Soviet purchase programs, logistics and everything, alternatives and realities 1937-43

[Dimlee]

So I'd point the finger on the top brass, that failed to push more towards the more powerful engines type ASAP, rather than on the factory workers making the respective engines.

Maybe so. The command system was dysfunctional in many ways. Engine makers, probably, had even less space for creativity than air construction bureaus.

What Western radial do you have in mind for the Tu-2, and when?

R-2600 or R-2800? From the prototype and further on, subject USA doesn't object to the exports and production capacity permits.

 

[TM06]

Soviet single engine fighters vs Bf 109

Plane.................wing area sq/ft.................normal T-O weight lbs
109-4...........................174..........................................6400
I-16 24........................160..........................................4220
LaGG-3.......................188..........................................6940
MiG-3..........................188..........................................7390
Yak-1............................184..........................................6270
Yak-7 (1941)..............184..........................................6530

Yes, I rounded off a little bit. Soviet weights tend to be rather variable.
Now for the I-185 fans.
I-185............................167.......................................7710-8230 (depends on version and source)
Basically the M-71 engine was a crude long stroke (and extra 14.5mm?) Wright R-3350 ( a R-3640 if you will). One can imagine the handling problems in a small fighter, 2 feet less wingspan and 30 sqft less area than a FW 190. Or compare to a LA-5.

It's worth noting that the I-185 M-71 Etalon in 1942 testing was found to be superior in manoeuvring to all German and Russian fighters tested at that time. So there must be things other than weight and wingspan/area at play here for that to be true. From what I could find, the I-185 was an extremely clean design that produced very little drag. There's definitely flaws and the M-71 had some teething issues to go through, but the I-185 would still be a competitively capable fighter, and possibly the best fighter they could hope for until the Yak-9U, La-7 and Yak-3, with the possibility of the I-187 and I-188 down the line as well.

 

[Shortround6]

So I'd point the finger on the top brass, that failed to push more towards the more powerful engines type ASAP, rather than on the factory workers making the respective engines.

They were pushing for more powerful engines as soon as possible. Sometimes too soon. They were somewhat trapped by the existing tooling and Russia did not have a lot of capability to retool.
The Soviets built around 150 M-106 engines which is a very large number for an experimental engine. Some were installed in production YaK-1 fighters but the combination was not used in service and the planes had the engines replaced by M-105 engines. About 50 Yak-9PDs were built with M-106PV engines in in mid/late 1944(?). The M-106 had been planned for several other planes in 1939-41. Some accounts are confusing (at least to me) with one source saying that the M-106 was phased out of production in May 1943 but later says that the M-106PV was flight tested in a Yak-9PD in Oct 1943 and a later version of the M-106PV was tested in a Yak-9PD in April of 1944. Perhaps the 50 M-106PVs that were built are not counted in the 150 M-106 engines?
The Soviets had planned to build 2000 M-107s (with 4 valves) starting in April 1941 and the completing the 2000 engines by the end of the year. But a number of problems with the engine limited production to just 29 engines in 1941. Production was started in 1942 but..............? Soviets stopped production twice post war to sort out problems.
Soviet leadership may have had a lot of problems. But they were, at times, willing to accept engines of a lower standard than some other countries. Sometimes they OK'd an engine for production after a 50 hour test and hoped to extend the overhaul live to 100 hours at a later date.
The top brass were not at all happy with the M-105 engine. But the M-106 and M-107 were not running reliably enough to switch over.
They are supposed to have built 686 M-107s in 1941-42. They had trouble with broken con-rods, pistons and crankcases.

 

[tomo pauk]

They were pushing for more powerful engines as soon as possible. Sometimes too soon. They were somewhat trapped by the existing tooling and Russia did not have a lot of capability to retool.
The Soviets built around 150 M-106 engines which is a very large number for an experimental engine. Some were installed in production YaK-1 fighters but the combination was not used in service and the planes had the engines replaced by M-105 engines. About 50 Yak-9PDs were built with M-106PV engines in in mid/late 1944(?). The M-106 had been planned for several other planes in 1939-41. Some accounts are confusing (at least to me) with one source saying that the M-106 was phased out of production in May 1943 but later says that the M-106PV was flight tested in a Yak-9PD in Oct 1943 and a later version of the M-106PV was tested in a Yak-9PD in April of 1944. Perhaps the 50 M-106PVs that were built are not counted in the 150 M-106 engines?
The Soviets had planned to build 2000 M-107s (with 4 valves) starting in April 1941 and the completing the 2000 engines by the end of the year. But a number of problems with the engine limited production to just 29 engines in 1941. Production was started in 1942 but..............? Soviets stopped production twice post war to sort out problems.
Soviet leadership may have had a lot of problems. But they were, at times, willing to accept engines of a lower standard than some other countries. Sometimes they OK'd an engine for production after a 50 hour test and hoped to extend the overhaul live to 100 hours at a later date.
The top brass were not at all happy with the M-105 engine. But the M-106 and M-107 were not running reliably enough to switch over.
They are supposed to have built 686 M-107s in 1941-42. They had trouble with broken con-rods, pistons and crankcases.

I think that it is pretty clear that I was pointing out towards the Mikulin engines as the ones that were more powerful.

 

[Shortround6]

It's worth noting that the I-185 M-71 Etalon in 1942 testing was found to be superior in manoeuvring to all German and Russian fighters tested at that time. So there must be things other than weight and wingspan/area at play here for that to be true. From what I could find, the I-185 was an extremely clean design that produced very little drag. There's definitely flaws and the M-71 had some teething issues to go through, but the I-185 would still be a competitively capable fighter, and possibly the best fighter they could hope for until the Yak-9U, La-7 and Yak-3, with the possibility of the I-187 and I-188 down the line as well.

I do have to wonder about the test.
I also wonder what they were comparing the I-185 to. A prototype Yak or Lagg or service versions?
For the installed power I am not seeing a huge advantage in drag, 600kph at sea level for 2000hp?
I also have to wonder how a service version would have performed. It is easy to make a "clean" design if you don't really care if the pilot can actually see for landing or over the the nose for defection shooting.

 

[tomo pauk]

They were pushing for more powerful engines as soon as possible. Sometimes too soon. They were somewhat trapped by the existing tooling and Russia did not have a lot of capability to retool.

And for the radials, favor the M-82 over the M-88 series ASAP.

 

[Shortround6]

And for the radials, favor the M-82 over the M-88 series ASAP.

Perhaps that could be done.
Assuming you have the tooling to make the M-82 crankcases (and a few other parts).
In the US the Wright Patterson plant/s never made more than 150 R-2600 B series engines.
The Cincinnati Plant built 10s of thousands of R-2600 B series but never a single A series engine.
The Patterson plant/s made about 110-120 R-3350s, The Cincinnati plant made 1 by the end of 1944.
The R-3350s that powered the B-29s were built at the Wood-ridge plant and by Dodge.

Yes the US had the luxury of building new plants. But in some cases they needed a lot of new tooling to make the new versions of so-called existing engines.

I worked in an old P & W plant in the early 70s. Yes we were making jet engines, but a lot of our tools were left over from WW II or the Korean war.
We had some new machines in certain areas and we had a lot of overhead cranes/hoists for moving parts around. By the 1970s most were electric. But some were small depending on location. Shop space was over 550,000sq ft (not counting office space) and we could not make an engine, we worked on parts sent in (forgings/castings etc) and finally assembley was done in other plants dozens of km away. A few times I saw a new machine being dragged through the factory using a small bulldozer and fork lifts to help 'steer'.

The M-82 may have been built in factory 29 using some of the machinery they had used to make the M-88s on. Perhaps one of our members can provide more details.
Sometimes different plants had to use different production techniques for the same engines/parts depending on the available equipment.

Perhaps the Soviets could have built more M-82s at the expense of M-88s.
The next question is if building M-82 powered IL-4s was going to show much advantage or if they could really make TU-4s in an IL-4 factory (or use the same materials?)

 

[TM06]

I do have to wonder about the test.
I also wonder what they were comparing the I-185 to. A prototype Yak or Lagg or service versions?
For the installed power I am not seeing a huge advantage in drag, 600kph at sea level for 2000hp?
I also have to wonder how a service version would have performed. It is easy to make a "clean" design if you don't really care if the pilot can actually see for landing or over the the nose for defection shooting.

Given that the test was started in early 1942 and was completed in November 1942 along with the usage of "all Soviet fighters", one could assume they would be testing against the Yak-1B, Yak-7A, early Yak-9, LaGG 23 series, and the early La-5? The German aircraft in question was a Bf 109 F-4, which it reportedly out-sped at sea level and at 5,000 m by narrow margins.
However the Etalon setter had an improved cowling design which boosted it to 400 mph at 5,000 m - about 10 mph faster than the previous aircraft without the new cowling design.
Most of the issues seemed to spring from the teething issues with the engine, however the M-71 would be getting the attention it deserves in this theoretical so one could assume that its issues would be lessened.
And besides, if the Soviets cared about landing or deflection visibility, they certainly wouldn't have fielded the long-nosed MiG-3! In all seriousness though, the I-185 seems to be relatively similar in forwards visibility to the La-5 and Yak-9, with the overall cockpit visibility being standard for Soviet fighter aircraft at the time.

 

[Dimlee]

The next question is if building M-82 powered IL-4s was going to show much advantage or if they could really make TU-4s in an IL-4 factory (or use the same materials?)

Did you mean Tu-2? Tu-4 required a whole new industry, not just a factory.

 

[Shortround6]

Did you mean Tu-2? Tu-4 required a whole new industry, not just a factory.

You are correct. I did mean the Tu-2.

 

[Shortround6]

Given that the test was started in early 1942 and was completed in November 1942 along with the usage of "all Soviet fighters", one could assume they would be testing against the Yak-1B, Yak-7A, early Yak-9, LaGG 23 series, and the early La-5? The German aircraft in question was a Bf 109 F-4, which it reportedly out-sped at sea level and at 5,000 m by narrow margins.
However the Etalon setter had an improved cowling design which boosted it to 400 mph at 5,000 m - about 10 mph faster than the previous aircraft without the new cowling design.
Most of the issues seemed to spring from the teething issues with the engine, however the M-71 would be getting the attention it deserves in this theoretical so one could assume that its issues would be lessened.

we can assume that 2000hp fighter should out perform panes with lower powered engines, especially much lower power. Assuming that the 109 and I-185 are about the same size (not going to argue over a few percent) the I-185 had about 50% more power, it should out-speed the 109F by a lot more than a narrow margin.
I have some real trust issues some Soviet test results. Heck, I have some trust issues some some American test results (P-39 test results lead the list).
Soviet turn test was often time taken to complete a circle, some times the exit speed needs to match the start speed and there is should be no loss of altitude? It is not only a test of wing loading, it is a test of power. A high power engine can drag the airframe around at a higher angle of attack without losing speed.
The M-71 had a lot of teething troubles. 18 cylinder engines had a lot of vibration problems. P&W had a lot of trouble with the R-2800 and Wright basically tossed out the original R-3350 and started over. This included a new crankcase several inches longer to allow room for bigger counter weights and for vibration dampers. Trick here was that the designer didn't know what he needed. He just designed the bigger crankcase to have room for later modifications/developments and as we know, the R-3350 in 1942-43-44 had a lot of troubles.
The Soviet union has a much smaller talent pool. Might have been a lot larger without the purges. American companies had large numbers of lower level engineers to work on specific problems. There is also a production problem. Simple arithmetic says that for every 100 M-82 engines you can build you are only going to get about 78 M-71 engines based on cylinder production.

And besides, if the Soviets cared about landing or deflection visibility, they certainly wouldn't have fielded the long-nosed MiG-3! In all seriousness though, the I-185 seems to be relatively similar in forwards visibility to the La-5 and Yak-9, with the overall cockpit visibility being standard for Soviet fighter aircraft at the time.

A lot of 1930s aircraft had poor vision to the front, and even worse vision to the rear. Too much had been sacrificed for speed (low drag). British very quickly started putting Malcom hoods on Spitfires. British stuck Malcom hoods on early P-51s in increase rear vision. Some countries accepted some really ludicrous cockpits/canopies on experimental aircraft.

There were a few countries that thought dog-fighting was over. Everything was going to be high speed passes.
Many specifications were asking for pushing the state of the art in speed. Most specifications either didn't specify vision or only gave a few general words.
French D.520 was bad mass produced one.
Corsair got a higher canopy.
The Soviet late model Yak's and LA-5 were not great, just not as bad as the I-185. It was possible to improve the I-185 but that might (probably) would mean more drag/loss of performance.
The 109 was crying out for a better canopy for the entire war. The Galland hood was not it.

 

[tomo pauk]

Perhaps the Soviets could have built more M-82s at the expense of M-88s.
The next question is if building M-82 powered IL-4s was going to show much advantage or if they could really make TU-4s in an IL-4 factory (or use the same materials?)

My cunning plan is to have the M-82-powered fighters in service at least 6 months before that was the case for the La-5, so they can impact the air war in the best part of 1942. Followed by the Tu-2 from the late 1942.

 

[tomo pauk]

@ everyone - how high should we rate the Il-2? Both the armored attacker idea, and it's materialization? Make more of them, or less, or keep at historical level?

 

[TM06]

@ everyone - how high should we rate the Il-2? Both the armored attacker idea, and it's materialization? Make more of them, or less, or keep at historical level?

Tough question. The IL-2 is in its own weird little limbo since there really wasn't anything like it elsewhere. Closest comparison was the Ju 87 but that was a dive bomber.

The armoured attacker concept was not an entirely flawed one, but the heavy weight of said armour combined with the heavy armament and the bomb load requirement did make the aircraft very slow and sluggish. On the flipside, the Sturmovik was very hard to take down and was highly effective as a demoralization tool against the Germans.
The IL-2 itself was largely fine, I'd argue it was the poor training, vulnerable gunner position and lack of proper escorts were the biggest issues.
And crucially, Russia didn't have any fighter-bombers that could adequately pick up the slack the way the P-47, Fw 190 or Tempest could.

It might be less of a headache to leave the IL-2 in its corner since it did what it needed to relatively adequately. The improved Mikulins discussed here would help, but that's about it.
However I do think the IL-10 could've entered service earlier and fully replaced the IL-2 earlier than it did historically.

 

[Shortround6]

My cunning plan is to have the M-82-powered fighters in service at least 6 months before that was the case for the La-5, so they can impact the air war in the best part of 1942. Followed by the Tu-2 from the late 1942

Well, a question is which version of the M-82 goes into production 6 months earlier? The M-82-111 or the M82A-111 or the M-82F or the M-82FN. Obviously the preferred choice is the
M-82FN But that version was not tested until the end of 1942, production started in Jan, 1943. It had a lot more changes than just the fuel injection.
You could have the M-82A-111 in large scale production a lot sooner. It was supposed to have a longer service life than the M-82-111. But it was a bit lower in power. No doubt it would the Lagg-3, just not quite as much. Engine life may be debatable, could be better or worse, I don't know.

I have not seen anything really definitive on the delay in getting the Tu-2 into production. Lack of engines is one, moving the factory was certainly a factor. Emphasizing Yak-9 production is another. I have not seen anything about material, like aluminum or wood being a factor. Actual plane was extensively redesigned in the 1943 gap making the plane lighter and easier to produce. Building more Tu-2s in 1942/early 43 might have been better than PE-2s or IL-4s but perhaps not quite the advantage it seems. Tu-2s were still flying with M-82 engines up until Aug 1943 when aircraft No 716 got M-82FNs.

@ everyone - how high should we rate the Il-2? Both the armored attacker idea, and it's materialization? Make more of them, or less, or keep at historical level?

The IL-2 is quite a puzzle. see below.

The IL-2 itself was largely fine, I'd argue it was the poor training, vulnerable gunner position and lack of proper escorts were the biggest issues.
And crucially, Russia didn't have any fighter-bombers that could adequately pick up the slack the way the P-47, Fw 190 or Tempest could.

IL-2 was simple to fly. However it did not perform all that well in the early part of the war, How much was due to the plane and how much was due to poorly trained pilots is certainly subject to question. I am not sure that IL-2s in the first few months lasted much longer than Battles over France/Belgium. One Soviet account says that the single seaters were lasting 7 missions before being lost (shot down or crashed?). Using pilots that could not fly much better than take-off, straight and level flight and land on return is not going to work well regardless of aircraft type.
Perhaps a better plane could have kept more pilots and gunners alive. Perhaps better pilots (and better escorts) could have reduced losses of IL-2 aircraft significantly. A real chicken or egg question.
But the problem of using small fighters (those small wings) meant that there was a lack of aircraft to turn into single engine bombers like even P-40s.
An IL-2 at around 4400kg empty is a significant investment in materials/labor for limited return (bombs dropped and missions flown?)

 

[tomo pauk]

Well, a question is which version of the M-82 goes into production 6 months earlier? The M-82-111 or the M82A-111 or the M-82F or the M-82FN. Obviously the preferred choice is the
M-82FN But that version was not tested until the end of 1942, production started in Jan, 1943. It had a lot more changes than just the fuel injection.
You could have the M-82A-111 in large scale production a lot sooner. It was supposed to have a longer service life than the M-82-111. But it was a bit lower in power. No doubt it would the Lagg-3, just not quite as much. Engine life may be debatable, could be better or worse, I don't know.

The early M-82 is just fine for 1942-43. It was making far better power than the main engine for the fighters of that time, the M-105PF, without much of weight and bulk increase.

I am not sure that IL-2s in the first few months lasted much longer than Battles over France/Belgium. One Soviet account says that the single seaters were lasting 7 missions before being lost (shot down or crashed?). Using pilots that could not fly much better than take-off, straight and level flight and land on return is not going to work well regardless of aircraft type.

Granted, not much of the high bar, but that seems much better than how long a Battle will last over Belgium or NE France in 1940.

But the problem of using small fighters (those small wings) meant that there was a lack of aircraft to turn into single engine bombers like even P-40s.
An IL-2 at around 4400kg empty is a significant investment in materials/labor for limited return (bombs dropped and missions flown?)

That is one of the reasons I've suggested that a fighter size of Spitfire is made.

 

[Shortround6]

The early M-82 is just fine for 1942-43. It was making far better power than the main engine for the fighters of that time, the M-105PF, without much of weight and bulk increase.

It is not just the power of the M-82 in the early versions. Yes an M-82 that makes 150hp less would still be quite an advantage over the early M-105 engines (earlier than the M-105PF)
But there were a number of quality and/or heat problems. Engine life was shorter than expected and even on the late 1942 M-82F engine things had not been fully solved. How much was engine and how much was cowling I don't know but engine temperatures were critical and engines were known to lose cylinder heads and at times, complete cylinders. Better training and keeping a closer eye on the temperature gauge?

Granted, not much of the high bar, but that seems much better than how long a Battle will last over Belgium or NE France in 1940.

Combat of the Battles in the BoF is a little skewed. On attacks on some critical targets (heavily defended) they were wiped out in very, very short order. On some missions attacking general supply routes (not bridges) losses were a lot lighter, of course they also were not causing a lot of damage. IL-2s attacking the same German Bridges in France, defended by the same number of guns, in the same numbers of attackers, might have suffered nearly the same losses. Losses for specific missions are hard to compare to 'averages' over several months.
The IL-2 had several problems that the Battle did not have. No rear gunner, this is as much (more?) having somebody in the back of the plane to warn to the pilot to take evasive action as it is to shoot down attacking fighters. Sending low time pilots into combat wo can barely fly the plane and expecting them to keep a good look-out to the rear was very hard even with a cockpit that offered good rear vision, which the IL-2 did not offer on the single seat version.

That is one of the reasons I've suggested that a fighter size of Spitfire is made.

This may have been a good idea, it might not have been a good fighter but as a single engine bomber it might have made sense?
The Devil might be in the details. Expected range might require more fuel and/or better radio/navigation equipment?
Requirements prior to June 1941 may have been different than requirements forced onto the Soviets in the Fall of 1941.
This would lead to a heavier plane than just hanging bombs off a 'fighter' even though war experience showed that the short range fighter bomber was the better solution most of the time.
Now the big wing fighter (P-40/Spitfire) needs a wing about 30% larger than the typical Soviet fighter. Since the Soviets were trying to use wooden construction this leads to several problems/compromises. Airframe weight is going to be heavier than for an aluminum aircraft. Granted the bigger wing allows for more fuel storage but the 1940-41 engines are a pretty weak lot. But the soviet designers can count on the M-106 and M-107 engines for production.................right
Big wing adds weight and drag. This might be OK for an IL-2 substitute. It is not OK for even a 2nd rate fighter.
The M-105PF doesn't show up until May 1942 and it not only has a shorter life, it has a number of internal modifications. LIke Piston pins, supercharger drive(?), crankcase modifications and reduction gear modifications. This is on top of the modifications made to the M-105PA engines in 1941 that strengthened the engine over the M-105P series.
Sticking an M-105P engine in a large wing "fighter" in 1940 is unlikely get a production 'contract'.

Now when in 1942 you might have been able to get the IL-2 'Junior' built I don't know. M-105PF engine gives you a useful increase in take-off/low altitude power and ditching the 23mm cannon saves a lot of weight (as does ditching a lot of the armor). Concentrating on 1-3 bombs (or 6-8 rocket rails) might give nearly as effective a warload.
Now, can you graft a big wing on Yak fuselage or Lagg fuselage to simplify production? or stretch an existing fuselage? Beef up landing gear?

Using the M-82 engine in 1943 opens up a lot of possibilities for a plane with a 230-260sq ft of wing. Problem is starting design in 1940-41.

 

[tomo pauk]

It is not just the power of the M-82 in the early versions. Yes an M-82 that makes 150hp less would still be quite an advantage over the early M-105 engines (earlier than the M-105PF)
But there were a number of quality and/or heat problems. Engine life was shorter than expected and even on the late 1942 M-82F engine things had not been fully solved. How much was engine and how much was cowling I don't know but engine temperatures were critical and engines were known to lose cylinder heads and at times, complete cylinders. Better training and keeping a closer eye on the temperature gauge?

I'm okay with 1600 HP. The 82F (F- forsirovany - 'forced') will make more power under greater boost = reliability might be taking a hit.

But the soviet designers can count on the M-106 and M-107 engines for production.................right

Combat of the Battles in the BoF is a little skewed. On attacks on some critical targets (heavily defended) they were wiped out in very, very short order. On some missions attacking general supply routes (not bridges) losses were a lot lighter, of course they also were not causing a lot of damage. IL-2s attacking the same German Bridges in France, defended by the same number of guns, in the same numbers of attackers, might have suffered nearly the same losses. Losses for specific missions are hard to compare to 'averages' over several months.
The IL-2 had several problems that the Battle did not have. No rear gunner, this is as much (more?) having somebody in the back of the plane to warn to the pilot to take evasive action as it is to shoot down attacking fighters. Sending low time pilots into combat wo can barely fly the plane and expecting them to keep a good look-out to the rear was very hard even with a cockpit that offered good rear vision, which the IL-2 did not offer on the single seat version.

IIRC there were no instances where the force of IL-2 send was wiped out, even in 1941.

The M-105PF doesn't show up until May 1942 and it not only has a shorter life, it has a number of internal modifications. LIke Piston pins, supercharger drive(?), crankcase modifications and reduction gear modifications. This is on top of the modifications made to the M-105PA engines in 1941 that strengthened the engine over the M-105P series.
Sticking an M-105P engine in a large wing "fighter" in 1940 is unlikely get a production 'contract'.

Now when in 1942 you might have been able to get the IL-2 'Junior' built I don't know. M-105PF engine gives you a useful increase in take-off/low altitude power and ditching the 23mm cannon saves a lot of weight (as does ditching a lot of the armor).

There is really no reason to pull out the M-105 engine out from a hat when discussing a big-ish fighter.
We already know that M-106 and -107 are not good, especially before 1945.

Using the M-82 engine in 1943 opens up a lot of possibilities for a plane with a 230-260sq ft of wing. Problem is starting design in 1940-41.

Since that kind of a fighter can be already designed around an AM-35A engine at 1st, that is no problem at all.

 

[Elan Vital]

A 2-speed S/C drive on an aero engine was a better thing than the Polikovskiy's swirl throttle that Mikulin used in the 1940s, despite the modern-days fame of the Polikovskiy's device.

Why not have both? I do guess that presumably Polikovskiy's work might have been hoarded by one engine manufacturer and not spread beyond the "Hispano-like engines".

About the Soviet armor. Modern tanks were with thick armor, reasonably powerful guns and engines. What seems to be lacking was reliability (until 1942?), 'human interface' (Yugoslav tankers commented that going from the T-34-85 into Sherman 76 was like going from a tractor into a taxi), crew visibility. German guns from early 1942 have had no problems in killing Soviet tanks at the normal combat ranges (while Soviets were pretty much in 1942 and 43 with what they had in 1941, bar the APCR ammo), and the German sights seem to be better than what the Soviets had.

Older Soviet tanks were easy prey for the German AT means.

I'm not sure how much is realistic to expect better reliability and everything considering the Soviet way of doing things and the effects of the invasion and relocation of the industry.

How much the KV-2 and T-28 were actually worth it?

The KV-2 was a normal stopgap design to take out Finnish fortifications. Better solutions were devised later on but were of no use to the USSR deep in the Patriotic War. Admittedly, there is no reason you couldn't pull a sorta SU-152 like some of the concepts drawn very early during the GPW, but it's possible the flexibility of a turret had been requested for KV-2.

T-28 is flawed but is pretty much par for the course in the early 30s. At least the Soviets went hard immediately with a 76mm gun (several models) and a powerful engine, and the T-28 served as a neat testbed for guns and the basis for many development concepts (torsion bars, Christie upscaled to slightly heavier weights...). One could also say that without the choice of a large and powerful engine like the M-17, the Soviets may not have launched the development of a similarly powerful diesel (V-2) early enough (1932 or so) to be fielded in numbers and to stay viable the entire war.

At least if we go with T-34, one of the factors behind the slow-ish progression in reliability was the intense pressure even before Barbarossa to give the tank to the troops, leaving few to no vehicles available to the manufacturer for aging tests. It is a difficult balance between ensuring proper development and adequate training and familiarisation.

Much like everywhere else, the development process of a tank in the USSR was incremental. It is very apparent with the multiple increases in turret dimensions for the T-34/76 before the hexagonal turret. 3-man turrets with larger turret rings were possible and existed already on the KV-1 and T-28, but I can only suspect that A-32 to T-34 development was very sequential due to doubts about how much weight could be held by the chassis, such that going with a 3-man turret from day one may have seemed too risky.

Arguably, an A-32/T-34 with torsion bars from day one was a practical possibility since the USSR had extensive experience with that since about 1937 and had even specified TBs for everything in 1938.

The only other missed opportunity for early GPW was the T-26 replacement debacle. Scope creep meant that a whole slew of candidates came and went until the T-50, while the T-26 remained a little too stagnant (at least in terms of automotives and suspension). A simple, moderate production ugrade in the late 30s might suffice.

A similarly quashed project of note was the KV-3 heavy tank. While it would probably be a logistical headache and likely nowhere near as viable as the IS-2, it would be a seriously tough target until the Germans fielded the more powerful long 75's and long 88's. Being based on the KV hull (up-armoured KV-220 specifically), it has the advantage of being ready a good bit before the IS series come into play, and the ZiS 107 mm was a devastating gun.

The KV-3 would likely run into the very same issues as Soviet heavy tanks beyond 50 tonnes, so not a practical proposition.

 

[tomo pauk]

Why not have both? I do guess that presumably Polikovskiy's work might have been hoarded by one engine manufacturer and not spread beyond the "Hispano-like engines".

There were engines made with both the Polikovskiy's device and 2-speed drive. AM-39, VK-107 and VK-108 among the Soviet engines.
If the engine has just a 2-speed S/C drive, benefit is much greater between SL and 3-4 km of altitude than if the S/C drive is 1-speed while the swirl throttle is incorporated. Talk about 200-300 HP on a typical high-power ww2 engine from 1941-44.
For a Soviet fighter that has the mix between the power of the AM-35A (high speed S/C drive) and AM-38 (low speed), that would've meant a fighter that can do ~600 km/h at 3-4 km, and 630 at 7 km, at least in prototype form. For comparison, MiG-3 was good for about 550 km/h at 3 km (again, as prototype). The RoC and time to height would've also been much improved.