The 64 million dollar question... where to begin!
Experimenting might be a great starting point – that approach certainly served Dick VanGrunsven very well when he created the RV-1 out the fuselage of a Stits Playboy with his own aluminum cantilevered wing design - but bear in mind he was already a graduate engineer and pilot when he began his experimenting:
https://en.wikipedia.org/wiki/Richard_VanGrunsven
If like me, your budget and engineering abilities are more modest, the 2023 RAeS + Coventry University online course that DFN mentioned is probably as great a place as any to begin. Just be prepared to accept that you'll be banging your way around in the dark for a long time to come, as in any rabbit hole, and the field of aircraft design is riddled with the things.
Barry Taylor (Vice-Chair, RAeS General Aviation Specialist Group) recently posted the first two of four sessions of the
2023 RAeS / Coventry University Light Aircraft Design Teach-ins’: Evaluate Your own Aircraft in X-Plane on YouTube, links below.
A quick review of the course to date (Session 1+2):
It's got some way to go to reach the standard of MIT's online learning material, particularly the audio, but if you focus on the content – delivered by the enthusiastic, very knowledgeable and industry-served Dr Rashid Ali – I have to say as a life-long amateur wannabe designer, it's a super course and I do hope they don't stop at four sessions but build on it in future.
As it says on the tin, the course is all about 'Evaluating Your own Aircraft in X-Plane', so the focus is less on the how's and why's of the details of aircraft design and more about getting you up to speed with flight testing a design in X-Plane by flying in the presenter's own simple stick plane, leaving you able to experiment more fully in your own time. As a guided learn-thru-play approach, I love the concept of the course!
Session 1:
https://youtu.be/QK-y4aykSBg
Topics: General discussion, open X-Plane and learn some of the available X-Plane settings useful for flight testing purposes.
Session 2:
https://youtu.be/uBioARhJZpc
Topics: A few generalised rules of thumb for light aircraft design, Playing with Dr Ali's simple stick-plane.
Other Resources:
https://www.x-plane.com/
You will need a moderately powerful graphics card to run the latest versions of X-Plane. Alternatively consider downloading an older version. The system requirements for each available version are linked below for convenience:
https://www.x-plane.com/kb/x-plane-12-s ... uirements/
https://www.x-plane.com/kb/x-plane-11-s ... uirements/
https://www.x-plane.com/kb/x-plane-10-s ... uirements/
https://www.x-plane.com/kb/x-plane-9-sy ... uirements/
2023 Teach-In Files - unofficial repository:
https://www.dropbox.com/sh/zv9i89qowx3v ... VV1pa?dl=0
Including:
A list of the books recommended by Dr Ali in Session 1.
The demo stick plane designed by Dr Ali for Session 2.
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Extras - a few interesting articles I've collected over the years:
https://www.dropbox.com/sh/gdhmaqxg6ihy ... jgxea?dl=0
... like I mentioned, the rabbit holes are endless! Good luck staying focused if you ever want to fly what you design.