A lot of work goes into building source data. Putting it out there in the open would be essentially doing their competition's work for them.
That said, there are only so many actual sources and we know many of them. In the case of the B239 it is Finnish sources and it matches everything wmaker has shown us that he has. Nobody has yet to produce anything that says otherwise. Putting out unsupported claims that something is off isn't how it works. You must provide the support. I've done it in the past and gotten changes implemented, you can do it too.
I doubt hiding the source data is all that big of an inconvenience for the competition, assuming they were looking for it on the AH BBs in the first place.
Second, any competitor with a mind to creating accurate FM's is not going to trust the AH BBs.
And last, if any competitor cared so little as to trust a BB post when modeling their flight sim, it wouldn't matter if the data they stole from AH was the best you could find, their entire game and FM is going to be such a joke as to completely remove them from the "competition" category.
There is no valid reason to hide the data from us.
Judging solely from wikipedia, I don't get the impression the Fins did any extensive flight testing on those aircraft. They apparently did brief, rudimentary flight tests before quickly sending them off to squadrons.
I can believe that because it was not an excessively cautious time period and because the Buffalo was an established a/c and likely delivered with plenty of flight test data as purchased.
This suggest what data is available, may come from combat reports and experience which is not an ideal source by itself.
