Editor’s Note: This interview was conducted by Rotor Drone Mag, and originally published in their May/June Issue. Check out the original piece here.
While drone pilots and cam ops are often in the limelight, drone engineers are the ones working with cutting-edge UAV technology. Rotor Drone Mag sat down with Aerospace engineer Suresh Kumar to hear his about his function in a drone services company and his technical perspective on the recent maturation of drone technology.
Suresh checking up on our DJI M600 while on set for The Flyer.
Q: How did you get into this field?
A: I have a master’s degree in Aerospace Engineering from the University of Cincinnati, but I had a specific interest in multi-rotor drones quite early on.
Five years ago, multi-rotor drones weren’t very popular. Everyone was using fixed-wing drones or helicopters. Multi-rotor drone technology appealed to me because of its simplicity. Drones and helis that had one big rotor are hard to control because the mechanism had to achieve a longitudinal and a lateral pitch change for any change in direction. Even the smallest mechanical failure could cause a critical failure.
Multi-rotor drones are much simpler, and therefore easier to build and control in the commercial space. I saw their commercial potential and decided to focus my Master’s thesis on Dynamic Systems and Control for Multi-Rotor Drones.
Q:Tell us a little about what you do now.
A: I’m currently the lead aerospace engineer at Aerobo, a company that specializes in high-end aerial cinematography for the media and entertainment space. As one of the first members of the team, I designed and helped build their proprietary heavy-lift platforms. During the day-to-day, I’m in charge of managing, testing, and assigning equipment to various drone jobs.
Q:Why did you build custom drones? Aren’t there plenty of commercial drones on the market?
A: There are now, but not when we started the company, back in 2015. There was no drone on the market that could pick up a payload of 20 pounds. DJI’s M600, didn’t come out until late 2016, and even then it was glitchy and unreliable. The demand for a drone that could carry a high-end cinematography camera predated the supply. We wanted to provide services, but the tools didn’t even exist yet.
Even now, as new drones enter the market, there’s very little in terms of hardware to accommodate the needs of our clients. We often custom-engineer rigs and add-ons to provide additional capabilities.
Q:What are the considerations when building a heavy-lift drone?
A: First, we needed to test dozens of motor and propeller combinations. We had to test and calibrate the thrust, current, voltage, and temperatures that the motors reached.
Next, because we were building for the media and entertainment space, we needed to build a system that can be beat up. Film equipment gets used pretty roughly. It’s built, deconstructed, thrown in a packed van, moved, and then has to be reassembled quickly.
Our Super X8 was built to be compact and stable in the wind. It has a full carbon-fiber airframe and an X8 coaxial configuration. It’s equipped with 18-inch carbon fiber propellers and KDE motors and runs on an 8 cell lipo battery. We basically had to take everything available on the market to come up with this. It cost $25,000 just for design work.
Q: What commercial drones do you use now?
A: Once the available equipment was built to be more safe and reliable, we started using off-the-shelf drones. We use the DJI Matrice 600 Pro, and the Matrice 600 standard for heavy-lifts. We also use the Inspire 2 and the Mavic Pro for smaller jobs. It really helped us scale our operations since many contractors are already familiar with these systems.
Q: How do you ensure that the drones are safe?
A: Every time we get a new piece of equipment, we do a lot of testing to get an understanding of how it works and what payload it can handle. We have a flying field near Coney Island that always has quite a bit of wind. It’s also where the lead pilot and I train our staff. We make sure all equipment and the people using it is up to standards.
Maintenance is also crucial to ensure the drones are up to standard. After too much wear-and-tear, the drones can lose propulsion, have sensor errors, drift, and experience a landing error— each of which will lead to a crash.
We make sure to check the health of the critical components every 10-15 flight hours. There are a few different components to this. First, we check that the fight controller, the compass, and the IMU modules and their wiring. Then, we do a touch test of the brushless motors and the propellers. I look for any bumps or nicks and replace the part if necessary. Then we check the free movement of the motor and blow out any dust or dirt using an air compressor.
We take no chances, since crashing on set is a pretty big deal. You’re dealing with talent and tons of extras. And when you crash a drone on a film set, you’re not just losing the cost of the drone— you’re damaging extremely expensive camera equipment. The stakes were much higher for us than for manufacturers like DJI and Parrot.
Q: What’s one of the most creative applications you’ve seen on a film set?
A: People see drones and they see the potential to do something cinematically that has never been done before. So we take on a lot of custom art and commercial projects.
Last year, Oreo was interested in an aerial Oreo dunk. We had to custom-build an aero-dynamic Oreo suite for the drone, which would then have to drop an actual Oreo from over a hundred feet in the air into a glass of milk. This involved 3D printing large plastic, perforated circles that enabled airflow. The sides were secured with metal sheet hinges and dozens of different materials were tested to make sure the drag coefficient was as low as possible.
Q: Do you have any advice for fellow engineers interested in working on drones?
A: One mistake that young engineers typically face is propulsion. When you want to design and build a drone, you have to start with the payload. The design considerations for lifting a toothpick are going to be drastically different than the design considerations for lifting a bowling ball. Consider the weight, and then work backward.
There are now e-calculators for multi-rotors that make this easy. You just plug in what you’re building for and it’ll help you calculate airtime, weight, etc.
Q: You seemed to foresee some commercial applications of drones. In your opinion, what’s the future of drone technology?
A: Well, the acceleration of innovation has been phenomenal. If you look at the timeline from the wheel to the car, from the car to the airplane, and from the airplane to the space rocket it’s incredible.
uberAIR and Bell Helicopter are already starting to envision a future where we have multi-rotors autonomously transport people. I think a reality in which drones usher in a Jetsons-era isn’t very distant. I would bet we will see that within our lifetimes.