ShKAS machine guns installed in the inner part of each wing. They were controlled from the gunner cockpit, who was also provided with the usual ShKAS in his cockpit that every SB had. 

There was also provision (although it was never installed) for a 12,7 ShVAK machine gun placed in the nose. 

In November 1934 the project received the ANT-46 denomination from Tupolev and the official DI-8 denomination from Soviet authorities. 
The prototype of this variant was completed in the summer of 1935 and flew for the first time in August 1935. During winter 1935-1936 it was tested with a ski landing gear and the engine cowling was changed.

It was tested by Tupolev KB until June 1936. Those tests revealed stability problems, for which it was considered to replace the tail unit with the one of the ANT-40IS 2, however, it was never completed. Another considered change that was never made was to replace the radial engines with Mikulin AR-34RN ones. 

Anyway, the project for the APK-4 recoilless guns was cancelled due to the arrest of its creator, Leonid Kurchevsky, so the ANT-46 project was left on hold. It was considered to replace them with two 20 mm ShVAK cannons in each wing or with a gun pack containing five 12,7 mm ShVAK machine guns placed in the bomb bay, like the British Bristol Blenheim Mk.IF. However, interest was lost, the ANT-46 was never presented to state trials and in 1937 Tupolev was also arrested, so his initials were banned from aircraft denominations and the planes were officially called TsAGI-40 and TsAGI-46.

Once in production, the SB 2M-100 (the denomination for the first production variants, powered by two Klimov M-100 radial engines) saw combat in the Spanish Civil War, from where some feedback was collected to improve the type's defensive armament. These experiments included the installation of an MV-3 turret or a new enlarged glazed cockpit in order to improve lateral visibility. 

Those experimental variants were completed during the course of 1936 and 1937 and, while most of them were unsuccessful, some defensive arrangements were carried over for later variants.

Sources:

1st https://en.wikipedia.org/wiki/Tupolev_SB

2nd https://massimotessitori.altervista.org/sovietwarplanes/pages/sb/tapani/prototypes/ant-40-46.htm

3rd https://massimotessitori.altervista.org/sovietwarplanes/pages/sb/tapani/prototypes/defensive.htm

4th Signal Squadron - Aircraft In action 194 - Tupolev SB in Action

Martin 139, South American and European Users

 

The Martin 139 (known in service with the United States Army Air Corps - USAAC) as B-10, was an American all-metal bomber, one of the first mass-produced in the 1930s that saw service with various countries. On this post we're covering the next ones:

• Argentina: Both Argentine Comando de Aviación del Ejército (Army Aviation Command) and Armada Argentina (Argentine Navy) used the Type 139. 
  In the mid-1930 the Army Aviation Command sought to modernise their bomber fleet and, in February 1937, after having studied other choices, they signed a contract with Martin for a total of 22 machines, which were designated by the company as Martin Type 139WAA (with the demonstrator being denominated just as Type 139WA). The bombers were assigned to the Regimiento de Aviación Nº1 (No.1 Aviation Regiment) at El Palomar Air Base, close to the capital, Buenos Aires and Regimiento 1 de Bombardeo (Bombing Regiment 1) of Villa Reynolds in the province of San Luis. They served until 1954, however, by that year the last three ones were being used as target tows. They were replaced by the native IAe-24 Calquin.
  The Argentine Navy acquired also a total of 12 new aircraft, plus a demonstrator, designated by the company as Type 139WAN. The contract was signed on 24th December 1936 and they were delivered in November 1937. They were assigned to two newly-formed bomber squadrons, one based at Punta Indio Naval Air Base, close to Buenos Aires and other one based at Comandante Espora Naval Air Base, close to Buenos Aires too. 
  This type was chosen by the Navy as the fuselage featured watertight compartments that could help with floatability in case of an emergency landing on sea and the type could also be fitted with EDO-made floaters. They also were the first airplane to feature a retractable landing gear to operate with the Argentine Navy. They all served until 1949.
• USSR: One aircraft, denominated by Martin as Martin Type 139WR, powered by two Wright R-1820-F53 Cyclone engines and Hamilton screws was bought by the Soviet Union for evaluation purposes. It seems that the performance of this machine wasn't satisfactory as no further machines were ordered by the Soviets and nothing is known about the fate of the aircraft. As there doesn't seem to be any graphical evidence of the type serving in Soviet colours, the drawing should be considered as speculative.
• Republic of Spain: The Spanish Republican Government had closed a deal for several Martin 139WSP (denomination given by the company), just before the outbreak of the Spanish Civil War. This deal also included the licensed production of the type by CASA, however, it was eventually blocked by the US State Department and the type was never delivered. When the Soviet Tupolev SB Katyusha appeared over the Spanish skies, many sources initially misidentified it as a "Martin Bomber"(which shouldn't come as a surprise as the Soviet aircraft types were kept under secrecy back in the 1930s).
  The presence of the 139WSP in the Spanish Civil War is even quoted by many authors and there are even some manipulated photographs, made with obvious propaganda purposes. We decided to draw a fictional version of the type serving with the Republican side.

Sources:

1. https://en.wikipedia.org/wiki/Martin_B-10

2. http://www.amilarg.com.ar/martin-139.html (translated)

3. https://web.archive.org/web/20200920135216/http://bioold.science.ku.dk/drnash/model/Spain/didnt.html

4. https://www.globalsecurity.org/military/systems/aircraft/b-10-foreign.htm

Junkers Ju.52/3m various European Users

 

The Junkers Ju.52/3m is a German cargo aircraft which was widely used all around the globe. It was used, among many other ones, by the following countries:

• Slovak Republic: Two Ju.52/3mg7e were purchased from Germany in 1942 when the Slovak Air Force (SVZ) replaced their old inherited Czechoslovak-made material. They were destined to their flying school. Their fate is not known, but they were most probably destroyed on the ground during an aerial strike. 
• USSR: The Soviet Union employed the Ju.52/3m both before and after World War 2. Before the war, the type was evaluated by the NII-VVS (Soviet Air Force's Technical Research Unit) in 1937. 
  The Soviet State airline, Aeroflot, began operating captured Ju.52/3m on the Perm to Samara aerial route in the summer of 1944. These aircraft were also used to transport sulphur from mines in Central Asia to Soviet factories. Many of them were retrofitted with Soviet RPK-10 radio compasses and remained in active service until the late 1950s.
• Sweden: The Swedish national airline, AB Aerotransport, bought five Ju.52/3m, (according to some sources it was just 5 of them) in 1932. Though the airline's main aircraft was the famous Douglas DC-3, the Ju.52/3m was kept in service for routes from Sweden to Germany. They were extensively used, even during the war years, with neutrality markings. After the War, they served until 1948. 
  In order to prepare the country for a possible invasion during World War 2, the Swedish Air Force hired five Ju.52/3m from Aerotransport which gave them the designation of 'TP-5'. They were employed in many different roles, like cargo, personnel and VIP transport, but also as trainers and some of them were allocated to train the first Swedish paratroopers, though, eventually, they never served as such.
• Yugoslavia: During the very end of World War 2 and the immediate postwar, the Yugoslav Air Force operated some ex-German Ju.52/3m. They were complemented in 1946 with two French-made AAC.1 Toucan which were ordered in late 1945. In 1950 they acquired four more Toucans and two years later they were replaced by the Soviet Lisunov Li-2, the Soviet copy of the Douglas DC-4. The AAC.1s were passed on to JAT, the Yugoslav state airline, which operated the type until 1964. Nowadays one of them is preserved in Belgrade.

Sources:

1. https://en.wikipedia.org/wiki/List_of_Junkers_Ju_52_operators

2. https://sv.wikipedia.org/wiki/ABA (translated)

3. https://en.wikipedia.org/wiki/AB_Aerotransport

4. http://www.vrtulnik.cz/ww2/slovac.htm (translated)

5. http://www.lietadla.com/historia/slov-heinkel.htm (translated)

6. https://wwiiafterwwii.wordpress.com/2020/04/11/aac-1-toucan-frances-post-wwii-ju-52/

7. https://www.avrosys.nu/aircraft/Transport/255tp5/255Tp5.htm

8. Signal Squadron - Aircraft in Action 186 - Junkers Ju.52 in Action

Beriev MBR-2, part two

 

The Beriev MBR-2bis was an improved version of the regular MBR-2 with a Mikulin AM-34N engine, instead of the original M-17 one. The AM-34N engine could deliver up to 750 hp of power and drove a two-bladed propeller. The MBR-2bis' fuselage was also modified to have an enclosed cockpit, a dorsal gun turret and an enlarged vertical fin. Around 750 units of this variant were manufactured between 1935 and 1940 (some sources claim it was until 1941 though) at aircraft factory No.31, located in the city of Taganrog. 

The first combat usage of the MBR-2bis was in 1938 during the Battle of Lake Khasan. Some MBR-2bis of the Soviet Pacific Fleet stationed in Vladivostok, took off to harass Japanese troops involved in the fighting. 

During the whole Winter and Continuation Wars, the MBR-2 and MBR-2bis belonging to the Soviet Baltic Naval Aviation were thoroughly employed during both conflicts, by both sides as up to five machines, both MBR-2 and MBR-2bis were captured by the Finns, who employed them in various roles, among them anti-submarine patrols, scout, rescue operations and propaganda leaflet bombing in the area of Lake Ladoga. 

They were also widely employed during World War 2, specially on the Black Sea, where they suffered heavy losses because of their weak defensive armament. In 1943 an MBR-2bis of the Caspian flotilla bombed the building of the Communist Party at the city of Elista, in the Kalamyk Autonomous Soviet Socialist Republic, when the city was occupied by the Germans, as it was serving as the headquarters for a German division. This attack was emblematic at its time, and was highly propagandised by the Soviet authorities. 

The last operational use of the Beriev MBR-2bis during World War 2 was during the Soviet Invasion of the Southern part of the Sakhalin Island, in August 1945. 

It's reported that when the Democratic People's Republic of Korea (DPRK - AKA North Korea) was established in September 1948, an unknown number of MBR-2bis was supplied to the newly created North Korean Air Force. Any further report of the MBR-2 in North Korea is unknown, they were probably destroyed during the course of the Korean War, and, as we couldn't find graphical information about it, the drawing should considered as speculative. 

Additionally, the MBR-2bis was also used by Aeroflot in various aerial routes all along the USSR until the late 1940s. 

One machine was experimentally fitted with a Mikulin M-103 engine which drove a three-bladed propeller and served as the basis for the more advanced, though unsuccessful albeit not because of technical reasons, Beriev MBR-7.

Sources:

1. https://en.wikipedia.org/wiki/Beriev_MBR-2

2. https://ru.wikipedia.org/wiki/МБР-2 (translated)

3. https://www.valka.cz/Berijev-MBR-2-M-34-kod-NATO-Mote-t102680

Beriev MBR-2, part one

 

The Beriev MBR-2 was a Soviet multi-roled flying which entered service with Soviet Navy in 1935.

Its design, which was the first aircraft designed by G.M. Beriev, dates back to the early 1930s when Soviet authorities considered there was a great need for short-range seaplanes which would perform the reconnaissance role. Initially, according to early design notes, it was going to be made entirely out of metal, but given the lack of aluminium (which was reserved only for bombers), it was decided to make it out of wood, material which the technical council of the Soviet Navy, gave the green light to work with.

The first prototype was completed in Moscow in 1932 and more machines were manufactured. Official prototype tests lasted from 1934 until 1937 with good handling and flight characteristics, it was considered superior to even some foreign flying-boats of the time like the Supermarine Walrus. The main test pilot was A.A. Ulsen and a Beriev MBR-2 was also the personal plane of Joseph Stalin to assist to a meeting about the Naval Aviation on 5th August 1933. Even if it was repudiated by A.N. Tupolev (maybe the most influential Soviet aircraft designer back in those years), who called it a "floating piece of wood", as the Soviet Navy was in need for a flying boat, and it had not bad flying characteristics, the type was officially adopted.

The initial prototype was powered by an imported BMW VI.Z engine mounted on racks above the main fuselage. Production models, those manufactured from 1934 onwards, were powered by a licensed version of that engine, the Mikulin M-17 which could deliver up to 680 hp of power. This aircraft could be fitted with either skis or wheels to allow it to operate from dry land. 

A commercial airline version, the MP-1 was also designed by Beriev, which served with Aeroflot (Soviet's main airline) and a freighter version in 1936. 

Sources:

1. https://en.wikipedia.org/wiki/Beriev_MBR-2

2. https://ru.wikipedia.org/wiki/МБР-2 (translated)

Breda Ba.64

The Breda Ba.64 was an Italian single-engined ground attack aircraft used by the Regia Aeronautica during the 1930s. It was designed by Antonio Parano and Giuseppe Panzeri and served in just two units from 1936 together with the Caproni A.P.1. It was written off from frontline duties in 1939 and replaced by the more powerful and advanced Breda Ba.65.
Developed from the previous Breda Ba.27 fighter, the Ba.64 was designed in 1933 to a requirement of the Regia Aeronautica for a multi-role aircraft capable of undertaking various roles like fighter, bomber and reconnaissance. It featured an all-metal low-wing cantilever monoplane with a wire braced tail unit and fixed tail wheel. The open cockpit was placed well forward of the fuselage in line with the wing roots to provide an excellent field of view down as well as forward. The headrest behind the cockpit was extended as a streamlined fairing all the way down the fuselage upper decking to the tail.
Two prototypes were built, serialed MM 249 and MM 250. The first one, MM 249 was a two-seater with a fixed landing gear while the second one, MM 250 was a single-seater with a semi-retractable landing gear housed in a cowling under the wings. Contrary to what wikipedia in English claims, both prototypes were powered by a single Alfa Romeo 125 RC.35 radial engine which yielded 650hp of power. It was the engine that would also power the production variants. It was armed with two Breda-SAFAT 12,7mm (0,5in) machine guns placed in the wing roots plus two additional Breda-SAFAT 7,7mm (0,3in) placed also in the wings and another defensive Breda-SAFAT 7,7mm in the observer's position firing backwards. It could also carry up to 144kg (317.5 pounds) of bombs under the wings and 400kg in the small bomb compartment located between the pilot and the observer.
It flew for the first time in 1934 and it was barely produced for one year as it was manufactured from 1935 until April 1936. Only 44 exemplars were made, all of them by Breda at their factory in Sesto San Giovanni, close to Milan.
Production aircraft were sent to serve with 5º and 50º Stormos, but pilots considered the aircraft to be ill-equipped to perform missions both as a fighter or as a bomber. It also suffered various flaws because it was underpowered, was heavy to control and had a tendency to enter high-speed stalls that led to a number of crashes. After seeing some limited-use in frontline duties, the Ba.64s were relegated to second-line duties in 1939 in the Regia Aeronautica, with some of them serving until 1943 as trainers with a modified cockpit.
Apparently, two Ba.64s were exported to the USSR in 1938 for evaluation purposes and a single machine served with the Aviazione Legionaria, the Italian volunteer air force in the nationalist side of the Spanish Civil War.

Sources:
1. https://en.wikipedia.org/wiki/Breda_Ba.64
2. https://it.wikipedia.org/wiki/Breda_Ba.64 (translated)
3. https://www.valka.cz/Breda-Ba-64-t1310
4. La Bancarella Aeronautica - Ali d'Italia 7 - Breda Ba.65 (the Ba.64 is mentioned as the forerunner of the Ba.65)

Kochyerigin DI-6

The Kochyerigin DI-6 was a Soviet two-seat biplane manufactured in the USSR during the late 1930s.
It was designed and developed at TsKB (hence its internal designation of TsKB-11) as a fighter capable of performing ground attack missions when fitted various types of weaponry. Initially it was going to be powered by a liquid-cooled V12 engine but, due to problems with its development, the Wright R-1820 radial one was chosen instead. It flew for the first time on 30th September 1934 and testing began in early 1935 with state acceptance trials taking place between May and November.
In spite of some structural weaknesses that were discovered during those trials, the type was ordered into production and deliveries to the Soviet Air Force began in spring 1937. Some of the problems encountered, like excessive vibration and a poor field of view for the rear gunner, were never fixed, and the various fixes rendered the aircraft heavier, adding around 160 extra Kg (350lb). It was produced until 1939.
It was a conventional single-bay biplane of mixed construction with cable-retracted main landing gear and was powered by a single Shvetsov M-25 radial engine which yielded 700hp of power. It was armed with two 7.62mm (0.3in) ShKAS forward-firing machine guns placed in the wings and another ShKAS placed in the observer's position. It could carry up to 40Kg (88lb) of bombs.
The pilot and the tail gunner sat in tandem cockpits with the pilot's one open and the gunner's one partially closed. To increase the rear gunner's arc of fire, the rear cockpit was set lower in the fuselage than the pilot's.
Apparently some sources claimed that the type saw combat in the Battle of Khalkin Gol against Japan during May to September 1939, and even in the Winter War against Finland in November 1939. However, there isn't any conclusive evidence of the type taking place in any of the battles as it was deemed obsolete by mid-1940.

Sources:
1. https://en.wikipedia.org/wiki/Kochyerigin_DI-6
2. Salamander Books - The Complete Book of Fighters
3. https://forum.valka.cz/topic/view/143262

Beriev Be-2 (KOR-1)

The Beriev Be-2 was an all-metal biplane which had two open cockpits for the pilot and observer respectively. It was designed to replace the obsolete Heinkel He.55 which operated from warships and shore bases.
Wings were braced and designed to be foldable in order to storage it inside a warship. It featured three floaters, a large central one plus two smaller ones on the wings. It was powered by a radial Shvetsov M-25 9-cylinder engine which yielded 700hp of power and was itself a copy of the American Wright R-1820. It was armed with two 7.62mm (0.3in) ShKAS machine guns placed on the upper wings plus another defensive one mounted on the observer position.
From the very beginning, the design was plagued with flaws, difficulties and handling problems. Anyway, as they lacked any other alternative to cover the role of a reconnaissance aircraft that could operate from a warship, it was placed into production.
It presented stability problems on the water while taxiing and there were also maintenance problems with the engine. As both of those problems were never really solved, the aircraft was relegated to training and secondary roles so most oftenly it was deployed from shore bases, than warships, as originally planned. Furthermore, delays on updating Navy's cruisers or building new ones, meant that suitable catapults weren't installed until 1939 approximately.
With the outbreak of the war with Germany, it was attempted to deploy the aircraft from warships but it proved to be pointless as the flaws were still there, so the chance of deploying it from warships was definitely abandoned. During the early stages of the war it was used as a shore-based reconnaissance and search/rescue aircraft in the Baltic Sea and some of them saw their floaters replaced by wheels and pressed into service armed with underwings pod machine guns to serve as improvised strike aircrafts during the Battle of Sevastopol. However, by 1942 they were definitely written off from service.

Sources:
1. https://en.wikipedia.org/wiki/Beriev_Be-2
2. http://www.airpages.ru/eng/ru/kor1.shtml

Polikarpov U-1

Preliminary note: This is some kind of special post as we're covering the Russian copy of the Avro 504K because it has some very interesting backstory.

The Polikarpov U-1 was the Soviet unauthorized copy of the Avro 504K. It all started during the Russian civil war, when am Avro 504K belonging to the British-Slavonic Air Corps (which was sided with the White Russians) crashed near the city of Petrozavosk and the engineer Sergey Ilyushin received the order of going to that zone to recover the airplane and dissasemble it. It was re-assembled again and pushed into service for the remainer of the war, with such good results that another engineer, Nikolai Polikarpov decied to copy it. Under Soviet command, it showed good results, as it served in their different pilot schools from 1921 until 1932 and in some cases until 1935. It also set a new record in the Soviet Air Force as it was the basis for the first experiments with solid propellant rocket boosters takeoff.

It also served in many Asiatic countries. Apparently it served with the Chinese Aviation Ministry, with the Imperial Iranian Air Force and with Mongolia.
The Persians bought them together with some Polikarpov R-1 and R-2, as the United Kingdom refused to sell them airplanes alleging that the terms of the treaty of Versailles forbid the sale of weaponry.
Apparently it also was the backbone of the early Mongolian People's Army Aviation as it served as their main trainer during the 1920s and most probably during the 1930s.

Sources:
1. https://ru.wikipedia.org/wiki/У-1 (translated)
2. http://www.airwar.ru/enc/other1/u1.html (translated)
3. http://defence.pk/threads/imperial-iranian-airforce.138734/
4. http://forum.valka.cz/topic/view/108784

Avia BH-33E

The Avia BH-33E appeared first on 1929 and it differed on the original BH-33 and the PWS-A in various aspects.
The slab-sided wooden fuselage was replaced by a welded steel-tube structure, it had an elliptical cross section achieved with the help of light formers and a spli axle vee-type undercarriage introduced to replace the original crossed-axle undercarriage.

Even if it wasn't originally ordered by the Czechoslovak authorities, which waited until the BH-33L, it did have some export success and three airplanes were bought by the USSR to preform some tests and 20 were sold to Yugoslavia which also purchased a production license, for the firm Ikarus at their plant of Zemun, close to Belgrade.

Two sub-variants were made one powered by the Bristol Jupiter VI, and the other one, which was the most produced, powered by the supercharged version of the Bristol Jupiter VII. One single BH-33 was fitted with a German BMW Hornet engine, however, as we couldn't find any graphical evidence, we haven't drawn it. It was armed with two Vickers 0.303in machine guns placed in the frontern upper part of the fuselage.

Sources:
1. Salamander Books - The Complete Book of Fighters
2. https://en.wikipedia.org/wiki/Avia_BH-33