Forum: General F-22A Raptor forum

At about 23 minutes in the 2010 F-22 Demonstration Team pilot starts talking about his performance. During the overview of the practice he mentions a few of the corrections and inferences the computer will make for the pilot while he is flying. For instance, to do the flat spins all he has to do is engage full rudder and pull the stick all the way back and the computer will nudge the elevons to get it to spin automatically.

Another thing that was mentioned was that after coming out of a roll I believe if the pilot just returns the controls to neutral the ECS will automatically return the jet to straight and level flight.

When describing his experiences with backwards flight in the F-22, he speaks as if the flight computer is some sentient being. "The flight control computer is trying to put the nose back down because it says 'hey you're flying backwards here you probably don't want to be flying the jet backwards' but what I'm doing is I'm actively telling it no I do want my nose up there"

I was amazed to learn these things. Are there any of capabilities of this sort that are not classified? How about videos of interviews with pilots?

You learn something new every day.

www.youtube.com/watch?v=m5Z_Eg5QFbM

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These aircraft no longer have positive or neutral stability. The computer is actually flying the aircraft; it turns the pilot's control 'recommendations' into control surface movements. I'm sure most of the Raptor's FCS specifics are OPSEC ground, but there is probably a lot of crossover with commercial or other unclassified systems.

southernphantom wrote:

These aircraft no longer have positive or neutral stability. The computer is actually flying the aircraft; it turns the pilot's control 'recommendations' into control surface movements. I'm sure most of the Raptor's FCS specifics are OPSEC ground, but there is probably a lot of crossover with commercial or other unclassified systems.

Dang. Some day in the far off future I hope to see much of these classified abilities made public. The next best thing would be to just join the AF and hope you land a spot on one of these crews. Hehe. Crazy Pilot

I've always wondered f there is a "guru" who can claim,credit for,developing the flight control laws for the F-22. I seem to recall an interview with Jon Beeseley who mentioned that it was the same,"guy" who wrote the flight control,logic for the,F-35. How likely is it tha5 a single person can claim,credit?..,some,super nerd perhaps?

southernphantom wrote:

These aircraft no longer have positive or neutral stability. The computer is actually flying the aircraft; it turns the pilot's control 'recommendations' into control surface movements. I'm sure most of the Raptor's FCS specifics are OPSEC ground, but there is probably a lot of crossover with commercial or other unclassified systems.

Absolutely not. As has been the case since fly by wire systems came about...well in the words of an old General Dynamics employee...The computer does not fly the plane, the pilot does. The computer is there to make the plane do exactly what the pilot tells it to do, but the pilot does all the instruction.

In the Raptor, the computer points the nose exactly where the pilot tells it too...its not a recommendation that the computer can decide against...it just does it.

popcorn wrote:

I've always wondered f there is a "guru" who can claim,credit for,developing the flight control laws for the F-22. I seem to recall an interview with Jon Beeseley who mentioned that it was the same,"guy" who wrote the flight control,logic for the,F-35. How likely is it tha5 a single person can claim,credit?..,some,super nerd perhaps?

Jon was misquoted (quite badly) in that article. What he actually said was that the guy who developed the control laws for the high angle-of-attack regime for the F-22 was doing the same part of the design for the F-35. Obviously, it takes a team to design (and validate) a system as large and complex as the flight control law for a modern-day jet fighter.

checksixx wrote:

...The computer does not fly the plane, the pilot does. The computer is there to make the plane do exactly what the pilot tells it to do, but the pilot does all the instruction.
In the Raptor, the computer points the nose exactly where the pilot tells it too...its not a recommendation that the computer can decide against...it just does it.

That's essentially true, but the list of exceptions and caveats is extensive. The control law applies tons of limitations and restrictions to what the pilot may be asking for at any given time. For example, limits are applied to allowable G, AOA, sideslip, and roll rate based on flight condition, aircraft weight/configuration, etc. These limits may be in place to prevent departures from controlled flight, structural loads exceedences, or other considerations. These limits are usually designed to allow some response (aircraft moves in the direction commanded, albeit way more slowly than the pilot might want). However, there may be times when a pilot input is completely ignored. Classic example - pilot decides to jam in full left pedal during a full stick, high-rate right roll. The control law may recognize that the resulting combination of roll rate and (requested) sideslip would result in a departure (or perhaps a structural loads exceedance) and completely ignore the pilot's input.
And then there is always the case of what happens during departed flight. Even on an F-16, any time the AOA limiter has been defeated the yaw rate limiter logic kicks on, and essentially all the pilot's roll stick and pedal inputs are ignored. The recovery logic for more-recent jets is similar - ignoring pilot inputs to self-recover the aircraft.

Forum: General F-22A Raptor forum

Capabilities of F-22 Avionics