By Richard Steeves, EAA 65309
My spouse observed that my deepening environmental concerns were expressed in my driving behavior but not in my choice of aircraft, which burned 10 gph. After selling my Coot amphibian in 2011, I looked for a smaller airplane that would have a reasonable range on pure electric power. I explored electric-powered self-launching sailplanes, but I eventually chose Earthstar’s eGull. I chose it because it was aerodynamically superior to most other ultralight aircraft, and I respected and trusted Mark Beierle, Earthstar’s CEO. Mark was extraordinarily helpful in finding the right aircraft for me and in modifying it to my liking.
The original builder was the late Bill Hanline. However, I worked with Mark closely to restore and rebuild the airplane, building a new 28-foot wing while converting it to electric power. Bravo is powered by a 40 kW electric motor that’s connected to an 11.4 kWh lithium-polymer battery, two 110-volt battery chargers, and a three-phase controller and integrating computer, all of which were taken from a Zero electric motorcycle and installed as a unit. The battery, located behind the pilot’s seat, allows up to 3,000 charges and discharges. The two chargers were placed in the nose area to optimize CG considerations. The motor drives a 71-inch, three-blade composite, ground-adjustable AeroLux propeller mounted in a pusher configuration.
Eventually, Mark encouraged me to fly my eGull, which I named Bravo, to EAA AirVenture Oshkosh 2018. At first, I thought he was joking. I was content to fly Bravo on short trips over the Wisconsin River, which is where I had been flying my Coot for decades. But he soon convinced me that flying cross-country, especially to AirVenture, would be an important accomplishment. It would demonstrate to the public that electric aviation has a future beyond local joyrides. To that end, Mark rewired the two onboard battery chargers so they could work simultaneously to reduce charging time. He also meticulously shaped and installed a snug cowling around the motor that reduced aerodynamic drag significantly, as demonstrated both in tufting experiments and in electric power consumption tests at various airspeeds.
For example, when I first flew Bravo, I needed 12 kW of power to maintain 50 mph in level flight. At the time, back in 2015, I thought that was pretty good, but now I can achieve that same airspeed with only 8 kW (10.7 hp), allowing much longer flights. I can get up to almost an hour before having to land for battery recharging. Mark has a well-placed faith in the power of good aerodynamics!
I was happy to have Mark fly next to me in an older, non-electric Soaring Gull during our flight to Oshkosh. He didn’t have a radio in it, but we were able to talk by cellphone, and he took some memorable photos along the way.
Our Monday arrival at the Ultralights area during EAA AirVenture caused quite a stir since Mark and his electric-powered Gulls were well-known to the announcers. It was fun to answer the questions of interested bystanders and to enhance Mark’s appreciation by regular attendees. I was also able to attend a meeting of Coot builders at the EAA Seaplane Base and visit with old friends there.
Five days later, I flew back to Sauk Prairie, Wisconsin, by myself, aided in navigation by a new GPS that I had purchased at the air show. To be extra safe for the 90-mile trip, I landed at 30-mile intervals at an airport to charge Bravo’s battery. During each two-hour stop, I often engaged in conversations with interested pilots near the gas pump. They were amazed to learn that the cost of an electric charge was often free, or only a dollar, compared with their cost of $20 or more per hour for a flight that was powered by gasoline.
My advice to others: You will be surprised and pleased by the quietness, simplicity, and low maintenance of electric flight as soon as you experience it.
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