← Back to NASA Technology Projects
Completed TRL 4 (started at 3, targeting 4)
A unique type of vertical lift propulsor is being designed/analyzed/ developed to push blade passage frequency harmonics above the human audible range, while also having low tip speeds to limit the other low broadband noise components of community noise. Use of distributed electric motors enables small propulsors to be designed in this way, with tight integration across the airframe. This strategy is shown in the figure, comparing the new 20,000 Hz and 285 ft./sec propulsor to 1.5' and 9.7' diameter propellers which have blade passage harmonics at the peak human hearing frequencies along with almost twice the tip speeds (with higher broadband ). Use of these small propulsors, each capable of 25 lbf thrust, enables their use in far more distributed ways than merely using propellers or fans. This enables advanced concepts to be developed that leverage airframe shielding to a much greater extent for further noise reduction, along with propulsor positioning to achieve directional reflectivity that causes the remaining noise to be focused upwards, and away from the community.
Benefit to NASA Aeronautics Quiet VTOL initiative
Listed on TechPort itself — the most direct way to ask about this specific project.
This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.
None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.