I have a Stuka under construction as well. Having acquired many, many books on this airplane, including a very nice plastic model, they all show (the 3 views), the ailerons tapering at the tips. There are many actual photos of the stuka clearly showing the ailerons a constant chord. This is a well known error, but something that would have to be addressed for competition. Again I suppose it is not how actually scale you airplane is, but how accurately it matches your documentation.