4 ms·

How does an F-14 and others of the same vintage fly? Isn't that all hydraulic servos? Not trying to be an ass, just curious.

colechristensen 7y ago
For the F-14 that doesn't seem to be the case https://wikipedia.org/wiki/Central_Air_Data_Computer https://wikipedia.org/wiki/Central_Air_Data_Computer They had flight computers that did ultimately actuate the control surfaces.
NegativeLatency 7y ago
The last couple generations of fighters have moved away from airframes that are passively stable (imagine a car or something that requires no control to remain upright). Newer designs are only stable when their attitude is constantly monitored and adjusted by control software. (To continue the metaphor, imagine a Segway or a pogo stick, more agile than a car) The benefit you get from giving up passive stability is increased maneuverability in the case of fighters.
- quickthrower2 7y ago
  Nice analogies! Thanks.
apta 7y ago
The F-14 and fighters of similar era have nothing on the F-16 and F-18 in terms of maneuverability.
alkonaut 7y ago
What actually moves the surfaces hasn't changed radically. It's a question of whether there is a computer that controls the servos, or just a stick that does it. A stable plane can fly with a stick controlling surfaces. Just like an ordinary cessna does. An unstable plane has to fly by wire, where a person moves a stick to ask the computer to tell the computer to roll the plane, and the computers calculate the necessary control surface movements and tells the servos to move. More importantly, the computer tells the servos to move the surfaces many times per second just to keep the plane straight, because it's not stable. Looking at a modern jet fighter from the outside it's hard to see just how unstable in they are. You can get some idea by looking at where the weight is (in an empty plane) vs where the surfaces are. They are built like a dart, but with the wing in the front and the weight in the back. Look at where the engine (the thing that weighs a lot in an empty fighter built from composites) starts in this cutaway: right under the tail! It's a backwards dart. https://www.slideshare.net/SaabGroup/saab-gripen-3d-cutaway https://www.slideshare.net/SaabGroup/saab-gripen-3d-cutaway

colechristensen 7y ago

For the F-14 that doesn't seem to be the case https://wikipedia.org/wiki/Central_Air_Data_Computer https://wikipedia.org/wiki/Central_Air_Data_Computer They had flight computers that did ultimately actuate the control surfaces.

NegativeLatency 7y ago

The last couple generations of fighters have moved away from airframes that are passively stable (imagine a car or something that requires no control to remain upright). Newer designs are only stable when their attitude is constantly monitored and adjusted by control software. (To continue the metaphor, imagine a Segway or a pogo stick, more agile than a car) The benefit you get from giving up passive stability is increased maneuverability in the case of fighters.

quickthrower2 7y ago
Nice analogies! Thanks.

apta 7y ago

The F-14 and fighters of similar era have nothing on the F-16 and F-18 in terms of maneuverability.

alkonaut 7y ago

What actually moves the surfaces hasn't changed radically. It's a question of whether there is a computer that controls the servos, or just a stick that does it. A stable plane can fly with a stick controlling surfaces. Just like an ordinary cessna does. An unstable plane has to fly by wire, where a person moves a stick to ask the computer to tell the computer to roll the plane, and the computers calculate the necessary control surface movements and tells the servos to move. More importantly, the computer tells the servos to move the surfaces many times per second just to keep the plane straight, because it's not stable. Looking at a modern jet fighter from the outside it's hard to see just how unstable in they are. You can get some idea by looking at where the weight is (in an empty plane) vs where the surfaces are. They are built like a dart, but with the wing in the front and the weight in the back. Look at where the engine (the thing that weighs a lot in an empty fighter built from composites) starts in this cutaway: right under the tail! It's a backwards dart. https://www.slideshare.net/SaabGroup/saab-gripen-3d-cutaway https://www.slideshare.net/SaabGroup/saab-gripen-3d-cutaway