The coanda effect:
I've always been struck by the magnus effect. Yes, that effect that causes soccer or tennis balls to change direction in the middle of the air. But how does it work?
It happens when an object travels through the air spinning, that causes that in the part of the body that goes against the wind a high pressure is generated, and in the part that goes in the direction of the wind the air sticks to the surface and comes out thrown in another direction, that creates lift.
Here a video explaining this effect on sports balls:
This effect causes lift, and also a lot of drag. That makes it an inefficient aerodynamic profile so in large scale aircraft has never been done, there have been several attempts but none very useful.
What has been done are boats with magnus effect "sails" that help a little to the engine and save fuel.
Here's my experiment, a plane with super small magnus wings. (22cm each, the biggest thing that fits in my 3d printer)
I designed the mechanical part in fusion360 to then be able to print it in 3D, the wings too, which as you will see later is not a good idea. The rest of the plane is wood and foam, botched job style, with hot glue, glue strings, and glue on all sides.
To move the rollers it has a 2300kv drone motor and to propel itself a cheap 750kv motor with 1045 propeller. and I use a 9 grams blue servo to turn the rudder. Come on, it's essentially a 2-channel airplane, although I use another one to be able to turn on the rollers.
The first "flight" here:
As you can see, it is not a total failure, it seems to generate lift and seems stable, so I continued with the project.
Rc pilot, build fly crash rebuild
After reprint the wing that broke I tested it again and this time with a battery of 4s instead of 3s.
Now it flies, and very well, you can see in the video the emotion of the moment, it seemed to fly by magic.
As each landing broke my 3d printed wings, in the end I used two ketchup boats that coincidentally had the same dimensions as the original wings, the bad thing is that in the next flight I loose one and the plane was destroyed.
This is the video resuming the whole project here you can see how it flies:
After seeing that it flies, the concept has seemed very interesting, now I'm working on another larger model that will be different, I will use savonius turbine profiles on the wings to turn with the wind and do not need the drone motor to turn, apart from making it bigger and with fuselage.
I hope you liked the project, In the next post I'll tell you how it is that this plane is so stable without horizontal stabilizers and without dihedral.