Why an electric R44 helicopter makes more sense than you think

By Elan Head | Vertical Magazine

When Martine Rothblatt decided she wanted to convert a conventional helicopter to electric power, she didn’t get much support from the aviation community.

The electric-powered R44 developed by Tier 1 Engineering for Lung Biotechnology. Test pilot Ric Webb noted that the electric R44 is much smoother than a conventional R44 on startup; otherwise, the electric helicopter flies similarly, he said. Tier 1 Photo

“I began asking other helicopter people I knew about that, and I have to tell you, every single person said, ‘No. It’s impossible, it’s ridiculous, it’s stupid, batteries are too heavy, maybe in 50 years when batteries are light,'” she recalled at a 2016 gathering of the Tesla Motors Club.

Rothblatt was undeterred, in part because this serial entrepreneur - named by Forbes as one of the world’s 100 greatest living business minds - has built her career on achieving the impossible. Rothblatt broke new ground in the ’90s as the founder of Sirius satellite radio; then, when her daughter was diagnosed with pulmonary arterial hypertension, she founded the pharmaceutical company United Therapeutics, which developed a new medicine to treat it.

More recently, a United Therapeutics subsidiary, Lung Biotechnology, has pioneered techniques for restoring damaged lungs to a state suitable for transplantation. “People told me this was impossible to do,” she said, yet these “remanufactured” lungs have been successfully transplanted into hundreds of patients who might have otherwise languished on transplant waiting lists. Now, the company is blazing a trail for xenotransplantation - the transplantation of animal organs into humans - as well as the 3D printing of organs, which could someday lead to a world of “organs on demand.”

Lung Biotechnology already uses helicopters to fly its remanufactured lungs to waiting surgeons. In Rothblatt’s ideal future, “when you’re talking about not a few hundred organs, but hundreds of thousands or millions of organs, you are going to need a very large fleet of helicopters delivering all these,” she said. For Rothblatt, a helicopter and airplane pilot who loves to fly but who also believes that global warming is “the existential issue of our time,” today’s fossil fuel-guzzling rotorcraft aren’t going to cut it.

As she put it, “What is really the point of saving people’s lives with an organ transplant if all of humanity could be wiped out in a climactic existential event from global warming? If we just think a little bit harder, we can do the good thing and the green thing at the same time.”

The aircraft’s twin electric motors are stacked together and provide redundancy in the event of a motor failure. “We’re basically flying a twin, if you want to look at it that way,” said Ric Webb. Tier 1 Photo

Rothblatt didn’t find support for her concept from any of the major helicopter manufacturers, but Kaman referred her to Glen Dromgoole of Tier 1 Engineering in Santa Ana, California, who agreed to take on the project. And thus, over the past three years - while companies like Uber have been touting high-profile urban air mobility projects that could take a decade or more to come to fruition - Rothblatt’s team at Tier 1 has been quietly developing an electric-powered version of a Robinson R44.

On Dec. 7, with test pilot Ric Webb of OC Helicopters at the controls, the aircraft set a Guinness World Record for the farthest distance traveled by an electric helicopter, flying 30 nautical miles around Los Alamitos Army Airfield in California. “Could we have gone further? Absolutely,” said Webb, adding that the team expects to eclipse this record “dramatically” as early as next year.

Rothblatt and Dromgoole don’t dispute that other electric vertical takeoff and landing (eVTOL) aircraft configurations would be more aerodynamically efficient. But getting eVTOL aircraft onto the market isn’t simply a technological challenge; it’s also a regulatory one. From that perspective, working with an already certified airframe makes a lot of sense, since it can cost tens of millions of dollars to certify an aircraft from scratch.

Moreover, it’s still not clear what safety standards the Federal Aviation Administration (FAA) will use to certify the multicopter and tiltrotor eVTOL designs now in development - which, unlike the R44 and other conventional helicopters, are incapable of autorotation in the event of a power failure.

“We didn’t want to invest resources in developing a new airframe,” Dromgoole explained. Using the R44 “allowed us to really focus on the key technology, which is the electric power unit.”

The aircraft’s 1,100 pounds of batteries are installed under the belly. Tier 1 president Glen Dromgoole acknowledged that “the biggest hurdle with electric aviation is improving the energy density of the power supply.” Tier 1 Photo

In fact, he said, the R44 is a surprisingly good fit for the project. It has a relatively efficient rotor system and a lightweight airframe that is normally paired with a very heavy Lycoming engine (an IO-540 with a wet installed weight of around 500 pounds/225 kilograms). In Tier 1’s first prototype, this is replaced with custom Yasa twin electric motors and a Rinehart motor control system that weigh just 100 lb. (45 kg), helping to offset the 1,100-lb. (500-kg) weight of the Brammo lithium polymer batteries that are attached under the belly.

Tier 1’s engineers were able to accomplish this retrofit without any modifications to the flight controls or drive system. “From an engineering perspective, I’m so impressed with the design, and the simplicity of the design. That’s really what makes it such a great electric helicopter,” Dromgoole said.

The fact that the R44 the world’s bestselling light helicopter is another bonus, as it means that used aircraft are plentiful. They’re also relatively inexpensive, especially as they approach their mandatory airframe and engine overhaul times. “You have them constantly running out of hours on their Lycoming engines, and we just throw those out anyway,” Rothblatt told Vertical. “We knew we would always have a large supply of cheap Robinsons.”

The aircraft that flew on Dec. 7 is the same one that first took to the air in September 2016, and set other records in early 2017. Tier 1 then paused the flight program to work on improving the underlying battery and motor technology. Now, it’s ready to incorporate its improvements into a new prototype that will fly in 2019. The company intends to pursue a supplemental type certificate for this version, and according to Dromgoole has already submitted a certification plan to the FAA. So far, the FAA has been “extremely supportive and interested in this project,” he said.

With a new and improved electric helicopter on the near horizon, this month’s record-setting flight was essentially housekeeping; a way to officialize the achievements of the first prototype before the second one proceeds to surpass them. Dromgoole said that with its second version, Tier 1 is aiming for at least an hour of flight time with 600 lb. (270 kg) of useful payload, and “we feel it’s very achievable.”

The team behind the aircraft celebrates their recent Guinness World Record. While Robinson Helicopter Co. had no involvement in the project, Robinson president Kurt Robinson told Vertical, “We are impressed with their accomplishment and agree that the design and efficiency of our helicopters makes them a good choice for this type of project.” Tier 1 Photo


These specifications would still limit the helicopter’s usefulness for many missions, which is probably why the wider industry has been dismissive of converting conventional helicopters to electric power. But what might be impractical for a charter operation could still be very viable for organ transfers. According to Rothblatt, the average distance covered by Lung Biotechnology’s helicopter flights is around 50 nautical miles, with some flights much shorter than that. And human organs make for comparatively lightweight cargo.

So while Tier 1’s modified R44 may not be the ultimate expression of the electric helicopter, it’s not without real-world applications. Crucially, it also appears to have a viable path toward certification.

“It proves that electric VTOL flight is possible . . . and it sets a baseline for the future,” Dromgoole said. “We’d like to be a leader in the technology. Hopefully other companies will follow.”