Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/339662
20 Vol.3 No.7 / July 2014 FLYING AN E-GULL LIKE MANY OF US, Mark Beierle had "the dream" when he was fi ve years old. He fl ew with absolute control, reliable power, and unlimited visibility. He was soaring quietly and smoothly and free as a bird. Unlike most of us, Mark took the old saying "follow your dream" literally. He committed himself to re-creating the fl ying experience of his fantasy. "It has been very dif cult to achieve," he said, "but the process has been educational." A self-taught engineer, Mark's fi rst aircraft was a twin-engine hang glider. The powerplant, however, was not nearly as reliable as the one in his dream had been. Mark continued to think about airplane design, realizing that the number one design principle is safety. "If you don't feel safe, then you're not going to want to go do it," he observed. "Having a plane that has the ability to land in small spaces in case you need to certainly gives a lot more pleasure to the expe- rience, because you won't say, 'I'm not going to go fl ying today because I might have some problem, and I don't know how to deal with it.'" One of Mark's important design features for safety is big windows, "because if you do have any problems with your pow- er system, you can pick out good places to land…" Other safety features of Mark's airplane designs include the ability to land in tight spaces, steel-tube construction "to help me mitigate the problems caused by my mistakes," and provisions for a ballistic recovery system. In the early 1980s, Mark designed and engineered his Laughing Gull ultralight. It improved on the hang glider's safety record and was the second Mark would build. The Laughing Gull was a tricycle-gear, high-wing airplane in the pusher confi guration. The Laughing Gull was later renamed the Thunder Gull, and Mark started Earthstar Aircraft. He was in the airplane business. Earthstar Aircraft's Gull series then grew into several ultralight machines, including the single-seat, 17.6-foot wing- span Thunder Gull; the 20-foot wingspan Thunder Gull-J; the staggered, two-seat, 24-foot wingspan Thunder Gull-JT2; the two-seat, 26-foot wingspan Thunder Gull Odyssey; the single- seat Soaring Gull with a 28-foot wingspan and powered by a Hirth F33 engine; and the Gull 2000. Although the product line was successful, the airplanes didn't quite capture the fl ying experience of Mark's dream. For one thing, the engines weren't exactly quiet. So it shouldn't be surprising that when electric motors be- came mature enough for aviation purposes, Mark became very interested. He bought dif erent motors so he could study them and evaluate their performance. Mark realized that existing mo- tors didn't meet his requirements, much less the aviation commu- nity's wildly varying needs for horsepower or physical size. "They would fl y," he explained, "but they weren't ready for prime time." Most designers of electric airplanes start with an of -the- shelf motor and build or modify an existing airframe. Mark worked the other way. He started with an airplane and built his own electric motor around it. Mark fl ies the e-Gull at EAA AirVenture Oshkosh 2013 powered by a Zero Motorcycles electric motor with a Rotax re-drive system. Its quietness and rate of climb impressed onlookers. This is the electric motor on Mark's 2013 machine; while it fl ew acceptably well, Mark wanted more performance for the aircraft so began designing a second motor...and that's when serendipity entered the process. While not a thing of beauty, the instrument panel for Mark's e-Gull provides all the information he needs...including information in the upper right gauge on the electric motor's performance and the state of its batteries. Photography by Jim Raeder and Mary Jones E A A E X P _ J u l y 1 4 . i n d d 2 0 EAAEXP_July14.indd 20 7 / 1 / 1 4 9 : 5 5 A M 7/1/14 9:55 AM