Usually planes are able to fly when air moves across the wings which generates lift. But how do fighter jets able to maintain lift while performing aerobatic maneuvers?
In: 342
Excessive thrust, coupled with thrust vectoring can create static stability. Thrust if the fire part coming out of the butt hole of the fighter plane. Vectoring is shooting your diarrhea in different directions while pooping a continuous stream of thrust. If you’re sliding into First, and your bowels are ’bout to burst, Thrust Vectoirng…
I assume you’re referring to the very slow flight regimes where the jet is still able to maneuver.
Simply put: very powerful engines, large flight control surfaces, and a really smart computer moving those surfaces.
Some jets have thrust vectoring—fancy exhaust nozzles that can point the engine thrust to enhance control/maneuverability.
There eventually comes a point where no speed = no flight. I used to fly the F/A-18E/F, and that jet flew slowly with absolute grace…but once you dipped to around 100kts, she would start to settle and the computer wouldn’t allow you to do much at all. In the double digits, gravity really took over.
Earlier in my career, my boss and I would fly into Edwards AFB in his 4 seater plane, I believe it was a piper cherokee. We would land on a secondary runway that was unmanned, but we would have to talk to the main tower to land and take off. A lot of times we would have to wait for the military planes to take off and sometimes they would just go straight up. I would look over and see my boss drooling at the power. He found out what you had to request to go straight up, I believe it’s a request for unlimited takeoff or something like that. I kept joking with him that he should request an unlimited takeoff in his Piper! One slow day he did, guys in the tower had a good laugh.
Every so often, a truly interesting ELI5 comes up, like this one. Liking all the responses!
Engines that produce more thrust than the aircraft weighs. A brick will fly if you pour on enough power.
At some point it’s utilizing downwash more than proper aerodynamic lift at high angles of attack. That of course provides less lift than the typical aerodynamic effect, but the power to weight ratio overcomes the rest while it keeps flying through a stalled condition. They get away with it because the engines are powerful enough to do so.
The other time you see this is with really really light small aircraft. RC model “foamy fliers” often have flat slabs for wings and may take advantage of downwash more than aerodynamics. Again over half the time it may be stalled, but it doesn’t matter for something like 3D flying. And again the power to weight ratio means the motor is able to pull it along regardless. It’s not exactly an efficient mode of flight though, so for something like gliders you’d still see a proper airfoil at that scale.
Depends on the maneuver. Sometimes, they still move fast enough to generate lift. Other times… they sail through the air like a rock.
Turns out that if you throw a rock at near Mach 1 it can fly pretty far. When they end the maneuver they gain speed again (either from falling or using the engine) and turn from a rock back into a plane.
You will often hear “energy” mentioned – both speed and altitude are energy in different forms (kinetic and potential) and you can trade them against each other. If you’re fast, you can pull up, and you’ll slow down but gain altitude. If you’re high up, you can go down, and you’ll accelerate. (This can actually be a problem if you need to descend a big plane quicky, e.g. if an airliner loses cabin pressure – you can’t go down without gaining speed, and you can only get rid of so much with flaps, speedbrakes, etc.)
Military planes often also have insanely powerful engines, to the point where they can *accelerate while going straight up*. But by managing energy correctly, that’s not needed for aerobatics. Glider pilots *love* loopings.
Some aerobatics can be flown even with big planes. For example, a good pilot can [fly a barrel roll with a 707](https://simpleflying.com/boeing-707-barrel-roll-seattle/), or you can take a [KC-135](https://en.wikipedia.org/wiki/Boeing_KC-135_Stratotanker), pull it up in a 45 degree angle, and then let it basically freefall like the above mentioned rock for a mile or so (first continuing upwards before falling down), the passengers [might get a bit sick though.](https://en.wikipedia.org/wiki/Reduced-gravity_aircraft)
The truth?
Nobody knows why planes are flying!
I’ll ELY15
I’m not an aerospace expert, but as a physicist (and teacher), my first thought is “what are you asking?” The term ‘lift’ likely has a specific meaning in the field which likely is subtly different from what that means to me intuitively, which may be yet more different from what you are asking.
To me, ‘lift’ implies a situation where the net force on the object points up(or at least ‘more up than down’) which causes an upward acceleration. In this case, the answer to how they “maintain lift” would be that dont.
If what you’re asking is more like how I would say “maintain altitude,” ie not fall out of the sky, the answer is a mix of that they actually kind of do (hey may fall a little bit but the amount fallen in time it takes to do the maneuver is small and safe) and what many others have explained: that they don’t fall (much) because of the immense forward thrust and consequent immense drag.
disclaimer: This is not ELI5, but I hope someone finds it helpful 🙂
Latest Answers