The cockpit tube looks like the engine section of the Apollo space capsule. I cannot stress enough how awesome this entire project is. The files are HUUUUGE and if you take a close look at them, you will certainly agree that this is justified. He incorporated every rivet, every cable, every ever so small knob... Just WOW.
But can somebody tel me if UHU does betatesting?
Rhaven has already answered the question, however, I wish to add that UHU often revises his parts and even build steps on-the-fly (he did so with the Tokyo Tower). If he finds something which can be enhanced or brought closer to the "real thing" he will do it whenever possible. In most cases it is the lack of reference material or new refs coming up during the design or build proces which might require these changes. The construction itself is pretty much straight forward and set in advance because of the master's experience in papercrafting.