Unveiling of Quiet Whisper Jet Airplane in San Diego
CA – In June, Mark Moore and Ian Villa of Whisper Aero showcased their technologically advanced airplane at the American Institute of Aeronautics and Astronautics (AIAA) Aviation Forum and Exposition in San Diego.
The Tennessee-based start-up has been working diligently to create the most silent propulsion system available for over two years. Whisper unveiled that a unique electric ducted fan powers its propulsion system, yet the specifics of what makes their fans more efficient than others had remained undisclosed.
Whisper has finally revealed more secrets about precisely how their aircraft flies. The company recently released four white papers explaining the propulsion system’s functioning and its potential for integration into multiple airframes.
Whisper’s Tricks to the Trade
Whisper claims it has reconstructed the fan concept to achieve the best noise reduction and usefulness results. They created a ducted fan with a large number of blades and a slow tip speed. When the rotation is sped up to a certain level, the frequency of the blade passing by will be in the ultrasonic range.
The noise generated by the fans and propellers is largely attributed to the blade pass frequency, which is determined by multiplying the number of fan blades by the rotational speed of the rotor. The sound generated by the spinning of the blades is almost inaudible to humans by pushing the frequencies into the ultrasonic range, with much of it being muffled by the atmosphere.
As a general rule of thumb, fans that rotate faster (measured in revolutions per minute, or rpm) produce more aerodynamic noise across a wider range of frequencies, thanks to their higher blade tip speeds. By shortening the blades, Whisper has been able to get a high rotational speed mixed with a low tip.
Whisper’s ducted fan design can be used for more than just powering airplanes. The engineering principles can be applied to almost any air-moving device to make it quieter. It can be adapted for use in various other products used daily, such as hair dryers, leaf blowers, and delivery drones.
The Whisper Jet can transport nine passengers and a pilot on regional trips of roughly 500 miles with a hybrid-electric powertrain. Otherwise, it can be powered by a fully electric powertrain, which would reduce its range to approximately 200 miles.
Whisper has conducted an extensive flight test campaign to verify the effectiveness of its propulsion system, utilizing five drones with various prototypes of the company’s electric ducted fans. Whisper has conducted much of its testing with a 55-pound drone that is said to be silent when flying at 200 feet.
Despite having created multiple technology demonstrators and building the Whisper Jet, the company has no intention of manufacturing it. Instead, they are hoping that its Whisper Jet concept will draw the interest of designers who may be interested in incorporating its propulsion system into their new planes, particularly those intended for regional air mobility.