Thanks for the link! Having taught technical and information illustration for many years, I understand what’s involved in producing profile illustrations, etc. Indeed, I was trained as a technical illustrator myself! I even worked in the aircraft industry (Fokker, Airbus and BAC, etc), and later, when teaching, for aviation museums (Science Museum, FAA, IWM Duxford and RAF Museum, etc). Unfortunately, the illustrations in the above link lack depth, contrast and form. In other words, they’re too flat! They also lack detail. I was brought up on the aviation profile illustrations of illustrators such as Peter Endsleigh Castle, Tony Bryan, John Weal, Peter Sarson, G. W. Heumann, et al. These illustrators produced their illustrations without computers of course, but their works in terms of detail, etc, are exemplary. There are modern illustrators using Photoshop and/or Illustrator who are producing high quality, detailed and realistic profile illustrations that are comparable, but unfortunately the majority simply lack conviction. They certainly wouldn’t pass muster if produced by one of my students!