The U.S. Army Combat Capabilities Development Command (DEVCOM), Army Research Laboratory researchers, University of Texas at Austin and Uber partnered to research the acoustic properties of electric vertical takeoff / landing aircraft that use distributed electric propulsion to power flight. These eVTOL aircraft could be used in future aerial surveillance and cargo transport missions using smaller rotors than traditional helicopters. Read more for a video and additional information.
What the teams discovered is that stacked co-rotating rotors may be significantly quieter than traditional paired rotor approaches, this improving performance for a flying craft. Currently, no stacked co-rotating rotors have been employed in existing aircraft. The ultimate goal is to find a stacked rotor configuration that produces considerably lower noise than the conventional rotor.
- [Bigger Alloy Sturdy Material&Anti-Collision]-- the helicopter with Alloy is very sturdy with longer lifespan, which is suit for kids and beginner to play as no serious damage or dysfunctional appearance after many times crashes.
- [Full 3.5 Channels & 2 Selectable Frequencies] -- Up, Down, Left, Right, Forward and Backward built-in Gyro to hover in the air. With Gyro Stabilizer, Moves More Flexible and Stable.2 Selectable Frequencies Let You Fly Up To 2 Helicopters At Once.
- [Multi-Protection for Helicopter]-- The helicopter with low-voltage and reverse connect protection and Jammed for inner Board. It can be beter to protect the helicpoter with these funtions when put battery wrong director or lower Voltage.
- [Suitable for indoor flying only]-- The best flight distance about 10 Meters and 5-8 flight time, the size 14.57*2.56*5.91 inch same with Paid, at which it must be paly indoor for Kids for best flight experience.
- [Helicopter with several certificates]-- FCC, CE, ROHS, EN71, EN62115, EN60825, R&TTE, PAHS, HR4040, 6P, ASTM,REACH. Compatible with US standard. It is very safety for kids playing.
The noise you hear from these smaller rotors is generated through fundamentally different physical mechanisms. Traditional modeling techniques need to be improved to account for all of the noise generated so that vehicle designers can be aware of what will actually be heard,” said Dr. George Jacobellis, Army research engineer at the laboratory’s Vehicle Technology Directorate.