I am trying to operate with numerical data (e.g., maximum speed deterioration), while you are merely stating your opinion. This can hardly be called a constructive discussion.
One more example: over 1000 Yak-3 (about 20% of the total production!!!) were not allowed to fly in 1946(!) due to various defects - both design and manufacturing. More than 700 of them had fabric aircraft skin with insufficient strength. It is statistics, not an opinion.
Sorry, with maybe 20 friends and acquaintances from the former Soviet VVS, I just don't believe you. And, as a retired engineer, I don't believe your "statistics" either. Statistics are a branch of mathematics at which I am a bit more then well-versed. I was in the original Motorola Six Sigma group and have written statistical applications for that company. Talking about 1000 of ANYTHING without talking about the rest of them sort of automatically invalidates anything called statistics and relegates it to mere numbers. It's like concentrating on 3 failures out of a sample of 5 and forgetting the 25,000 acceptable units already manufactured. Did they have a few bad quality airplanes? Yep.
In fact, they made 4,848 Yak-3s and 16,769 Yak-9s. That's maybe 21,000+ Yaks of the same general variety. Actually more, for a grand total around 37,000 including Yak-11s.
Many were made when the factories were being continuously bombed, day after day. AND those same factories were uprooted and moved across the Ural Mountains and remade back into factories and were expected to take up where they left off right away! All within a short time. That's not quite a reasonable request to most people, but it's what they had to deal with.
Quibbling about quality under those circumstances smacks of an agenda to discredit Yakovlev when, in fact, Stalin had made producing Yak-3/9s a condition for the workers' and plant manager's continued survival. They have turned out Yak-3s if they had to make then out of paper mache and lawn mower engines! Nobody decides to die because they didn't even try to live.
We have vastly different opinions about the quality of Soviet airplanes. Let's let if go at that and say we agree to disagree. It's really nothing to me if you like Soviet hardware or not. I take it you don't fly any or work on any, so what does it matter? Cheers, bf109xxl. Happy agenda. Press ahead in this new year.
You only have to go look up quality failures in German slave labor-produced airplanes to see that the Soviet Union wasn't the only country with a few quality issues when hard times showed up. Heck, they even had a Heinkel He 162 disintegrate in-flight during a demonstration for the Luftwaffe due to slave labor glue sabotage, killing the pilot and crashing the airplane. Definitely a high-profile quality problem. That does NOT mean the Germans didn't make good-quality airplanes; they DID.
Overall good quality does not preclude all failures. In fact, nothing will. Zero defects was a good catch phrase, not an achievable goal over the long term when manual processes were involved.
Trying to operate with numerical data is laudable, if it is available and accurate. If it is, maybe show it? I haven't seen primary Soviet WWII data in some years and would welcome the primary data. Cheers to you.