The lead electrical engineer that helped design the Tesla all-electric battery-powered semi-trailer truck is one of the three people that have created a company that is developing an unmanned aircraft system, or drone, that could be used on fires, as well as other functions. Joshua Resnick, the CEO of a new company, Parallel Flight Technologies, said he worked on the Tesla semi project from the time it was first drawn up on a napkin through its introduction to the public in 2017.
Parallel Flight Technologies is building a drone with a much longer endurance and a larger payload capacity than those currently being used on wildfires. Most drones can only stay aloft for 20 to 30 minutes and can carry a few pounds of cargo — less if they are transporting more. Parallel Flight Technologies expects their aircraft to be able to transport 75 of pounds for one hour, or 50 pounds and stay airborne for 2.5 hours.
On any aircraft the power to weight ratio is critical. Eliminate weight or add power and it can travel longer and farther. The primary limiting factor in electric-powered aircraft is the weight of the batteries. Until there is a huge leap in battery technology we’ll be unlikely to see them powering aircraft with more than 50 pounds of cargo while staying aloft for more than 15 minutes.
So we need new, or at least, different technology if we hope to see a drone carrying a portable pump, fire hose, and fuel to a remote site on a wildland fire.
“We are building a new drone technology and it can be used for a lot of different things, but wildfire would really be the use case that was the impetus for me to even start on this project,” Mr. Resnick said. “We had a fire not far from our home in Santa Cruz, California in 2017 either right before or right after the Santa Rosa Fire, and it was after that that I started looking into the different ways that unmanned systems could be used in a wildfire effort. That’s when I started understanding that using unmanned systems to resupply firefighters could be very useful especially when manned aircraft could not fly due to smoke inversions or nighttime.”
Hybrid systems, using a gas engine to drive a generator which powered electric motors to spin the propellers, have been tried before, but it was not much more than strapping a generator to a drone which added too much mass and weight to be practical. Also, the many power conversion steps led to a loss of efficiency.
“We have developed a parallel hybrid drone,” Mr. Resnick said, “where the propellers are powered by a combination of gas and electric. The electric motors provide the responsiveness so the aircraft can maneuver and the gas supplies the duration and the high power to weight ratio.”
The aircraft is powered by four hybrid power modules, each with a gas-electric combination. The 2-cycle gas engines work in combination with the electric motors, which provide very high peak thrust as well as redundancy. Larger aircraft in the pipeline could be powered by other fuels, such as diesel or jet fuel.
In fall of 2018 the company built a proof of concept aircraft, and in August, 2019 successfully demonstrated heavy lift capability and duration with a new prototype aircraft. In 2020 they expect to be ready for joint exercise missions with several agencies interested in the aircraft.
“I want to find ways to integrate this new technology with the existing solution,” Mr. Resnick said. “I don’t see it as a replacement for helicopters, we’re talking about a much smaller payload. I’m seeing, for example, smoke inversions where helicopters are grounded at nighttime or early dawn before manned aircraft are flying, to be able to operate our drones to do some of this work, while finding ways to deconflict the airspace between drones and manned aircraft.”
I noticed that in photos of the prototype the props appear to be made of wood. When I asked Mr. Resnick if that really was the case, he yes, the props on the prototype are wood due to the cost. If a prop was damaged during testing, they would be out about $100. If made of carbon fiber, such as might be used on the production version, the cost would be about ten times higher.
The U.S. Department of the Interior has leaped into the use of drones in the last few years and currently has over 800 unmanned aircraft. In 2018 they flew over 10,000 drone missions. Parallel Flight Technologies is consulting with personnel in the DOI who have experience in establishing and operating a drone program.
The DOI was recently in the news when their entire drone fleet was grounded except for those needed for firefighting and other emergency services. It turns out that all of the DOI drones are either entirely made by a Chinese company, DJI, or have chips or other parts that are manufactured in China. The Wall Street Journal reported that “the Department of Homeland Security was concerned about drones’ capacity to observe and transmit prohibited infrastructure surveillance and conduct cyberattacks.” Mr. Resnick said the Parallel Flight Technologies drones will be American made and will conform to security specifications required by the DOI and Department of Homeland Security.
Mr. Resnick said they are working closely with Drone Amplified who they hope can build a larger drone-mounted plastic sphere dispenser (PSD) system for Parallel Flight Technologies’ upsized drones so that they can be used to ignite burnouts or prescribed fires. Drone Amplified recently introduced a PSD, Ignis 2.0, that can hold 400 to 450 spheres that ignite 30 to 45 seconds after being released from the drone. Their previous system, Ignis 1.0, carried 150 spheres.
Parallel Flight Technologies is raising funds through an equity crowd funding effort which is open to the public for anyone to invest in the company.
Parallel plans on selling a small number of initial aircraft in late 2020 to its first customers before full production begins in 2021.