(For learning purposes) Is it possible to make a flappy bird game using GDevelop?
Obviously yes. 
Flappy Bird is an easy and cheap game to do, it is hard to think about a game engine that can’t make a Flappy Bird style game 
Searching for “Flappy Bird” here in the forum I found this post in the French section, a Flappy Bird example + sources, a nice work (the files are still online):
[url]Flappy Bird + Source - #7 by loustak]
How does it work? When I click ‘preview’ nothing happens.
It’s a native project, when you do a preview the scene editor (should) becomes the game scene, try to start a preview and press the spacebar to make the bird flap. I don’t think so, but since you have problems with native preview again… maybe there is something wrong with your GD installation 
Remember that you can change the platform, so you can make it a Web project and preview it in the browser, I’ve already explained you how to do it
The spacebar works. Also how would you export the game, since GDevelop does not allow you to do that.
Just click on “Compile as executable” (just under the export button) and the native game will get exported.
I did. But how do you export to android?
You can’t with native games. But, you can recreate a Flappy Bird on the HTML5 platform.
Ok so how would you do that? Also the flap in this flappy bird game is not very good.
You can (and should) modify the code (give credits), there can be new GD features to make the code working and looking better. By the way, I think you’ll not find any full project here (+ sources) to sell a cheap copy
I just want to see more current tutorials.
Excuse me, I have connected your posts (hit game + make money with GD + good Flappy Bird working example) 
Again, I’m sorry, please, accept this gif as a way of apology, it shows how to modify the target platform or preview:
Hi, i want to study this flappy bird example but code is not online anymore.
Can you tell me please where to find sources?
Thanks in advance