Wouldn't you agree that the PE-8 Had a fundamentally sound airframe and aerodynamics, it had heavy armament stations including a rear gun position. Any of the Soviet Inline or Radial Engines that were used successfully in their single engine types would have made it work. The PE-8 wasn't prioritised for these engines because the Soviets were engaged in a ground war and the western allies had a major bombing campaign.
The PE-8 may very well have had sound airframe and aerodynamics, it may have been a bit dated but so was the B-17. It's defensive gun armament was heavy only in comparison to other Russian or German bombers. Plenty of British, American and Japanese bombers had tail gun positions. They help but certainly don't change the need for either escorts or flying by night. I am sorry but of the 4 major Russian aircraft engines if WW II only 2 are going to work. The PE-8 is a
big airplane that weighed about 2 tons more than a B-17G did empty and had about 42% more wing area. Trying to use M-105 engines is simply not going to work, you can the plane off the ground and fly it but speed (both top and cruise) are going to be dismal and ceiling is going to be
very low. The M-88 radial might offer a bit more ceiling but it too, is too small for the job. Both engines are going to have to be flogged to get
any performance out of a PE-8 and that will lead to short service life and unreliability. Using a pair of M-88s on a 20,000lb bomber (IL-4) is a bit different than using four of them on a 60-70,000lb bomber. That leaves the AM-35/38 family and the M-82 radial for major engines and the Diesels as outsiders. Since planes built with the diesels had them yanked out and replaced with AM-35s that should tell us all we need to know about the diesels. There is a reason the Germans built DB603 engines instead of using hot rodded DB 605s in Some of the Do 217s. Bombers need engines that have high climb and sustained power ratings, not engines with high 1-3-5 minute ratings.
If the Russians are on the German or Polish Border this bomber lets them bomb all of the UK and France with bombloads of around 3-4 tons. The Soviets are going to be interested in carrying the fight to the enemy rather than just engaging in a ground war with the allies. The engines will then be supplied to the PE-8.
The bombing campaign would have to be at night (no escort fighters) and use the AM35/38 engines or M-82 engines. Trying to bomb France may be doable on a sustained basis. Trying to bomb the UK is a lot harder, they have much more advanced notice. The North Sea is not a semi neutral route the Russians can use like the RAF used it. PE-8s vrs British 1943 night fighters? Neither of the available engines will give the PE-8 the ceiling that was originally hoped for with the fuselage mounted supercharger booster engine.
It was a design essentially cut out in 1941 given proper development I think a solution would be found.
solution, such as it was, was using a pair of ShVAk cannon instead of the single 12.7 and pair of 7.62s.
that is still a rather light armament.
Being not judged as good as a Me 109F4 or G1 is no great shame. Up to Mid 1942 these aircraft are the best fighters in the world.
Perhaps but by fall of 1942 they get demoted. Aug 1942 sees 3 squadrons of MK IX Spitfires in action. Sept of 1942 sees the 500th Typhoon delivered. Several squadrons of Allison Mustangs were also in service in Aug of 1942.
and the LA-5 was the best Russian fighter. Spitfire Vs could handle any other Russian fighter and the Spitfire packed much more firepower.
That's not quite the full story.
it's close enough.
A wing which stalls at 14 degrees when given slats will stall at 21 degrees.
only if the slats extend the full span of the swing.
It's probably more a matter of how the engines are serviced, philosophical. The Russian engines were designed to be field serviced with more frequent bust smaller services rather than sent back home.
It can also have a lot to do with the quality of the lubricating oil, the quality of the bearings, how often the oil was changed and checked for metal particles.
Hercules engines were able to give the power they gave and last as long as they did in part, due to the fact that their main bearings were imported from Sweden. British built bearings would work as well.
Either way they have an aircraft that can bomb the UK and France. A 1000 bomber raid, the VVS has absorbed German radar tech so they have a FuG 217 tail warning radar, radar altimeter and an aircraft big enough to drop a ton of chaff and windows.
Russians might do better to have the German electronics industry (or as much as the captured) simply build them decent radios for their aircraft and tanks. German industry might also be able to provide
water proof feild phone wire so Russian field phone networks don't short out when it rains (or heavy dew). doesn't do much good to have tail warning radars and radio altimeters if not all your aircraft have radios (or radios that work).
In order for slats to increase the stall angle of a wing by 50% you need full span slats, NOT slats in front of the ailerons. The short slats can do wonders for retaining aileron control at low speeds or high angles of attack but slats that only cover about 40% of the span (not including the fuselage) are not going to give you anywhere near that increase in stall angle. The majority of your wing will stall at the same angle, the slats will allow the pilot to keep control (mostly) and keep the plane from spinning. 
