Hi, this is my first post, I have a Graupner Shark which is just about finished, Hobby Lobby is closing the kit out but has run out of the stock drive unit, so I am using 2 550 mabuchi's running counter rotating props direct drive.
Graupner's directions show a bare wire antenna about 12" long, I have always heard this is a bad idea, but was just going to try it and see, then I got to thinking about the motor design, the stock drive unit has gears which isolate the motor from the outside, mine is direct drive with steel shafts, so the motor armatures are conductive to the water. I am thinking about backing up and insulating the shafts to keep the noise out of the water. I am also trying to decide what to do with the antenna, the whole sub is only ~23" long, so some of the antenna must be outside, but just trailing a limp sealed line seems a little risky on the props.
1: do most of you insulate the prop shaft from the motor?
2: any ideas on getting a springy, insulated wire to use outside the hull?
Here is a link to the Kit so you can see what it looks like.
It was orig. over $200 just for the hull, so they are really dumping it.