3D Printable RG65 Prototype Update - Video

This 3D printable RG65 is now in its 4th iteration already during this New Zealand winter. So far we're seeing some promising speed from this little rocket ship. This boat is aimed at the club racer who wants something a little different and a project they can experiment with using their 3D printer. The other person this boat suits is someone who wants a cool, simple RC sailboat.

 

The coolest aspect of this boat is it comes in a variety of configurations. You can print the hull as a standard rig set with stays, jib, and mainsail. Or you can print the hull as a single sail Una rig setup for a really simple and quick build. In the video you can see the Una rig is awesome! I really didn't expect it to be so fast! The Una rig slots in place backwards then locks in place with a simple notched plate glued to the mast. The whole rig is extremely simplified. Only 3 printed fittings and 3 carbon rods for the mast, boom, and topper. The whole Una rig swivels in the mast well and uses the exact same electrics setup on a removable plate as the standard rig. You can build two boats using one set of electrics.

 

The files, which will likely be $20 USD for the set, will include the two hull types, 3 bulb weights — 550g, 508g, 480g — and 3 rudder sizes you can choose to print. This will allow you to have a play with different configurations and balance to your choosing. Both the standard and Una rig will have A & B sizes in the included sail plans.

The design started by selecting a keel aerofoil shape that is well regarded: the NACA 0012. We took this foil shape and designed it into a 3D printable package with carbon fibre rod internals attached to a 3D printed bulb shell. Really easy to print and make yourself. The bulb is filled with lead shot pellets and voids filled with polyester resin. The two bulb parts simply CA glue together as a last step. Strong, simple, and perfect shape.

 

The design of this boat is a continuation of the ideas in the RS760 but with an emphasis on speed and acceleration. The total sailing weight has been kept as low as possible while still allowing an easy-to-print boat for anyone to print and a boat that is durable. We have a 1280g boat with a bulb of 508g in its current configuration. We have tested bulbs of 600g, 550g, 508g and are about to also test a 480g bulb configuration. So far the 508g bulb seems very fast but I want to see what a lighter setup does.

 

The electrics are a very simple setup with a 1:1 sail arm that uses a cheap standard servo. The rudder servo is an Emax 20g mini servo. The battery is a 4xAAA 4.8v pack weighing 52g. The receiver we prefer is a RadioMaster R86 — small, light, and cheap. Overall this keeps this build down on cost.

More importantly is the placement of the electrics. From my experience racing dinghies in New Zealand I know you always want to keep weight out of the ends of sailboats. This improves pitching in waves and also improves responsiveness and acceleration. All electrics sit on top of the keel location under the round hatch. No heavy items sit outside the keel box area, meaning all the main weight culprits are centralised.

The hatch is a 3D printed twist-on lid, watertight and tape-free. The servo horn screws are accessible through this hatch for any adjustments needed and the servos are mounted on a plate which screws in place, making the servos easy to remove and maintain or put into another hull. You can make two boats — one Una rig and another standard — but use one set of electrics.

I hope to have this design available in the coming months. Please subscribe if you want to be kept informed.

Happy sailing!

Bryn