How do the Zipline Silent Propellers Work?

How do the Zipline Silent Propellers Work?


In a recent video, YouTuber Mark Rober showcased some innovative Zipline drones that are designed to deliver medical supplies in Rwanda. While the drones themselves are impressive, there is one aspect of their design that has caught the attention of many: the Silent Propellers. Specifically, the propellers are shaped in a way that reduces noise, but how exactly does this work?



Zipline's Silent Propellers Explained



To understand the noise-reducing design of these propellers, it's important to first understand how sound is created when a propeller spins rapidly. As the blades move past a stationary point, they create a pressure disturbance that propagates away from the blade. The frequency at which this happens is called the blade passage frequency, and it's equal to the rotational frequency (i.e. how fast the propeller is spinning) times the number of blades on the propeller.







Traditionally, propellers with four blades are spaced evenly so that they are 90 degrees apart. However, this creates a lot of different frequencies, including a loud frequency at the blade passage frequency and harmonics of that frequency. By contrast, unevenly spaced blades (e.g. spaced 30 degrees apart) create a lower frequency that is perceived as quieter by humans. When Zipline designed their propellers, they used this principle to create a quieter design.







Zipline's propellers have two blades with a counterbalance on the other side, and the blades are unevenly spaced to reduce noise. By raising one blade slightly higher than the other, Zipline eliminated the interaction that occurs when blades overlap, which creates a lot of broadband noise. While this design is less efficient than traditional propellers, it creates less noise and is therefore better suited for the Zipline drones' intended purpose of delivering medical supplies.







Another design that reduces noise in propellers is the toroidal propeller, which uses a different method to reduce the formation of vortices and create more coherent airflow. This design is especially useful for quadcopter drones, which are known for their high-pitched buzz noise. Wing's delivery drones suffer from a high-pitch noise that has led to complaints from residents in .







Overall, the use of unevenly spaced blades and toroidal propellers can significantly reduce noise in drones and other aircraft. However, the benefits of uneven blade spacing depend on where the listener is located. For example, unevenly spaced blades may be less effective at reducing noise for someone standing behind the drone, but more effective for someone in front of the drone.



In conclusion, the design of propellers plays a crucial role in reducing noise in drones and other aircraft. Zipline's propellers, in particular, use uneven blade spacing to create a lower frequency that is perceived as quieter by humans.



While this design may be less efficient than traditional propellers, it is well-suited for the Zipline drones' intended purpose of delivering medical supplies.



Link to paper mentioned in the video: Reduction of Tonal Propeller Noise by Means of Uneven Blade Spacing





Share via:



Get your Part 107 Certificate



Pass the test and take to the skies with the Pilot Institute. We have helped thousands of people become airplane and commercial drone pilots. Our courses are designed by industry experts to help you pass FAA tests and achieve your dreams.



pilot institute dronexl

FTC: DroneXL.co uses affiliate links that generate income.* We do not sell, share, rent out, or spam your email, ever. Our email goes out on weekdays around 5:30 p.m.


https://skydanceimaging.com/how-do-the-zipline-silent-propellers-work/

Comments

Post a Comment

Popular posts from this blog

DJI RC 2 Review (Everything You Need to Know)

Image
There is no denying it. The original DJI RC, released in 2022 with the Mini 3 Pro, was a hit. The main appealing factor about the then-new remote controller was that it was a more affordable all-in-one solution than the extremely expensive DJI Smart Controller and its successor, the equally expensive DJI RC Pro. One year later, we have an updated version of the DJI RC , the DJI RC2, which currently works only with the DJI Air 3. In this article, we’ll be doing a deep dive into the DJI RC2, focusing on: - Build quality - Size and Weight - Sustained Screen Brightness - Various Features, etc. Additionally, we’ll discuss whether it’s worth getting over the newly released DJI RC-N2. Top Drone Courses Benefits of the DJI RC2 One can look at the DJI RC2 and immediately realize that it will be a beneficial piece of added tech for the Air 3 and subsequent drones that are released thereafter. Integrated Screen The first thing noticed on the RC2 is the Android-based, 5.5″ integra...
Read more

DJI Mini 2 Errors: What They Mean (And How to Fix Them) | Droneblog

Image
Nothing brings a drone operator down quicker (pun intended) than bad weather and drone error codes.  We wait until it gets better with the weather, eventually, although our highly anticipated day of flying is ruined.  However, drone error codes can be more than simply waiting out the issue or hoping it resolves itself. Error codes and the inability to fly the DJI Mini 2 because of these errors can be a nuisance, but, when those codes are decoded, explained, and suggestions on how to fix the issue come to the fore, things get easier. We’ll be looking at a laundry list of DJI Mini 2 error codes, what they mean, and the steps to fix them.  The codes will be listed numerically to locate specific codes easier within the article. These codes are: Code 10001Code 10016Code 10022Code 10023Code 30007Code 30008Code 30047Code 30049Code 30050Code 30055Code 30060Code 30064 Code 30085Code 30105Code 30168Code 30210Code 30224Code 30226Code 40002Code 40011Code 40012Code 40021Code 180016Code 180030Code 1...
Read more