Modular Helical Vertical-Axis Wind Turbine for Urban Wind

When thinking about engineering that spins, my first ideas were drones and RC vehicles. Both are based on rotation, and both are relatively possible for a student to build. However, these spaces are already highly saturated, and I did not see a way to create something meaningfully different or broadly useful in any way that was new.

The idea for this project came during a particularly windy day while playing soccer with my friend. Despite the wind being strong, it was not consistent in direction or in speed, and wind would stop and start randomly. For me, this led to a question: why is so much urban wind effectively wasted?

Traditional horizontal-axis wind turbines struggle in cities. This is why there are hardly wind turbines in cities, and why they are generally found in suburbs or farms. Urban and Semi Urban wind is low-speed, turbulent, multi directional. In addition, large turbines are impractical in environments with many buildings. To find some way to tap into the wind that is being wasted, I began researching vertical-axis wind turbines (VAWTs), which are capable of capturing wind from any direction.

This project is a helical vertical-axis wind turbine designed specifically for these conditions. It is not optimized for maximum energy output. Instead, it follows a quantity over quality approach. Since this wind is low quality, but many turbines can be installed due to low cost. Rather than relying on ideal conditions, this design focuses on continuously capturing small amounts of energy from wind coming from all directions.

The result is a low-cost (~$30 not including a battery to store the charge), modular and upgradable, multi-directional, urban wind turbine that uses a spinning motion to extract usable energy from these winds.

Note: I will begin with an introduction for the Make it Spin Engineering Student Contest, if you are here to build your own VAWT, skip to step 12. However, to fully understand why it is the way it is, I would read through the whole thing as much as possible.

Note #2: This is not completely a beginner course, you will have to solder some stuff, and to some degree you will have to make the best choice on what you need based on your setup, what can be bought where you live, and what your energy needs are. I will try to make it as easy as possible for you to make your choice, but ultimately some of the stuff is up to you.

Design

1. Fusion360
2. OrcaSlicer

Items

1. Any DC/AC Low RPM, Non Geared Motor [~$20]
2. For the specific dimensions of this project, it must have 8mm output shaft and a 52mm dimeter (standard dimensions)
3. Any 3D Printer Filament (~200 grams of preferably PETG) [~$2.5]
4. Any Low Voltage Harvesting Board [~$2]
5. Either:
6. Low voltage rectifier
7. Schottky diode bridge (4× SS14, SS24, SS34, or 1N5819)
8. (preferably) Ideal Bridge Rectifier
9. M4 x 250mm Fully Threaded Rod [~$2]
10. M4x0.7mm Round Coupling Nut [~$1.5]

Total cost of items: ~$30

Tools

1. 3D Printer
2. Wire Cutters
3. Multimeter (for testing)
4. Soldering Iron
5. Flux
6. Solder
7. Strong Glue

Spinning is a core function of this design.

This turbine relies on continuous rotation to:

1. smooth out irregular wind (in direction and speed)
2. avoid dead zones common in straight-bladed designs
3. stay active even when wind direction changes rapidly
4. self start

Because the turbine spins around a vertical axis, it never needs to turn or align itself with the wind. Any wind that reaches the blades rotates the turbine, which is critical in environments where wind direction is unpredictable and varies.

https://www.researchgate.net/publication/342185455_Aerodynamic_Performance_of_a_Quadrotor_MAV_Considering_the_Horizontal_Wind

A vertical-axis wind turbine can accept wind from any direction, which makes it a solid option for urban use. The helical design builds on this purpose.

The helical blade shape:

1. distributes aerodynamic forces along the height of the rotor
2. reduces torque ripple and vibration
3. ensures that some portion of the turbine is always producing rotational force

Rather than having all blades stall and engage at the same time, the helical geometry staggers the force from the wind. This leads to smoother, more consistent spinning, especially at low wind speeds.

While it does not maximize the RPM, it ensures that the turbine stays in motion.

https://www.mdpi.com/1996-1073/14/2/393

Traditional turbine optimization focuses on efficiency under ideal/perfect conditions, but urban wind rarely creates those conditions.

This project is for when:

1. wind will be weak
2. wind direction will change constantly
3. airflow will be turbulent and obstructed

This project aims to capture such otherwise "low quality" wind. Even small amounts of airflow contribute to rotation.

In short:

1. less waiting
2. more spinning
3. more total captured motion

(The image shows the general idea, but mine did not turn out exactly the same since I made a helical VAWT)

This wind turbine was designed as a mechanically modular system rather than a single fixed structure.

Instead of optimizing one helical turbine, this project was made based around 2 repeatable vertical modules that can be stacked to increase height, swept area, and total energy capture (and a cap for the top). Each module uses the same blade geometry, shaft diameter, and mounting interface. This allows additional sections to be added without redesigning the core system. Since they are uniform, modifications can be made and blades swapped out easily without having to start over from scratch. This saves filament and time.

This approach makes the turbine more:

1. scalable in height
2. adaptable to different environments
3. easier to repair, modify, or upgrade

Because all modules contribute to the same rotating shaft, a single low-RPM motor can be used to harvest energy from the entire assembly. This approach prioritizes accessibility and makes vertical scaling possible even when only one generator is available.

Since urban environments often limit horizontal space but allow vertical expansion, vertical stacking is a easy and simple way to increase performance. If vertical space is also limited you can have just one module. If you have space, multiple modules can be combined to form a taller turbine that intersects more wind layers.

Further, since I have open sourced this design, anyone can create a blade specialized for their needs.

https://www.witpress.com/Secure/elibrary/papers/ESUS23/ESUS23008FU1.pdf

Modularity in this project goes beyond the mechanical design.

Each turbine module can be paired with its own generator and low voltage harvesting circuit. This allows power to be conditioned locally before being combined with other modules.

Depending on needs and the application, multiple modules can be connected:

1. (in a series) to increase voltage
2. (in parallel) to increase current
3. (as independent inputs) into a shared storage system

Using low voltage harvesting boards ensures that even small amounts of energy produced by individual modules are captured and can be used. As more modules are added, the total available power increases without requiring changes to the core turbine design.

This makes the system flexible and adaptable to different storage methods, loads, or experimental setups.

https://www.researchgate.net/figure/Multi-generator-series-compensated-power-system_fig13_352770211

This turbine was designed to be built using accessible materials and basic tools. Since I used a cheap, available $20 motor, I also used 3D printing, because it cuts down on the parts needed and can be used to create an optimized design which would be otherwise difficult to construct with PCV pipes or other such materials.

The blades are shaped into a smooth helical twist around the central axis, with 3 supporting ribs in the center. The top and bottom of these are threaded to ensure that the motor spins.

I had a few key considerations in making this design:

1. maintain consistent curvature across all blades
2. keep spacing symmetrical around the shaft
3. avoid sharp bends that introduce stress or imbalance

The goal was not aerodynamic perfection, although I wanted to get close, but rotational balance. Even force distribution allows the turbine to self-start and maintain motion in variable wind.

At this point, I cut the design into 3 modules. The first module is moderately tall, the second somewhat tall and a cap. This can be connected to each other by screwing all into a rod, and by gluing them all together. This ensures that you can make it as tall as needed by using the modules of the needed height and save on filament costs for supports.

I then created another set of 3 blade modules that are significantly wider and rotate more to capture more wind. Since this is quite a bit larger and wider, I went with 2 modules that can be interchanged rather than 3.

This final version is an in-between of both of the others. It is decently wide, so as to capture a moderate amount of wind, but so as not to take up too much space and be too difficult to print.

I then went ahead and made a case to house the motor, with a small space to hold circuitry and if applicable a battery that can be sealed.

Note: From the next step, my process paper part of the Instructable ends, and I will actually explain how to make one for yourself.

This project is intentionally flexible, which means there are several valid choices depending on what parts you have access to and what you want to optimize. This section is meant to help you decide what to use to better serve your needs rather than me giving you one “correct” option, as I outlined in the introduction.

Motor Choice

A DC motor produces DC voltage directly, which makes it the easiest option for beginners and if you want to keep it simple. If where you live wind moves in one direction primarily, the output can be fed directly into a low-voltage harvesting or boost converter directly, so I would recommend this option.

Use a DC motor if:

1. you want the simplest wiring
2. your turbine consistently spins in one direction
3. you are prioritizing ease of testing and debugging
4. you want a cheaper motor [avg cost is ~$20]

Limitation: If the turbine spins in the opposite direction, polarity will reverse unless a rectifier is added (which I would recommend you add in any case).

AC motors, require rectification before the power can be used or stored. However, this wastes more energy, and costs more, so this is only really viable if you have something specific in mind for what to do with the power and have a lot of wind.

Use an AC motor if:

1. your turbine will reverse direction a lot
2. you want polarity-independent output
3. you plan to combine multiple mechanical configurations
4. you can afford/want a better, pricier motor [avg cost is ~$50]

Tradeoff: Requires a rectifier and slightly more electrical loss.

Rectification

There are a few different rectification options for AC motors or even DC motors if wind goes both ways where you will put up your VAWT. Do note that I would not recommend choosing your rectification until you have tested the energy output of your VAWT in wind.

Bridge Rectifier Module (Simple but need lot of energy produced)

Prebuilt bridge rectifier modules are simple, reliable, and easy to wire. They ensure correct polarity regardless of rotation direction.

Use this if:

1. you want plug-and-play wiring
2. your voltage is comfortably above ~2 V (and only if you know that it will be)
3. you value simplicity over maximum efficiency

Low-Voltage or Schottky Diode Bridge

Schottky diodes have a lower forward voltage drop than standard silicon diodes, making them better for low-voltage energy harvesting.

Use this if:

1. your turbine produces only 0.5–3 V
2. you want better efficiency than a standard bridge
3. you are comfortable soldering

Ideal Bridge Rectifier (Best performance)

Ideal bridge rectifiers use MOSFETs instead of diodes, drastically reducing voltage loss.

Use this if:

1. you are harvesting very low voltages
2. efficiency is critical
3. you want maximum usable output from weak wind

Soldering Your Own 4-Diode Bridge

You can also just build a rectifier manually using four diodes. This works well and is cost-effective. However this has a high skill barrier to entry, and the performance depends on the diodes you used.

Use this if:

1. you already have diodes
2. you want to customize the layout
3. you are comfortable soldering and testing

To start building your Helical Vertical Axis Wind Turbine, first decide on your desired height for the turbine. Once you have decided on your desired height, you can start printing modules to add up to your desired height. For demonstration purposes, I have printed one of each module. I would recommend using PETG, since it survives better in heat, and white filament for less warping in the sun.

Once you are done printing as many module as you need, print the case and its lid.

Note: The lid for the case will likely need some sanding, due to the low tolerance of the design.

To start the assembly, place the hollow rectangle in the hollow part of the base to create the base for the VAWT. After that, just put the motor into the hollow cylinder part of the base.

After that, get some glue and put it on the top parts of the blade, and then add another blade. Repeat this until it is at the desired height. I would recommend doing this outside, because strong glue may have fumes.

After that, take your rectification (if applicable) and your low voltage harvester and a battery if desired and put them into the hollow crevice in the base as shown. After that, just seal it up with the lid. The lid should be a very snug fit, and you make want to add some tape to ensure waterproofing since the VAWT will likely stay outdoors.

Once I finished the build, I waited for a windy day to test out the design in real-world conditions. Without load, I had previously seen it get up to 5v with me spinning it by hand, but under load and in actual wind it gets to about 3v at the highest, with an average of about 1.6v or so.

I then tested its self starting ability outside in the wind. It takes a bit of time to actually start on its own, the video is sped up slightly to turn it into a gif without losing all the image quality.

This project did not turn out exactly as I originally imagined, but I think that is part of the process.

My initial goal was not to build a high power wind turbine, but to find a way to capture urban wind for use in some way. Along the way, I learned that designing for weak, turbulent wind such as that in urban settings requires very different priorities than designing for ideal conditions. Maximizing efficiency on paper is not as important as ensuring consistent rotation, low startup torque, low cost, and mechanical stability.

One of the biggest takeaways from this project was the importance of modularity. By designing the turbine as a stackable system rather than a single object, I was able to cleanly experiment with blade width, height, and configuration without starting over each time. This made iteration faster and helped me test and revise rather than forcing me to perfect the designs.

This testing also showed me the reality of power losses. Even though no load voltage can looked promising, real world performance under load shows reality. Seeing the voltage drop to around 2 to 2.7 V under load helped me understand rectification losses, generator choice, and why low voltage harvesting circuits matter so much in small scale energy systems.

When I create a V2 of this project, I will focus on reducing mechanical friction, experimenting with different blade profiles and motors, and testing multiple stacked modules in parallel electrical configurations. I would also like to collect longer term data on how much power it can generate over a longer period of time.

Overall, I learned a lot from this project, especially about energy generation and how to make the most of non ideal conditions.

This project builds on the work and research of others.

My vertical axis wind turbine concepts and helical blade research were inspired by research from MDPI, ResearchGate, and WIT Press. I have linked all of my sources on the specific step in which I implemented the research.

All CAD models were designed by me using Fusion360, and slicing was done using OrcaSlicer. I would not have been able to complete this project without Fusion360's student plan, and the developers who made OrcaSlicer free and open source.

Finally, thanks to my family who tolerated a growing collection of printed turbine parts, test assemblies, and wind experiments.

As I approach the end of the instructible, I want to add another thing before the end. I promise this won't take too long, so bear with me.

I made this with the idea of creating a method for anyone anywhere to capture wind to use as energy and open sourced the whole thing. I will shortly be creating a Github repository for this project. If you decide to create one such VAWT, please do let me know what worked for you and what didn't and what you modified to make it work for where you live. If possible, please add to the repository and/or comment or dm me here on Instructables.

Thanks in advance. ＜（＾－＾）＞