Bernoulli sshmernouli....who cares how a wing lifts?

[ottawa,kan]

I remember high school physics. In fact I even taught it at the 9th grade general science level for awhile. I remember learning about how a wing generates lift because the air flows farther along the top than the bottom...or some such rot. This was long before I learned to fly. Anyway I guess that's all wrong and Bernoulli was a fool? Or Newton had a better lesson plan? But does it really mater, as I fly my actual airplane? There's lots of stuff that does matter, like angle of attack, or loading in a steep turn, or falling off during a stall. But the physics of lift? I'm pretty sure I don't care. When I drive my skidloader, do I need to remember " equal and opposite forces" as I lift and move something? Or can I just realize that "yeppers the job gets done. What an awesome machine." Same with driving a car. No one studies the physics. They just learn to drive. And text while they do it of course.

[xsbank]

[Strega]

This is the difference between a pilot and an operator.

[AuxBatOn]

Stinson, when you drive a car, you can stop on the side of the road when something goes wrong. In an airplane, not so much. Knowing as much as you can on how stuff work on your airplane will save your ass and your passengers' ass when shit hits the fan.

[iflyforpie]

You are right, there is no real need to learn in detail the exact process of how a wing generates lift to know how to fly an aircraft. After all, they probably taught it wrong in ground school anyways.

What IS important is that you recognize the conditions required for creating lift and how to keep those conditions in effect. That is where maintaining or using correct airspeeds, respecting stall warnings, and properly trimming your aircraft come into play.

As for Bernoulli, he was right. Air does accelerate over the wing creating a vacuum (although not because of the longer distance over the top of the wing).

As for Newton, he was right too. Air does downwash off the wing creating an equal and opposite reaction to lift the aircraft (but not because it bounces off the bottom of the wing).

[E-Flyer]

This is the difference between a pilot and an operator.

Well Said.

Also, when you know what is going on you see the bigger picture; thus, you are able to troubleshoot much better if a situation occurs out of the norm. You know, it's people like you who become statistics. If you're given a problem outside of the box, you would most likely not know what to do because you didn't put the time and effort to understand how all those little basic concepts are added up to your cognitive knowledge.

It's like a pyramid, if you don't build a strong base, it will fall apart.

I'm not saying that knowing particularly how Daniel's principle works is the reason for you to be a better pilot. For all I know you might be a well respected individual in this industry; however, having knowledge leads to you having a better understanding of how the dots are connected. Hence, you will be able to make better decisions and be that pilot who saves 300 passengers one day

It's not just understanding the theory, it's knowing how to apply it.

Lastly, the attitude you seem to portray indicates a further lack of knowledge in many other subject areas since you don't seem to care.

But then again, the real learning comes from your job, so do your own math homework.

I don't know, that's my 2 cents (flame away).

[C23flyer]

Could I have a couple of examples of the shite hitting the fan, where knowing Bernoulli's or Newton's theory would save my ass? I would especially like to hear from the "pilots" and not just the "operators."

[taylor498]

This is the difference between a pilot and an operator.

kudos. my thought exactly.

[ditar]

If I don't need to understand how my airplane flies, why should I need to know how my aircraft's systems work. Afterall, isn't it enough that I know how to program the FMS and which switches do what? That's great while everything is working, but what about when things start breaking? As pilots we are responsible for having some knowledge of how the systems operate and interact behind the scenes so that when things do go wrong we can form a picture of what will be affected. This doesn't mean that I have to also be an engineer and an avionics tech and understand what every nut, wire, and hose is for. But I'm sure most of us can think of little quirks unique to our particular aircraft's systems that would be very nice to know items in the event that those systems start misbehaving.

Similarly, I don't need a Ph.D. in physics to fly my airplane properly and understand what keeps it in the air, but some level of understanding of the physics behind it does make the difference between the airman/aviator/pilot and just an operator. I speak from my own experience that when I started to learn the intricacies of theory of flight I gained a much better appreciation of why the airplane does what it does, and it made me a better pilot in the process. It helped me understand what I could and couldn't get away with, and more importantly why I could or couldn't. Such knowledge isn't only relevant when things go bad, but in fact every time you climb into the pilot's seat. Now every time I climb into the plane and take off, I feel an almost visceral connection with the machine and the forces that keep it aloft. Why would I not want to know how it works? I just don't get it.

[C23flyer]

Could I have a couple of examples of the shite hitting the fan, where knowing Bernoulli's or Newton's theory would save my ass? I would especially like to hear from the "pilots" and not just the "operators."

[Strega]

ok here is an example,

you are flying the mighty C-150, you enter a spin to the left, let it fully develop, and upon recovery, you find the rudder pedal is stuck (this has happened numerous times and has actualed generated an AD to address the problem).

What do you do to recover?

[blueskies777]

so...........

how do you get out of the spin.

how high are you when you entered the spin?

[C23flyer]

ok here is an example,

you are flying the mighty C-150, you enter a spin to the left, let it fully develop, and upon recovery, you find the rudder pedal is stuck (this has happened numerous times and has actualed generated an AD to address the problem).

What do you do to recover?

To clarify, this is not an example. This is a problem, without a proposed solution. So, go ahead and finish your example, citing Bernoulli in your train of problem-solving thought as the 150 loses altitude.

Faced with a similar circumstance in an experimental aircraft, a test pilot (or should I say "operator") was ready to bail when he recalled quite accidentally that by applying an in-phase pitch rocking technique he could break the stall, accomplished by deflection of the elevators and was then able to recover from the spin.

[Hedley]

Strega, you're stealing my material

It would be nice if every pilot had a Phd in fluid
dynamics, but that would be overkill.

There are lots of things a pilot need to know
about - how a wing works, how an engine
works, how a radio works, airspace, regulations
etc etc - but he does not need a Phd in all
of these subjects to be an adequate pilot.

A specialist in each of these areas might
think that pilots should have a Phd in their
specialty, but let's be realistic.

Most pilots can get by if they know that
the top of the wing should be clean, and
that pitch attitude is a proxy for angle
of attack for the "straight and level" crowd.

[Big Pistons Forever]

C23

I think what you have described is a recovery from a spin that has gone flat.

If the rudder is jammed hard over I would think you would be in a world of hurt. The only thing I can think of is full out of spin aileron ( in the C150 the ailerons are more powerfull than the rudder ). Normally out of spin aileron speeds up the spin (ie increases yaw rate) but if you at the same time abruptly applied full down elevator there might be a sweet spot right where the wing unstalls and the ailerons bite, allowing you to regain control. Pure speculation on my part and something I hope I never experience.....

[Hedley]

Nope. Here's a hint: how can you rearrange the spin so
that the stuck rudder helps you?

Mind you, even if you momentarily recover from the spin,
the rudder is still stuck, so the odds of re-entering a
spin are pretty high.

I might mention that paperwork shuffling aside, spins
are aerobatic maneuvers, and IMHO should be performed
in aerobatic airplanes with an aerobatic instructor with
parachutes on. But that's just my take on it, and I have
been viciously attacked here for having this opinion.

I guess I'm just not as brave and knowledgeable as
you guys here!

[Strega]

Heres a hint, you need to make the hard over rudder "dissapear"

If you understand how the air is flowing around the aircraft, you will know what to do.

Iv tried this in a 150, and having a stuck, hard over rudder, when spinning at 2000AGL or higher (as per most flight training) should not end in dirt poisoning.

[BTD]

I can't see how knowing all of the details of how a wing works will help you in that situation. Even if you are well versed, pulling that information out and working through the problem in your head to figure when the perfect time to do something, would probably take longer than the time you have. If you have already thought about the problem before going up because 150s have occasionaly had stuck rudders, then don't spin it intentionally.

Your time would probably be better spent learning the systems of the 150 to know why the rudder jams and possible ways to free it. As a last ditch effort I'd give the door a try on the opposite side to the spin. If I recall correctly its supposed to be open a crack before a forced landing anyway.

I'm all about learning as much as you can about anything. But I fail to see a situation where having intimate knowledge of fluid dynamics as Hedley has said will save you. Besides that the stuff FTGU has in it is all BS anyway.

BTD

[BoostedNihilist]

http://www.allstar.fiu.edu/AERO/flight12.htm

good info, simple fluid dynamics... I found it interesting.

How would you get out of a spin with a stuck rudder?

I would try kicking the living shit out of the opposite rudder myself.

[Strega]

http://www.allstar.fiu.edu/AERO/flight12.htm

good info, simple fluid dynamics... I found it interesting.

How would you get out of a spin with a stuck rudder?

I would try kicking the living shit out of the opposite rudder myself.

you would soon then be dead.

[BoostedNihilist]

How would you get out of a spin with a stuck rudder?

[Strega]

Think about it, if you understand how your airplane works, the solution is simple.


Hedley, do you agree?

[iflyforpie]

I recall a story about the Grumman Cheetah being susceptible to unrecoverable spins due to the fuel being flung out to the wing tips in the tubular spar and creating a ton of rotational (angular) momentum.

NASA sent one of it's test pilots out with a parachute in a Cheetah to try different spin recovery techniques. He wound up in an unrecoverable spin. He was about to bail out, so he opened the canopy and stepped out over the windscreen to jump and the plane recovered.

My point is: Here was a pilot who must of had more than a passing knowledge of aerodynamics. I suppose he could have said that by opening the canopy he was effectively increasing the surface area of the tail and by moving his body forward he was moving the aircraft's C of G forward, thus increasing the directional and pitch stability of the aircraft.

But no, he was saving his own skin and saving the plane was a bonus. Even if he knew what he was doing you don't need to understand fluid dynamics in great detail to understand stability. And fluid dynamics doesn't say anything about the angular momentum of a spinning aircraft.

[Hedley]

Anything is easy if you know how

I regularly enter and exit inverted spins below 1,000 AGL
(did it 4 times this weekend). Hard for the crowd to see
it otherwise. Again, it's easy if you know how!

Was that too much of a hint?

[BoostedNihilist]

I recall a story about the Grumman Cheetah being susceptible to unrecoverable spins due to the fuel being flung out to the wing tips in the tubular spar and creating a ton of rotational (angular) momentum.

Wasn't that the aa1a?