The 2400-OT was a unique project that allowed the BFD team to push the limits to make one of our largest systems yet. The 2400-OT runs 2400mm from motor to motor and swings 8x 30” propellers. Many of our systems run a over under motor configuration also known as a CoAxial configuration, however, this specific model will be used for agriculture and we wanted to have the ability to have dispensing payloads underneath the propellers if necessary. The specifications for this project were pretty open, fly a heavy payload for as long as possible and make sure it will be able to be transported in an 8’ trailer. The main goal for this aircraft is an experimental agricultural platform for dispensing a chemical payload over fields and crops. More work needs to be done on the flight controller side so this project is still ongoing. Since the hardware side has come together quite nicely, we thought it would be a good time to show you what we’ve been up to. The great thing about this project is we've learned a lot of new lessons that will be applicable to other smaller aircraft as well.
Let's take a stroll through this build and look at some of the unique characteristics. We'll start from the inside and work our way out.
1000 Amp Power Distribution Board and Center Hub
The 2400-OT utilizes the new state of the art power distribution board from Gryphon Dynamics. The board is centrally located and handles the power distribution to the motors as well as signal management for the ESCs and other low voltage systems. It was originally intended for an X8 motor arrangement so we had to do some relabeling to keep all our single wire straight.
You'll also notice the inner booms are a twin octagonal boom. Typically we use a single boom for the inner arm, however, because this aircraft could exceed 170 lbs, the double boom is a safer bet. These double booms are one piece, not simply two booms next to each other. This system is extremely strong and because the arms run all the way through the center of the aircraft the entire system is extremely sturdy even under heavy payloads.
Value Added System Integrator
After doing some flying and testing, we found some ways to improve on the aircraft. On the above picture you can see that the aircraft's original landing legs have a fairly narrow stance. As this aircraft is huge and may be landing on uneven surfaces, we decided to fabricate some bracketry to widen the leg stance. This would allow you to safely land even on a incline.
In the photo above you'll notice the Y joint in the arm is exposed. This is the stock configuration that comes from Gryphon. The arm is structurally sound but exposes some wiring to weather and debris. We improved upon this design by adding weatherproofing to these joints.
This aircraft was a great experience to further our knowledge about building and operating heavy weight aircraft. Looking forward, we'll be experimenting with more flight controller and ground controller options. The key objectives for the next version is to have a system that will automate all of the piloting. We'll be doing further testing on terrain following, spray control, package delivery and obstacle avoidance. Because we've successfully demonstrated these mission requirements on other smaller aircraft, it will be great to get all of these features into one large unit.