I would say you could get his IQ tested he sounds like a gifted child , how exciting that must be for you to see your son drawing pictures with so many details,he has an enquiring mind and in order to be able to feed it you may have to enroll him in a gifted programme or even one of the schools as he may be well ahead of others.in his grade.Good Luck you are in for an interesting life with your son.
This is normal for an engineer. ;D Ain't it grand?
Feed this by buying him electronics kits, and really good maps and globes, and keep him interested.