I found what I believe to be a copy of my "A Way Too Long Discourse on Flight Model Disputes" from late 2008 or early 2009 (before WoP went modded, but the basic points remain applicable). I'll "reprinted" it due to popular demand (okay, just one guy asked for it 
). Please try to keep these points in mind when talking about your sources for a particular planeset change.
I just realized that the post is so long that it exceeds the new post-size limits, so I'm breaking it up into two posts. Introduction. It is not uncommon on this forum, and especially on the other Il-2 forums over the years, for people to complain that Oleg’s flight model for a particular aircraft model is “porked” (worse than real-life) or “too uber” (better than real-life). In fact, there is an active thread on the Spits Maps and Missions sub-forum which has raised flight modeling at times.
I have at times in various posts in this forum alluded to problems in determining the “real-life” flight model. I wanted to go ahead and discuss those problems in more detail (“oh no, not another lengthy post from Mack, and this one with subtitles at that” exclaims the assembled populace - ha ha). Many, but not all, of my comments in this post are based in part upon an article I read several years ago, but which I unfortunately cannot now locate online despite repeated and extensive efforts. Other comments are simply a result of my “real-life”, occupational habit of examining, and often attacking, the credibility and probative value of evidence submitted for a particular proposition.
My goal is to encourage people to think long and hard about their position before complaining about flight models in Il-2 (if only by thinking, “If I bring up this flight model criticism in a post, Mack will probably do a 20-page reply post” - ha ha). Of course, I’m as guilty as anyone of making blanket critiques of flight modeling, so this post is partially directed at me.
Oleg’s flight model for each plane (as modified by patches, and as constrained by computer coding issues) is presumably based upon his team’s view of that particular plane real-life flight model. Furthermore, many of the complaints about Oleg’s flight model for a particular plane are presumably based upon the complainer’s view of the real-life flight model for that plane. The question is therefore, with respect to each aircraft: “What was the plane’s real-life flight model?” There are several different sources that can be reviewed to answer that question, but each source suffers from deficiencies.
Manufacturer Specifications.
For instance, as a source for real-life flight models, one can review specifications published by the aircraft’s manufacturer. By specifications, I am referring to the data published by the manufacturer on aircraft dimensions, capabilities, and flight characteristics. This is probably one of the primary sources used. Those manufacturers specifications are useful, but aren’t necessarily correct and complete, either.
In the first place, I think that most will agree that private, for-profit manufacturers at times exaggerate the capabilities of their planes to varying degrees, especially when trying to sell it to governments and/or to meet procurement requirements. For instance, if the government says it wants the plane to go 450 kph at 1,500 meters, bidders will likely show that in their claimed specifications (which claim might be “truthful” in the sense of doing it with a 10%, high-octane fuel load, removal of guns, pilot armor, and radio, and in a dive). We all come to expect exaggeration whenever undergoing a sales call; it wasn’t any different with respect to aircraft sales in the 1930s and 1940s, particularly since military sales were the primary source of revenue for most aircraft companies at the time. . In addition, in totalitarian countries during the late 1930s and early 1940s, I suspect that there would have been an incentive to exaggerate aircraft specifications in order to satisfy the (at times unreasonable) demands of the leaders (e.g.- “Yes, Our Dear Leader, the X aircraft satisfies each and every one of the fifty-eight requirements that you ordered our design team to meet upon pain of death”). Of course, even in “free countries”, it is not unknown for subordinates to lie or exaggerate achievements or capabilities to their superiors either, for a variety of reasons.
Moreover, at times, the manufacturer in question may have published several different specifications for the same model of aircraft. Some specifications may actually represent “goals” and not “objectives met”. Other specifications may be from earlier in the design and manufacturing process, and do not accurately represent the flight characteristics of the final production version of the aircraft. Additionally, different departments of the manufacturer may utilize different specifications; for instance, the marketing department might use different specifications when trying to make a sale than the engineering department when studying flight-test failures. On other occasions, one design team of a manufacturer might understate capabilities of an aircraft created by another design team or overstate capabilities of aircraft created by its team, as part of a competition over limited resources for their competing aircraft projects. In many cases, there might be multiple sets of differing specifications, without clear descriptions of the date, stage, etc. identified. Furthermore, where records have been lost or destroyed during or after WWII (e.g.- bombing raid or seizure by invading army), perhaps only a single set of specifications remains and it is unclear whether or not it is the “official”, authoritative version. Accordingly, there may be some question as to whether, or which, particular specifications are those for the final, production version of a particular model of aircraft.
It is also conceivable that, on occasion, a manufacturer might understate the capabilities of its aircraft, in an effort to obtain additional funding for “needed improvements”. Please remember that we’re talking about “war profiteers” in the old vernacular (ha ha).
Furthermore, depending upon governmental requirements for secrecy or for political purposes, the actual specifications of a particular aircraft might have been modified, for better (e.g.- “look how great our new plane is, so enemies should beware”) or for worse (e.g.- “don’t let our enemies know how good [or bad] our new plane is”). Additionally, some specifications or test records, etc. might still be designated “top-secret” and might never have yet made publicly available [maybe more from oversight at this point, than anything else].
There is another problem with any sort of specifications insofar as they are supposed to reflect the ideal aircraft, or, in some cases, the typical aircraft, if properly manufactured with proper components using proper processes and techniques. During wartime, many aircraft would not meet those “ideal-plane” or “typical-plane” standards for a variety of reasons (e.g.- different factories, different workforces in a particular factory, sabotage, laziness, use of slave labor, poor oversight and supervision, bombing raids, poor assembly, poor or inconsistent components, etc.). Some countries in WWII also still used artisanal or small-workshop production (as opposed to more-standardized factory production) for at least some components of aircraft. Importantly, quality-control standards were not the same during WWII (especially in war-torn countries) as you might find today. Depending upon who was working with what components that week, an aircraft constructed that week might have some minor, yet appreciable differences from one constructed the following week or the prior week. Even today using modern quality control methods, different production runs of the same product will often have slight differences (e.g.- one run of a particular make and model of carpet or tile will usually have a slightly different color than another run of the same make and model). I also seem to remember old jokes about not buying cars constructed during December, since the workers may not have the same level of focus on their craft.
Along the same lines, many pilot accounts from WWII and other wars describe individual aircraft of the same make and model being slightly different from another similar aircraft in the same squadron (e.g.- “The Major always takes plane #2 because it is - or seems - faster than plane #4"). Sometimes those differences could be due to the manufacturing process (e.g.- Bob filled in to assemble the right elevator because Jim was out sick), or instead simply due to in-theatre maintenance (e.g.- Roger the crew chief takes better care of his plane’s cooling system than Fred the crew chief).
Governmental Records.
Another commonly-utilized source for flight models is government test bureaus or agencies. This is another useful source, but likewise has its drawbacks.
In some cases, maybe there wasn’t much testing of a particular plane, and the bureau for whatever reason simply accepted much, if not all, of the manufacturer’s claimed specifications. Additionally, it is not always clear as to what testing criteria was used or what developmental stage of the particular model was tested. Testing wasn’t necessarily always done on the final production model (but perhaps a similar one, for which the production go-ahead was given, with some final suggested modifications). In addition, manufacturers would commonly make sure that a “perfect” plane was sent for testing, and the “perfect” plane was probably better-built [with more quality control efforts] than the “typical” run-of-the-mill factory-built plane. Testing also was usually done at the beginning of, or right before, production, as opposed to during the middle of production, and there might be further differences between the tested plane and the typical mid-production plane. Testing criteria could differ, as could testing techniques and testing personnel. Depending upon what group tested a particular plane under what circumstances, different results might follow. As we all know, different people usually grade or judge things differently, whether through personal preference, “how I was taught or raised to do it”, bias, prejudice, self-interest, improper promotion [e.g.- I like the X plane more than the Y plane, and will do anything to make the X plane “win” the competition]. or even corruption. There is also a problem of what test records remain, and the nature and completeness of the existing test records [similar to problems with manufacturer specifications]. To the extent the government testing involves in-flight testing, additional problems are present as described below.
Flight Test Records.
A third major source of flight model data is comprised of records of flight tests. These are very useful, but like the others, not perfect.
Indeed, there are many variables that can affect the results of flight tests. Was a special, “perfect” plane used? What was the fuel load-out? What was the weapons load-out? Were particular components taken out [or added] for testing purposes? Was special or extra-high octane fuel used? How were the instrument calibrated? What were the weather conditions? What was the skill level of the pilot? What were the personal preferences or prejudices of the pilot? What was the pilot told to do, or not do, in the test? How “controlled” was the test? In addition, what records of flight tests remain? Are those complete records? Are they necessarily accurate ones? For instance, does the only extant flight test records for a particular model represent the typical flight test, or is it instead the aberrational flight test?
In a similar vein, flight testing of captured opposition aircraft provide some advantages (e.g.- avoid pro-enemy propaganda claims about aircraft capabilities), but also has its own disadvantages. The same flight-test concerns raised above apply here, but, added to it, are problems relating to the condition of the aircraft [e.g.- crash-landed but rebuilt; found in water and drained; abandoned in “working condition” at airfield [perhaps because it was a “bad” plane], the usual lack of design manuals or training manuals for enemy plane, the lack of test pilot experience in such an enemy plane, perhaps the inability of the test pilot to fully read or understand the gauges, differences in fuel, oil, or other materials, differences in maintenance and repairs, differences in test pilot preferences and experiences (e.g.- if I only usually flew, and loved Hellcats, would I be the best pilot to test out a captured Oscar), and the simple variables in particular production-runs or individual aircraft.
