Wednesday, April 2^nd 2025 – Nashville, TN

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Whisper Aero and Tennessee Tech have been awarded a $500,000 TNGO (Transportation Network Growth Opportunity) award by TNECD (Tennessee Department of Economic and Community Development) to advance the development and testing of the Whisper Ultralight, a single seat powered glider capable of UltraQuiet™ flights. Tennessee Tech faculty and four students will support ground testing, ensuring the safe integration of engines, batteries, and controllers before flight. According to Whisper Aero CEO Mark Moore, “this project will help position Tennessee’s as a leader in mobility innovation and highlights the power of state partnerships in advancing transformative technologies.” By bringing together industry, academia, and government, it lays the groundwork for a future where regional flights aboard electrified aircraft are possible from more than 70 airports in the Vvolunteer Sstate.

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The Whisper Ultralight is a retrofit of an Aériane Swift3 glider with two of Whisper’s eQ250 propulsors, capable of 80 lbf each. The Whisper Ultralight has a wingspan of over 40 ft with a maximum L/D of 35:1 and can be stressed to a design loading of +6/-4g. The zero control surface deflection trim speed is now 45 mph, equal to the best glide speed. The retrofitted Swift3 glider is designed for a low speed, low power cruise speed of 42-55 knots so that cruise power required is only 6.5 hp. Power-off glides from a few hundred feet showed a low sink rate. The powered version has a climb rate of 1,250 ft/min for self-launching capability. Whisper is teaming with Steve Morris, designer of the Aériane Swift3 glider, and Brian Porter, a championship SWIFT pilot and test pilot for this program, to make this a reality.

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Battery modules from Electric Power Systems (EPS) will power the glider for demonstration flights. With EPS EPiC 1.0 power batteries, the powered-on flight range is 109 miles. Whisper previously demonstrated its propulsors operating with Electric Power Systems’ EPiC 1.0 batteries live at UP.Summit 2024. EPiC 2.0 energy batteries would boost the range to 170 miles. “EPiC 2.0’s leap in energy density and thermal performance has enabled a significant increase in range, a clear validation of our next-gen cell technology,” said Electric Power System’s CEO Nathan Millecam. “We’re proud to power this Whisper Ultralight and are impressed by what the Whisper team continues to achieve in advancing electric aviation.”

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Two additional technologies that could be tested in subsequent flight test phases are a small micro-turbine that provides range extension to 400 miles or 10 hours of endurance, as well as an embedded propulsor that enables gliding or thermaling with no extra propulsion drag.

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Flight testing is expected to show that the powered glider can be flown a few hundred feet away from neighborhoods without any disturbances, while carrying a 220 lbm payload with full range. Early flight tests will be conducted in more remote areas initially to establish this capability.

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The Whisper Ultralight also opens the door to new US Department of Defense opportunities. Earlier this year, Whisper tested the propulsors it is retrofitting on its glider statically at White Sands Missile Range’s Acoustic Range Complex (WSMR ARC). Results were breathtaking for Whisper and its customers.

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Whisper most recently was selected for STRATFI (Strategic Finance Extension) and OECIF (Operational Energy Capabilities Improvement Fund) funding awards with the support of PEO ISR/SOF (Intelligence, Surveillance, Reconnaissance and Special Operations Forces Directorate), AFLCMC Rapid Sustainment Office (RSO), and AFRL (Air Force Research Lab), amongst others. These STRATFI and OECIF efforts extend work started in 2021 to accelerate the development of Whisper’s hardware and software innovations. Both contracts are intended to accelerate the development of multiple airframes that would leverage Whisper’s propulsors to extend longer range, higher speed, and survivability required for future missions. Whisper may return to WSMR ARC for acoustic test flights of its Whisper Ultralight.

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