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Project SU-101 as an alternative to the aft guns

Project SU-101 as an alternative to the aft guns

By the end of World War II in a number of countries, the development of self-propelled artillery, especially the middle class, I began to falter. The concept of "gun larger caliber on the same chassis," gradually stopped working. Cannon "normal" type marker become so, that there were problems with the ACS chassis, with the installation of the same gun in a rotating turret provided equivalent in terms of results. This was especially true of average SAU.

And in Germany, and in the USSR, and in the UK, and the United States work gradually came to, that the average tank will have the same gun, which is placed on the ACS. In addition, in some countries (especially in the Soviet Union and Germany) faced with an overload of the bow of the motor vehicle. In this regard, I began the search for alternative solutions. Thus was born "Uralmash-1» - the most unusual Soviet SAU end of the war.

In search of a promising arrangement

3 July 1944 year by the Red Army adopted a self-propelled artillery SU-100. This machine was the best among the Soviet medium-ACS-war period. In addition to a more powerful 100-mm D-gun system 10C, self-propelled gun had commander's cupola and a beefed-up 75 mm armor protection frontal part of the housing / deckhouse. However, it became increasingly evident, that is the limit of this chassis. Combat weight compared to SU-85 rose 2 t, what is worse, They came to the nose of the car. As a result of an overload of the front road wheels and suspension, from the end 1944 Year of the troops began to arrive complaint.

However, it was not the only problem. If the SU-85 gun forward forward for the dimensions of the hull was a little less 2 m, he made it in the SU-100 3350 mm. This created additional problems in combat conditions.. Increased risk of damage to tools when driving on rough terrain, in the forest and urban environments. Besides, More tests on a prototype SU-100 observed a gradual settling of the suspension of the front road wheels.

Project SU-101 as an alternative to the aft guns

For KB UZTM these problems were not the news. more autumn 1943 , work began on the SU-D25, variations of the SU-85 with a commander’s turret and a 122-mm D-25S gun. Departure of the gun was 3300 mm, and the combat mass increased to 32 t. Later, the SU-D25 project formed the basis of another machine - SU-122P. Meanwhile, the problems were apparent excessive load on the bow and too large departure of the barrel.

These problems are evident even earlier - on experienced heavy self-propelled units, which were developed on the basis of ISU-152. Furthermore, and the first proposals to address this issue have appeared in the case of heavy self-propelled guns. In late March 1944 EDO factory №100 year under the leadership of NF. Shashmurina has drafted a comprehensive modernization IS-2 aft crew compartment.

Parallel, judging from the sketches, It planned to establish on the same base and self-propelled artillery with aft crew compartment. For several reasons, further projects have not progressed, but in the summer 1944 , the relay passed to UZTM.

Project SU-101 as an alternative to the aft guns management department was divided with the fighting compartment. In contrast to the more recent projects, tunnel between the combat compartment and control separation on SU-100M1 not provided

should say, that the aft of the crew compartment for the Soviet SAU, including the middle class cars, It was not something entirely new. Also in 1941 year in the development of medium tanks, fighter A-46, it was decided to use just such a layout. She had both obvious advantages, and no less obvious disadvantages. The main advantage was that, that the barrel is either minimal, either it was not at all. In the case with open or semi-open ACS coarse location crew compartment becoming a significant advantage in terms of the supply of additional ammunition.

Disadvantages, too lacking - this close separation of management, and much more dense arrangement of the engine compartment, and a number of problems, of access and maintenance of the power plant, and the cooling system. The most the main problem was that, that required substantial reworking chassis. In wartime, not every tankostroitelnaya Power was ready for such a.

In the USSR, the immutability of the chassis has been one of the most important points, and such a solution is difficult to challenge - it allows you to quickly set up production of new combat vehicles. The exception was the family of Su-76, which implemented the aft of the crew compartment, but here we are talking more about the extent of forced. Chassis T-70B in its original form was not suitable for the manufacture SAU, the creation on its base of the motor vehicle is a thing of the mandatory.

Project SU-101 as an alternative to the aft guns Because, that the transmission remains in the aft, Height SU-100M1 compared to the SU-100 increased 100 mm

Another fine point is that, that the search for new arrangements have begun simultaneously in several countries. This is especially true in Germany. In the second half 1944 it became evident, resources that the chassis of the German light and medium tanks, fighters come to an end. The load on the front road wheels has reached its limit, and even often came for them - with the obvious results.

In this case, already had quite a good experience heavy fighter Panzerjäger Tiger tanks (P). During October and November 1944 , Krupp produced designs of light and medium tank destroyers aft crew compartment. However, them in the 6th Division of the Department of Arms rejected - especially for a large mass, which would lead to suspension of the overload. However in itself is interesting, that the thoughts of the designers were moving in the same direction.

Project SU-101 as an alternative to the aft guns ESU-100, electromechanical transmission option

When exactly did UZTM Design Bureau begin work on alternative SU-100 variants, unknown. What you can say exactly, so it is the first appearance of these machines in terms of scientific research in tanks and self-propelled guns in the 2nd half 1944 of the year. The document, dated 22 August 1944 of the year, clause 4 in the category of new medium tanks was listed specimens "Self-propelled artillery unit on the basis of the T-34 and T-44 with a gun D-10S or D-24 and the rear crew compartment".

UZTM allocated for the development of a technical design and working drawings 100 000 rubles, deadlines were 3-4 neighborhoods 1944 of the year. In the case of the base T-34, the existing SU-122P, two more cars were added. It's about self-propelled guns, which received the designation Su-100M1 and ESA-100. They were largely identical in terms of installation of arms, body configuration and the basic chassis concept.

Project SU-101 as an alternative to the aft guns Electromechanical transmission was not only bigger, but also heavier. In connection with its installation had to be recomposed and branch management, and a motor-transmissionnoe compartment

The total length of the body in comparison with the SU-100 increased by only 40 mm. The height of the machine on the roof of the cabin increased by 100 mm - to 2300 mm. It was in many ways a necessary measure, since the height of the fighting compartment decreased. This happened due to the recomposition of the chassis. The power plant and the cooling system is moved into the center housing. In this case, transmission and other powertrain components remain in place, that is, in the rear of the machine. In this regard, it was necessary to carry out a long shaft from the motor to the gearbox, as well as policemen guards.

Also in the upper aft cabin sheet makes a big hatch for access to the CAT. This problem was not new - a similarly arranged experimental self-propelled gun GAZ-71. Despite the decrease in height inside the fighting compartment, ammunition SU-100M1 even increased - to 39 caliber 100 mm. Combat mass at the same time grew by a ton (in comparison with the SU-100), reaching 32,6 t. However, it was not only the layout - the thickness of the frontal plate of the cabin was increased to 90 mm. The maximum speed was estimated at 47,5 kmh.

Project SU-101 as an alternative to the aft guns The driver’s seat had to be shifted to the left

The control department was also redesigned. Like the German Ferdinand self-propelled gun, it had no connection with the fighting compartment. Also, the lack of space led to, that the fuel tanks were placed in the control unit. The driver was placed in the center of the control compartment. Similarly SU-100 driver's hatch stayed in the frontal housing.

Project SU-101 as an alternative to the aft guns SU-100M2, alternative to the chassis T-44A

In general, the ESA-100 was similar to the Su-100M1, but it turned out more difficult - the combat mass reached 35 t. This was due to the fact, that the ESU-100 used an electromechanical transmission, developed jointly with the design bureau of plant No. 627. This transmission was one of the branches of electromechanical transmission, which was implemented on heavy tanks ECV and IS-6 (an object 253). The transmission elements were not only heavier, but also more. As a result, the number of cartridges for D-10S decreased to 35 pcs.

Significant changes have occurred in the engine compartment, and in the department of management. Too oversized the GT-627 generator forced the designers to shift the engine forward - as a result, it partially ended up in the control compartment. The driver’s position was shifted to the left, rearranged and fuel tanks. Due to the increase in mass, the maximum velocity decreased to 42 kmh.

Project SU-101 as an alternative to the aft guns Due to the lighter and lower chassis, the SU-100M2 looked more profitable, than SU-100M1

As mentioned above, T-34 was not the only base for the promising su-100 changer. 18 July 1944 of the year, GKO Decree No. 6209c “On the Organization of Production of T-44 Medium Tanks at Factories No. 75 and No. 264 of the People’s Commissariat for Tank Industry” was signed. 18 August T-44A went for testing (modified version of the tank), according to their results 23 September 1944 year was issued order No. 573c on NKTP, which indicated a list of improvements, which you had to make before launching the series. Nonetheless it became apparent, that the launch of the T-44A in the series is just around the corner. In short, the appearance of the self-propelled gun SU-100M2 project was a logical step.

Project SU-101 as an alternative to the aft guns We managed to win a little mass due to the larger bevels of the bow

From the point of view of the general layout, the SU-100M2 largely repeated the SU-100M1, the same was true for the ammunition volume. At the same time, the use of the new base allowed to reduce the height on the roof of the cabin to 2200 mm, that is, to the level of SU-100. Furthermore, and the combat mass began to comply with the SU-100 - 31,6 t. Similarly, the SU-100M1 driver was located in the center of the control compartment, at the same time, the bevels of the bow of the hull.

Besides, the driver’s hatch disappeared from the front plate of the case, he was transferred to the roof of the control compartment. In parallel with this, the thickness of the armor also increased.. Similarly, the T-44A upper and lower frontal parts of the body reached a thickness 90 mm, and the sides in the thickest place reached 75 mm. The speed was estimated at the level of SU-100M1, but the fuel supply decreased from 560 to 450 l. At the same time, a more powerful V-2-44 engine was placed on the tank, consuming more fuel.

Project SU-101 as an alternative to the aft guns SU-122-44, alternative with bow placement of the fighting compartment. At a certain stage, it was this machine that looked priority

Finally, the last of the projects was SU-122-44. This machine was no longer an alternative to the SU-100M1 or SU-100, and SU-122P. It was developed according to the "classical" scheme., that is, with the placement of the fighting compartment in the bow of the car. This project was created more as a backup in case of, if the scheme with the aft arrangement of the fighting compartment does not justify itself.

An essential advantage of the SU-122-44 was that, that of all new projects, he demanded the smallest amount of alteration of the T-44A chassis. However, while the departure of the barrel was 3070 mm, while the rest of the machines did not exceed a meter. In connection with a different layout, with thicker armor and a more powerful weapon D-25T, the combat mass SU-122-44 reached 32,8 t. On the other hand, when compared with SU-122P, it became clear, that mass growth was worth it.

Of all the submitted projects, SU-122-44 was the most spacious, which affected the conditions of the calculation, and ammunition (he made 40 shots - a third more, than much larger ISU-122). This machine was superior to the ISU-122 and armor protection, since the 90 mm upper frontal sheet was tilted 60 degrees. Based on the durability of the IS-2 with a straightened frontal part of the body, such armor provided protection against the 88 mm Pak gun 43 at a distance of 500 m. true, calculation question from 4 human.

practice shows, that to work with the gun A-19 and D-25 two charging, otherwise the rate of fire did not exceed 2,5-2,75 rounds per minute - this was confirmed by the tests of SU-122P.

“Only one will remain”

Finally, projects of new self-propelled guns were prepared by UZTM Design Bureau 7 October 1944 of the year. In all cases, the general leadership was led by L.I.. Gorlitsky, and the lead engineer was N.V.. Couric. By mid-October, design documentation for five machines was sent to NKTP, including SU-122P. However, by that time the SU-122P was built and went to factory tests. Already the first tests showed, that the average speed of the car was lower, than in the SU-100. In general, it became increasingly obvious, the chassis T 34 has come to the limit of modernization.

Project SU-101 as an alternative to the aft guns Initial configuration SU-101, prepared by the beginning of March 1945 of the year. In this form manufactured prototypes

Against this background, it seemed quite logical decision NKTP about projects CB UZTM. base T-34 It is no longer regarded as a promising, so ESA-100 and SU-100M1 immediately were behind. 26 October 1944 year VA. Malyshev has signed an order on NKTP №625s, according to which the People's Commissariat of the tank industry chose to implement projects based on the T-44A. according to the order, It was required to prepare a CB UZTM 25 December documentation on the modified draft Su-122-44, and SU-100m2. In this case, Su-122-44 turned into two cars - and SU44-100 SU44-122.

In addition to the D-25S, subject to the implementation of a variant with a 100 mm gun D-10C. The chassis is also subject to revision - in particular, grew armor protection. Thickness increased to frontal sheet 120 mm, and board up 75 mm - thereby, with a front projection the machine is protected against fire 8.8 Then 43 L / 71 at all distances. Judging by, what Su-122-44 was paid to improvement of more attention, at that time in NKTP this car was considered more promising.

Project SU-101 as an alternative to the aft guns Compared with the SU-100M2, a major re-arrangement was carried out, as well as enhanced armor protection

Despite a higher interest in the improved SU-122-44, there were enough points in the order for the alteration of the SU-100M2. TO 1 January 1945 years it was supposed to get a revised project, wherein the power unit is displaced to the right, and the place of the driver - left, to provide it with a passage in the fighting compartment, as it did on the Su-76M. Besides, such reconfiguration allows for a more convenient access to the engine and powertrain components.

Over the place of the driver provided for manhole, wherein, similarly T-44, It was provided the opportunity to ride in the stowed position, leaning out of the hatch. On the commander's cupola was mounted anti-aircraft machine gun DSK, It planned to put the barrel blowing system, and aft fastened smoke bombs MDSH. In total it needed to make 11 improvement items.

Project SU-101 as an alternative to the aft guns In order to reinforce the bead cutting of an angle set 45 degrees

Optimism about the development of Su-122-44 was short-lived. December 1944 of the year, when calculations of ACS with reinforced armor were made, it became evident, that this machine is probably a dead-end path of development. The thing is, that combat weight gradually grew, and T-44, and so had some problems with the durability of bandages rollers.

Besides, considerable influence exerted test results SU-122P. Finally, alone T-44, the chassis is planned to use as much as intact, It was a big question mark. The development of its plant №75 went hard, Moreover, much of the documentation, arrived from the factory №183, It was converted. In this way, UZTM face the prospect of a few months to get stuck in a job just for the development of the chassis of T-44. In short, meaning in the Su-122-44, and its development was lost.

Project SU-101 as an alternative to the aft guns SU-102. Initially, this machine different from the SU-101 only weapons. In practice, the sample had a mass produced internal changes

In this regard, the director of BG UZTM. Murzuq decided that, The plant of the works on SU44-122 and refuses SU44-100, concentrating on the development of an improved version of the SU-100m2. This Murzuq notified Malyshev, who greeted the initiative with understanding plant. Need to say, that the Office of the self-propelled artillery SC GBTU almost from the start did not consider the "classic" version of ACS based on the T-44 as the main. If you look at the work plans of the third department of the UCA GBTU spacecraft for autumn-winter 1944 of the year, there appears "Control over the manufacture of self-propelled artillery systems design with rear crew compartment". Su-122-44 in these plans is not.

For the consideration of the revised draft in January 1945 year came a special commission NKTP, He headed by IS. March. Having reviewed the projects on the spot, The Commission agreed with the conclusions KB UZTM. Option aft crew compartment looks more promising. calculations show, even in the case of increasing the thickness of armor combat weight increases insignificantly. Besides, in the fighting compartment fits not only the 100-mm gun D-10S, but more bulky D-25. Following the results of the Commission identified a number of deficiencies, which had to be eliminated in the final version of the draft.

Project SU-101 as an alternative to the aft guns Corpus SU-101, prepared for firing

The final version of the project SU-100M2 was presented in March 1945 of the year. As a result of improvements and strengthening of the reservation, the combat mass grew to 32,4 t. Despite this, NKTP management appreciated the new development of KB UZTM. 7 Martha 1945 year was signed an order on NKTP №107s, according to which the project was approved, assigning him the designation "Uralmash-1". according to the order, to 1 May was supposed to get the first sample, armed with a 100-mm gun D-10S, he was getting the SU-101 index.

TO 15 May the second sample was made, which had the SU-102 index, he received a 122-mm gun D-25s. The Uralmash-1 case was also manufactured, intended for shelling. The latest changes were made to the design before manufacturing.. The cooling system and ventilation of the fighting compartment were processed, the engine-transmission compartment was isolated, ammunition increased to 40 shots, increased suspension and increased armor protection of the gun, as well as the lower frontal leaf.

Project SU-101 as an alternative to the aft guns In terms of buildings, the SU-101 and SU-102 were the same, manufactured them at UZTM in March 1945 of the year

According to the plan of the USAA GBTU KA for the second quarter 1945 of the year, the design and manufacture of two prototypes Uralmash-1 cost 1 500 000 rubles (by 750 000 for each sample). However, work on the project began in March. During this month, the body workshop of UZTM managed to lay and manufacture three buildings, as indicated in the order of NKTP No. 107c. In this way, already in March project documentation for Uralmash-1, at least, touching the case, was already ready.

Project SU-101 as an alternative to the aft guns In the manufacture took into account alterations of the chassis T-44, entered at the end 1944 year factory number 75

The final version of the Uralmash-1 hull had many differences from the SU-100M2. To begin with, the thickness of the frontal part of the cabin was increased to 120 mm, and the side sheets of the cabin were reinforced to 90 mm. At the same time, the angle of inclination of the cutting boards increased significantly to 45 degrees. This was done to make the logging sides more resistant to flank fire.. Great attention to the protection of the sides was not accidental.

As shown by studies of the impact of domestic armored vehicles, hit rate, received from flanking fire, was high. therefore, unlike German tanks and self-propelled guns, new generation of Soviet combat vehicles assumed a high level of side protection. true, this created some difficulties with the placement of the calculation of the fighting compartment. for example, for the commander’s turret had to make a special tide on the port side.

Besides, in comparison with SU-100M2 the number of hatches in the roof of the fighting compartment decreased. Only the commander’s cupola and panoramic sunroof remained. The fan also had to be displaced - from the center of the roof to the rear right corner.

Project SU-101 as an alternative to the aft guns Unlike the forehead and sides of the hull, the feed remained pretty thin, what played a role in the trials

28 April 1945 years on UZTM received an instruction from NKTP and GBTU KA on testing the hull. The test program arrived two days later.. According to the program, shelling was carried out by an 85 mm gun, 100-mm gun D-10S, as well as the German 88 mm Pak gun 43 L/71. In addition to armor-piercing shells, bombardment tests were carried out by high-explosive shells. As a matter of fact, with the bombardment of 88-mm high-explosive shells tests and began. When hitting the forehead, cutting of the bolts of the fixed armor of the gun was noted.

The situation was worse when firing the same shells on the sides of the hull: destruction of seams of the connection of the bottom of the deckhouse to the hull. Two more hits were on the port side, at the same time, the welding of the roof of the commander's cupola to the visor diverged. Similar damage was observed when shooting on the starboard side.. The most critical hit in the right stern leaf of the hull - it destroyed, and also vomited aft hatch.

Project SU-101 as an alternative to the aft guns Cutting forehead was invulnerable to caliber shells 85-100 mm. At the same time, the shock wave cut off part of the bolts of the fixed armor of the gun

A total of 11 rounds of 88 mm high-explosive shells. Despite the mixed results of firing at side and aft sheets, overall structural strength satisfactory. To strengthen the connections of the side sheets, two assembly options were proposed.. Both options involved locking the sheets, which provided higher strength.

Project SU-101 as an alternative to the aft guns Extremely unpleasant result of the hit of an 88-mm high-explosive fragmentation projectile. As a result, the welding of the roof of the commander’s turret to the visor broke

The greatest volume of lesions of the body (52 pieces) accounted for German caliber armor-piercing shells 88 mm. It revealed, that the upper frontal part of the body, and also the upper frontal part of the cabin is invulnerable for all distances of defeat. The lower frontal part was struck, calculations showed, what's the ultimate distance, on which she does not make her way, is 740 m.

Worse things were with the sides of the cabin. calculations have shown, that the maximum distance of non-penetration of the logging 867 m, while the left side is less durable due to the presence of a ledge under the commander’s turret, as well as increased metal slate. As for the vertical sides thick 75 mm, then they were not a serious obstacle to the German gun and made their way at any distance of defeat.

Project SU-101 as an alternative to the aft guns The upper frontal sheet of the body was also not broken

Tests by domestic caliber armor-piercing shells 85 and 100 mm showed similar results. The amount of testing they turned out to be small: 3 shots from the gun D-10S and 22 caliber gun shots 85 mm. As with Pak 43, the upper frontal sheets of the hull and wheelhouse were not affected. In general, the results of the shelling showed satisfactory strength of the hull, although there was enough food for thought. To start, weld failure cases revealed (this defect was quite common for UZTM).

There were also complaints about the strength of the joint sheets of the bottom of the body. The visor of the commander’s turret was vulnerable, which was struck and high-explosive, and armor-piercing shells. There were complaints about the design of the exhaust pockets.

Project SU-101 as an alternative to the aft guns The result of getting a high-explosive shell in the stern of the hull

Based on the test results, the commission pointed out the need to ensure reliable protection of the lower frontal plate of the hull and strengthen the visor of the commander’s turret. It was also required to separately test the armor assembly assembly. In connection with the unsatisfactory test results of shelling the stern, it was necessary to increase its resistance to the level of SU-100. Reinforced pockets and exhaust, as well as finalized connection sheets of the body.

Project SU-101 as an alternative to the aft guns Suggestions for strengthening the connection between the sides of the hull and the wheelhouse

The special opinion was expressed by the representative of NII-48 G.I.. Fedoseenko. In his opinion, lowering the height of the bottom redana did not make sense, since the probability of him being struck by fire was low, and the choice of optimal armor needed to be decided in conjunction with NII-48. By the way, in the report, which NII-48 prepared on the basis of the study of SU-101, It noted, that KB UZTM did a great job, creating a very successful hull and wheelhouse design. Its strength compared to previous medium and heavy self-propelled guns has increased significantly. Furthermore, at the time of creation, Uralmash-1 had the most powerful protection among all the medium-sized self-propelled guns available then.

«Armored» heated

The task of NKTP and GBTU GA to create an average self-propelled installation of a new generation at UZTM approached as responsibly. As mentioned, three cases of Uralmash-1 were welded in March 1945 of the year, a 27 April, i.e. ahead of schedule, the first sample went into a test run. As it follows from the order of NKTP No. 107c, first made SU-101, armed with a 100-mm gun D-10S.

Project SU-101 as an alternative to the aft guns The prototype SU-101 during the test run, end of april 1945 of the year

Compared with the original project SU-100M2, significant changes have occurred, including in terms of machine layout. Prudently abandoned the idea of ​​placing the transmission and drive wheels, since it reduced the volume of the fighting compartment and complicated the motor-transmission group. Now the drive wheels and the transmission is placed in the front part of the body. of course, This complicated service, However, the situation did not look so critical.

The thing is, that the overhead plate consisted of two sections, at the same time, to dismantle the gearbox, it was necessary to turn the implement as far as possible to the left, raise the front section of the plate and remove the radiator, after which it was possible to proceed to dismantle the checkpoint. Complicated, but compared to the wonders of juggling, that were required to mount the gearbox at Jagdpanther, not so problematic. Things were more complicated with the dismantling and maintenance of the power plant. There, it was already impossible to do without dismantling the gun mount.

Project SU-101 as an alternative to the aft guns Gun at maximum elevation

Significantly redesigned and the fighting compartment. In connection with providing greater protection for the sides, the volume of the fighting compartment decreased, which led to a decrease in ammunition. Instead 40 cartridges for D-10C fit 36 pcs. However, due to the disappearance from the fighting compartment of the transmission elements and the shaft cover, its height increased. Besides, the reduction of ammunition to the D-10S was affected by the installation of the anti-aircraft machine gun DShKM. Ammunition for anti-aircraft machine gun amounted to 7 boxes, not to mention 16 disks to PPSh submachine guns.

Project SU-101 as an alternative to the aft guns It is at the maximum declination angle

The rearrangement and increase in armor protection affected the combat mass of the SU-101. She made up 34,09 t, ie 1,5 t more project, prepared in March 1945 of the year. On the other hand, aft crew compartment possible to distribute the load more evenly. Besides, the results of the processing of the project outreach trunk outside the case was only 600 mm.

However, the urgency of developing machines are not allowed to implement some of the requirements to finalize the "Uralmash-1». for example, tunnel from the driver's compartment in the fighting compartment was provided, but there was no isolation of the engine compartment. There were other flaws, which were revealed during the factory tests.

Project SU-101 as an alternative to the aft guns At the time of the creation of the SU-101 was the most secure medium-sized self-propelled guns in the world

According to the results of the first break-in SU-100, carried out 27 April 1945 of the year, preliminary results were obtained. A uniform load distribution on the track rollers and good torsion bar suspension were noted.. As the first tests showed, the mobility of the SU-101 was not inferior to the SU-100, since the car had a more powerful B-44 engine. A good view from the driver’s position was also noted..

Unlike the T-44, the driver’s hatch did not rotate around its axis, but the periscope instrument MK-IV was preserved, as well as the ability to ride in a stowed position, leaning out of the hatch. Also, praise was given to the hatch door in the aft deckhouse., facilitating entry into the fighting compartment and simplifying the loading of ammunition.

Project SU-101 as an alternative to the aft guns The installation of additional tracks provided increased protection for the SU-101 at medium and long distances

However, there were enough negative points. Overheating of the control compartment became one of the most important. The reason for this was the lack of proper insulation of the engine compartment. Of course, you can remember the T-60, T-70 and SU-76M, where also for the most part there was no motor partition, but compare light cars with medium self-propelled guns, having a much larger and more powerful motor, incorrectly.

In addition, overheating came from the gearbox., and from brake bands. As a result, serious overheating was felt in the spring., from which the driver suffered primarily. Even with the hatch open, the driver was able to drive on the highway no more than 7 km, after which he had to leave SU-101. In this case, the temperature of water and oil was 100-110 degrees. About march long 10-15 I had to completely forget.

Project SU-101 as an alternative to the aft guns The presence of a large aft hatch-door significantly simplified landing inside the fighting compartment and loading ammunition

Problems came to light not only with overheating. Working with the gearshift lever was inconvenient: it was too far to the right, not even speaking about, that was very hot. The idea of ​​installing control levers on the upper frontal sheet was also recognized as unsuccessful.. When shells hit the upper frontal plate, there was a high risk of disabling them., and the location itself turned out to be inconvenient. For this reason, during the testing of the SU-101 hull by shelling, the placement of the control levers was not taken into account..

Problems, revealed by the results of the first factory tests, forced to significantly modify the second prototype. As a result, the prototype SU-102 came out for testing much later than the schedule - 24 June 1945 of the year. Initially, this vehicle had to differ from the SU-101 in its gun mount.. Because, that the D-25s system had a greater mass, SU-102 turned out to be heavier - 34,77 t. Ammunition at the same time decreased to 28 shots. However, the SU-122P had even less ammunition (26 shots), also, do not forget about the presence in the ammunition 4 boxes for DShKM.

Project SU-101 as an alternative to the aft guns SU-102 in final configuration. NIBT Polygon, begining 1946 of the year

As a result, the SU-102 was designed with 10 change points. To start, the control system turned out to be rearranged. Most of the levers were moved from the upper front plate to the floor. The driver's seat was moved to 250 mm back, installed new viewing devices in the driver's hatch.

A lot of work has been done in terms of improving the situation with the temperature regime.. An additional fan was introduced to blow the gearbox and onboard clutches, as well as blowing the motor manifold. Motorized partitions were installed to reduce overheating, which also covered the transmission elements; finally, the water radiator has been increased.

Project SU-101 as an alternative to the aft guns As the tests progressed, various changes were gradually made to the car.

According to the results of the second break-in run, it turned out, that thanks to the rearrangement of the control system, it turned out to be no less convenient to control the SU-102, than the SU-100. The situation with the temperature regime has also improved. At least now the car could pass without stopping 25-30 km. However, overheating in lower gears has not gone away, what the representatives of UZTM stated. As a result, both cars were sent for revision..

Before the main stage of factory tests, both machines were modernized.. Now the intake of air for the engine was carried out not from the engine, and from the fighting compartment. To improve the situation in the control compartment, double metal walls with asbestos lining were made, and the partition sections were sealed.

Project SU-101 as an alternative to the aft guns The combat weight of the SU-102 approached 35 tons, which greatly affected the reliability

Before running tests, both cars were checked at the shooting range.. The SU-101 was able to calculate 10 shots of 2 minutes 15 seconds, while the styling was used as on the left, and right. It noted, that the gas content inside the fighting compartment remained within normal limits, the electric trigger worked normally. The fire tests of the SU-102 passed in a similar way.. When firing, the rate of fire was obtained 2 shots per minute.

Project SU-101 as an alternative to the aft guns SU-101 while crossing the ford, end of july 1945 of the year

Factory run tests started 24 July 1945 of the year, during them the cars had to pass 300 km to the village of Ognevo and back. However, SU-102 left the race pretty quickly: on the 58th kilometer of the way the gearbox broke down, after which the car was removed from testing. SU-101 passed the run from 24 by 27 July, breaking 210 km on the highway and 92 km on a heavy country road.

During the determination of the maximum speed, the car accelerated to 53,8 kmh. For the SU-102, the maximum speed was 48,2 kmh, at the same time there were problems with the fingers of the tracks. The average speed of the SU-101's pure movement was 18,5 kmh, and the average fuel consumption is 198-219 l 100 km. In this case, the water temperature was 112 degrees, and oils - 108 degrees.

However, more interesting were the temperature readings inside the control compartment. With the driver's hatch open, it was 33 degrees, but in the closed position it increased to 66 degrees. However, we must take into account the fact, that from the very beginning the SU-101 had more problems with overheating.

Project SU-101 as an alternative to the aft guns As shown by tests, the car quite successfully overcome the ford depth 0,9 m

Beyond the run tests, fording tests were carried out, as well as slopes and ascents. SU-101 easily overcame the ford deep 0,9 m, rise at an angle 23 degrees, and also a roll of the same steepness. More serious obstacles were simply not found, and the testers indicated, that the SU-101 clearly has a power reserve. The tests of the radio station were also successful.. However, full special testing program was not performed, because at the 255th kilometer of run, the diffuser seal failed.

Project SU-101 as an alternative to the aft guns Tests for overcoming descents and ascents

29 July SU-101 entered factory overhaul, during which many defects were discovered. 4 August, the director of UZTM issued order No. 30c, according to which the design of the SU-101 was 12 fixes and improvements. A significant part of the improvements concerned the cooling system. The car came out again for testing 25 September - in two days it passed 106 km on the highway and 9 km on a country road.

As a result of the changes, progress was made with the operation of the cooling system. Even in the most loaded mode and with the driver's hatch closed, the temperature in the control compartment did not exceed 45 degrees, but usually kept within 24-33 degrees (true, and the ambient temperature did not exceed 6 degrees). On the 113th kilometer of the run, the thrust for turning off the left side clutch burst, as a result SU-101 delivered to the factory in tugs. Also, typical for the T-44 problems began to appear with damage to the rubber tires of the road wheels.. Anyway with the main problem, that is, with overheating, the UZTM team for the most part managed to cope.

Project SU-101 as an alternative to the aft guns 23-the machine overcame the degree rises without much effort

While in Sverdlovsk, work was underway on testing and revision of "Uralmash-1", brainstorming took place in GBTU SC and GAU SC. The end of the Great Patriotic War did not mean at all, that the arms race was over - rather the opposite picture was observed, at least on paper. In the autumn 1945 year GAU KA compiled a list of design works for 1946 year. It included the development and manufacture of a prototype "100-mm high-power self-propelled gun for a medium artillery gun with a rear-mounted fighting compartment".

Even earlier, in late August 1945 of the year, USA GABTU has prepared its plan, this time on 1946-1950 years. according to him, on the basis of "Uralmash-1" it was planned to produce also an open ACS, armed with either a 122 mm D-25s cannon, or a 152-mm howitzer-gun ML-20. In addition to them there was a ZSU with a pair of 57-mm anti-aircraft guns., as well as a mobile observation post.

Project SU-101 as an alternative to the aft guns SU-102 during tests at the NIBT proving grounds. By that time, "Uralmash-1" was no longer of particular interest to the GBTU.

All these plans were never realized.. At first, a number of problems, which were tested by machines of the Uralmash-1 family, was associated with chassis overload. They could only be solved if the base was changed to the T-54 as a more reliable one.. This was once again confirmed by the field tests of the SU-101., carried out in 1946 year. Also at the NIBT proving grounds, the car was recognized as too cramped, the problems with overheating are still there.

Secondly, to 1946 year in Sverdlovsk became, in fact, no one to develop the car. KB was rapidly decreasing, production of the SU-100 was discontinued, and UZTM switched to peaceful products. As a result, no "Uralmash-1" as of 1946 year in the plans of NKTP did not appear. The work began from scratch at the plant No. 174 in Omsk - as a result, the ACS Object was obtained 600, which was adopted by the Soviet army 15 Martha 1954 of the year.

As for Uralmash-1, then he became one of the dead-end branches of the development of Soviet medium-sized ACS. SU-101 has survived to this day, currently on display in the Patriot Park.

/Yuri Pasholok, warspot.ru/

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