Nice work, especially for just starting out. I personally am not a huge fan of airbursh weathering, many times it looks to evenly applied to my eye, though it certainly has it's benefits and certainly can be well done. All of these engines were done primarily with acrylic paint and weathering powders. Online resources, namely YouTube helped me out a ton in developing techniques in addition to prototype pictures which can essentially serve as a guide. I only really got into weathering about 6 months ago, and the WM F unit shown below is my most recent work. A bit of practice goes a long way!
