From dawn to dusk, we hear how electric propulsion is going to save the Earth. Whatever your belief about the hazards of fossil fuel, electric propulsion is coming. When is another matter. Air taxi ventures based on multicopter designs are drinking up funds by the tens or hundreds millions of dollars, probably billions by now. I don't have a shred of doubt that these will lead to genuine changes in transportation… but I would not hold my breath until such services become common. I suspect it will be many years yet. However, today, electric propulsion for ultralight aircraft works quite well, especially when it serves a purpose. For soaring pilots, power is about getting to altitude where they can explore ridge, thermal, or wave lift. Those who love such flying, like me, seek out the best machine that might deliver that capability. Ultralight Design’s Ego trike can.

High-Tech Composite

Anyone who knows hang glider wings will admire both the construction and substantially higher performance of what's called a rigid wing — more common hang gliders are called flex wings. One such is fitted to the Ego trike. In fact, the sleek undercarriage was designed with this wing in mind. The wing known as ATOS, however, has been around much longer. Felix Rühle is the designer behind the A-I-R company. A-I-R is a stylized acronym for Aeronautic Innovation Rühle. Years ago, I flew dual with Felix in a version of the ATOS wing very similar to that used on Ego trike, that is, it was made to carry two persons, as an aid to training. Here's my article from that experience (about the wing; no trike carriage was involved). ATOS VX is the largest, 46-foot-span model, a high performance glider certified at 550 pounds. The American outlet for these products, A-I-R USA, said, "[ATOS VX offers] light air soaring unmatched by any other hang glider." As we flew around dual, I remember thinking that this heavier-capacity ATOS VX wing was perfect for lightweight-trike-assisted soaring. In addition, as sharp-eyed readers will note in the two-aircraft image nearby, ATOS is not pure weight-shift. Moving your weight is the control input but the action results in surfaces moving. Leaving out how it accomplishes this, I assure you it means this long-span wing handles with remarkably light input via gentle body movement only. Weight shift control inputs can't get much simpler: move yourself the way you want to go. Your body (and carriage) is the joystick. First introduced in 2018 Ego Light was purposefully designed in an electric version for standard ATOS glider owners, the foot-launched variety. Gross weight on the electric propulsion Ego, using a standard ATOS glider is compatible with U.S. Part 103 rules. The light trike is equipped with smaller single-pack battery giving a flight endurance around one hour. "Ego is designed specifically for thermal flying," said the company. This means a one-hour endurance is plenty to carry you aloft where you shut it off and hunt for lifting conditions. Ultralight Design was established in 1999 by Miloslav Novotný using his knowledge and experience piloting paragliders, trikes, and three-axis ultralights. Miloslav succeeded at several international and European championships prior to establishing Ego. Before starting his business, Miloslav spent five years in the Mercedes BMW automotive development group in Stuttgart. Here, he met Felix Rühle, ATOS glider designer in 1998. "It was a beginning of a successful cooperation in the field of technology and first-series manufacture in Germany." Later, production of ATOS moved to the Czech Republic under Miloslav's direction. "The largest part of Ultralight Design’s production is currently for the German company A-I-R company. We are working closely together," he said. "Since the start of serial production in 1999 we have produced more than 2,000 ATOS gliders."

Flying Quietly

"A very quiet electric motor delivers an extraordinarily intensive and specific flight experience," said the company. They observe that an electric propulsion is very well suited for thermal soaring due to its reliability when called upon for frequent restarts. Such ease of restart is especially useful for a soaring neophyte; every time you lose the lift you can power back up and try again. Ultralight Design noted, "We have been actively flying trikes with a history of operation over six years. When the battery installed in your trike reaches its lifetime, it will be possible to replace it with a new type. Thanks to the fast development in electric automotive industry we can expect new batteries with a double capacity and maybe half price." Then they added, "Our sales statistics are definitely interesting. At present, 25% of the flying machines we are producing have an electric drive." For those unsure of electric, Ultralight Design offers Ego trikes with combustion engines. Paramotor engines appropriate for Ego and ATOS have undergone a number of changes in last seven years, Ultralight Design said. "The result is a very good performance with a minimum fuel consumption of around 3 liters (0.75 gallons) per hour of flight. "The low fuel consumption of standard Mogas gives you over five hours endurance and over 300 kilometer (185 miles) range on one fuel tank. To close, in a nearby photo you see the two-seat version Ultralight Design showed at Aero Friedrichshafen 2023. Rounding out their line is great but for true-blue soaring enthusiasts, Ego and ATOS might be a motorglider you can afford. Contact the company for pricing.

TECHNICAL SPECIFICATIONS: Ego Weight-Shift Trike with ATOS wing all specifications provided by manufacturer

• Empty Weight — 106 - 137 pounds, including emergency parachute system
• Wheel Track — 59 inches
• Wheel Base — 67 inches
• Dimensions When Dismantled — 69 inches X 17 inches X 25 feet 10 inches
• Engines —
  • 2-stroke with electric starter FlyEngine F200, 24 horsepower at 6400 RPM
  • Alternatively, Polini 250 dual spark, 36 horsepower at 7200 RPM
  • Or, electric: Rotex Electric REX30 16 kW (21 horsepower) at 2400 RPM
• Propeller — solid, fixed-pitch Helix 1.4 meter (55 inch), 2 blades, folding
• Minimum Speed (ATOS VR wing) — 21 knots
• Glide Performance — exceeds 20:1
• Minimum Sink Rate (engine off) — 177 feet per minute
• Powered Climb Rate — 400-1,000 feet per minute
• Powered Cruise Speed — 30-50 knots
• Fuel consumption at Cruise Speed: 0.5-1.3 gallons per hour

ARTICLE LINKS:

• Ultralight Designs, manufacturer's website for Ego trike
• AIR, manufacturer's website for the ATOS wing series
• Article on my flight experience with ATOS wing designer Felix Rühle (Ego trike was not involved)
• A-I-R USA, American representative website

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If you aren't sure trike flying is for you, this compelling video could change your mind. Come along as an Ego pilot takes us for a flight among the clouds on a lovely day with wonderfully smooth air. It's all flying with background music… SPECIAL FEATURE TO THIS VIDEO — Once playing you can use your mouse to move the image around to your liking. Try it! https://youtu.be/4FkR2nEX6u0 The following video shows you much more about the marvelous ATOS wing. https://youtu.be/Jddi5puQAVU Elements for ATOS wings appear in the following image.