Question: Is It Illegal to Have Scaled Torpedo Systems in an RC Submarine?
A real submarine torpedo is an underwater tube-launched missile that carries a deadly explosive charge.
Answer: There are true torpedo setups and other explosive weapons for all kinds of RC vehicles but they are typically used in the film industry and RC clubs that hold reenactments of specific eras of war simulations. These weapons systems generally require a permit or license.
However, non-explosive torpedo systems are a different story. Even toy subs for children may come with working torpedo systems that fire small plastic or rubber torpedo-shaped pellets. When building your own RC sub, if you want to have a working torpedo system you'll need to plan for that when acquiring the internal electronics and the radio system.