I want to share my experience of building airframes. I made a lot of these and still I think there are things optimize and improve. My point is, if you want to get into this sort of thing, let this be an inspiration of what is possible.
Also check out    / iforce2d   dude makes bit more involved build vids, they were very helpful.

Now you may say, that hardware stores don't usually stock carbor fiber composites... That's correct. I don't think I would be able to find any replacement for that, but for lighter planes you can use wooden reinforcement too, it's just no good for rough handling of course. Also that is not quite point of this video.

Technical stuff:
Using 2830 1100KV motor, 8x6 prop
Efficiency of this plane is 1.12W / kg*km*h^1

With smaller wing, efficiency was 1.34W / kg*km*h^1
Now I am thinking, that having canopy could push this under 1W per weird unit, that would be quite nice, but still it wouldn't be too amazing.
Perhaps 1300KV motor can improve this even bit more...

Consider, that with 76Wh battery and 0.8W / kg*km*h^1 this plane would fly nearly 100km. That is actually quite impressive. Hmmmmm I am thinking about getting 4G controll link now :)

Bit of back story:
So I was like 15 walking on the hill and I wondered how much power do you need to fly? Can you human powered plane that would support your weight?
Tl;dr: it depends a lot (mainly on weight and speed) you need like 510kW at least with ultraultralight airframe assuming no other energy inputs like thermals and reasonable speeds of ~80km/h. So no, not really

Now I live in quite busy airspace, so one day I saw a plane flying near small airfield and I decided to learn more about plane design and make my own and learn basics of flying and stuff. So I read some stuff, watched some videos, and started experimenting.

Designing planes is easy: as long as center of gravity is correct, even brick can fly. Technically flying is easy too. My mistake was to make 3 channel plane with rudder as sole yaw/roll control. This is OK so far as you make plane that is good. When you are experimenting, there is great chance of getting into spirals which are sometimes impossible to recover from, because, this is what happens when you use too much rudder. It may seem obvious to you as now it is to me, but it is not obvious at all I never heared anybody ever mention it. That could save me few months of "research"... Hell even now I would probably suck at proper coordinated flight.

The reason why I wanted to use rudder is that the construction is much easier that way. Making V tail with just 2 servos is really super quick, and I think it is even more durable. So it is really tempting to skip making ailerons alltoghether. You may think that you would be able to iterate and correct for design mistakes, but how if you can't fly for more than 30 seconds? In my case, during takeoffs torque from prop caused plane to roll, which fundamentally can not be trimmed with rudder, unless you are willing to fly bit sideways, that is... So this was very frustrating to figure out.

So to sum this up: Best is to start with own designs once you know how to fly, or just don't trust untested designs and don't rely on rudder to be able to correct for unoptimal design.