proof for how planes fly??

Does anyone know why planes fly? I counted 11 Theories of Flight and there doesn't seem to be any proof for any of these theories. Like a real experiment on a real aircraft using the scientific method?

All I get is equations (Navier-Stokes) when i ask an engineer or professor; which isn't what we're taught at flying school.

The official explanation of flight that pilots are taught is impossible and implausible. Even NASA thinks so (see "incorrect theories of flight?).

 

Navier-Stokes is what is tested by experiment. It's basically a combination of mass, momentum, and energy conservation.

Anything substituting for that is going to be wrong at some level.

If you're looking for the source of lift, it's circulation, but that's a special case of Navier-Stokes.

Besides, every pilot knows it's money that makes planes fly.

 

The problem is that navier-stokes is just an equation; is describes flight, it doesn't explain the physics.

 

Its FM.

And we're all magicians.

 

there's no "magic"

 

That's a truly artificial distinction.

It's conservation of mass, momentum and energy. That's not physics?

 

clearly, there is magic.

 

Total lift=Cl x p/2 (rho) x S x V2

Or in helicopters, we just say we beat the air into submission. How's that for physics?

 

so no one has any proof then?

 

Look up.

 

This diagram should be the primary illustration in every PPL ground school Theory of Flight class

 

Can you prove that the voices you hear in your headset came through the air?

 

sure you can do an experiment using the scientific method.

OK, it's now 13 theories for how planes fly if you include "magic" and "headset voices"

 

I dunno but I've been doing it (flying) for over 40 years. All I do is pull back to go up, down to go down, works good last long time.

Or you can just read this if you can stay awake:

 

The proof is that an engineer can use the equations to predict how an airplane will fly, and it will indeed fly as predicted.

 

I disagree vehemently!

I am certain that if one put that book in a wind tunnel, mounted with a modest positive angle of attack, and then crank 'er up, it will generate a measurable lifting force.

 

its money!

 

"Engineer", "equations", "predict"...Now we are doomed.

 

The scientific method you say. OK. Here's the theory. If I build this thing I theorize it will fly. Now for the experiment. It flys.

 

That.

Having said that, most of the popular "explanations" of how lift is generated fall somewhere between nonsense and crap. If the explanation invokes a curved surface on top and a flat surface on the bottom, then it is wrong.

The simple way to think about is is the simple fact that air is flowing off the trailing edge from both above and below the wing. And, given that air has viscosity, the flow streams end up flowing in the same direction at the same speed. Air is thus deflected downwards, and in accordance with Newton's laws, the airplane has to provide the reaction force. And, in accordance with Bernoulli's law (which can be derived from Newton's laws and a couple assumptions) you can calculate circulation and the necessary pressure differences that keep the airplane in the air. Now, there is a bit of a chicken and egg thing between the circulation and the pressure, but in the end, the math works.

Interestingly enough, the basic Bernoulli equation assumes no viscosity, but lift doesn't happen without viscosity. But, from the math perspective, that's about as simple as the equations get.

 

Until you've passed the PPL, it is whatever the FAA says regardless of how inaccurate or incomplete it is

 

That's an engineering method. The op specifically requested a scientific method.

 

The Scientific Method is to study what happens, make a theory that describes it, then test it. In this case, engineering skills are used in crafting a detailed theory. Running the test to confirm or reject the theory is the capstone of the Scientific Theory. A scrupulous scientist would then refine the theory with additional engineering calculations, refining the theory after each test. This is where aviation was from ~1901 through the 1950s. Therein much documentary video of these tests on YouTube, complete with brief summaries of the results.

 

Biggles--

Get yourself to Lower Alabama. I'll show you the Owners Manual for my plane, which describes how it is supposed to perform In the air. Then we will both get in the plane, I'll work the controls and you record your observations. When we land, we will compare the two. You decide if the plane flew according to the theories described in the book. Then we can both leave the airport with better educations.

 

Without money, planes don't fly. Simple enough....

 

Forget the theories. All of them. Forget about Bernoulli, forget about Newton. An aircraft in flight is supported by money. Trust me.

 

Your sense of humor is mia this morning.

 

Because I haven't had my Christmas Eve flight yet, despite having drunk my coffee and eaten breakfast. It's actually warm out, I may drive the convertible to the airport!

 

The scientific theory:
The weight of the paperwork has to be equal or higher, than the gross weight. Only then can an airplane fly.

 

I like "Fundamentals of Aerodynamics" by Anderson - current editions command textbook prices, but if you can sometimes find older editions (4th or earlier) for $10 or $20.

https://en.wikipedia.org/wiki/Scientific_method

Theory: airfoils generate lift because the top is curved, bottom is flat.

Hypothesis: airfoils with curved bottoms and flat tops won't generate lift.

Prediction: You can't fly upside down in a Citabria.

Observation: Oops.

Theory: Circulation

Hypothesis: calculate the pressure / velocity distributions

Prediction: You can fly upside down in a Citabria.

Observation: Flying upside down is fun.

 

Enjoy the day!

 

Out my way it's been snowing steadily for the past 24 hours and still coming down. When it finally stops I will have several hundred feet of driveway to plow. So although we will "enjoy" a white Christmas, that won't stop us from officially hating you for being able to put the top down on your drive to the airport.

 

And throw enough money at it!

 

I feel a treadmill discussion coming on...

 

OK; thanks for the responses - this is similar to what I hear elsewhere. Let me try something new: Planes fly for the same physics as why boats float; buoyancy. By pushing air (or water) downwards equal to their own mass. Same as why birds fly. I haven't heard this anywhere else before, but no one has been able to disprove it. The great thing is that you could test this, just measure the amount of air that a plane pushes down. Planes take off when they're pushing enough air down to compensate for their weight.
I did a video on it: - "Buoyancy explains how planes fly" (in 4 minutes)