The Coanda Effect Test Bench

A part of the GFS-UAV project
Created on April 2, 2006 - JLN Labs - April 4, 2006
Toutes les informations et schémas sont publiés gratuitement ( opensource ) et sont destinés à un usage personnel et non commercial
All informations and diagrams are published freely (opensource) and are intended for a private use and a non commercial use.

To understand and study deeply the Coanda Effect applied to the construction of an efficient UAV, I have built a dedicated Coanda Effect Test Bench (CETB). With such an apparatus, I shall be able to test various shapes of hull and thus understand how to find the best curve...

The CETB uses a high power blower commonly used to blow the dead leaves in the garden. I have used a blower Handy Power HP1500S (1500W) which is able to provide up to 380 m3/h of air flow. I have added a wide plastic adapter (200x60 mm) and some flat pannels so as to get a laminar flow at the output.

The blower is powered with a 2 KVA voltage regulator which allows a fine tuning of the air flow.

The Coanda curved shape to be tested is connected at the CTEB output with an adhesive tape used as hinge.

The air flow is measured at the output of the CETB with a digital wind speed meter.


When the air flow reaches 10 m/s the curved shape lifts-off quickly due to the Coanda Effect.

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Click on the picture to download the video (3.8 Mb)

Some wool markers have been also added along the curved surface to visualize the air flow.

Below you will find the video of this test with the wool markers.

Click on the picture to download the video (4.8 Mb)

The upward trust has also been measured with a balance attached to the Coanda surface,
below you will find the datas test results.

Comments from Jean-Louis Naudin : With the Coanda Effect Test Bench (CETB), I am now able to optimize the efficiency of the curve of the hull for building an efficient UAV based on the Coanda effect. It will be easy to build various shapes of Coanda hull and compare their performances...

Click here to download the US Coanda Patent US 2,108,652 (pdf)
Click here to download the French Coanda Patent FR 796,843 (pdf)

For more informations, please contact Jean-Louis Naudin :

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