I'm sure others have thought of this idea before, but I don't think I've ever seen it demonstrated online - so thought it might be worth posting. It's a very quick + simple way to economise on the cost of radio equipment and speed controllers for your models by making the receiver and ESC into a self-contained unit (more or less) which can be switched from one model to another almost as easily as changing batteries.
The receiver and electronic speed controller, along with on/off switch, are attached to a backing plate (this one is styrene plastic, plywood would work just as well) with strong double-sided sticky tape. The ESC is permanently plugged into one channel of the RX, the other channel (steering) has an extension cable into which the rudder servo's cable is plugged when the system is installed in the model.
The ESC's battery cables (red + black) are attached to a Tamiya-type connector as usual (the fuse isn't necessary but is a worthwhile safeguard). The ESC motor cables (blue + yellow) are also attached to a Tamiya connector. Each model set up to use this removable radio has its motor(s) wired up to a (female) Tamiya connector.
The ESC shown is the basic Viper Marine 15 but you can use any type, depending on the type of model you want to run; also a 2.4ghz digital radio could be used just as easily as the 27mhz crystal type shown.
To install the system in a model, just plug in the battery, motor and rudder servo connections - it can be unplugged and installed in another model just as quickly. The system can just as easily be set up to use a radio with 3 or more channels - you just need more servo extension cables. The one thing I haven't sorted out is the radio aerial (which needs to be raised as high above the waterline as possible). I'll probably make this removable as well, with an aerial wire permanently installed on each model and connected to the removable RX using a co-ax/microphone-type pin connector.
Here you can see the system installed in one model
and another - it took under a minute to swap it over.
With this setup, a couple of radios and ESCs (along with a set of spare crystals for each frequency, if you're using crystal rather than 2.4ghz radios) will be sufficient for as many models as you like (theoretically you only need one, but having two allows a friend/fellow club member to operate another of your models at the same time, and also allows you to use a second model as a "rescue boat").
The system does have some issues and drawbacks, such as:
- Models needs to be set up to use the system, with a Tamiya connector for the motors, a permanently installed radio aerial with connector (as mentioned) and an easily accessible free space in the hull for the radio/ESC unit. Easy access to the hull interior is necessary (so it isn't suitable for models where the scale design means only small access hatches are practical)
- The radio unit isn't secured inside the hull - as it weighs very little, this shouldn't cause stability problems for the average scale R/C boat with a heavy battery and/or ballast, but it may be a problem for lighter models. Velcro-type attachment pads for the backing plate could be a solution to this.
- The system can only be installed in models for which the ESC is suitable. Hence, if all of your model boats have completely different ESC requirements (e.g you have a tug, non-scale fast electric speedboat, scale fast launch/MTB, and a larger, slower scale vessel such as a warship or trawler) it isn't much use.
All the same, it seems to be a very good way to cut down on the cost of radio gear for models without much added inconvenience. I'm planning to use this setup (with two 2-channel 27mhz units and one 4-channel 2.4ghz) for all my current and future R/C boats, other than the few that need a more powerful ESC (and sailing models that don't need one at all!)