Whisper Aero and Tennessee Tech University have received a $500,000 research grant from Tennessee’s state government to demonstrate quiet flight with an electric glider. The so-called “Whisper Ultralight” will be a modified Aériane Swift 3 glider featuring two of Whisper’s eQ250 ultraquiet ducted-fan propulsors.

Funding was awarded through the Tennessee Department of Economic and Community Development’s (TNECD) Transportation Network Growth Opportunity (TNGO) initiative, which aims to “make Tennessee the No. 1 destination in the Southeast for automotive and mobility R&D investment,” TNECD said in an April 2 announcement.

The Swift 3 is an ultralight, single-seat, electrically-powered glider based on the Swift Light, a foot-launched, tailless sailplane with a 42-foot wingspan. Originally designed as a hang glider in California during the 1980s, the Swift Light is manufactured by Aériane in Gembloux, Belgium.

Swift—short for “swept wing with inboard flap for trim”—was a collaboration between Bright Star Gliders and a team of Stanford University students. One of those students, Steve Morris, is now working with Whisper to help develop the Whisper Ultralight, the company announced on April 2. Whisper has also enlisted Brian Porter, a world champion Swift hang-gliding pilot, as the chief test pilot for the Whisper Ultralight.

“The Ultralight is a test platform we intend to spiral upgrade to test increasingly more mature Whisper innovations on future dual-use aircraft,” Ian Villa, Whisper’s COO and chief product officer, told AIN. He said the first flights are expected to take off this year, likely in the fourth quarter but potentially sooner, adding that work has already begun. 

Villa explained that Whisper chose the Swift 3 for this project because of its high aerodynamic efficiency, noting its lift-to-drag ratio of 35. “This gives us more time to stay in the air and test our propulsion technologies across test demonstrations,” he said.

The ducted-fan eQ250 propulsors being integrated with the Swift 3 are smaller than a foot in diameter and deliver 80 pounds of thrust with a thrust-to-weight ratio greater than 5:1. Whisper has already tested several iterations of the technology on demonstrator drones it developed for various contract awards from the U.S. Department of Defense.

According to Whisper, Tennessee Tech faculty and four university students will conduct ground tests of the Whisper Ultralight to ensure the safe integration of the aircraft’s batteries, propulsors, and controllers. 

“All of the design, integration, and test work is starting in Tennessee. As we build up more time on the retrofit, we may choose to move to other test ranges with our DoD customers,” Villa said.

Located in Cookeville, Tennessee, the university is about a 45-minute drive from the Whisper Aero Flight Test Center at Crossville Memorial Airport (KCSV).

“At Tennessee Tech, one of the ways we put students first is by seeking out hands-on, experiential learning opportunities just like those that will be provided through this TNGO award,” said Phil Oldham, the university’s president. “We look forward to using these award dollars to place students in internships working directly with Whisper Aero leaders. By learning from an electric propulsion innovator like Whisper Aero, our students will gain invaluable perspective and can take what they have learned in the classroom and apply it right here in Tennessee.”

For the flight demonstrations, the Whisper Ultralight will be run on Epic 2.0 batteries supplied by Electric Power Systems (EPS), a Whisper partner.

In October 2024, Whisper and EPS joined forces to combine Whisper’s quiet propulsion tech with EPS’s batteries to produce certifiable electric and hybrid-electric powertrains on Part 23 aircraft, including both clean-sheet designs and retrofits under supplemental type certificates. Whisper demonstrated its propulsors with EPS’s Epic 1.0 battery system at the UP.Summit event in Bentonville, Arkansas, when it announced the partnership.

The partners have since been working on a Part 23 retrofit concept that leverages Whisper’s eQ250 propulsors and the “jetfoil” integration seen in the Whisper Jet regional airplane concept.

EPS’s Epic batteries have also been selected by Diamond Aircraft for an all-electric version of its DA40 trainer, and Ampaire is using Epic batteries in its hybrid-electric Eco Caravan. With the EPS Epic 1.0 batteries, the Whisper Ultraquiet will have a powered-on flight range of 109 miles, whereas the Epic 2.0 batteries would extend that range to 170 miles, according to Whisper.

“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 EPS 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.”