Electric Airplane Powered By Solid-State Batteries Completes Test Flight

Helios Horizon has successfully completed a test flight of an electric aircraft powered by solid-state batteries, marking a significant milestone in electric aviation. Unlike previous unmanned tests, this flight involved a human pilot, Miguel Iturmendi, who is also the founder and chief test pilot of the organisation. The experimental aircraft, which is 25 feet long with a 61-foot wingspan and a maximum takeoff weight of 1,300 pounds, flew at approximately 60 miles per hour in short pattern flights below 500 feet. These initial flights focused on assessing handling and centre of gravity changes due to the new battery installation, paving the way for more ambitious stratospheric tests planned for later in the year. The solid-state battery packs used in the aircraft were assembled by Helios Horizon from commercially available cells sourced from multiple suppliers, rather than being manufactured in-house. Each battery weighs around 80 pounds and delivers an energy density of 410 watt-hours per kilogram, a substantial improvement over the 260 Wh/kg offered by the previous lithium polymer cells used. The aircraft can operate with either two or four batteries, equating to between 160 and 320 pounds of battery weight. However, the current cost of these solid-state battery packs is approximately $30,000, which is three to four times higher than conventional lithium polymer alternatives, though prices are expected to decline as the technology matures and scales. Solid-state batteries offer several advantages that could transform electric aviation, including significantly higher energy density, faster charging times, and improved safety. The batteries tested can charge from near empty to 80% in under 15 minutes and are more stable under high temperatures or physical damage, reducing the risk of fire compared to traditional lithium-ion cells. These benefits are critical for extending flight range and improving operational efficiency, addressing some of the key limitations of current electric aircraft power sources. Looking ahead, commercial certification and widespread adoption of solid-state batteries in electric aviation could be realised within the next two to three years, contingent on regulatory approval and advances by battery manufacturers. Helios Horizon’s test flight represents an important step towards that future, demonstrating the practical viability of solid-state technology in manned electric flight. The organisation’s ongoing research and upcoming stratospheric envelope expansion tests will further explore the capabilities and limits of these batteries in demanding flight conditions.