RC Boat

Overview

This is a brushless electric radio-controlled racing boat: a deep-vee mono hull that planes across the water at around 60 km/h under throttle and rudder commands sent from a handheld transmitter. The Hull & Deck is a molded fiberglass/ABS shell with a bonded deck and a removable hatch, and a ring of rubber seals keeps the electronics bay dry where the shaft and hatch break the surface. A stainless turn fin under the transom bites the water so the boat can corner hard without spinning out.

Inside the hull sit the four major systems. The Brushless Motor is a sensorless inrunner brushless motor wrapped in a clamp-on cooling jacket. Its torque reaches the water through the Driveline, a flexible cable shaft running through a stuffing tube to a brass propeller behind the transom. The Onboard Electronics receive the pilot's commands over a 2.4 GHz link, and a 4S Battery Pack pack supplies the high current the motor demands. Because everything that carries power also makes heat, a Water-Cooling Loop loop scoops water as the boat moves and pushes it through the motor jacket and the speed controller.

How it works

The pilot holds the Transmitter, a pistol-grip handset whose wheel sets rudder angle and whose trigger sets throttle. It encodes both channels and sends them over 2.4 GHz to the onboard receiver, which decodes them many times per second. The throttle channel goes to the water-cooled ESC, which switches battery voltage across the brushless motor's three phases to spin it at the commanded speed; the rudder channel drives the servo in the Steering assembly, swinging the stainless rudder to turn the boat.

Drive reaches the water through the flex shaft: the motor coupling spins the cable inside the stuffing tube, and the propeller at the far end pushes water aft to make thrust. The rudder doubles as a water pickup, forcing water up into the silicone lines of the cooling loop whenever the boat is moving. That water passes through the motor's jacket and across the ESC's cooling plate before dumping overboard, which is what lets the motor and controller run at racing current without overheating. The LiPo pack feeds the whole system through a sealed power switch, and its management board protects the cells and balances them on charge so the pack survives the high discharge rates these motors pull.