Whisper Aero, Mark Moore’s startup in Crossville, Tennessee, fields devices to move air, ranging from leaf blowers to fairly large airplanes. The company recently showed a lineup of three aircraft, starting with a dual-motor powered flying wing hang glider to a nine-passenger silent medium-range carrier. Each benefits from the quiet propulsion system developed by Moore and his team.
The Whisper Lineup
Whisper Aero plans a range of craft from a single-seat ultralight sailplane to a small lightplane-size cargo carrier to a nine-passenger transport. All are capable of flying autonomously, and all will be powered by from two to 30 Whisper Aero eQ250 propulsors, each capable of 80 pounds of thrust. In this video, Manfred Ruhmer, seven-time world Class 2 ultralight soaring champion among other honors, shows off his Aeriane Swift 3, taken aloft by an Eck-Geiger electric motor, and then elevated by its light weight and Manfred’s piloting skills. It will be fascinating to see how The ship will perform with twin ducted fans.
Tennesse Tech and $500,000 Will Help Us Find Out
AIN online reports, “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.”
An April 2 announcement from the Tennessee Department of Economic and Community Development’s (TNECD) Transportation Network Growth Opportunity (TNGO) initiative, wants to. “make Tennessee the No. 1 destination in the Southeast for automotive and mobility R&D investment.”
Designed by Ilan Kroo at Stanford University along with several students, the Swiift (Swept Wing with Inboard Flap for Trim), was a collaboration with Bright Star Gliders. It, and subsequent variants, have been built in Belgium. Now, Steve Morris, one of the students involved in the original design, is working with Whisper to turn the Swift into the Whisper Ultralight. Brian Porter, a world champion Swift hang-gliding pilot, will be chief test pilot for the craft.
Ian Villa, Whisper’s Chief Operating Officer and Chief Product Officer 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 eQ250 propulsors will be less than a foot in diameter and deliver 80 pounds of thrust each. Several iterations of the technology have already been tested fro the U. S. Department of Defense.
Whisper’s explaination of the components of its ducted fan propullsors
Whisper notes their fans are, “20 dB quieter and 20% more efficient than comparable quiet propulsion systems.” It might be difficult to find comparables, with Whisper’s unique design features, although their chart shows noise levels of small model aircraft electric ducted fans. In hard numbers, the little fans can produce from five to five hundred pounds of scalable thrust and speeds from 40 to 400 knots (46 to 460 mph, or 74 to 740.8 kilometers per hour).
Its 35-to-1 lift-to-drag ratio enables to ultralight to cruise around at 45 to 55 knots (51.7 to 63.2 mph) on a mere 6.5 horsepower, and with full output from the motors achieve a 1.250 foot-per-minute climb rate.
One aspect of their quietness has been further explained by Flying Magazine. “The ‘blade passage frequency’ moves up to more than 16,000 Hz – outside the range of most human hearing but not, supposedly, high enough to freak out the beagles.” This “sweet spot” for frequencies inaudible to humans and unperturbable to dogs is a bit of auditory genius for Whisper and helps the product live up to its name..
The two eQ250s on Whisper’s flanks will enable early testing of the oompact powerplants, and help further their use on the larger machines. The video explains Whisper’s work with computerized design systems to speed evaluaton of the new systems.
Looking at a Larger Picture
Whisper will take lessibs learned from long-term motor tests on the flying wing and apply those to their Air Force CLA (Collaborative Logistics Aircraft), a form of liaison airplane, but with the ability to slip quietly into combat zones.
CLA Light (foreground) and Heavy enable short take off and landing (STOL:) whiile lifting significant loads considerable distances
The smaller “light” cargo carrier can haul 500 pounds 200 nautical miles (230 statute miles), or travel up to 2,000 nautical miles (2,300 statute miles) with no payload. Powereed by 12 or the propulsors used on the Ultralight, the Group 3 UAS (Unpiloted Aeroal System) can take off and land with an ultra-short 50 foot ground run. Batteries are recharged by an on-board 40 kilowatt powerplant. Can can be accessed through a wide-opening nose cone.
The larger CLA totals 10,140 pounds (4,600 kilograms) and can carry 3,000 pounds (1,300 kilograms) 800 nautical miles (920 statute miles), and ferry itself 3,000 nautical miles (3,450 statute miles). Its 30 eQ250s enable 300-foot takeoff rolls and its 600 kW powerplant can help it hit 250 knots (288 mph). These performance figures make each machine in the Whisper lineup formidable contendters in electric and hybrid aviation.