Interesting video if you like planes/flying on the F22 flight control.
Nice, I'll check this out..
cheers for link, this has pleased my inner geek
The guy is so laid back about flying, being a test pilot, combat missions.
What I would give to achieve that level of calm control!
Was about to watch, but over an hour!
Is the basics that the F22 is inherently unstable (as are most fighters) and thus flown by wire via computer, rather than a Cesna, which is inherently stable?
The F22 is a lovely aircraft though, probably the last of its kind.
It is an amazing piece of technology and I love it for that alone but...
...it is also a testament to how much we feel the need to kill other people and that makes me sad :o(
But only bad people to be fair
The F22 is a lovely aircraft though, probably the last of its kind.
Yes.
Although, J-20, Su-57, F-35, tick most 5th gen boxes, but I don't know that any are as all round impressive as a standalone aircraft. The F22 is quite spectacular.
That was great. Main takeaway for me was just how much he is willing to trust the software to do stuff, he just expects it to work so he can focus on something different although there was a recognition of knowing what 'mode' the software was in so he knows how to then expect the controls to react to what he does.
@leffeboy yeah just after showing one going in after a bug was discovered in the software - whilst landing...
Good vid tho, thanks.
@leffeboy yeah just after showing one going in after a bug was discovered in the software - whilst landing (or during a touch and go to be pedantic)...
Good vid tho, thanks.
<edit> That 'mode' thing is what I think is called 'law' over here. I have a chum who was a test pilot in the RAF then BAE for Typhoon. He talks of 'control law' which is how it's implemented in the Typhoon a 4th gen fighter.
Software on aircraft is engineered with the same rigour as all the hardware. Its a very different and more reliable animal to the stuff that makes your mobile phone tick. No more or less trustworthy than the airframe itself.
It's hard to go on an airplane now and not be in a situation where software is controlling some critical piece of kit with life threatening consequences for errors.
Software on aircraft is engineered with the same rigour as all the hardware. Its a very different and more reliable animal to the stuff that makes your mobile phone tick. No more or less trustworthy than the airframe itself.
Tell that to Boeing with their 737 MAX ..
737max was a failure at aircraft system design level. No issue with the software, it would be a mistake to think so.
Software's all to DO178C or equivalent in the US nowadays, lots of work, and i mean lots of work going into it, there's so many new and improved systems onboard these days, likes of the F35B with the auto-eject feature, to the US aircraft using the Auto-GCAS, which basically has the aircraft fly itself in the event of an incapacitated pilot.
The F22 is a beauty, and at the top of the tree in terms of the survivability onion, but as with all things, it's just a cat and mouse between the aircraft and the air defence systems, you never know what breakthrough will come next that could make expensive kit a bit pointless!
Clever how it shifts fuel around to keep the centre of gravity after it drops a bomb or fires a missile and knows how much to shift with each different type of weapon.
Tell that to Boeing with their 737 MAX
If you watched all the video, you’ll see that a bug in the original software led to an instability and the F22 crashed. Pilot was OK. Go around with afterburners meant the system couldn’t decide which flight control was needed and it oscillates and falls to the ground.
Cause was PIO, excess gains on surface movements with gear up + afterburner, software functioned as designed, again to attribute the error to software kind of missed the point, the software per se is implementing the aircraft system requirements and very often the fault is way higher up the design tree than when it starts being actual software, as it was here. I'm surprised the lecture stated that it was software error, although that's quite a broad catch-all term and quite easy to throw out. Basically, the airframe designer is calling out how far the surfaces need to move during the various flight modes; the software makes that happen, but the error was made before software got involved.
Detail
http://pages.erau.edu/~rogers/as309/Videos/YF-22%20Crash.htm
The SAAB Gripen had similar prototype issues with PIO; albeit at landing. Similar low speed and thus high gain (surface movement) situation.
