Charles Blouin's Posts (5)

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Crowfunding Update, Four Years Later

Four years ago, Chris Anderson posted a list of delayed Kickstarter campaigns. I was intrigued by this list and came back to it a few times over the years. 2014 and 2015 was the peak of the drone hype.


Unsurprisingly, most crowdfunding campaigns were late. Surprisingly, however, most (10 out of 17) crowdfunding matured in companies that are still around almost 5 years later. Crowdfunding is not the only way to start a business, but it looks like it was quite beneficial for those companies at that time. Alternatively, we could say that Chris Anderson is quite good at selecting crowdfunding campaigns!

Here is the updated spreadsheet. Let me know in the comments if I made a mistake.

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I will discuss the challenges of designing this database. Searching for the right propulsion components for a UAV is tough. There is not much data available, and what is available from suppliers is not standardized or reliable. Even with the right tools, you still have to buy and test many components before finding the right motor and propeller. My team and I have extensive experience with dynamometers, so we have a good understanding of the issues, but we still had some serious challenges when designing a database.

Racerstar%20BR2306S%202400kv%20Dalprop%206040%20Close%20up.jpg?profile=RESIZE_710xRacerstar BR2306S 2400kv and DALPROP 6040

Dynamometer tests produce a lot of data. This data is very sensitive to the test conditions. The first obvious challenge in a user-contributed database is figuring out how to create a standardized test environment. There is, unfortunately, no international standard on propulsion test for small UAVs. I can say from personal experience with hundreds of businesses and universities that everyone does it differently. It is also not possible to record the entire test environment, so we cannot only use software checks. In the end, we came up with multiple solutions to minimize the variance between the test. First, we developed a strict test procedure and environment with a checklist. Second, all the tests are done with a script and uploaded automatically to minimize the risk of operator error. Third, the test script has multiple checks to test for data consistency. Finally, all the test data is available in the database and we encourage people to upload pictures and comments, so other users can verify the data accuracy and comment on it. We intend to implement a voting system so more people can help catch incorrect data.


Sample Data for the Xoar TA130-25 KV80

Another challenge is regarding sorting and categorizing the data. We developed a component-test model where each component can be associated with multiple tests, and multiple tests can be associated with multiple components. For example, this coaxial test has two motors and two propellers. If you click any of the components, you can see all the tests that were done with this component. This test-component model is important for data analysis. You can already see the data plotted on each component and test page, but it is possible to do more. We are working on an analysis module that will allow you to extract the fundamental motor and propeller parameters (Kv, i_0, C_t, C_p, etc…) from multiple tests. Those parameters will also be searchable.



The data in the database will always be freely accessible if contributors choose to make their data public. We are planning a model similar to GitHub where users pay only for private components hosting and analysis. We currently only support RCbenchmark test tools, but we are definitely open to supporting other tools if other people develop motor and propeller dynamometers.


Test of the Xoar Coaxial 47 and 40 inch prop

Next on our list of feature is display unit selection, advanced analysis and search, and an option to share embedded graphs on forums and websites. I invite you to browse the database and submit feedback! The database is still in alpha, so some features are missing, but it is already useable for searching, categorizing and data analysis.

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Pacific Drone Challenge


The Pacific Drone Challenge, inspired by the Xprize, has the goal of pushing the boundaries of what is possible with civilian drones. You have to do it for your name in the history books as there is no financial prize. Could we see this challenge accomplished by the DIY community? Getting the permits, insurance and having a pilot licence is not for everybody, but many are flying aircraft as a hobby, so it is possible. Right now, the Japanese company Irobotics and the organisation SabreWingAircraft accepted the challenge.

A quick calculation seems to show that battery only is out of the question for that distance. The best gliders have a 70 to 1 ratio. This would mean you would have to start at a height of 100 KM (or realistically, climb 100 km over the whole trip). Even if your plane was only made of batteries and it had perfect efficiency, the energy density of batteries is barely enough to provide the energy required (using an energy density of 950000J/kg). Optimization of the motor, the propeller and the air-frame is will be critical to succeed.

How would you go about this challenge? Build from scratch? Modify a glider? Use a flying wing? Let me know in the comments!

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Thrust Stand for Large Motors


My colleague and I received a lot of help from the DIYDrones community two years ago when we launched the Series 1580 with our company RCbenchmark. We had just finished our masters in robotics. After a lot of work, we are now releasing the Series 1780, a dyno to test motors and propellers producing up to 25 kgf of thrust.

Although this tool is intended for businesses and universities, it uses the same open source software used on the Series 1580 and the Series 1520. I have made more videos on our Youtube channel regarding motor and propeller theory since the Series 1580 was released.

It is not a tool for hobbyists, but I know a lot of you work professionally with UAVs too. Hopefully it will be used for one of those hover bikes in development :). We developed custom load cells with our load cell manufacturer. When testing motors this size, EMI become much more a problem. We had to add extra shielding and galvanic isolation almost everywhere.

Here are the specs:

  • Voltage (0-60 V).
  • Current (100A continuous, 150A burst).
  • Power (0-6000W).
  • Thrust (±25 kg).
  • Torque (±12 Nm).

The system will also support coaxial testing, something a lot of larger UAV designers requested. Coaxial is slightly less efficient, but more compact. I am available in the comments if you have any question regarding motor and propeller testing. I had the opportunity to work with hundreds of businesses, researchers and hobbyists who tested all kinds of motors and propellers, so I may be able to help.

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Almost a year ago, I posted here about how VR technology could help control and perform research on UAVs in an indoor environment and at a more affordable cost. Currently, the most advanced indoor UAV research lab in the USA and Switzerland are using camera-based motion capture systems. Unfortunately, those systems cost tens of thousands of dollars, require calibration, and are not very portable. I think the lack of availability of motion capture equipment is a factor significantly limiting UAV research and development.


My team and I are now releasing the Otus Tracker, a motion capture system and software package designed specifically for indoor UAVs and robots! The Otus Tracker has similar capabilities to camera-based motion capture, but is 5-10 times cheaper, portable, and does not require calibration.


The Otus Tracker and the RCbenchmark tracking lab have the following characteristics at launch:


  • Sub-millimeter accuracy tracking

  • 250 Hz refresh rate

  • Very low latency (<5 ms)

  • 5 m x 5 m x 5 m tracking area

  • Plugins for C, C++, ROS, Matlab, LabView and Python. You can also code your own plugins in other languages that support UDP communication.

  • Control code examples (including the code for the demo in the launch video)

Controlling a drone is hard. You need infrastructure to make it work. We hope that with the Otus Tracker, software, and examples we provide, we are significantly lowering the financial and technical barrier needed to develop and do research with UAVs, whether it is in SLAM, artificial intelligence, control, or swarm. We are planning to add to our documentation to help new researchers get started with UAV development.



The Otus tracker is developed by the same team that worked on RCBenchmark’s motor testing tools: the Series 1580 (5 kgf) and the upcoming Series 1780 (25 kgf). Our dynamometers are used by hundreds of hobbyists, businesses and universities worldwide. I think we have quite a unique position in the UAV industry, as we have worked with many of the important players. Based on their feedback and the fact that measuring the position and orientation of a drone was one of our biggest problems when we developed UAVs (the other problem being measurement of thrust and motor efficiency), we decided to develop the Otus Tracker.

The tracker is shipping now! Please let me know if you have questions in the comments, or contact our team at


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