Whisper Aero

Whisper Aero

Designs electric propulsion systems for aircraft

Overview

Whisper Aero designs and manufactures electric propulsors, focusing on electric ducted fans to power quieter, more efficient propulsion for aircraft, drones, and other devices. Its tech reworks how electricity becomes thrust so noise shifts to ultrasonic frequencies, claiming up to 100x quieter performance. The company acts as a propulsion-system supplier across defense, commercial, and civil aviation markets, with customers such as the U.S. Air Force and NASA and concepts like the Whisper Jet. Its goal is to scale production and broaden adoption of ultra-quiet propulsion across multiple industries, including consumer tools and HVAC, through diverse revenue streams and partnerships.

Significant Headcount Growth

About Whisper Aero

Simplify's Rating
Why Whisper Aero is rated
B-
Rated B on Competitive Edge
Rated B on Growth Potential
Rated C on Differentiation

Industries

Hardware

Industrial & Manufacturing

Aerospace

Defense

Company Size

51-200

Company Stage

Series A

Total Funding

$49.7M

Headquarters

Crossville, Tennessee

Founded

N/A

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Simplify's Take

What believers are saying

  • August 2026 Swift flights logged 130 minutes, validating powered testing in Tennessee.
  • June 2026 Mach Industries and DIU RIMES expand Whisper into Navy runway-independent drones.
  • FY2026 federal awards show $2.4 million committed, including Air Force, NASA, and Tennessee support.

What critics are saying

  • Air Force and Navy funding still precede revenue; 2027 flight tests remain unproven hardware.
  • T1 leaf blower costs $599, squeezing adoption against cheaper EGO and Stihl battery tools.
  • If JetFoil misses certification or payload targets, Whisper becomes a science-project supplier, not a business.

What makes Whisper Aero unique

  • Mark Moore’s NASA DEP pedigree and JetFoil’s stall-proof, near-vertical takeoff architecture.
  • eQ250 ducted fans shift blade noise ultrasonic, enabling 52 dB leaf blowers and quiet aircraft.
  • Whisper sells propulsion components across defense, aviation, and consumer tools, not whole aircraft.

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Funding

Total Funding

$49.6M

Above

Industry Average

Funded Over

3 Rounds

Notable Investors:
Series A funding typically happens when a startup has a product and some customers, and now needs funding to scale. This money is usually used to grow the team, expand marketing, and improve the product. Venture capital firms are frequently the main investors here.
Series A Funding Comparison
Above Average

Industry standards

$15M
$8.2M
Discord
$15M
Canva
$30M
Kalshi
$41.4M
Whisper Aero

Benefits

Health Insurance

Dental Insurance

Vision Insurance

Paid Vacation

401(k) Retirement Plan

Relocation Assistance

Professional Development Stipend

Growth & Insights and Company News

Headcount

6 month growth

↑ 31%

1 year growth

↑ 31%

2 year growth

↑ 31%
Tech Funding News
Sep 11th, 2026
MIT dropout's Mach Industries doubles valuation to $3.7B in three months with fresh $600M round.

MIT dropout's Mach Industries doubles valuation to $3.7B in three months with fresh $600M round. September 11, 2026 * Mach Industries raised $600 million more, taking its Series C total to $900 million. * The round values it at $3.7 billion, more than double the $1.8 billion mark it hit in June. * Total funding tops $1 billion across five rounds since the company launched in 2023. Mach Industries has made its own funding round look cheap. Three months afterEthan Thornton, the 22-year-old founder and CEO, closed a $300 million Series C at a $1.8 billion valuation, the defence manufacturer has come back for $600 million more. Investors have priced it at $3.7 billion, more than double where it stood in June. The extension pushes the Series C's total size to $900 million and takes Mach's lifetime funding past $1 billion, just over a year after a Series B valued it at $470 million. Ribbit Capital, Infinite Capital, Bedrock Capital, and Sequoia Capital all doubled down in the second tranche, the same group that led the June round. "Modern deterrence requires an industrial base capable of building relevant capabilities at the speed and volume the mission demands. This investment allows us to continue expanding that capacity while moving new platforms from development into production faster," said Thornton. Ethan Thornton's vision on a new defence industry. Mach builds vertical takeoff and landing drones, long-range strike systems, and counter-drone platforms out of a 115,000-square-foot headquarters in Huntington Beach, California. But its real pitch to investors is upstream of any single weapon. In May, it paid roughly $50 million in cash and equity for Exquadrum, a solid rocket motor startup, beating out at least eight other bidders for a company sitting on a supply-chain bottleneck that drone demand has made acute. That deal became the basis for Mach Energetics, a new unit that sells rocket motors and energetic systems to external customers. A second unit, Mach Propulsion, is chasing the same playbook in jet engines. A field that's getting expensive fast. Mach isn't the only one raising at speed. Anduril more than doubled its valuation to $61 billion in a $5 billion round led by Thrive Capital and Andreessen Horowitz in May, and Shield AI raised a $2 billion package, $1.5 billion in equity plus $500 million in preferred financing from Blackstone, at a $12.7 billion valuation the same spring. The manufacturing-first argument Mach is making has also shown up at Hadrian, which raised $1.37 billion at a $7.87 billion valuation in August to build precision parts for other defence primes. Mach also picked up a Defense Innovation Unit contract in June, partnering with Whisper Aero to develop a maritime strike aircraft called Atlas, adding to earlier Army-funded work on its Strategic Strike missile. None of this settles the actual question hanging over the sector: whether any of these companies can manufacture at the volume their valuations now assume, or whether venture money is once again pricing ambition years ahead of a factory's ability to deliver it.

BBC
Aug 20th, 2026
How landscape gardening is being electrified.

How landscape gardening is being electrified. 13 hours ago Christine RoTechnology Reporter, Los Angeles Part of the soundtrack to a day in southern California is the drone of petrol-powered gardening equipment. Noise is one of the main reasons that cities around the US are banning petrol landscaping tools or encouraging electric alternatives. These alternatives have the additional benefits of reducing carbon emissions, vibrations and the exposure of landscapers to pollution. In addition they can mean longer working hours, as they can be used at times when residents demand quiet. Today, I'm taking part in training run by the American Green Zone Alliance (AGZA), an organisation supporting the transition towards electric landscaping equipment. To my surprise, the electric backpack leaf blower I strap on is not much heavier than my normal rucksack. Using the blower to herd balls around the park feels fairly intuitive, though naturally I'm much clumsier and slower than the pro landscapers. As for noise, there's still a buzz, but the sound is higher-pitched and not quite so loud as the familiar petrol-powered machines. The move to electric power is attracting new companies to the market for gardening kit. US aerospace start-up Whisper Aero is one of those firms. Its main business is electric propulsion systems for aircraft. But in 2022, after the Covid-19 pandemic made many people more sensitive to noise, and following a couple of years of research and development, the company realised that its aerospace-grade fans would work well in leaf blowers. "Our technology is cleaner, quieter and more efficient than other air-moving technologies that exist today," according to Andrew Terajewicz, Whisper Aero's director of air management. "And the leaf blower is the perfect mix of this." The battery on Whisper Aero's blower lasts up to 50 minutes at full power. The company has had to scale up its manufacturing volume in its expansion to consumer technology. Online pre-orders of Whisper Aero's handheld leaf blower started this year. It's priced at the high-end of electric leaf blowers, which are often more expensive than traditional petrol versions. But for that you get a machine which is less likely to disturb the peace. "It is so ultra quiet yet powerful, that the brain has a hard time understanding what's happening," says Dan Mabe, the former landscaper who founded AGZA. Whisper Aero aims to further develop its products, including a backpack leaf blower that would be better suited to professional landscapers. Even with innovation like that, petrol-powered machines are unlikely to disappear anytime soon, particularly for professional landscapers. For a start, petrol machines are much more powerful, which makes for quicker work, so less time is spent lugging around heavy equipment. Terajewicz says that heavy-duty petrol backpack blowers can reach a maximum blowing force of about 50 newtons. The handheld Whisper Aero blower typically runs at about half that, though it can go higher. Another big issue is runtime. Professional gardeners like to use their blowers at full throttle. "For us, it's a little bit hard to use electric," explains Carlos Camarena, a supervisor for a California landscaping company. Camarena's company uses electric tools where they're required to, in cities with ordinances banning petrol tools. But when they have a choice, they stick to petrol. His company typically uses batteries that last for about 30 minutes. A crew has six batteries charging at any given time; each takes about 45 minutes to reach a full charge. Then there's the considerable upfront cost of going electric. One landscaper estimates that it would cost his business around $10,000 (£7,540) to transition all their equipment. The subsidies and rebates offered by some local governments may not be enough to offset the cost of the switch. The change would be even harder for landscapers who work as sole proprietors, with a single vehicle and limited space for charging and storing equipment. Added to that is the weight of tools with multiple batteries, and the cost of accessories to hold them all. Nevertheless the biggest makers of power tools are investing in electric. Stihl, a power tool manufacturer headquartered in Germany, aims for battery-powered equipment to make up 35% of its sales by next year, and 80% by 2035. It's on track to meet the 2027 goal in Europe, though sales in the US have been slower. To help reach its targets, the company opened its first plant solely manufacturing batteries and tools, in Romania in 2025. "We like to say that we are dual-technology leaders," says Paul Hicks, senior marketing and product manager at Stihl GB. "So we are being very open with our customers if in some cases a petrol tool may be a better solution for them... But in the large majority of cases, battery-power tools pay off fairly swiftly because of the cost of fuel." In May, Stihl announced a new battery system that uses high-performance batteries. These batteries use a relatively new, more efficient design for lithium battery cells, known as tabless cells. Tabless cells have 60% more peak power than standard cells, according to Hicks. This means that the batteries charge faster, and landscapers can take fewer batteries out to sites. The batteries are also relatively lightweight. Mabe believes that overall, for gardeners embracing long-lasting electric equipment, "There's big rewards if they can make it work." Back in southern California, landscaper Camarena sees the benefits of electric tools. "We don't contaminate the air," he says. "When we use the gas blower, some people get mad. They are reading a book or something." More Technology of Business

AVweb
Aug 20th, 2026
Whisper Aero flies electric Swift glider.

Whisper Aero flies electric Swift glider. Three piloted flights begin testing of the company's electric ducted-fan propulsion system. Thursday, August 20, 2026 at 12:31 PM ET Key takeaways: Whisper Aero has begun piloted testing of its electric propulsion system on a modified Aériane Swift 3 glider in Tennessee. Test pilot Zac Majors completed three flights totaling 130 minutes using two of the company's eQ250 electric ducted-fan propulsors. "[I] could really do whatever I wanted with it," Majors said. "I look forward to flying it again." Powered Swift. Whisper announced plans for the aircraft in April 2025 as part of a partnership with Tennessee Tech. The company said each eQ250 installed on the Swift would produce up to 80 pounds of thrust. Five EPiC 1.0 battery modules from Electric Power Systems provide power for the aircraft. Whisper projected a cruise speed of 42 to 55 knots, a climb rate of 1,250 feet per minute and a powered range of 109 miles. The project received a $500,000 Transportation Network Growth Opportunity award from the Tennessee Department of Economic and Community Development. Whisper said Tennessee Tech faculty and four students would assist with ground testing of the engines, batteries and controllers before powered flight. From glider tests to powered flight. Earlier this year, Whisper began flying the Swift in Tennessee under an experimental airworthiness certificate before installing the propulsion system. The company said it incrementally increased the aircraft's weight during those flights to evaluate handling and performance at the higher weights expected for the powered configuration. Whisper has now moved into powered testing and plans additional flights in Tennessee before evaluations with government customers later this year, according to FLYING. During an early morning full-power pass at 100 feet agl, the company measured the aircraft at about 52 dB(A) against a background level of 34 dB(A). Whisper said the initial flights met their planned objectives for evaluating the propulsion installation, batteries and control systems. Matt is AVweb's lead editor. His eyes have been turned to the sky for as long as he can remember. Now a fixed-wing pilot, instructor and aviation writer, Matt also leads and teaches a high school aviation program in the Dallas area. Beyond his lifelong obsession with aviation, Matt loves to travel and has lived in Greece, Czechia and Germany for studies and for work.

Urban Air Mobility News
Jun 18th, 2026
Whisper Aero joins Mach Industries programme to develop autonomous systems for the US Navy.

Whisper Aero joins Mach Industries programme to develop autonomous systems for the US Navy. eVTOL developer Whisper Aero is joining the Mach Industries-led programme to develop advanced autonomous systems for the U.S. military and its allies, under a contract award for the Defense Innovation Unit (DIU) Runway Independent Maritime Expeditionary Strike (RIMES) programme. "Serving as the aircraft integrator, Mach Industries will lead development and overall program execution for the effort," said Mach in a press release. "Mach Industries will execute this effort through a strategic partnership with Whisper Aero. Together the team is leveraging commercial technologies to design and deliver Atlas, a next-generation aircraft with a novel aero and propulsion approach that gives the warfighter an entirely new advantage for operations in contested environments." Mach Industries' integration of Whisper Aero's JetFoil(TM) in a scalable aircraft design, enables entirely new concepts of operations, said Mach. "Atlas can use unimproved rotary-wing landing zones, while maintaining the control simplicity of a fixed-wing aircraft and a thrust-to-weight ratio that is less than half of what is required for vertical flight. This, along with highly efficient propulsors, result in significantly increased range, as well as radical reductions in acoustic signature. The combination of these attributes, along with price points that enable low-cost mass, gives Atlas the ability to reduce cost per effect and fuel per effect in a contested environment."

Urban Air Mobility News
Jun 3rd, 2026
Whisper Aero working with USAF on electric contested logistics aircraft.

Whisper Aero working with USAF on electric contested logistics aircraft. Whisper Aero has unveiled a new family of systems for contested logistics known as Collaborative Logistics Aircraft (CLA) during Special Operations Forces (SOF) Week. "Light (500 lbm payload) and heavy (3,000 lbm payload) variants of CLA were revealed utilizing Whisper's proprietary UltraQuiet(TM) propulsion and JetFoil(TM) integrations for conventional and short takeoff and landing (STOL)," said the company in a press release. "Development of these aircraft is being accelerated by the US Air Force who has selected Whisper Aero for funding via Strategic Finance Increase (STRATFI) and Operational Energy Capabilities Improvement Fund (OECIF) contracts. Whisper's propulsion systems are the core enablers for these platforms, said the company. "Multiple eQ250 propulsors, capable of 80 lbf of thrust, are integrated into the leading edge of the wings of these aircraft, in a concept known as JetFoil, to achieve coefficients of lift as high as 14, critical for short takeoff and landing from degraded runways. eQ250 propulsive efficiency improves at higher speeds, enabling higher speed flight of up to 250 kts with reduced acoustic and thermal signatures compared to existing turboprop or turbojet propelled aircraft. Static performance has been verified through tests with the Air Force Test Center (AFTC) at White Sands Missile Range's (WSMR) Acoustic Range Complex (ARC). "Whisper Aero has been selected for STRATFI and OECIF funding by the US Air Force to advance its CLA development. This comes after multiple years of maturing and validating its propulsion technologies together with AFWERX and the Air Force Research Lab (AFRL) on prior small business contracts. "First, Whisper is leveraging its Ultralight, a retrofitted Swift3 glider with two eQ250s to gather flight test data and advance the thrusters to technology readiness level (TRL) 7/8. Whisper recently announced a USD500K effort by the State of Tennessee in conjunction with Tennessee Tech to accelerate this effort. After successful civil flight tests, the team expects to advance to testing with the Air Force Test Center at White Sands Missile Range's Acoustic Range Complex in 2026. Once the Whisper Ultralight is airborne, the engineering team will set its sights on the CLA Light, a 1,300 lbm Group 3 UAS capable of carrying 500 lbm payload over 200 NM or ferrying over 2,000 NM with no payload. The CLA Light is a clean sheet design leveraging JetFoil arrays of twelve eQ250 on its main wing to enable CTOL or STOL with a 50 ft takeoff/landing ground roll. Its long range and STOL capabilities are enabled by a 40 kW powerplant and a small battery and can dash at 175 kts. The nose easily opens to reveal an accessible payload bay for cargo specialists to load and unload necessary supplies. The team expects flight tests for this aircraft to begin in 2027. "CLA Heavy will then build upon the learnings of the CLA Light and its flight test campaign. As a 10,140 lbm optionally crewed retrofit Group 5 UAS, the CLA Heavy will feature a new wing with eQ250 JetFoil arrays for CTOL or STOL flights with a 300 ft takeoff/landing ground roll. Its 50 ft wingspan features 30 higher voltage eQ250s proven out on the glider and CLA Light, enabling more robustness in flight due to no critical propulsor parts or subcomponents. Equipped with a 600 kW powerplant, the CLA Heavy will be capable of up to 250 kt speeds, 800 NM range with 3,000 lbm of payload, or 3,000 NM ferry flights with no payload. While the aircraft has been designed for cargo missions, it can be reconfigured for multiple missions where STOL and UltraQuiet(TM) flights may be enablers."

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