After more than a year of design and development, I've built version 2 of the iQuad custom tilt-rotor quadcopter which is capable of achieving high forward speed by tilting its rotors forward in flight. After several days of flight testing and tuning, I was able to achieve stable hover and incredibly fast forward flight. Near the middle of the video, you can see the iQuad hitting a top speed of 53.3 miles per hour on the third flight of the day! This was achieved with a 40 degree forward tilt of the rotors.

For stability control, I'm using an APM 2.5+ and a modified version of the 3.0.1 arducopter firmware. Big thanks to R_Lefebvre and Gary McCray for convincing me to switch to the 3.0 version and other suggestions. To support tilt-rotors, I created a new body configuration, which adds servo control and does the proper mixing of the pitch, roll and yaw inputs depending on rotor tilt. I also added logging for the tilt input and servo angles, which was very helpful for debugging some initial stability problems. For the final phase of the project, I'm planning to add four wings that will wrap around the metal arms (and maybe some tail-fins), to allow a full transition to forward flight.

Here's another video of me having some fun with the iQuad. Near the middle of the video you can see the iQuad hovering in place while tilting forward/back.

A few months ago, I posted some video and pictures of a tilt-rotor quadcopter called iQuad. Since then, I've been working on building a new version of iQuad which is lighter, has a cleaner design, and adds FPV. The new iQuad weighs 1600 grams w/o batteries (down from 2260) thanks to a carbon fiber body and custom-built rotation mechanism and landing legs. My goal for this version is to achieve faster forward flight and eventually add 3D-printed wings to get airplane-like flight characteristics.

The previous iQuad used unmodified arducopter firmware, with the tilt servos being directly controlled by one of the channels on my radio, which limited the tilt angle at which the APM was still able to produce stable flight. For this version, I am going to control the tilt servos directly from the APM, for which I'll need to write some custom firmware. (any help would be appreciated as I am new to arducopter development)

Here are some more photos:

I just finished building a tilt-rotor quadcopter. I started the project about a year ago, starting with a 3DRobotics quad frame to learn the ropes. At this point, the only thing that remains from the original quad is the APM and ESCs.

I planned to add wings on the arms to allow the quad to generate lift while flying forward, but I haven’t gotten around to trying that yet. The original design also had four servos so each arm could tilt independently, but that ended up being too heavy and too difficult to synchronize the servos, so I ended up changing it to have just one servo in the front and one in the rear. This lets the quad fly forward/backwards without having to pitch forward and allows for differential control of the two servos to control pitch in forward flight.

The main drawback right now is that it's too heavy. For the next version, I'd like to reduce weight and streamline the design. I'll probably replace the wooden frame with carbon-fiber, get rid of the wheels, and use the space inside more efficiently so I can fit the APM and an FPV system inside the body. Below are some videos and pictures from my build. This is my first blog post on diydrones, so I hope you like it!

Here's what's on the inside:

Completed iQuad before flight:

(the mast on the back was a GoPro mount which I ended up removing to reduce weight)