Product Review: Rotor Bits

by | Dec 16, 2014 | reviews | 0 comments

As you probably know, there are many different types of multirotor. All multirotors share a similar set of parts:  a flight controller, some motors, some props, a battery, and some ESCs. Different multirotor designs have different numbers of motors, but the general set of parts is the same in every type of multirotor. This means that if you are interested in experimenting with building different types of multirotors, you can usually recycle parts from one multirotor to the next, which can save a lot of money. For example, my first multirotor was a quadcopter, and my second was a tricopter. I was able use take three motors, three ESCs, the battery, and the flight controller off my quadcopter for use in my tricopter, which saved me a whole bunch of money.

The only part that cannot be recycled from one multirotor build to the next is the frame since each multirotor has a different number and configuration of arms. Actually most multirotor frames cannot be reused from one multirotor build to the next; the exception is Rotor Bits from HobbyKing.

Rotor Bits is a modular multirotor construction system.

Rotor Bits is a modular multirotor construction system.

Rotor Bits is a modular multirotor construction system; it’s like Legos for multirotors. Rotor Bits is based on a set of standardized connections and dimensions. There are many different Rotor Bits available, and all can be put together, taken apart, and reconfigured to make just about any multirotor type or design you can imagine. Unlike with other multirotor frames, you can repurpose Rotor Bits parts from one multirotor build to the next, making Rotor Bits perfect for anyone who wants to experiment with different multirotor designs.

To see Rotor Bits in action, check out my Rotor Bits tricopter Instructable.

Rotor Bits Parts

There are dozens of different parts available for Rotor Bits and I certainly don’t own all of them. But I wanted to take the first part of this review to introduce you to the different types of Rotor Bits parts.

The Hubs

At the risk of making this review a little more confusing, I am going to start with parts I call “hubs.” Hubs are the only Rotor Bits parts that cannot be reused for different multirotor designs. Hubs are the parts that go in the middle of the multirotor and hold the flight controller, among other parts. There is a different hub for each different type of multirotor: a triangular tricopter hub, a square quadcopter hub, and a hexagonal hexacopter hub.

You could probably reuse the hubs to a limited extent, like you could probably use the square hub to make a “T” style tricopter, but in general you will need a different hub for each type of multirotor.

The Rotor Bits tricopter hub.

The Rotor Bits tricopter hub.

The Connectors

There are many different types of Rotor Bits connectors: T connectors, 45 degree connectors, 45 degree Y connectors, 60 degree connectors, and 60 degree Y connectors. All of the connectors (and the hubs) accept a common side of rods, 10mm square rods (below). All of the connectors also have holes for M2.5 bolts.

A Rotor Bit's 90-degree connector on a 10mm carbon fiber tube.

A Rotor Bit’s 90-degree connector on a 10mm carbon fiber tube.

Motor Mounts

Motor mounts fit onto the ends of the arms so you can attach motors. There are two basic models of motor mounts. You can have motors mounts with holes pre-drilled for motors with 17.5mm mounting holes. Otherwise, you can have motor mounts without any holes pre-drilled so you can drill your own holes and make the motor mount fit whatever motors you have.

A Rotor Bits motor mount.

A Rotor Bits motor mount.

Arms

All of the Rotor Bits hubs, connectors, motor mounts, and other pieces are designed to work with 10mm square rods as arms. There are two different types of 10mm square rods available for Rotor Bits. The first are plain carbon fiber tubes. The second are specially-extruded anodized aluminum tubes. The aluminum tubes are themselves available in two different types:  plain, or pre-drilled with holes every 10mm, which matches the hole spacing on the other Rotor Bits parts.

Rotor Bits Review

Rotor Bits occupies a somewhat unique position in the market and it is the uniqueness of the Rotor Bits system that is its greatest strength. The Rotor Bits product line is perfect for people who want to experiment with different types of multirotor. Rotor Bits is designed as a modular, reusable, interchangeable multirotor building system. So parts used on one multirotor build can be taken apart and reused for the next build.

Rotor Bits can also be used to build some of the most affordable multirotor frames possible from any commercial frame product. The Rotor Bits tricopter and quadcopter frames cost only $30. The affordability of Rotor Bits parts is also great should any parts be damaged in a crash.

Speaking of surviving crashes, the Rotor Bits components are quite strong. All of the hubs, connectors, and motor mounts are made from glass-fiver-reinforced injection-molded plastic. The parts are all very resistant to cracking.

A tricopter built with Rotor Bits.

A tricopter built with Rotor Bits.

The biggest downside to using Rotor Bits for multirotor frames is that there are very limited mounting options for multirotor components. The Rotor Bits hubs are only designed to accommodate the HobbyKing KK2.1 flight control board. Furthermore, once the KK2.1 is mounted, there is little room for any other components. There isn’t even a convenient way to mount batteries to the Rotor Bits hubs. It is usually possible to find ways to mount components, like strapping them to the arms or sides of the hub, or even using Rotor Bits’ modular design to create mounting sections, but it is not the most convenient system for building more sophisticated crafts because of the limited mounting space.

Along the same lines, there is no place to mount a camera gimbal or FPV gear.

Space can be a bit tight on Rotor Bits frames.

Space can be a bit tight on Rotor Bits frames.

So Rotor Bits is a fantastic system for building multirotor aircraft on a budget or for experimenting with different types of multirotors. But Rotor Bits is not ideal for building more complex multirotors because of limited options for mounting components. It is certainly possible to build more sophisticated crafts, like crafts with camera equipment or GPS, but it requires a more complicated frame configuration.