No problem, I'll be sticking to just ships from now on. My foray into FD was just a disaster.
When I visited Reina Sofia Museum in Madrid, Spain, a few years ago, I saw the sketches by Pablo Picasso before they had evolved into what is now known as one of his masterpieces: Guernica. Seemingly, it took a lot of time for Picasso to bring together the sketches to make up Guernica.
It takes time and patience to come up with a mature drawing here or somewhere else. Please don't be discouraged. Otherwise, I will feel guilty of being an obstacle for your efforts. However, here is a little advice from an IT project guy and a system analyst: prioritize your projects and attempt only similar ones at the same time. By similar ones, I mean the ones that have common elements such as chassis, hull, weapon systems, electronics etc. Also be sure that there is enough material to catch the details: pictures, drawings, data... If not, you may end up with a drawing that is too simple. Or worse, you may make wrong assumptions for the missing details. Your drawing becomes somewhat wrong then.
Regards...