Powerplant Paradigm Shifts Seen, Discussed at EAA’s AirVenture 2025

Story and photos by Ken Kula

 A piston engine burning leaded fuel is the common way to power both yesterday’s and today’s non-turbine equipped airplanes. Current global intent to replace leaded fuel with an alternative power source (which would reduce environmental pollution) is leading to innovations in fuels and motor designs which are making headlines regularly. EAA’s AirVenture Oshkosh 2025 was a good place to talk with some of the leaders in the alternative energy fields, and to see some of the hardware which will facilitate a cleaner tomorrow. Here are several examples of what was on display at Oshkosh in July:

Alternate fuels:

Currently, the most common octane rating for “avgas” is 100LL (100 octane low lead). There’s a push by at least one large consortium to do away with any leaded avgas in the U. S. by 2030 and other organizations are pushing plans to cease the use of leaded fuel in Europe by 2032. In response to this replacement, Swift Fuels LLC has developed their UL94 (unleaded 94 octane, ethanol-free) fuel and is working on their 100R unleaded fuel. Swift’s UL94 is free of lead emissions and has similar octane characteristics as current 100LL avgas. In the U. S., slight changes to avgas compositions occur from season to season and State to State to meet climatic differences, but Swift’s UL94 does not need these variations. Swift Fuels’ display was centered around a Beech G18S “Twin Beech” which is being used by Dynamic Aviation. Built in 1959, the Pratt and Whitney engines are using Swift Fuel’s UL94 without issues. A lot of FAA paperwork is required before an aircraft owner can regularly use the unleaded fuels, but that limiting process has been in use for a number of years. A specific aircraft receives a Supplemental Type Certificate (STC) to use Swift’s UL94. While it’s still under the certification process for 100R fuel, when it becomes available the FAA will have to address how to move forward with the STC process.

Electric power crackles in the air:

BETA Technologies displayed a pair of CX300 ALIA CTOL (conventional electric aircraft) at AirVenture. One aircraft was on static display with a passenger configuration, while the second aircraft was in a freighter configuration. There are at least four CX300 airframes plus a prototype active now, and the A250 VTOL (vertical lift electric aircraft) is well into its developmental phase. BETA Technologies is based in Vermont, and has a facility in Plattsburg, New York too.

The latter aircraft flew a series of spirited aerial displays during the week’s air shows, and one airframe graced the Boeing Plaza during Tuesday’s yearly Innovations Day.

Czech aircraft maker Bristell and the Swiss aviation electric propulsion pioneer H55 have joined forces to produce the B23 Energic, an electric powered training aircraft. The Swiss B23 Energic will begin deliveries in 2027 and reported that its first two years’ worth of production was already sold out as AirVenture began. The initial B23 arrived in Oshkosh in the midst of an eight state Across America demonstration tour… Oshkosh was their seventh stop, and the aircraft and team would ultimately make almost 200 demonstration flights in Florida, Alabama, Arizona, Nevada, California, Colorado, Wisconsin, and New York. The electric motor proved its exceptional ruggedness at Centennial Airport in Colorado; Energic flight test engineer and pilot Celine Bonnefous spoke about their visit where they encountered a high density altitude value (9,500 feet) which grounded almost all normally aspirated engined aircraft that day. The H55 electric motor and battery system performed well in the 96 degree F temperatures at a field elevation of more than a mile high, allowing multiple flights that day with no adverse affect on their flying scenarios. After their stop in Oshkosh, the team would go on to finish their tour on Long Island, New York.

Not a surprise to some in the field, H55 is headed by the team that put together the Solar Impulse solar-powered around the world journey, spearheaded by the co – record breaking pilot André Borschberg. The company is striving towards “Enabling the aviation industry to reach net zero. Accelerating quiet, efficient and affordable aircraft commercialization by supplying certified electric propulsion systems with aircraft integration solutions for the general aviation and regional transport categories.” Not only will the electric power for the B23 Energic result in no harmful airborne emissions, but another positive note is that engine noise has been reduced noticeably.

Textron eAviation has brought Pipistrel Aviation under their wing, as Gabriel Massey, eAviation President and Managing Director reports: “Pipistrel by Textron eAviation is the global leader in electric aircraft and is focused on the future of sustainable flight. We are committed to bringing the next generation of sustainable aircraft to the market backed by Textron’s 100 years of expertise and restless spirit of innovation.”

The Pipistrel Velis Electro is already in production, as it was the first all-electric two seat training aircraft certified and produced. Currently the aircraft has a seventy minute endurance with reserves per flight, just about perfect for flight training sorties.

Joby Aviation Inc. displayed a mock-up of their all-electric air taxi. The company expects to be flying their first production aircraft soon, having used prototype airframes for testing so far. With contracts in the Middle East, Europe and New York City for air taxi service inked, the U. S. Air Force has carried out suitability tests with the prototype too. Toyota Motor Corporation has invested heavily in Joby, and upcoming Asian trade show events will present the air taxi to potential customers there.

These five examples of new, cleaner aviation technology were all on display at EAA’s AirVenture Oshkosh 2025, including the Swift Fuels LLC proven UL94 unleaded avgas, three proven and flying electric-powered aircraft – Beta Technologies CX300 conventional electric aircraft, the Bristel B23 Energic powered by H55’s electric motor, and eTextron’s Pipistrel Velis Electro, the oldest (and most mature?) certified electric-powered training aircraft design. Add to that the Joby Aviation’s mock-up of their already flying air taxi. There were undoubtably more alternative-powered designs on the airfield, these are just five highly visible ones. What were once called dreams on the drawing board just a few years ago, were shown to be a new reality this year and will no doubt expand in the future of aviation.