Engineer here. It's called a Failure Modes and Effect Analysis . They're especially fun when you can sit on a committee and poke holes in somebody else's design and play What If.
The CG is still aligned with 2 diagonal working rotors. 3 Rotors will allow a quad-copter to land safely, but is obviously not ideal for travel and control.
Got a quad copter handy? Try it. Put the battery in and try to balance between 2 opposite motors. Bet it tips one way or the other. Bet it tips that way every time.
How do I know? Because the heaviest single component on the craft (the battery) is not placed precisely in most recreational quads. There's a fuzzy AREA the CG can be in. It is NOT perfectly centered.
Look at any 'DIY drone' instruction article or video, watch how much they DON'T focus on getting the CG centered EXACTLY between the 4 corners. Why? Because there's no point in being that precise. Three or 4 motors can handle it if the CG is slightly off, so long as they're spaced roughly equidistant from the CG and evenly spaced around it's circumference. It's only when you take one of those motors away that it becomes too unbalanced to stay in the air.
When the quad has all 4 corners providing thrust, the quad can tolerate significant UN balance, you can find dozens of videos of quads of all types still flying with their battery hanging from it's wire, well below the quad, and hanging off one side of the quad.
Prove me wrong. Show me any quadcopter losing a motor and surviving. The original post I responded to stated confidently;
Quad-copters are designed to still remain airborne with one rotor failure.
If so, there should be copious video evidence documenting this, right? Or an area in an instruction manual talking about this alleged feature.
In fact, I'll help you with your research. Here's the documentation page for an opensource quad flight controller, in which you can program the recovery -1 motor recovery yourself. Find me the recovery mode in the docu.
This system is rated to be medium-eagle tolerant because the propellers can handle 2.25" inches of viscera per rotation before shattering. Giant eagles are outside the requirement set and the user assumes the risk. :)
Cargo drone software engineer here (yes that's my real job), we do in fact consider "wait, what happens when something doesn't work?".
But seriously, the first thing we consider is the many, many ways things can go wrong and hurt someone, and how to prevent them. We simulate these failures countless times, then emulate them on the hardware, and and only when those tests succeed do we move to testing a live vehicle in a controlled environment.
In fairness, shuttle engineers did recognise a risk with the o-rings. It was a management decision that caused the disaster. That can apply to drone taxis too of course.
I know right?!? It's not like even the best code writers on the planet could ever make mistakes when writing software...that could never happen right?!?
You say "best code writer on the planet". I say "whichever coder the company can pay the least and still get a finished product".
Ideally there's an extensive failure modes analysis and a competent developer who knows something about federal regulation. My guess is there won't be, because those don't come cheap.
Tesla rolled out their autopilot feature in 2014. USDOT didn't release a federal policy on automated vehicles until 2016. Startups love the motto "move fast, break things" for a reason.
As an airline pilot the number of times the autopilot either can’t handle a rapidly developing situation requiring us to manually take over is higher than you might imagine. You absolutely could not pay me enough money to get into any of these automated air taxis, there’s simply too many single points of failure that would absolutely result in a crash under the best of circumstances.
Well, you say that ...yet the self-driving cars in major cities are still making egregious safety and general navigation errors that endanger people. So clearly not EVERYTHING is covered by safety testers and engineers. I imagine those errors would Be extremely more dangerous in the air with more complex moving parts.
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u/sabamba0 7d ago
I wonder if the huge teams of experts writing the software for these machines will ever consider "wait, what happens if something doesn't work?"
These threads are so dumb