What is fit?

[callador]

In addition to the plane not being propelled forward, the reason a plane flies is the difference in pressure above and below a wing. Without air flowing around the wing, you get no pressure differential, resulting in no flight.

This is not really true. They teach this in basic PPL aerodynamics, but Bernoulli's principle is not the main reason why an airplane flies. On a standard C172 there is a pressure differential for sure, since the wing camber is different from the top and bottom, but on symmetrical wings this is less of the case. Also, if you fly a 172 inverted, it will still fly, but your AOA is much different to produce the same state of flight.

Anyways, the main reason why an airplane flies is Newton's third law. Even on something as small as a Cessna, over 13ft of air above the wing is being thrown down as the wing plows through the air. This downwash creates an opposite reaction which gives you lift. This is also why the treadmill doesn't work. Think of a wing like an oar in the water. The wing has to plow through the air to make lift. The wheels turning woudn't do anything. Even w/o an engine the airplane still produces lift, just not enough to counteract gravity!!! Well, gliders can cheat this, but you get the idea.

Again, this is just late night ramblings. There is a lot more to it if you guys are interested... in another forum for sure. Check Jetcareers.com... lots of technical stuff there to see. I just had to comment on the Bernoulli thing, since I got bashed by the FSDO on my CFI checkride for that.

Take care.

 

[MASShole]

So, thanks for the long-winded agreement?

 

[TrainingAdict]

Then how do some jet planes lift off without going down a runway?

 

[MASShole]

Magic.

 

[bacon]

I was kinda hoping you'd chime in cellador.

Not that I understood half of what you said, but it's nice to see that after all these years I still can't understand a single verb of pilotspeak.

 

[bacon]

Then how do some jet planes lift off without going down a runway?

Thrust applied in odd directions. Like when you're in a small shower with a fat woman.

 

[TrainingAdict]

I've embarassingly done that before.

Didn't work out too well.

 

[bacon]

I've embarassingly done that before.

Didn't work out too well.

The key is to grab them like you would a duffel bag. They're pliable. Scratch, claw, bite if you have to, but don't fall down. Don't ever fall down.

 

[callador]

Then how do some jet planes lift off without going down a runway?

Wing lift. Sorry if I was rambling. So you throw the power levers forward and the thrust starts pushing you down the runway. As you start moving the wings start to produce lift. At first it isn't enough to get you off the runway, but as you get faster the wing produces more lift. This has to do with wing's angle of incidence. So even though the nose is still parallel to the ground, the wing has a slight + angle of attack to produce lift. You may not see it, especially on faster jets, but its there.

There are 2 ways to produce more lift. Go faster... we saw that in my last post. More air over the wing means more lift. The other is to change the wings angle of attack to the relative wind. If you increase the angle you will throw more air which again produces more lift. Basically this is pitch. The elevator controls this (which is typically set on the horizontal stabilizer). The horizontal stabilizer is like an upside down wing as well. No need to go into balancing the forces, but basically if you pitch the nose up you will get more lift, or if you increase power/speed. So even if your engines failed, its not like you just fall out of the sky, the wing still produces lift, but not enough, so you start to glide. Now big airplanes glide for shit, so good luck. But small ones can land pretty well in fields etc.

 

[callador]

So, thanks for the long-winded agreement?

Actually not really agreeing. It does happen on some airplanes, but that force alone does not produce lift. Some planes hardly fall into bernoulli's principle, but they fly because of newton's third law. So basically it can aid it, but isn't the main reason why an airplane flies.

I hope that clears it up. End 16 hour duty days and maybe we will be more coherent!!!

 

[bacon]

Wing lift. Sorry if I was rambling. So you throw the power levers forward and the thrust starts pushing you down the runway. As you start moving the wings start to produce lift. At first it isn't enough to get you off the runway, but as you get faster the wing produces more lift. This has to do with wing's angle of incidence. So even though the nose is still parallel to the ground, the wing has a slight + angle of attack to produce lift. You may not see it, especially on faster jets, but its there.

There are 2 ways to produce more lift. Go faster... we saw that in my last post. More air over the wing means more lift. The other is to change the wings angle of attack to the relative wind. If you increase the angle you will throw more air which again produces more lift. Basically this is pitch. The elevator controls this (which is typically set on the horizontal stabilizer). The horizontal stabilizer is like an upside down wing as well. No need to go into balancing the forces, but basically if you pitch the nose up you will get more lift, or if you increase power/speed. So even if your engines failed, its not like you just fall out of the sky, the wing still produces lift, but not enough, so you start to glide. Now big airplanes glide for shit, so good luck. But small ones can land pretty well in fields etc.

Don't forget thrust augmentation.

 

[TrainingAdict]

The key is to grab them like you would a duffel bag. They're pliable. Scratch, claw, bite if you have to, but don't fall down. Don't ever fall down.

I tried doing her from behind and wasn't successful cuz of all the fat.

I didn't even bother lifting her up like a duffel bag because back then my bicepz could only curl 35/arm and deadlift was at 135.

The lesson here is to train your biceps well.

 

[bacon]

Actually not really agreeing. It does happen on some airplanes, but that force alone does not produce lift. Some planes hardly fall into bernoulli's principle, but they fly because of newton's third law. So basically it can aid it, but isn't the main reason why an airplane flies.

I hope that clears it up. End 16 hour duty days and maybe we will be more coherent!!!

The F-4 proved that with enough thrust, even a brick can fly.

 

[joshetc]

for me fit is being able to bang my girl for longer than 15 minutes without passing out from over-exertion

edit: by girl I mean my left hand

edit2: and by 15 minutes I mean 3 minutes

 

[MatterOverMind]

So, thanks for the long-winded agreement?

The plane WILL take off.

 

[SocraticMethod]

So, will the plane take off?

...

 

[bacon]

The plane WILL take off.

MOM believes it will fly. He believes it will touch this guy. He thinks about him every night and day. He spreads his legs and noms away.

I may have botched the lyrics but the moral is... don't piss on adolescents.

 

[callador]

The F-4 proved that with enough thrust, even a brick can fly.

Yep. Even a regular F16 can prove this too, or the nasa space shuttle. They can be in conditions where there is no lift because the wing is either stalled or not getting lift. They have enough thrust to counter gravity. Normal commercial jets don't have a thrust value anywhere near that though. But under normal flight conditions, F16 like their wings too!

***Bernoulli's doesn't deal with thrust, it is just talking about a pressure difference above or below the wing... which only happens when the wing is producing lift.

 

[bacon]

The F-16? You mean the Lawn Dart???

 

[callador]

The F-16? You mean the Lawn Dart???

Heh, my old boss use to fly those. Apparently the F4, F5's were the real death machines!!! They still use the old F4 design on the T38's. When I was working out of KGTR (right next to KCBM, Columbus AFB) they had a bad accident that killed the student and instructor. My old boss told me all about it. They are fly by wire and there is just some servo that can accuate.. it has happened in the past but not often enough for the air force to fix it. So on take-off it just violently rolled over and pasted both of them on the runway. Sad.

I haven't flown anything completely fly by wire... I know the Airbus is like that too. It is like playing a flight sim.