I understand that it would be easier with someone else's pre-built FC, but that's like telling Amelia Earhart to cross the Atlantic in her pane by putting it on a boat.
No... No it's not even close.
if we stick with the Amelia, its like telling her not to take her first long range flight on an airplane engine she designed herself.
Using a prebuilt FC just gives you a base line to compare your solution against. Since you will 100% be reinventing solutions to solved problems, it's worth to at least know what a reference solution should preform like.
Hard to design a road worth car, if you have never driven a road worth car, you dig?
You could still develop a wifi control solution to control a pixhawk or other flight controller.
Meanwhile, personal experience tells me that Wifi is not an outright limitation here.
Not saying its an outright limitation. Saying it's not optimal and has some p bad issues as is since it is optimized for a different use case.
The are many well documented RC over WIFI/FPV over wifi projects and all come to the same conclusion, latency is no issue for rc, somewhat of an issue for FPV, and range is an issue with stock WiFi stacks as soon as you start pushing more than a few hundred meters.
For that matter, you know that Parrot AR.Drone that was (is?) so popular recently in the consumer market? That thing runs on a computer that's almost identical to a Pi (in terms of its ARM processor, 1GB ram, and Linux OS), it relays both RC and FPV over mere mortal Wifi, and it's stable enough to sell like hotcakes. Obviously that's a different animal from the aeronautical perspective, but the use case is well tested for realtime RC and FPV via IP, via 2.4ghz Wifi.
And the delay is quite siginificant for more than just puttering around at a slow pace.
Also, look at the range on the parrot AR, 200 feet. No where near what you are trying to reach.
These projects are not really that comparable in end goals if you look deeper than the surface of what protocols are used.
I've done pretty extensive testing of the latency, and as far as I've been able to measure, it's just under 200ms.
yeah that's p bad. I would not risk my aircraft with that kind of delay unless it was fully autonomous. At that point it makes recovery via FPV very difficult any way though.
My streaming video solution is based on these guys' post, if you want to learn more.
I have come across that project before, most FPV feeds however are 60FPS interlaced, so it will look quite choppy in comparison.
I've seen plenty of YouTube videos of people operating their FPV equipment at 1200mhz, which seems to work great for them, but I'm just saying I'd mildly prefer a lower frequency where possible, and I've also seen people using (approx.) 900mhz FPV equipment.
But if you are running 2.4 for control, it's unsafe to run a lower freq for FPV since you could easily out fly your control range with no visual warning.
Also, having built dozens of UHF, VHF, and HF antennas, I'm confident that it would be very easy to significantly outperform a $15 dipole with some wire, a measuring tape, and a soldering iron. (Having an antenna analyzer is also very helpful.)
Unlikely to out preform it, but since you have an analyzer you can at least get it equivalent. All the VAS antennas are tested/tuned before shipping.
OK, about the long-distance thing: I also really only want to fly up to about 1000-1200 meters distant from the Wi-Fi access point.
Good luck with that, here is someone who has done a lot of the heavy lifting with a similar project to give you an idea.
https://befinitiv.wordpress.com/
I regularly use the access point (Picostation M2) at >1200m out with my cell phone, let alone a decent Wi-Fi antenna.
And what does a speed test and drop packet test look like at this range? You start to have a lot of multipathing and end up with re-transmissions or lost packets.
If you want to know the practical details, I live in a 100 acre farm and at least before I have a lot of experience with the equipment for this experiment, I would keep my flight path over my own land, with maybe a few corners over the surrounding forest service land.
Why not go UHF for control then? Seems like on less than a watt and a DIY antenna you should cover that area with minimal issues.
My friend, who lives a mile and a half away, is connecting at 15mbps with consumer equipment. That's massively overkill for a ~800kbps video feed.
Is that bi directional? Again quality of link, not just total packets down stream is important.
OK, so again, I appreciate the time you spent to look into this more carefully. But I still have not actually identified an insurmountable challenge here,
I didn't say there is one, just that you are more likely to find success simplifying version 1 of your project then growing it in iterations.
If there are other details that it would be important for me to know based on the assumption that the purpose of the experiment is not to fly a remote controlled airplane, but to let a Pi fly a remote-controlled airplane, I would be very pleased to hear about them.
It seems like in your mind, the project is "use a pi as a FC and wifi for everything." Good luck.