IV – The final project :

In early 1927, A. Rozhkov, a permanent member of the Artillery Committee, was tasked with continuing the design of a “cannon- and machine-gun-armed” armored car based on the same AMO F15 SP (special) chassis. Refinement of the design was handled by a joint team from the T-Bureau and the AMO design department (where the aforementioned B. Strokanov and E. Vazhinsky were working). The Izhora Plant took charge of the armored hull. During summer 1927, the AMO SP chassis prototype was manufactured and tested near Moscow. In the autumn, the blueprints were transferred to the Ordnance and Arsenal Trust of the Main Military-Industrial Directorate of the Supreme Council of the National Economy (VSNKh), where further development was carried out by a team led by V. Zaslavsky. There was pressure to produce results quickly, especially given the « war scare » of 1927, which involved the anticipation of an imminent conflict with Great Britain, Poland, and possibly other nations. The issue of a « mobilization-ready » armored car, one suitable for rapid entry into mass production, became increasingly urgent. Therfore, by a decree of the Revolutionary Military Council (RVS) of the USSR dated October 24, 1927, and before any production and tests, the armored car was officially adopted for service under the designation B-27. Subsequently, the blueprints for the vehicle, then designated B-27 in official documents, were sent to the Izhora Plant for the fabrication of the armored hull. On December 19 of that same year, the Artillery Directorate signed a contract (No. 5666/95) with the Izhora Plant for the armoring of the first batch of 54 vehicles. In early 1928, the first prototype hull was transported from Leningrad to the AMO plant in Moscow, where assembly of the armored car began under the supervision of Rozhkov, Stroganov, and Vazhinsky. Assembly was completed in March, after which the B-27 entered testing. The armored car had a hull riveted from 3-8 mm armor plates on a frame made of angle iron. The hexagonal turret was modeled after the MS-1 tank turret. It was topped with a mushroom-shaped cap with viewing slits for observing the battlefield.

The four-man crew had two doors in the sides. Observation of the road from the forward control station was through two hatches with viewing slits, and just below them were two small hatches located in the frontal hull plate. The driver in the aft control station had a similar hatch in front of him. In addition, there were viewing slits with armored latches in the sides of the hull.

The armored car’s armament consisted of a 37mm Hotchkiss cannon (PS-1) and a 6.5mm Fedorov machine gun in separate mounts on the two front walls of the turret. Additionally, a searchlight was mounted in a special armored box on the right side of the turret. Ammunition consisted of 40 shells and 2,775 6.5mm rounds. The armored car was equipped with a standard AMO engine producing 35 hp. Engine cooling air entered from below through a special sump and louvers in the front armor plates. The vehicle had fairly large headlights, which were covered by folding armored covers in combat situations. The battery was mounted in a special compartment underneath the right side of the vehicle, accessible through a special armored cover. The combat weight of the armored vehicle with a crew of four was 4,450 kg.

The B-27 tests were conducted on March 24, 27 and 31 by a commission appointed by order No. 47/1 of March 20, 1928 for the Autonomous Inspectorate of the Red Army supply, consisting of the chairman of the 7th section of the Artillery Committee Ozerov, the chairman of the 6th section of the Artillery Committee Boyno-Rodzevich, permanent member of the Artillery Committee Rozhkov, assistant to the permanent member of the Artillery Committee Ivanov D., the head of the 6th department Valkash, the chairman of the acceptance committee of the artillery acceptance of the Autonomous Inspectorate of the Red Army at automobile plants Bige, assistant to the head of the 5th department Topilov, the commander of the 3rd armored division Sheremetyev and representatives: from the infantry and armored forces inspection Derevtsov, from the cavalry inspection Vertogradsky and from the 2nd department of the Red Army Headquarters Smirnov. The preliminary inspection report for the “B-27 armored vehicle, built according to the design of the permanent member of the Artillery Committee, Rozhkov, at the AMO and Izhorsky State Plants” stated the following:

“1. The changes made by the Ferraro State Automobile Plant to the standard transport and military chassis of the AMO F-15 are expressed in the modifications of the front steering wheel, front control pedals, gear shift and brake levers, and the installation of a rear control post.

2. The armored hull, manufactured by the State Izhora Plant, can accommodate four people: the vehicle commander, who is also the gunner, two drivers, and one assistant.

3. The armored body in the rotating turret carries: a 37-mm Hotchkiss tank gun with modifications and a shoulder rest, made according to the design of the assistant permanent member of the art committee Ivanov D. at the Moscow Ordnance Plant and a Degtyarev automatic gun, installed together with a ball mount in a nest device of the Shpagin system, made by the Kovrov machine gun plant.

4. According to Rozhkov’s design, the machine gun armament was to consist of twin inverted 2.5-line Fedorov machine guns, as suggested by D. Ivanov, manufactured at the Kovrov Machine Gun Plant. However, in order to transition to a standard type, a Degtyarev machine gun was subsequently installed in a temporary ball mount with a temporary shoulder rest.

5. The armored body racks are equipped to hold 2,775 rounds of ammunition, stored in magazines for the Fedorov assault rifle and 40 rounds for the 37mm cannon. The vehicle can hold approximately 2,000 rounds of ammunition for the Degtyarev machine gun, in 63-round magazines.

6. Fuel is supplied by vacuum from the main 80-liter fuel tank, protected from the crew by a 4-mm armor wall, or from an additional 8-liter tank using gravity. Gasoline is transferred from the main to the additional tank using a double-acting pump.

7. The electrical equipment consists of a starter and dynamo installed in their proper place. »

On March 21, 1928, during the first test run over a distance of 56 km along the route 2nd House of the Revolutionary Military Council of the USSR – Ilyinka – Solyanka – Khitrov Market – Vorontsovo Pole – Taganka – Smolensky Market – Borodinsky Bridge – 25th kilometer of the Mozhaisk Highway and back to the AMO plant, the commission established:

“1. A car on a straight section of a wet highway develops a maximum speed of 45 km/h, the average speed on a highway with large sections in very poor condition is 30 km/h, the speed in reverse is 13.5 km/h.

2. The machine is capable of overcoming climbs of up to 4% in direct gear and climbs of up to 9% in third gear.

3. The car is easy to control in both forward and reverse. The right front wheel is visible through the side hatch to the right of the front-wheel drive driver.

4. The use of the turret and weapons is straightforward.

5. The team’s existing headgear (helmet or cap) is inconvenient, as it doesn’t protect the head from impacts during jolts. The long overcoat also interferes with the team’s ability to enter the vehicle, as well as control it and its weapons. »

On March 27, 1928, the armored vehicle was delivered to the Kuntsevo firing range of the Higher Rifle School, where it was tested with target shooting. The commission’s report assessed the firing results as follows:

“1. The Degtyarev machine gun with a temporary shoulder rest gives a dispersion when firing for accuracy (distance of 100 steps with 100 rounds) in bursts of 3-5 rounds, a dispersion area of ​​24 x 32 cm, and with magazines, a dispersion area of ​​23 x 21 cm.

1. A 63-round magazine is fired continuously in 5–7 seconds.

2. The bag for catching spent cartridges with a neck made for Vozdukhoflot does not cause delays when emptied in a timely manner.

3. The machine gun is not mounted in the ball successfully.

4. The field of view in the machine gun ball mount and gun mantlet is not sufficient and requires increasing by using an optical sight.

5. The transition from the cannon to the machine gun and back is carried out without hindrance and takes 15 seconds when the vehicle is in place.

6. Firing from a cannon and machine gun from a stationary position is convenient; firing from a moving position was not carried out. »

On March 31, the vehicle underwent another short test run and was then returned to the factory for inspection of its components and assemblies. This concluded the B-27’s preliminary testing. Based on its findings, the commission compiled a report, which was sent to the heads of the Artillery Directorate and the Supply Directorate. The report concluded as follows:

“Based on the preliminary tests conducted, the commission notes:

1. The choice of the 1.5-ton AMO F15 truck chassis for armoring from among the vehicles manufactured domestically for transport and military purposes provides the most advantageous means of organizing supplies, repairs, replenishment of personnel, and deployment of armored vehicle units.

2. The modifications made to the standard chassis ensure ease of maintenance of the vehicle and do not entail high costs for adapting this chassis for armor.

3. The body of an armored vehicle, with a fairly rigid design, can be prefabricated separately from the chassis and is large enough to accommodate the crew, weapons, and ammunition. With the designated placement of observation slits and hatches, the armored body provides satisfactory observation of the battlefield.

4. The size of the machine gun ammunition is sufficient for firing short bursts for 35–40 minutes, and the cannon ammunition is sufficient for successfully firing at 5–6 targets at a distance of up to 1 km.

5. The fuel supply allows the vehicle to travel a distance of up to 350 km.

Recognizing, on the basis of the above, that the vehicle meets its purpose, the commission finds it necessary to produce the following additions and weapons:

The assistant driver and the rear wheel driver are to be armed with submachine guns so that the armored vehicle can simultaneously fire at three targets.

The Artillery Directorate must now begin the following work:

a) improving the cooling of Degtyarev machine guns in order to ensure the possibility of continuous firing from magazines of at least 1000 rounds;

b) improvement of the ball machine gun mount;

c) equipping the ball mount and gun mask with optical sights.

The artillery department should, after the snow melts, organize a long-distance test of the vehicle, at least 500 km, both on the highway and on various dirt roads, to test its cross-country ability and endurance. »

It should be noted that not all commission members agreed with this assessment. Some considered the reverse speed insufficient, others pointed to the chassis being overloaded, and still others noted the weakness of the machine gun fire and the small ammunition capacity compared to the twin-turret Austin and Fiat tanks, which could carry up to 10,000 rounds. However, all these disagreements did not hinder further work on the B-27.

The artillery directorate’s leadership scheduled the main technical test of the new armored car for early June. An order dated May 25, 1928, appointed a commission chaired by Topilov, head of the 5th Department of the Red Army Artillery Directorate (he was later replaced by Rozhkov).

By this time, the B-27 had undergone a number of modifications. For example, the mushroom-shaped turret cap now opened rearward, allowing the commander to more easily observe the surrounding area. The louvers in the radiator armor plates were removed, as they provided no protection from bullets or lead splashes during gunfire. They were replaced by removable armor plates that were attached to the hull sides during stowage. The box housing the large searchlight was removed, replaced by a small one inside the turret, covered by a hinged hatch. The armored car received smaller headlights without armor covers. Furthermore, the engine armor was modified to allow for its removal without removing the hull. The fuel lines were split into two lines, and the driver’s seat was raised by 50 mm.

The armored car was tested intermittently from June 6 to July 3, 1928, along the route: Yudino railway crossing – Lapino village – Saloslovo turnoff – Seleznya River bridge – Borki village – Buzayevo village – Kolchuga – Razdory – Rublevskoye Highway – Borki – Buzayevo – Usovo-Odintsovo and Buzayevo-Kolchuga road junction. The vehicle traveled a total of 627 km, 567 of which were on the highway and 59.4 km on unpaved roads. The B-27’s cross-country ability was found to be equivalent to that of a loaded 1.5-ton truck: on poor dirt roads, it often got stuck and had to be extricated by manpower or a truck. The vehicle’s fuel range was 180-200 km on the highway and 100 km on unpaved roads, and visibility was satisfactory. Overall, the B-27 performed well, and the commission recommended in its conclusion that it be adopted into service by the Red Army.

The reports of all tests were presented to the Chief of Supplies of the Red Army, N. Dybenko, who, after studying them, sent a letter to the Chief of Staff of the Red Army with the following content:

« Due to the fact that the existing armored vehicle materiel in the Red Army was obsolete and had long since reached its depreciation point, and was becoming almost completely unusable, the Artillery Directorate of the Red Army’s Armed Forces began designing a new armored vehicle in early 1927. Its design, based on tactical and technical requirements, was based on a vehicle type being built in Soviet industrial plants. The most suitable vehicle for armoring turned out to be the 1.5-ton AMO F-15 truck from the Avtotrest plant, which is in large numbers in use in state, cooperative and industrial enterprises of the Union. Thus, by using the standard chassis produced in the USSR as an armored vehicle, the issue of providing the Red Army with armored vehicles during mobilization and spare parts for them in wartime is resolved in a positive sense. Based on the above, at the end of 1927, the AU US RKKA implemented a project for a new armored vehicle and built a prototype, which was thoroughly tested by a commission with the participation of representatives of the AU, the RKKA Headquarters, the Inspectorate of Infantry and Armored Forces, the Inspectorate of Cavalry of the armored division. Based on the above, I request that you submit a proposal to the Revolutionary Military Council of the USSR regarding the adoption of the AMO armored car, model 1927, into service with the Red Army, assigning it the designation BA-27 (AMO armored car, model 1927), and regarding the provision to the Artillery Directorate of the right to make subsequent improvements to the design of the vehicle, depending on the results of long-term testing and the experience of armored cars serving in units of the Red Army.

APPENDIX: photographs, table of basic data, draft order of the Revolutionary Military Council of the USSR. »

On October 24, 1927, by decree of the Revolutionary Military Council of the USSR, the armored car was accepted into service with the Red Army under the designation BA-27. Production was entrusted to the Izhora Plant, and the chassis was supplied by the AMO Plant.

On December 19, 1927, the Red Army Artillery Directorate signed contract No. 5666/95 with the Izhora Plant for the armor plating of 54 BA-27 vehicles in the first batch.

On January 6, 1928, another contract was signed with the AMO Plant for the supply of 54 special chassis for these vehicles. The contract with the Izhora Plant was subsequently revised to include the 55th vehicle, an unpaid prototype, and 20 armored vehicles were to be transferred to OGPU units. This order was completed in December 1928.

It’s worth noting that more than half of the first batch of armored vehicles were produced using 4-7 mm thick armor plates manufactured at the Izhora Plant back in 1922. To test their quality, two firing tests were conducted, a large and a small one, during which the plates were fired at with armor-piercing and pointed bullets from a distance of 375-600 meters.

The assembled armored hull was also accepted according to specially approved specifications: gaps up to 1.5 mm wide were allowed at the joints of armor plates for a total weld length of no more than 200 mm. On the first seven vehicles, local gaps in the joints were allowed to be no more than 2 mm wide for a total weld length of no more than 100 mm. Initially, the gap width was stipulated to be no more than 1 mm, but, given the Izhora Plant’s complaint about significant wear on the edge-grinding machine, the military accepted the plant’s proposal to allow this value to be 1.5 mm, corresponding to 200 mm.

On January 10, 1929, the Artillery Directorate signed Contract No. 549/86 with the Izhora Plant for the production of an additional 74 BA-27s. However, production of the second batch was delayed. Both the Artillery Directorate and the Izhora Plant lacked the necessary equipment, tools, and materials, and there was a severe shortage of skilled workers. The dynamics of armored car production during this period can be traced in the military representative’s report dated December 8, 1929: « The first 20 vehicles were manufactured in October, 12 in November, 11 by December 8, for a total of 43. 11 are 90% complete, 8 are 80% complete, 8 are 70% complete, 11 are 50% complete, and 3 chassis are available, for a total of 73 vehicles. »

In December 1929, the Revolutionary Military Council of the USSR established the Directorate of Motorization and Mechanization of the Workers’ and Peasants’ Red Army (UMM RKKA). It was given full responsibility for forming armored units and supplying the army with tanks, armored cars, and tractors.

On December 28, the Artillery Directorate transferred to the UMM RKKA « all rights and obligations under the contract with the Izhora Plant for armored vehicles. » After reviewing the situation, the leadership of the Directorate of Motorization and Mechanization signed Contract No. 9022170 with the Izhora Plant on February 21, 1930, for 105 BA-27s in the third batch, with the order due in December. However, the plant’s capacity did not allow for the delivery of such a large number of armored vehicles to the troops.

On May 13, the military representative of the Red Army’s UMM reported in his report « On the inspection of the fulfillment of orders by the Izhora Plant »:

1. Order 1927/28 for 55 vehicles: 55 delivered;

2. 1928/29 order for 74 vehicles: 70 delivered, 4 at the factory. According to plant administration engineer Obukhov, they will be delivered by May 20–25. The delay in delivery was due to a lack of parts: gas tanks, valves, etc.

3. The 1929/30 order was for 105 vehicles, of which not a single one was delivered by May 8. Fifteen airframes were under construction, and 30 chassis had arrived at the factory by May 8. »

Nevertheless, in September of the same year, a contract was signed with the Izhora Plant for another 65 BA-27s of the fourth batch with the following delivery dates: 20 in October, 20 in November, and 25 in December.

In the summer of 1931, production of the BA-27 ceased. By this time, only 86 of the 170 armored cars ordered by the Red Army’s UMM had been completed. Thus, the total production of BA-27s from 1928 to 1931 amounted to 215 armored cars, including the prototype. However, the latter was de-armored in 1930.

It should be noted that the only external difference between the third-batch BA-27 and the first and second-batch vehicles (the fourth remained only on paper) was the battery compartment cover. Since the battery compartment was raised, the size and configuration of the cover were reduced.

According to documentation, the armored cars were painted as follows: « …Protective color on the outside and white on the inside. Each vehicle bore markings on the inner side of the doors reading ‘AB-27 GIZ,’ along with the year of manufacture and the military serial number. A copper plate bearing the aforementioned inscriptions was affixed to the front internal bulkhead. »