As the FAA nears a final rule on beyond visual line of sight (BVLOS) drone operations that could unlock more expansive commercial missions, a California-based startup has set a new benchmark for the longest flight of a prototype electric drone weighing 5-20 kilograms.
Uncrewed aircraft systems (UAS) developer SiFly, which emerged from stealth in May, this week said Guinness World Records validated a 3-hour, 11-minute flight of its Q12 drone, eclipsing the previous high by nearly one hour. With the record-setting flight, the company believes it is close to unlocking the full potential of quadcopters, which are characterized by a quartet of rotors.
“We’ve got millions of quadcopters being made every year for consumer applications,” Brian Hinman, founder and CEO of SiFly, told FLYING. “Why can’t that thing scale up? And why can’t it be made efficient? There is no good reason why.”
Added Logan Jones, SiFly chief business officer: “If you look at light helicopter data, the top end of those missions is two hours, and it’s really limited by fuel burn and human fatigue issues. We wanted to both meet and exceed helicopter level performance, but do it with the affordability and usability of the drone.”
The endurance milestone “couldn’t be more relevant,” Jones said, with the FAA’s publication of a notice of proposed rulemaking (NPRM) for Part 108.
The regulator began awarding temporary BVLOS waivers in 2020. Those operations are steadily growing. But the proposed rule would accelerate the trend, opening BVLOS flight to drones with a maximum takeoff weight (MTOW) up to 1,320 pounds—so long as they meet a set of airworthiness and design criteria.
Few UAS have the endurance to take full advantage of expanded operations under Part 108. Hinman created SiFly to address that “technology limitation problem.”
“You have to have a system that operates for hours on a single charge, not minutes on a single charge,” he said, “that goes many, many miles, rather than just a couple.”
Hinman believes the Q12 could generate “enormous demand” in agriculture and public safety. Already, the company has racked up hundreds of preorders. And demand is only growing.
“Once [Part] 108 came out, it just further accelerated the market and buying patterns,” said Jones.
Helicopter Performance, Drone Economics
The FAA released Part 107 regulations for small UAS nearly a decade ago. But SiFly always dreamed bigger.
“Our opinion is [Part 107] locked in place certain technology configuration decisions…and it really froze innovation in the space,” said Hinman.
The quadcopter is one of the most popular UAS configurations, particularly for camera and other hobby drones. DJI, the world’s largest producer of consumer drones, employs the four-rotor architecture across the bulk of its products. While popular, these designs are often limited to one hour or less in the air.
“The quadcopters that are out there, including all the DJI ones, they’re like a big flying brick,” said Hinman. “There’s nothing aerodynamic about them at all.”
Drone delivery operators such as Zipline and Wing have incorporated fixed wings into their designs to expand the envelope. SiFly, though, saw untapped potential in the classic configuration.
“The question we asked back at the beginning was, what can we do to make a quadcopter optimized for forward flight?” said Hinman.
While in stealth, the company made two critical breakthroughs.
The optimal battery weight fraction for rotorcraft, Hinman said, is about two-thirds. SiFly is approaching that target—batteries accounted for about 60 percent of the record-setting drone’s weight. The cells also discharge at about one-sixth the rate of electric vertical takeoff and landing (eVTOL) batteries, meaning the Q12 does not require any “exotic chemistries.”
“It’s essentially like a giant flying battery, and that’s what we look like,” Hinman said. “We’ve got a cavernous hole in the middle of the drone, and we slide a giant brick of battery into the middle of it.”
SiFly’s other key innovation involves the Q12’s propeller.
Smaller rotors tend to have high disc loading, requiring more power to generate lift. The Q12’s large rotor, by contrast, enables low disc loading and greater efficiency.
Unlike quadcopter blades that suffer from a “whole bunch of taper and twist,” the drone’s smooth, flat blades reduce aerodynamic drag. Using many blades allows the rotor to spin slower, making the aircraft “virtually silent” at 100 meters altitude.
“You want to have at least three blades on your rotors, and the blades should look more like propellers,” said Hinman.
The Q12’s rotor plane is tilted about 10 degrees forward so that its nose angles up in hover. The nose remains up when pushing over to create thrust and levels out when cruise speed is reached.
“You put all this stuff together, and that’s how you end up in a place where you can hover for two-plus hours and cruise for three-plus hours,” said Hinman.
Endurance Record
Jones said SiFly has been working to break the three-hour mark for years.
In May, for example, the Q12 flew in Michigan’s inaugural Uncrewed Triple Challenge, during which it achieved the longest flight by a multirotor drone with a 10-pound payload. It was the only drone to complete the 63-mile course in wind gusts up to 32 mph.
The UAS broke the three-hour mark a few weeks prior to its record-setting flight after previously maxing out at about two hours and 45 minutes on a single charge.
“Effectively, we’ve been flying bricks around because we have aerodynamic treatment on the fuselage,” Hinman said. “It was the last month or so in preparation for the world record that we actually started putting skins onto the fuselage, and of course, that makes a huge difference.”
SiFly has spent the past 18 months mapping the Amaral Ranches in California’s Salinas Valley, where the Q12 set the endurance record on July 26.
The clock started when the drone lifted off at sunrise. Personnel then flew it to a 600-meter-wide orbit at roughly 50 meters in altitude. The Q12 orbited autonomously at about 31 mph airspeed, with a lift-to-drag ratio of 4.0 placing it in the range of helicopters. Per Hinman, a ratio of 7.0 is “very achievable.”
“We did it over that large of an orbit because constantly turning, you actually burn a little bit of power,” he said.
When the drone’s battery dropped to two percent, SiFly brought it to a hover to drain the remaining power before gently setting it down. Guinness World Records required the flight to be monitored by a group of witnesses, including an engineer from NASA’s nearby Ames Research Center.
Ames’ research, Hinman said, has explored the viability of a design like the Q12.
“The numbers actually look really good, not only in terms of performance, but you end up at a cost point that’s dramatically lower than the stuff that you see out there today in the eVTOL space,” he said.
Entering the Fray
SiFly envisions a wide range of applications for the Q12. But its focus is primarily on agriculture and public safety, which per Jones sit in the “sweet spot” between what customers want and what regulations permit.
On the public safety side, for example, the company has tested the use of an optical zoom camera for Drone as First Responder (DFR) and other programs. It is developing the ability to read a license plate from 1,000 feet away, which would allow law enforcement to operate drones at a safe distance from the public. The firm is also exploring thermal and lidar integrations.
The Q12’s 10-pound payload allows it to carry more weight than competitors, including extra sensors and imaging technology that could be used for agriculture. SiFly has integrated a Sony ILX-LR1 camera, for instance, to support mapping and inspection.
Regardless of the use case, Q12 customers will not require a docking system for takeoff, landing, or charging. The UAS can be broken down small enough to fit within checked airplane luggage. Unused battery packs are charged while the drone is in the air, allowing for quick swaps.
“You land the thing and it takes two minutes to swap a battery, and you’re back in the air again for another two hours,” Jones said.
Electric drones also avoid the maintenance associated with internal combustion engines. Hinman said the batteries should be able to last at least five years.
“I put my hand on the motors, and they’re just slightly warm, so we’re not pushing anything hard,” he said. “We’re not pushing the motors hard. We’re not pushing the batteries hard. So we believe that the platform that we have is not only efficient in flight, but is going to be super reliable long term.”
The Q12, Hinman added, is “really a sensor platform.” But the company is also developing a much larger Q250 with a 550-pound MTOW.
“At that point we can start moving some serious payload around,” he said.
SiFly envisions the two drones operating in concert.
“In agriculture, for example,” Hinman said, “you would not want to use an expensive platform—the spraying platform—to look around and find the places to spray, because that would be a misuse of the capital.”
Rather, the Q12 could map areas of a field to be sprayed by the Q250. In aerial firefighting, the Q12 could use a thermal camera to identify blazes to be doused by its larger counterpart. Or, in search and rescue, the Q250 could deliver supplies to a stranded person discovered by a fleet of smaller drones. Hinman said SiFly is even exploring casualty evacuation.
The San Bernardino County Fire Protection District in California plans to deploy both UAS for fire suppression and search and rescue. Last week, SiFly and the Oregon Department of Aviation signed a wildfire mitigation and medical delivery partnership.
Many of these operations will remain limited until Part 108 is finalized. But Hinman said SiFly is “pretty excited about the document as it’s drafted now.”
“More broadly, the opportunity with electric aviation is going to extend into general aviation,” he added. “MOSAIC is real now. The ASTM standards need to happen, but I think we’re going to see a bunch of activity in the GA space as well.”
Adding to the momentum are a pair of White House executive orders that direct regulators to lift restrictions on domestic drone production and operations, including those on BVLOS flight.
Hinman said SiFly still has a “long way to go” to unlock the Q12’s full potential. But within one year, he predicted, it will achieve a four-hour flight—surpassing the capabilities of most helicopters.
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