Bad Science and the Truth..

[vintage1]

Wittgenstein has staed in typical Teutonic efficiency that 'The Truth is whatever is the case' In one crisp sentence defining the nature of the beast, without permitting any notion that 'whatever is the case' is knowledge that can ever be accessible to a human mind.

On attempting to summarise a Kantian type position on the reality of the observable world, my good friend remarked 'what you are saying is that whatever is the case, appears to us filtered via an array of preconceptions!'

A phrase to treasure.

The philospohy of science is very important, and one of its greatest proponents, Dr Karl Popper, arrived at a succinct series of definitions as to what constitutes science, as distinguished from pseudo-sceince.

Since this forum seems to becme periodically infected with the grosser forms of the latter, it may be worth outlining the essential structure of 'Poppers Remedies' to distil good science, from bad, whilst leaving the Truth severely alone, as it is, in fact, and always has been, somewhat outside the scope of science, and reserved for the delectation of those who espouse Faith rather than Reason, as a way of arriving at Certainty.

Firstly, what Karl says, is that the business of science is not to uncover the Truth, although he takes a somewhat ambiguous position in that area, but to formulate hypotheses, or conjectures, that have the following properties.

1/. They must fit the facts as they are agreed.
2/. They must in general be capable of refutation: That is they must embody some practical way in which if they do not (always) fit the facts, they may be tested and therefore shown to be wanting.
3/. They should be practically meaningful. Statements such as 'griblets are good' whilst they parse correctly, have no meaning without definition of 'griblets' and 'good'
4/. It is desirable that Occams Razor be applied, to reduce over complexity.

He is of te strong opinion that these hypotheses are not deduced from the evidence, but are propositions that are created in order to fit the facts, a position which stronly de-emphises the position that science uncovers truths, or discovers things that were there already. IN fact the reverse is true. Science is the construction of an imaginary edifice that sits 'behind' the facts of the physical world, and which is hypothesised to 'give rise to ' those facts.
Some modern physicists would say that it is in fact no more than that, and any relationship between the edifice, and 'wahtever is the case' is unproven, arbitrary, statistaically unlikley, and of no actual interest. Science is, in this mode, not concrened with the truth-behind at all: it merely suffices for it to generate an abstraction that allows the outcomes of manipulations of the physical world to be successfully predicted.

However simple minds need simple explanations, and just as in Religion, there is a temptation for the high priests to use the shorthand form of a hypothesis and say such things as 'gravity exists' when what they really mean is that 'the concept of gravity explains things that we all agree on, consistently and accurately'..and of course such sloppiness of expression leads to precisely the sort of mess we see here, where half understood concepts are parroted by those who do not understand them, beyond the limits they were designed to be accurate to, and so on.

How does all this apply to a real problem?

Well compare the staments

"God created the Earth 6000 years ago, and the heavenes and the stars and all that is in it"

and

"as far as we can tell a few billions of years ago there was one almighty singularity, out of which emerged the physical universe, its laws, space and time, and the rest is history.."

Though superficially similar one is a scientific theory and the other is not.

Both give a simplified explanation of the situation we find ourselves in, both might be true..why is one scientific and the other not?

The answre lies less in what they are, than in what we can do with them.

The Creationist statement is totally irrefutable. There is no way it can be shown to be wrong..by definition God must stand completely outide of the whole priocess, and therefore be totally inacessible to refutation of existence. The whole theory, that sounds so grand and so simple, and explains everything, in reality explains nothing at all. It gives no hint as to what the future might bring. It has zero predictive power. Any events that happen, no matter how unexpected are covered by shiftng the definition of the Deity. It simply states as an article of Faith, that God done it, for reasons of his own, and basically whatever happens is cos thats the way he would have wanted it. Big deal. It wasnt inertia or Kinetic energy that crashed your plane, it was God. Blame God, and don't go poking around with stiuff you dont understand, or he'll crash the next one as well.

So, it can't possibly be refuted, as it has no predictive power. It's just an explanation.

Compare and contrast te Big Bang, which may or may not be true.

For a start, its simpler..well to a scientists it is..rather than creating a large and varied Universe all at once..or in 7 days - whatever - it merely requires that one single extremely small twist in a neutral energy state be allowed to happen, and according to the nature of that twist, everything else eventually follows on.

It fits the detailed facts...that projecting timelines backwarsds seems to lead to a convergence at a particular time in the past, and thet the timelines of events themselves seem broadly to be stable acording to fixed law, and the extrapolation of those laws into the future allows accurate predictions to be made, predictions which in general come true, insofar as they are computable. So in essence it ia actually SIMPLER (Occams Razor) is falsifiable, and has meaning..

That doesn't make it a fact though, or even True. It just works, that's all. At least according to the best measurements that have been made so far.

Mutatis mutandis, a Big Bang and Creationism can be made equal, if you remove prehistory, and simply replace it with an Act of Creation at some lesser point in the past, in which not only was everything created, but the laws according to which it runs also constructed. However nothng in this process sets a particular creation time: teh figure of 600 yeras was I belive arrived at by adding up all the ages of all the Jewish Tribes that comprise the Old Testament, and thereby deriving a figure.

And therein lies the rub. IF you take the literal historical fact of the Bible as a priori fact - fact that supersedes all observed fact that you might tinker with today, then of course that has to be the one and only explanation.

If however you regard the Bible as in interesting part historical part allegorical collection of the oral record of a particular culture's philosophy and ideology, then you can square the circle by assigning an allegorical menaing to Genesis, which actually isn't inconsistent with science at all. Not at the philsophical level anyway. 'And there was light' is about as close to 'a big bang' as you can get..in Hebrew..:D

Hence the 'array of preconceptions'

Wherever you drive the stake of A priori fact..in the Bible, or in the measurements you make today, to a large extent determines the world you find yourself obeserving..a mechanical universe, rollingt inexorably from a singularity to heat death, or a custom designed sandpit for souls.. :rolleyes:

THis is the point to be made, the facts themslves are not even facts: Talk to someone with advanced dementia, whose memory no longer allows them to actually measure the passage of time, and you find that they will insist that they have just been doing something that is the last thing they remember doing..playing on the seashore as 5 year old..or whatever..without memory, we can't know there is time..but is our memory accurate?..The world MIGHT have been created last Tuesday, alomg with all our memories and the bible as well. We can't ever prove that it wasn't...

Which is why Popper would firmly reject the notion. What cannot be refuted has no value in science, but it can make a good scifi plot..

To do science, we first have to agree on the facts. Facts are things that seem to be true, that we can agree on. Then we may construct theories to predict new facts on the basis of facts we have already agreed on. Which is why scince is full of careful definitions as to what the elements of its language actually mean..definitions that the pseudo scientist walks through in hobnalied boots, picking up a clod here and a bit there, and mangling them into fanciful explanations that sound impressive, but don't actually fit the way science actually is.

Take the recent arguments realting to 'Kinetic energy' This is VERY carefully defined in terms of mass and velocity. Velocity is vERY carefully defined as something that has no absolute value, but can only mebe measured in realtive terms to a pint which als has velocity, or to a co-ordinate frame thats is - fir the purposes of soind teh sums DEFINED to have zero velocity, even if its travelling aroud tthe palce at extremely high speed.

Yet people who accept that velocity is relative, and gaily spout the formula for kinetic energy as a function of velocity, cannot see the inevitable corollary, that kinetic energy is therefore a relative and not a fixed quantity..How come? presumably because real energy is an absolute..a kilowatt hour is not relative to anything at all.and because kinetic energy is called 'energy' they get all muddled up..Two half remembered science lessons get stuck together and confused..and the ability to go back to facts and work from them to see how the theories actually work is missing, and the teachers themeslves probably never understood what the course book said anyway, and certainly hadn't studied the philsophy of science at all.

No wonder the world is in such a mess. Everyone wants simple truths and certainties, and to feel smart and to feel they understand what's going on behind the scenes, and to discover the Truth. Only the really smart people get to the bottom, though, and report back that the Truth may well be 'whatever is the case' but don't expect to figure it out with a few half undertstood formulae and a couple of grab bag concepts. The Truth is that the Truth is unknowable. Science ain't the Truth, nor are its concepts demonstrably anything more than ideas that work..but if understood completely for what they are, they DO work.

Or to put it simply. Any fool with a bit of imagination can explain the past..but it takes a heck of a lot of careful hard work to predict the future.

Any fiol can crsh a plane and say 'I got the CG wrong..it was a downwind turn..it was interference..I got laminar flow separtion on the wingtip'..AFTER its happened. It teks a lot better application of science to get te CG right BEFORE the plane flies, and get the washout in BEFORE it tipstalls, and to understand the problems of controlling a model flying in one frame of reference from a viewpoint firmly placed in another.

To paraphrase the cartoon I posted up in another thread

"You don't expect me to do co-ordinate vector transformation whilst trying to fly a model, in my head, do you?"

"NO Mr Bond, I expect you to crash"

;)

[chipmonk]

not bad,but science is a learning experience and i wish you would learn to use a spell checker,with 61 spelling and grammatical error`s,how can you cope in such a perfect world

[phat23]

Another classic post Vin.

Oh, and the spelling/grammarical errors are all part of your charm. Don't change a thing.

[MarkusN]

not bad,but science is a learning experience and i wish you would learn to use a spell checker,with 61 spelling and grammatical error`s,how can you cope in such a perfect world
Says the guy with the greengrocer's apostrophe.

Sorry, couldn't resist.

[vintage1]

Now who in the world reported that for TROLLING?

When a discussion on the philsopohy of science isn't allowed in a fiorum on Science..what is going on?

[funfly2]

Says the guy with the greengrocer's apostrophe.

Sorry, couldn't resist.But chipmonk didn’t claim he knows the truth…

The first post is another example on how to write a lot without saying anything new, but denying the fact that inertia exists and that kinetic energy and potential energy are real forms of energy.

All objects or particles, no matter how small or how big and regardless they’re in motion or not anywhere in the universe, have energy.
:cool:

[Julez]

Great posting!

I safed it on my computer.

[MarkusN]

When a discussion on the philsopohy of science isn't allowed in a fiorum on Science..what is going on?
Funny thing, that. I notice quite different behaviour on English language forums compared to those in German:

In German any form of smart-assery and mental one-upmanship seems to be much more prevalent. I sometimes get really annoyed by that, even though I am guilty of the same crime often.

However, on that very subject you started there, there has been a heck of a thread on www.rc-network.de. (It started as a discussion on creationism and darwinism and quickly evolved into a more general philisophical thread.) And even though the subject is very touchy, contributors managed to keep it civil.

So, let's try to show the guys there that we can do it here as well, shall we?

But chipmonk didn’t claim he knows the truth…Nor did vintage1. Quite the opposite actually.
He did, however, claim that he understands the model of kinetic energy as presented by today's accepted science better than you. And much as I hate to say so, I have to agree.

Relativity is a bitch. It easily screws with your head, even if you don't go up close to the speed of light.

[mnowell129]

Gee whiz, I didn't realize this thread was into existential dilemmas and the search for the holy grail. Perhaps the answer is 42?

I certainly understand the relativity issue, so there's no argument.
However in my reality of engineering where I work, I occasionally have to make some baseline assumptions just to compute some practical results. Whether velocity and inertia are philosophically vapor, mere ponderances of a human mind, or formulas on stone tablets handed down from the great spirit, the customer often wants a practical answer to a practical problem and the calculation of change in energy or velocity or a power calculation in an earth fixed reference frame generally provide a useful, if not faith free, philosophically pure, theoretically scientifically truthful and intellectually satisfying, answer.

I suppose I should infer from this thread that the next time I become tempted to use a formula for a non-real quantity, that I should simply sit and meditate on my relative position and see if the problem moves with me or is in fact in another reference frame. :)

[MarkusN]

Where on earth was that proposed? But being an Engineer you know that you have to assess fitness of your simplified model for the problem at hand.

And that is often the problem with pseudo-science: Arguments are put forth for the sake of truth, without having understood the basic prinicples, but thumping the hard-learned formulae.

[funfly2]

...
Nor did vintage1. Quite the opposite actually.
He did, however, claim that he understands the model of kinetic energy as presented by today's accepted science better than you. And much as I hate to say so, I have to agree.

Relativity is a bitch. It easily screws with your head, even if you don't go up close to the speed of light.Well, then you could be kind enough to enlighten us why Kinetic energy is not real energy, as well as telling us what real energy actually is and why, according to your apparently 'profound' understanding on this matter...

:cool:

[Brandano]

because two bullets flying in a vacuum next to each other have absolutely no energy when one is seen from the other, while they have a lot of energy when they smack into something. But then it could be the energy of the target hitting the static bullets at speed. How can you define what is actually moving?

[funfly2]

because two bullets flying in a vacuum next to each other have absolutely no energy when one is seen from the other, while they have a lot of energy when they smack into something. But then it could be the energy of the target hitting the static bullets at speed. How can you define what is actually moving?Underbar...
How come that the bullets are flying (moving)?
It means that they were stationary before - no?

Now, the work required to accelerate the bullets to a given speed is Kinetic Energy.

The kinetic energy of an object is the extra energy which it possesses due to its motion.
Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.
Negative work of the same magnitude would be required to return the body to a state of rest from that velocity.

According to Einstein, even at rest, an object has the amount of energy equal to:
E = mc^2
Where:
E is the rest mass energy.
m is the object's mass,
c is the speed of light in vacuum

:cool:

[macboffin]

not bad,but science is a learning experience and i wish you would learn to use a spell checker,with 61 spelling and grammatical error`s,how can you cope in such a perfect world Whilst accepting that your count of 61 errors is correct,( I have not checked), is such detective work the best use of your time? Could you not be better employed in sticking your fingers together with CA glue, or otherwise commiting aeromodelling?

[macboffin]

because two bullets flying in a vacuum next to each other have absolutely no energy when one is seen from the other, while they have a lot of energy when they smack into something. But then it could be the energy of the target hitting the static bullets at speed. How can you define what is actually moving? Unless they have been fired from a smooth-bore gun, they do have considerable rotary energy relative to each other, they are spinning like crazy!
Unless the target is spinning at a comparable speed when they impact, the results will be different; the rotary motion adds to the kinetic energy, hence impact results will be different.
So there!

[macboffin]

Expanding on the subject of stuff moving, whether it be fingers writing stuff on walls and moving on, (This is commonly known as Graffiti, because it was invented in Italy) or bullets ; from the first moment of manufacture, let alone digging and refining of ores, bullets are in motion. Supposing that the manufactury is near the equator, they are spinning round the centre of the Earth at approximately a thousand miles per hour.add to this the motion of the Earth in it's orbit around the Sun, and the motion of the Sun around the centre of the Milky Way galaxy, together with the motion of the Galaxy away from wherever the centre of this Universe is ............... (Assuming that it IS expanding) Ain't nothing static nowhere nohow! Oh, I forgot all rhose cute little quarks and electrons and all that stuff whizzing about the place in little circles,( mostly) which make up the physical object we call a "Bullet".

[MarkusN]

It's correct that real energy is needed to accelerate stuff. However, we are always looking at systems with a boundary. If we start out with a certain state inside those boundaries, each element has its initial kinetic energy defined by its speed relative to the (arbitrary!) datum. Changing that state requires energy transfer. How much energy each object has depends on our selection of datum!
The closest thing to absolute kinetic energy would be if the datum was selected to be the CG of the universe. Happy easter-egg hunting finding that! And that's only for translational movement. Now we also need to somehow fix rotation in space...

Looking at a plane moving in an (unaccelerated!) air mass it is sensible to draw the boundary around the plane and a sensible amount of air and to move the datum along with the air mass. The model is simplest that way, and the results correspond with observation.

Now, as soon as the plane moves out of those boundaries (e.g. hits the ground), other boundaries are sensible and more complicated rules have to be applied.

[vintage1]

Look: all the issue was supposed to be was to illustrate that all knowledge is relative, and some knowledge is relative to knowledge that is itself relative, and finally that because all knowledge is relative, any old garbage works when EXPLAINING things. However proper science isn't about convenient or comforting explanations, its about predicting the future.

i.e if what you want is merely an EXPLANATION, seek a priest.

If you want to be able to mainpulate the physical world in a predictable way, then that needs a long hard brain wrenching study of the issues involved, and they are not at all always intuitive, and get increasingly weird the deeper you dig.


Pseudo science is about convenient and seemingly convincing explanations, preferably ones that can't be shown to be wrong :D

Science is about accurate explanations that DO predict the future and CAN be tested and shown to be wrong, but actually haven't been shown to be wrong (yet)

That's all.

Oh, and some engineering really can't be easily understood without a basic grounding in the calculus, and if you haven't got that you shouldn't maybe presume to voice an opinion.

[funfly2]

It's correct that real energy is needed to accelerate stuff. However, we are always looking at systems with a boundary. If we start out with a certain state inside those boundaries, each element has its initial kinetic energy defined by its speed relative to the (arbitrary!) datum. Changing that state requires energy transfer. How much energy each object has depends on our selection of datum!
The closest thing to absolute kinetic energy would be if the datum was selected to be the CG of the universe. Happy easter-egg hunting finding that! And that's only for translational movement. Now we also need to somehow fix rotation in space...

Looking at a plane moving in an (unaccelerated!) air mass it is sensible to draw the boundary around the plane and a sensible amount of air and to move the datum along with the air mass. The model is simplest that way, and the results correspond with observation.

Now, as soon as the plane moves out of those boundaries (e.g. hits the ground), other boundaries are sensible and more complicated rules have to be applied.If you assume that the plane is moving through the air or that the air is moving through the plane, whichever you choose, you have real kinetic energy involved keeping them moving in relation to each other.

If the plane hits the ground, a transfer of energy will take place from the initial motion kinetic energy into other forms of kinetic energy, such as thermal energy, sound energy and eventually also stored potential energy, like gravitational energy.

A rock resting at the top of a hill contains gravitational potential energy.
Hydropower, such as water in a reservoir behind a dam, is another example of gravitational potential energy.
However, since the earth is moving, all of them have kinetic energy related to other points in the universe.

:)

[Odysis]

I may have missed something, but why is there this emphasis on real vs imaginary energy?

[funfly2]

I may have missed something, but why is there this emphasis on real vs imaginary energy?Check out:
http://www.rcgroups.com/forums/showpost.php?p=9422974&postcount=160
It also is suggested on the first post in this thread by the same author (despite some parts have been edited).


But remember that energy is neither created nor destroyed - we just change it from one form of energy into another form.

In order to move, the car engine burns gasoline, converting the chemical potential energy in gasoline into motion kinetic energy.
Solar cells change radiant kinetic energy into electrical kinetic energy.

Energy changes form, but the total amount of energy in the universe stays the same.

[MarkusN]

I may have missed something, but why is there this emphasis on real vs imaginary energy?
Because funfly2 gets hung up on Vin calling kinetic energy 'not real' when he should more properly have called it 'not absolute'.

Funfly2 you can save your smirking smiley. I am aware how 'real' kinetic energy is. I think you will agree however, that depending on the reference system you choose, it is debatable (or a question of definition, rather) in which element of the system that energy is stored or from which it is taken. Brandano has pointed that out very aptly in the "two speeding bullets smacking into an obstacle' model. And please spare me the "but they are spinning" splitting of hairs. We all know that this is not relevant to the discussion but rather a smoke screen.

[funfly2]

Because funfly2 gets hung up on Vin calling kinetic energy 'not real' when he should more properly have called it 'not absolute'.
Don't tell me that it was also my fault.
And you was the one telling us that Vint explaned it very well...
:rolleyes:


Funfly2 you can save your smirking smiley. I am aware how 'real' kinetic energy is. I think you will agree however, that depending on the reference system you choose, it is debatable (or a question of definition, rather) in which element of the system that energy is stored or from which it is taken. Brandano has pointed that out very aptly in the "two speeding bullets smacking into an obstacle' model.
But the work required to accelerate the bullets to a given speed is Kinetic Energy, no matter how relative it may be.
And when the bullets smack into an obstacle there is transfer of energy, no matter how relative it may be.

:)

[MarkusN]

But you use your absolutistic model of kinetic energy to postulate that there is such a thing as a dangerous downwind turn in steady moving air. Or even such a thing as "windshear induced by a tight turn".

Which is wrong, wrong, wrong whichever way proper science looks at it.

That was my case when I said that Vin has got it right.

Speaking of the speeding bullets: Once we look at that system not knowing how they got their state there is no way of knowing "who carries the energy". For all we know they may have entered our speeding inertia system from outside without ever having been shot from a barrel. In which case our reference system will have brought the energy. It's all a matter of the standpoint you choose.

Rather macabre example, but there have been two cases in the news here recently about stupid kids dropping heavy objects from overpasses on cars on the motorway. In one case resulting in a fatality. To the victims it was rather irrelevant if the wooden block smashing through their windshield got its energy from getting shot at the car or if the car smashed into that block with its own speed.

[Odysis]

Ah, so this isn't a "real" vs "imaginary" discussion, more of a frame of reference discussion.

Akin to the old centrifugal vs centripetal force discussion?

I must say though, I do like the point of this discussion. I'd never considered the explain the past / predict the future side of the house. Always nice to have one's views expanded

[ciurpita]

vintage1

my son is very caught up in these conspiracy theories. i think your explanation can be very helpful in trying to make him more rational and realistic about life.

thanks very much
greg

[mnowell129]

Look: all the issue was supposed to be was to illustrate that all knowledge is relative, and some knowledge is relative to knowledge that is itself relative, and finally that because all knowledge is relative, any old garbage works when EXPLAINING things. However proper science isn't about convenient or comforting explanations, its about predicting the future.

Pseudo science is about convenient and seemingly convincing explanations, preferably ones that can't be shown to be wrong :D

Science is about accurate explanations that DO predict the future and CAN be tested and shown to be wrong, but actually haven't been shown to be wrong (yet)


This is well stated. Goes along with how hard it is disprove a negative hypothesis...
But this :

Oh, and some engineering really can't be easily understood without a basic grounding in the calculus, and if you haven't got that you shouldn't maybe presume to voice an opinion.
This doesn't apply to me since I have much more than a basic grounding in calculus, but I'm offended. This is pure snobbery. It's not that you aren't educated and thoughtful, Vin, you're an intellectual snob.You don't even take the time to spell properly and use reasonable grammar, reinforcing an attitude of flippant disregard to the little subjects of your "lectures".
Consider that information transfer is an impedance matching problem and if the source and sink don't match, all the source does is make wasted noise.
Thanks for this object lesson, it will help me remember to check my humility today. :)

[funfly2]

But you use your absolutistic model of kinetic energy to postulate that there is such a thing as a dangerous downwind turn in steady moving air. Or even such a thing as "windshear induced by a tight turn".

Which is wrong, wrong, wrong whichever way proper science looks at it.
Just telling that something is wrong, wrong, wrong doesn’t prove you’re right.

:)

[vintage1]

This is well stated. Goes along with how hard it is disprove a negative hypothesis...
But this :

This doesn't apply to me since I have much more than a basic grounding in calculus, but I'm offended. This is pure snobbery. It's not that you aren't educated and thoughtful, Vin, you're an intellectual snob.



I spent many many years being tolerant of fools: in a nice ideal society there is the time to do this. Latterly, I don't feel that we can afford the luxury. I don't mind being patient and explaining things, but when it comes down to 'I'm right and you are wrong' with a bunch of stuff that betrays utter ingorance of the subject matter at hand being used to 'make the point' I honestly don't know how to proceed.

Either you have to use science, correct science, to make a scientific point, or avoid science altogether. To prtetend to use science to mislead people into making bad decsisions, is..well I dont't know what to say really.


The bad typing is largely because right now I am in total agony with just about every muscle in my neck screwed up and it makes it harder to go back and correct everty mistake.


You don't even take the time to spell properly and use reasonable grammar, reinforcing an attitude of flippant disregard to the little subjects of your "lectures".
Consider that information transfer is an impedance matching problem and if the source and sink don't match, all the source does is make wasted noise.
Thanks for this object lesson, it will help me remember to check my humility today. :)

Fine. Think what you want. Sure I've got anagenda. Trying to teach science the way it was taught to me, by equally obnoxious, but nevertheless very clever people who were careul enough not to be wrong very often.

I am as dismayed by people who talk about 'scientific fact, and scientific truth and scientific proof' JUST a much as I am by people who glibly peddle other views of the world as 'as valid as science'.

Hence the 'lecture'. There are no scientific facts, no scientific truths and no scientific proofs of anything in te final analysis, all there is is a body of models of the world that have one overriding advantage over other bodies of knowledge and ideas about the world. They have been tested. and largely they seem to work.

Science - real science - doesn't clain to be the truth. It merely notes that if its dictates are followed carefully, in the areas where they are applicable, the answers will match reality. Its the best way of predicting the future we have and thats all it is. However its a lot better at that than anything else, so we use it.

You can carry a picture in your mind of what science seems to imply is happening behind the scenes, and get the right answers, but there is no guartantee its 'real' or 'true'.

And if you are carrying an inaccurate picture (with respect to what the science actually says), you will get the wrong results as well.

Now you take over and explain the concepts of frames of reference and relativity to people here who are essentially denyig that this makes any difference to anything..

[vintage1]

Just telling that something is wrong, wrong, wrong doesn’t prove you’re right.

:)

If you had bothered to follow the arguments, you would realise that nothing proves anything is right. Ever.

However, things and people who actually DO the experiments may be proved WRONG.

But sitting in a chair and simply asserting the validity of your claims and disregarding logical presentations from others doesn't make them right either.

"Ther are unicorns at the bottom of my garden, flying models who never crash in downind turns".

Prove me wrong.:D

[funfly2]

If you had bothered to follow the arguments, you would realise that nothing proves anything is right. Ever.

However, things and people who actually DO the experiments may be proved WRONG.
I said it once, and I say it a gain, your philosophical ramblings are not worth my time.
You keep saying nothing relevant but muddying the waters.
So I’ll be short:
Be objective and tell us why Kinetic Energy is not real energy and what is real energy for you?

:rolleyes:

[vintage1]

I said it once, and I say it a gain, your philosophical ramblings are not worth my time.
You keep saying nothing relevant but muddying the waters.
So I’ll be short:
Be objective and tell us why Kinetic Energy is not real energy and what is real energy for you?

:rolleyes:


Because it is a relative issue. As is potential energy. It all depends what frame of reference you are measuring it against.

You want to measure it in one frame and then apply that to another as 'proof' of something.

Thats not legal according to the rules.

Its tantamount to saying that something that weighs a ton, will still weigh a ton in outer space..

[funfly2]

Because it is a relative issue. As is potential energy. It all depends what frame of reference you are measuring it against.
I know it's a relative issue and I've never claimed otherwise, but it doesn't make it unreal.

If a plane is flying through the air, it has kinetic energy related to the air and also kinetic energy related to the earth in case it has some ground speed, which results in inertia too.

If not, when do you think your real energy occurs?




You want to measure it in one frame and then apply that to another as 'proof' of something.

Thats not legal according to the rules.
No, I'm referring to the same frame whenever I tell about the plane's kinetic energy.



Its tantamount to saying that something that weighs a ton, will still weigh a ton in outer space..
I've never said that.
The weight of an object is due to the earth's gravitational force, but the weight is proportional to object's mass.
Both the plane and the air are subject to earth's gravitational force.

:)

[kristianb]

Dear Vintage1,
thanks for Your interesting and clear posts!
Keep up the good spirit!
vbr KristianB

[Brandano]

The only form of energy considered absolute (for the moment?) is heat. Heat only moves from a warmer object to a colder object, there's no escaping that And eventually everything in the universe will reach the same energy state, the heat death of the universe. This is the energy Einstein refers to in his grossly misused E = mc^2 formula. Incidentally, again according to his theories it isn't possible to accelerate m to a speed of c^2 (nothing can go faster than c, which is the speed of light and is absolute in each frame of reference), so in theory you can't convert mass into energy... but then again you can, and it has been done. Anyway, the only way some mass can have no energy is if it's brought to 0 degrees kelvin, but apparently mass is a manifestation of an electromagnetic waveform, and once you bring it to 0 kelvin it ceases to exist. Ah, again, 0 kelvin isn't an absolute measure. It's something near or about -273 degrees centigrade, but it hasn't ever been reached yet and the actual value for it can only be somehow inferred, the scale moving downwards every so often with every new attempt to reach 0 k. Ok, that's enough "science for the layman", rip it apart for all you like, but rest assured I haven't made up any of it :).

[funfly2]

As a matter of fact Thermal Energy or heat is also part of Kinetic energy, as it is the result of vibration and movement of the atoms and molecules within substances...

Geothermal energy is an example of thermal energy.

:)

[rosco]

Vingate1,
Great posts. Very brave...
I have learned something today. Thanks.
cheers
rosco

[mlbco]

funfly2,

I don't know if this will help answer your question, but please take a look at this and read it carefully:

http://www.rcgroups.com/forums/showthread.php?p=5711332#post5711332


Steve

[Neil Stainton]

Another wonderful post Vintage. You are a darn site more patient than I would be...

Keep it up.

Neil.

[funfly2]

Just wonder whether you are members of a self-admiration society?

:D

[vintage1]

No, I'm referring to the same frame whenever I tell about the plane's kinetic energy.


You may be, but the plane doesn't know about your frame of reference.

It only knows about how its moving with respect to the air. And that doesn't change.

Unless you fiddle with the sticks, because you THINK it ought to be flying with respect to the ground.

And, Mr Bond, because you cannot appreciate the difference and do vector trasformations in your head, and think you know better than Newton, and Nature, the bloody thing ends up NOT flying at all. In pieces.

At which point its kinetic energy with respect to the frame you have erroneously chosen - the ground - gets actualised into a sick crunching sound as Nature tries to tell you that you should have left it in the box to start with.

Blaimng all that on pseudo science may make you feel better, but it wont stop it happening again and again.

Untill you appreciate that the moment a planes wheels leave the ground, it flys entirely with respect to the air around it, and what the ground is doing has no relevance at all until it touches it again, you will not be a pilot of any competence.

And heaven help us of you ever have to land on an aircraft carrier in zero wind. You will be telling us sagely that whether you land from behind the carrier or from the front of it as it steams along will make no difference, because without any wind, the kinetic energy of the plane is the same in both directions...

[Neil Stainton]

Just wonder whether you are members of a self-admiration society?

:D

Where do you see me admiring myself? I think you meant mutual.

Anyway not self. Not mutual. No society. Apart from that you are being as perspicacious as usual.


Neil.

[Odysis]

Vinc,


I'm having a rough time wrapping my head around the idea that the plane doesn't care whatsoever about the ground. For the sake of simplicity, let's assume the Earth frame is Newtonian. I'll talk here full scale, as the instrumentation is so much better (read: exists), but the same can be scaled down as the basic physics don't change.

If the aircraft's kinetic energy state were determined purely with reference to the air, gusts would have to effect on indicated airspeed; the aircraft would simply keep a constant IAS (kinetic energy wrt the air), and the passengers would be jostled around. This however doesn't happen; the needle wobbles around like crazy. Hence 1/2 the gust factor is added to Vref when landing - to allow for this gusting.

I wonder though... In a model aircraft context, is the mass of the aircraft so small, the time (distance) it takes to change speed (energy) just too small to bother, and it's close enough to say they're the same? This is, for those unsure, how we can say smoke travels along streamlines in a windtunnel, even though they have mass.

Or have I totally missed the point?

[funfly2]

Where do you see me admiring myself? I think you meant mutual.

Anyway not self. Not mutual. No society. Apart from that you are being as perspicacious as usual.


Neil.Thanks for correcting, I meant mutual, as you may have noticed English is not my native language, but I know enough of it to see the flaws in Vint reasoning...

I’m rather busy right now, I’ll be back later.
:)

[funfly2]

You may be, but the plane doesn't know about your frame of reference.

It only knows about how its moving with respect to the air. And that doesn't change.
It doesn't change with respect to the air just as long as you keep flying in the same direction and at the same airspeed.

But, as soon as you change your flight direction, you introduce a disturbance into your previous steady state condition, which momentarily gets unsteady.
How much unsteady and how long, will depend on how you fiddle with your sticks...

You wrote it yourself:

Unless you fiddle with the sticks, because you THINK it ought to be flying with respect to the ground.


Further:

If there’s airspeed, there’s kinetic energy related to the air.
and
If there’s also ground speed, there’s also kinetic energy related to the earth.

But whatever the situation (in motion or stationary related to earth), the plane has always inertia too.

:)

[ciurpita]

didn't martin simons try to explain some of this (i.e. relativeness) with the example of flying a model inside a moving aircraft carrier where inside the cavity of the aircraft carrier, the model was not subject to the winds external to the ship, the air movement past the ship due to its movement across the water, nor the up and down motion of the ship due to the waves? then imaging turing on a large fan.

[mnowell129]

Hmmmmm. I'd like to restate the hypothesis in engineer speak, just to make sure I'm following the discussion.
This is what I'm convinced of, anyway.

An aircraft making a constant rate turn, aircraft relative, in a constant moving air mass, will make a perfect circle with respect to the moving air mass, at constant altitude. The aircraft speed will be constant with respect to the air mass, with a fixed magnitude constantly rotating direction velocity vector. The scalar magnitude of the inertia will be constant with respect to the air mass.
The same aircraft ground relative will make a prolate cycloid in the direction of the moving air mass. The ground relative scalar magnitude of the inertia will make a sinusoid, the inertia changing from energy alternately obtained from and released to the moving air mass with respect to the ground (the basis for dynamic soaring as I understand it).
The crash phenomena occurs when an earth fixed pilot (or an aircraft fixed pilot trying to reference a ground reference object, like the end of the runway) tries to make a turn in the moving air mass and attempts to coerce the prolate cycloid into a ground referenced circle and makes a higher G turn than the aircraft's aerodynamics relative to the moving air mass will support, causing the aircraft to stall and possibly crash.

The bottom line from a piloting perspective is that you need extra airspeed when making a turn while transitioning from a air mass relative flight pattern to a ground based flight pattern, except when the air mass and ground have the same reference (i.e. no wind).
Radio control pilots are especially at risk as they have no airspeed indication other than a ground relative, human estimate (which humans are particular poor at).

The addition of non-steady-state air mass movement means that the frequency response of the air/ground relative transition may exceed the frequency response of the aircraft's ability to increase airspeed. Rough translation, if you have gusty conditions you may stall because the gust may suddenly leave you with not enough airspeed.

Pardon the interruption, but I'll wait to see some argument that convinces me otherwise.
p.s. this thread provided an epiphany, that the extra ground relative inertia comes from the moving air mass, not the aircraft.

[Brandano]

ciurpita, the up-down motion of the ship will most likely affect the system inside it, so it isn't quite a fitting example. The motion of the ship should be steady for it to be irrelevant. The reason why the fact the ship is moving can be ignored is because everything within it is moving in the same way, and conserves the same inertial moment. Any maneuver within the ship is the same as if it was outside in still air because the component that is the movement of the ship is always summed to every initial and final state in the same way. It's a bit like resolving an equation by multiplying or dividing on both sides of the = sign by the same amount. The amount is irrelevant, the results are always equal anyway.

[vintage1]

Vinc,


I'm having a rough time wrapping my head around the idea that the plane doesn't care whatsoever about the ground. For the sake of simplicity, let's assume the Earth frame is Newtonian. I'll talk here full scale, as the instrumentation is so much better (read: exists), but the same can be scaled down as the basic physics don't change.

If the aircraft's kinetic energy state were determined purely with reference to the air, gusts would have to effect on indicated airspeed; the aircraft would simply keep a constant IAS (kinetic energy wrt the air), and the passengers would be jostled around. This however doesn't happen;



It sure does. I've been in one where the steward was white knuckled hanging on to the seat end strectched out down the aisle..

Its all a matter of scale. A big enough gust can tip any plane all over the place. Ours being smaller, are more affected. Thats all..

the needle wobbles around like crazy. Hence 1/2 the gust factor is added to Vref when landing - to allow for this gusting.

No argument there. But that's GUSTING not a steady wind. Our mutual friend maintains that a plane in a steady wind at altitude, behaves differently depending on whether its going upwind or downwind. Because 'it's kinetic energy is different'

[MarkusN]

p.s. this thread provided an epiphany, that the extra ground relative inertia comes from the moving air mass, not the aircraft.
Good point. The discussion with ff2 had me come to similar conclusions, though I couldn't have worded them quite as aptly.

As for DS: It's not so much about the ground references as about two packets of air moving at different speeds. But since in the end you have to keep the plane close to the pilot, ground reference comes into play as well.

[vintage1]

Hmmmmm. I'd like to restate the hypothesis in engineer speak, just to make sure I'm following the discussion.
This is what I'm convinced of, anyway.

An aircraft making a constant rate turn, aircraft relative, in a constant moving air mass, will make a perfect circle with respect to the moving air mass, at constant altitude. The aircraft speed will be constant with respect to the air mass, with a fixed magnitude constantly rotating direction velocity vector. The scalar magnitude of the inertia will be constant with respect to the air mass.
The same aircraft ground relative will make a prolate cycloid in the direction of the moving air mass. The ground relative scalar magnitude of the inertia will make a sinusoid, the inertia changing from energy alternately obtained from and released to the moving air mass with respect to the ground (the basis for dynamic soaring as I understand it).
The crash phenomena occurs when an earth fixed pilot (or an aircraft fixed pilot trying to reference a ground reference object, like the end of the runway) tries to make a turn in the moving air mass and attempts to coerce the prolate cycloid into a ground referenced circle and makes a higher G turn than the aircraft's aerodynamics relative to the moving air mass will support, causing the aircraft to stall and possibly crash.

The bottom line from a piloting perspective is that you need extra airspeed when making a turn while transitioning from a air mass relative flight pattern to a ground based flight pattern, except when the air mass and ground have the same reference (i.e. no wind).
Radio control pilots are especially at risk as they have no airspeed indication other than a ground relative, human estimate (which humans are particular poor at).


Well there you are. Someone who CAN perform the mental transform between frames of reference and won't crash on that account.

The addition of non-steady-state air mass movement means that the frequency response of the air/ground relative transition may exceed the frequency response of the aircraft's ability to increase airspeed. Rough translation, if you have gusty conditions you may stall because the gust may suddenly leave you with not enough airspeed.


Also 100% true, but not where the argument started.

The arguments was whether the actual physics of flight changed according to whether you were going upwind or downwind, or wheher this was merely a perceptual problem.

It would seem that those that don;'t know how to fly, prefer to deal in variable laws of Nature, propped up with half understod theory, than admit they just made a mistake.

So nothing new there then ;)


Pardon the interruption, but I'll wait to see some argument that convinces me otherwise.
p.s. this thread provided an epiphany, that the extra ground relative inertia comes from the moving air mass, not the aircraft.

That's one way of looking at it.

The general case is to say that Kinetic energy is a measure of the work you can get out of the interaction between two bodies according to their relative velocities. It has no absolute value.

Inertia is a property of mass alone, with respect to its acceleration relative to the fixed mass of the rest of the Universe (Gee: How does it know its there?). It doesnt change at all ever. Unless the universe changes or velocities approaching the speed of light occur, but that in itself is debatable, as there are other ways of interpreting relativity. Perhaps you meant momentum, which is another relative quantity, and does NOT imply energy directly..

You could say that Newtonian wise, mass is an intrinsic invariant property of a body, but momentum and kinetic energy are the effects of moving that body from one velocity frame to another. DLG soarers work because they are constantly trasnitioning fom a high velocity wind to a low one. And back again.

There is a curious relationship betwen Newtonian and Einsteinian models though., Whereas in the Newtionian there is no absolute velocity, there does Seem to be absolute ROTATION .Or possibly absolute DIRECTION. Objects that spin experience internal stresses (centripetal forces) that non rotating objects do not.) but who is to say whether the object is spinning, or the rest of the universe spinning around the object? Can I by firing up a gyroscope get the universe to fly apart? Einstein solves that by saying in effect, it doesn't matter. The answer in his model is the same. Palpably in Newton's Universe, it does.

This should be enough to warn anyone that all these lovely models only work up to a point. The truth is whatever is the case. The models are only as good insofar as they get the right answers.

Or fly, for the other sort. ;)

Its like friction. The 'laws of friction' works for elastic materials quite well. It doesn't work well at all as the materials tend towards plasticity. Otherwise doing burnouts at the track start would be pure braggadaccio, instead of a quite useful way to increase tyre grip..

If I rememberrightly, the geneisis of the idea of heat and energy and work as a realted series of issues came about because some smartass boring canons, noted that they got hot, and needed cooling. YThe widely held theory ws that the cutting of themetal relseased heat somehow that was intrsinic in th emetal. Till this smartass tried using a blunt drill and showed the cannon got just as hot. He then figured it was the poor sweating horses that turned the drill that made the cannon hot somehow. And the harder the pushed and the further they walked the hotter the cannon would get.

Silly man. He could have just rubbed his hands together to see the same effect.

The mediaevalists considered the world was made of Earth, Air, water and Fire. Well so do we, we call them solid, liquid, gas, and plasma..and laugh at how primitive they were..

Which just goes to show that the world contuinues largely unafffected by what we think it is. Fortunately..for science anyway. But of great annoyance to those who feel that the world OUGHT to conform to their ideas, even when, patently, it does not.

[funfly2]

Our mutual friend maintains that a plane in a steady wind at altitude, behaves differently depending on whether its going upwind or downwind. Because 'it's kinetic energy is different'Wrong.
Why do you keep misinterpreting me?

I’ve never referred to a plane in a steady state going upwind or downwind..
I am referring to changes from one situation to another.

But you may keep admiring each other in your mutual admiration society, exchanging your misinterpretations if that really makes you feel happy.

:rolleyes:

[mlbco]

...The same aircraft ground relative will make a prolate cycloid in the direction of the moving air mass. The ground relative scalar magnitude of the inertia will make a sinusoid, the inertia changing from energy alternately obtained from and released to the moving air mass with respect to the ground (the basis for dynamic soaring as I understand it)....

p.s. this thread provided an epiphany, that the extra ground relative inertia comes from the moving air mass, not the aircraft.

mnowell129,

I don't know if you had a chance to look at the thread I referenced in post #38 (http://www.rcgroups.com/forums/show...332#post5711332), but this is exactly what I was trying to explain. The motion of the airmass in response to the plane is key in understanding the aircraft's energy balance as calculated by a based ground observer.

Regarding dynamic soaring, if you force the airmass at the same frequency as the circling aircraft and with the correct phase, the airmass will pump energy into the plane through its lift vector and the aircraft will gain energy. To do this the airmass needs to be "forced" and this is exactly what a sharp wind gradient represents. When a model pierces the gradient with the correct phase of motion, energy is gained by the model. I think the airmass-motion model is important because it explains two tricky phenomenon (downwind turns and dynamic soaring) while showing how closely related they really are.

Steve

[mnowell129]

I don't know if you had a chance to look at the thread I referenced in ...but this is exactly what I was trying to explain.

Yes I did see it, I just needed to state things in language that was clear and concise to me.
I think the airmass-motion model is important because it explains two tricky phenomenon (downwind turns and dynamic soaring) while showing how closely related they really are.
Steve
Ditto, I now have a somewhat unified theory that explains both downwind turns and dynamic soaring. Now if my DLG will just get here so I can play.

[Texas Buzzard]

I for one do appreciate the original post - very much. Vintage1 has taken a large amount of time to reuncover some of the things we haven't thought about for quite some time. He showed a vast array of the knowledge of various topics and presented them in an interesting manner.

Those who ONLY see spelling errors or who want to throw cold water on Vin's post should be sent to sit in the corner for an hour.

He didn't tell us many new concepts, nor did he intend to - but he did an exercise in THINKING. Thanks Vin! :)

[Bobber Bob]

Hi Texas Buzzard...

Thanks for "getting it"... It has been VERY frustrating to see (read) the comments that talked all around (and against) what "V" was trying to say.

To quote you... "...but he did an exercise in THINKING. " Exercise IS work, and that may account for all of the tangents we have been reading. Remember, work is something "useful" being done ! I rest my case...

Something that was even more sad for me, was I fwd'd the original day's posts to a friend that I normally have a certian respect for his thinking process, and his reply was;

"Ok - now why did you have me read this article? I think I "enjoyed" the comments more than the article."

So SAD !!!

Bob Reynolds
. "ComeUpHere"

[funfly2]

Vint the one who claimed that kinetic energy "is not real energy".
So what is real energy then?

Has aircraft no inertia when "moving in a sea of air"?

If a heavy hot air balloon is alongside a light hot air balloon in light wind and suddenly both are hit by a strong gust, do they stay together or does the light one pull away?

Further, there are other forces involved in a turn that disturb the ideal steady state flying scenario:

The lift required in a banked turn is greater than the lift required in straight, level flight.
During a turn, the pilot of a powered aircraft must use the elevator to increase the angle of attack and generate more lift in order to keep the same altitude.

In turning flight, the lift has to exceed the aircraft weight, and is equal to the weight of the aircraft (mg) divided by the cosine of the angle of bank:

Lift during a turn = mg/cos phi
Where g is the accelaration due to gravity
and phi is the angle of bank.

The radius of the turn can be calculated as follows:
r = v^2/g*tang phi

The formula shows that (for a given angle of bank) the radius of turn is proportional to the square of the aircraft’s airspeed.

.

[Tom Harper]

Good Vintage,

Science requires that your argument be valid.

You state the argument as:

"The arguments was whether the actual physics of flight changed according to whether you were going upwind or downwind, or wheher this was merely a perceptual problem."


Clearly the physics of flight do not change with heading. But, that is not the argument you are making. You are arguing that anyone who has made an observation contrary to yours is guilty of promoting psuedo-science.

You are basing your argument on the fallacy of a distributed premiss. You are using upwind and downwind as Universal Positives. The fallacy stems from the fact that Universal Positive terms are distributive. The characteristics that you assign to "upwind" and "downwind" are distributed to all wind conditions in which others experience "perceptual problems".

Newtonian equilibrium occurs in a special case of moving air masses. That is where the air mass is uniform and moving at a constant rate and only in the same plane as the model. In that case there is no difference between upwind and downwind flight.

The air conditions encountered by modelers vary dramatically with time and place. 1-Cos profile gusts are far more common than motion at a constant rate. It is also more common for the air to be turbulent than laminar and it may contain vertical components that are large compared to the size of the model.

The reaction of a model to a 'downwind' or 'upwind' turn depends upon the above conditions and the phase of the model's motion with respect to them. The reaction of the model will always follow the laws of physics. What is observed from the ground depends on the behavior of the air mass. The actual behavior of the air mass in the immediate vicinity of the model is unknown.

So, when one observes a model gaining altitude on an upwind turn it is not always an error in perception. In fact when a model is completely unaffected by wind you are observing a special case.

Indeed, the physics of flight rule.

I suggest that you read (or perhaps reread) Steve's excellent post and those that follow.

http://www.rcgroups.com/forums/show...332#post5711332)


Tom

[funfly2]

funfly2,

I don't know if this will help answer your question, but please take a look at this and read it carefully:

http://www.rcgroups.com/forums/showthread.php?p=5711332#post5711332


SteveThanks for the link.
I've read the contents carefully and regret to disappoint you but I do fully agree with the arguments proposed by the NASA scientist:

Consider an aircraft flying with thrust=drag at each instant of time.
The aircraft flies with airspeed Vo and the wind speed is Vw.
When the aircraft has turned downwind, the groundspeed is (Vo+Vw) and the kinetic energy as seen in the ground-fixed reference frame is KE=0.5*m*(Vo+Vw)^2 (m is the aircraft mass).

When flying upwind the KE=0.5*m*(Vo-Vw)^2 and is substantially less than the downwind amount.
Since the lift vector always acts 90 degrees to the airspeed it can do no work on the system.
The thrust=drag and can also do no work since they cancel each other.
Therefore, the aircraft must drop such that the change in potential energy (m*g*h) equals the change in kinetic energy 0.5*m*(V)^2.
Therefore the plane will drop when heading downwind and climb when heading upwind.

.

[vintage1]

Thanks for the link.
I've read the contents carefully and regret to disappoint you but I do fully agree with the arguments proposed by the NASA scientist:

Consider an aircraft flying with thrust=drag at each instant of time.
The aircraft flies with airspeed Vo and the wind speed is Vw.
When the aircraft has turned downwind, the groundspeed is (Vo+Vw) and the kinetic energy as seen in the ground-fixed reference frame is KE=0.5*m*(Vo+Vw)^2 (m is the aircraft mass).

When flying upwind the KE=0.5*m*(Vo-Vw)^2 and is substantially less than the downwind amount.
Since the lift vector always acts 90 degrees to the airspeed it can do no work on the system.
The thrust=drag and can also do no work since they cancel each other.
Therefore, the aircraft must drop such that the change in potential energy (m*g*h) equals the change in kinetic energy 0.5*m*(V)^2.
Therefore the plane will drop when heading downwind and climb when heading upwind.

.

Oh dear oh dear oh dear..

[vintage1]

Vint the one who claimed that kinetic energy "is not real energy".
So what is real energy then?


Something that is intrinsic and absolute.

I was trying to make it simpler.

Kinetic energy is neither intrinsic nor abolsute. It is relative.


Until the plane touches the ground, its kinetic energy with repect to the ground is absolutely irrelevant. What counts is kinetic energy with respect to the air it flys in. Since it doesn't increase its airspeed going downwind, there is no need to lose potential energy. Or altitude.

Your confusion arises from the fact that you want to reference everything to the ground. Just because you happen to be standing on it. This is true ego centricity, and will result in crashed planes.

[funfly2]

Something that is intrinsic and absolute.

I was trying to make it simpler.

Kinetic energy is neither intrinsic nor abolsute. It is relative.
Yes, it is realtive, but you still didn't give us an example of absolute energy...
:rolleyes:




Until the plane touches the ground, its kinetic energy with repect to the ground is absolutely irrelevant. What counts is kinetic energy with respect to the air it flys in. Since it doesn't increase its airspeed going downwind, there is no need to lose potential energy. Or altitude.

Your confusion arises from the fact that you want to reference everything to the ground. Just because you happen to be standing on it. This is true ego centricity, and will result in crashed planes. Of course the Earth matters!!

The air is linked to the Earth as well as the plane and the water and the rocks and so on are all linked and affected by the Earth...
Every mass which is located within Earth's gravitational field has Weight = m*g
with g standing for the acceleration due to gravity (on Earth approximately 9.8 m/s²)
and m standing for mass.

And every mass located anywhere in the Universe has inertia.

On the surface of the Earth the nature of inertia is often masked by the effects of friction which brings moving objects to rest relatively quickly unless they are coasting on wheels, well lubricated or perhaps falling or going downhill, being accelerated by gravity.
This is what misled classical theorists such as Aristotle who believed objects moved only so long as force was being applied to them.

F = m*a (Force = mass × acceleration)
By this formula, the greater the mass [or weight on earth], the less a body accelerates under a given force.

In this context the same equation is often written as:
W = m*g

As long as you deny fundamental principles of physics, you keep living in a steady state of denial.

.

[ciurpita]

Therefore, the aircraft must drop such that the change in potential energy (m*g*h) equals the change in kinetic energy 0.5*m*(V)^2.
Therefore the plane will drop when heading downwind and climb when heading upwind.


so if you were flying circles inside the cavity of an aircraft carrier,while the ship is under way (10 ~= mph), you would expect the aircraft to gain altitude (or is it lose) when the aircraft changes it's direction so that it is flying in the same direction as the motion of the ship, and lose altitude when it changes it's direction to travel in the opposite direction as the ship?

you're saying you calculate the KE of the aircraft by adding it's airspeed to the ship speed? so if the aircraft speed is roughly the same as the ship's, the "absolute" speed of the aircraft may be zero (and KE ~= 0) when it travels in the opposite direction as the ship.

[vintage1]

Of course he means that. That's why aircaft flying east find themselves immediately at transonic speed as soon as they leave the ground, since the equator is 'moving' at about 1,000 miles an hour. Due to the rotation of the earth!

I have decided that the he is in fact trolling: The alternative explanation that he really believes all this rubbish, is too depressing to contemplate. :cool:

[vintage1]

Yes, it is realtive, but you still didn't give us an example of absolute energy...
:rolleyes:



Of course the Earth matters!!



I nver mentined the Earth: I said 'ground'. Typical troll tactic. Change the playing field.



Snip irrelevant facile explanitin of gravity...

[quote]
As long as you deny fundamental principles of physics, you keep living in a steady state of denial.

.

And finally, the last gasp of the troll, the mirror trick: Ascribe your own mistake to the other party.

Well you will only be the second person on my ignore list.
Or are you indeed teh first as well? easy enough to have two identities..

[mlbco]

Thanks for the link.
I've read the contents carefully and regret to disappoint you but I do fully agree with the arguments proposed by the NASA scientist:

Consider an aircraft flying with thrust=drag at each instant of time.
The aircraft flies with airspeed Vo and the wind speed is Vw.
When the aircraft has turned downwind, the groundspeed is (Vo+Vw) and the kinetic energy as seen in the ground-fixed reference frame is KE=0.5*m*(Vo+Vw)^2 (m is the aircraft mass).

When flying upwind the KE=0.5*m*(Vo-Vw)^2 and is substantially less than the downwind amount.
Since the lift vector always acts 90 degrees to the airspeed it can do no work on the system.
The thrust=drag and can also do no work since they cancel each other.
Therefore, the aircraft must drop such that the change in potential energy (m*g*h) equals the change in kinetic energy 0.5*m*(V)^2.
Therefore the plane will drop when heading downwind and climb when heading upwind.

.

Did you read the next paragraph? That is the one that explains why this argument is wrong:

This argument is fundamentally wrong because the lift vector actually does work on the aircraft when measured in the ground-based reference frame. Although the lift vector is 90 degrees to the local airflow, it is not 90 degrees to the ground speed vector and hence does do work on the system which is exactly equal and opposite to the kinetic energy change mentioned above. The result is that the altitude and total energy of the aircraft remains constant, just like one would estimate from an energy analysis based on the wind frame of reference.

The math behind this takes some time to work out, but it has been done. The danger of using an energy analysis in a dynamics problem is that it's very easy to do it improperly. You need to look at the vector form of the energy equations and work from there. The NASA scientist was wrong because he applied the energy analysis in the ground-based frame and then incorrectly accounted for the work being done in the wind-frame. You can't switch reference frames when using these equations, they must be applied in one or the other in order to properly balance.

Steve

[Tom Harper]

Vintage,

Nope, funfly2 is on his own.

You might consider my post. I do not challenge your physics. The problem is that you are using a special case to counter a range of observations. A model will respond to a gusting air mass.

Tom

[pmackenzie]

Thanks for the link.
I've read the contents carefully and regret to disappoint you but I do fully agree with the arguments proposed by the NASA scientist:

Consider an aircraft flying with thrust=drag at each instant of time.
The aircraft flies with airspeed Vo and the wind speed is Vw.
When the aircraft has turned downwind, the groundspeed is (Vo+Vw) and the kinetic energy as seen in the ground-fixed reference frame is KE=0.5*m*(Vo+Vw)^2 (m is the aircraft mass).

When flying upwind the KE=0.5*m*(Vo-Vw)^2 and is substantially less than the downwind amount.
Since the lift vector always acts 90 degrees to the airspeed it can do no work on the system.
The thrust=drag and can also do no work since they cancel each other.
Therefore, the aircraft must drop such that the change in potential energy (m*g*h) equals the change in kinetic energy 0.5*m*(V)^2.
Therefore the plane will drop when heading downwind and climb when heading upwind.

.


You are ignoring the change in speed of the air mass the plane flys in. This can't be ignored because the air is part of the system.

Since it has a huge mass it takes only a tiny change in its speed for the energy equation to balance out and give the correct and easily observed answer that a plane does not drop when heading downwind and climb when heading upwind.

Pat MacKenzie

[funfly2]

so if you were flying circles inside the cavity of an aircraft carrier,while the ship is under way (10 ~= mph), you would expect the aircraft to gain altitude (or is it lose) when the aircraft changes it's direction so that it is flying in the same direction as the motion of the ship, and lose altitude when it changes it's direction to travel in the opposite direction as the ship?
That's a different condition.
Notice that you keep referring to flying in circles, which if done right may be considered as flying in a stead sate condition. But I am not referring to such a condition.

If you're moving straight and level flight (inside the carrier) you have a certain kinetic energy related to the carrier and to the air inside it and another kinetic energy related to the earth with a value depending on whether you are flying in the same direction as the motion of the ship or not.

If you're flying inside the ship at ~ 10mph (related to it) in opposite direction as the ship, you've kinetic energy related to the ship and to the air inside it, but potential energy related to the earth because the ground speed would be zero in this case.
If you suddenly make a turn, you change that steady state condition by getting a suddenly 'crosswind' related to the air inside the ship, this reduces temporarily your airspeed, then you either increase power, apply elevator in order to keep altitude or just let the plane sink a bit to gain airspeed again.

.

[Tom Harper]

ff2.

So when the crew plays basketball tween decks, does the team facing the stern have an advantage?

Tom

[funfly2]

ff2.

So when the crew plays basketball tween decks, does the team facing the stern have an advantage?

TomAs far as the ball is concerned, it doesn't need airspeed to keep 'flying' but just the work done by the players to transform its potential energy into kinetic energy.

[Cory]

There are only two ways that a plane will unintentionally climb when it turns downwind:

There is a coincidentally timed gust that raises the plane's airspeed just as it is turning. The fact that you're turning has nothing to do with it. If you were flying upwind at a constant speed and altitude you would also climb with the increased airspeed. This is just a different form of the airspeed increase gained when flying through the shear layer while DSing. The increase in energy is due to the transition between two different airmasses.
The plane flew into a thermal.
The pilot screwed up.
There is no #4.


There are only two things that cause a plane to unintentionally descend when it turns downwind:

There is a coincidentally timed gust that lowers the plane's airspeed just as it is turning. Once again, the fact that you are turning has nothing to do with it. If you were flying downwind at a constant speed and altitude you would also descend with the decreased airspeed. Just like, but opposite the first example, the decrease in energy is due to the transition between two different air masses.
The plane flew into "sink".
The pilot screwed up.
There is no #4.


So....if the plane flying the circle or traffic pattern inside the moving aircraft carrier climbs or descends, it's either due to #3 above, a rare coincidence of the A/C turning on at just the right time, or a wave moving the observer's reverence frame making it look like it changed (OK moving that big of a reference frame is going to cause an updraft or downdraft and will actually cause the plane's flight path to change relative to the center of the earth / the center of the solar system / the center of the universe / or any other "steady" reference frame). ;)

[Ron Williams]

Wonderful thread. You are a gem, Vintage1.

[funfly2]

I nver mentined the Earth: I said 'ground'. Typical troll tactic. Change the playing field.
you are just splitting hairs as trolls use to do.
The 'ground' is part of the Earth and in fact it's hard linked to it, didn't you know that? now you know.




And finally, the last gasp of the troll, the mirror trick: Ascribe your own mistake to the other party.
Wonderful, you have given us a perfect description of yourself.

Still waiting for your example of a real form of energy.
:rolleyes:
.

[funfly2]

...
So....if the plane flying the circle or traffic pattern inside the moving aircraft carrier climbs or descends, it's either due to #3 above, a rare coincidence of the A/C turning on at just the right time, or a wave moving the observer's reverence frame making it look like it changed (OK moving that big of a reference frame is going to cause an updraft or downdraft and will actually cause the plane's flight path to change relative to the center of the earth / the center of the solar system / the center of the universe / or any other "steady" reference frame). ;)Just take your indoors little foamy and try flying it in 15mph wind outside, sure you'll manage as it will always be "flying in circles in the same sea of air"…
:rolleyes:

Keeping flying in circles as free flight sailplanes do is not the same scenario as flying straight in same direction and suddenly making a turn.

:)

[slipstick]

Keeping flying in circles as free flight sailplanes do is not the same scenario as flying straight in same direction and suddenly making a turn.

So let's get this right. You are claiming that flying continuous circles won't cause any problems and it doesn't matter what the radius of the circles are even though it's completely obvious that at some point on that circle you turn from upwind to downwind and vice versa. In your view it's only when initially flying straight and then making just one 180 degree turn of the same radius as the circle and trying to fly straight again that your downwind problem happens ?

So how far do I have to fly in a straight line before I've accumulated enough of whatever I need to cause the problem ? Is the "suddenly" important ? If so what exactly does it mean ? Are you actually talking about a sharp turn radius or do you really mean that I must not decide to turn until the instant before I move the stick ? Let's have a bit more precision ;).

BTW some of my indoor models will fly outdoors in reasonable winds....it's the well trimmed free flight models that work best and that's because they're not subject to (ground referenced) piloting errors ;).

Steve

[funfly2]

If you've ever been involved in proportional integral differential (PID) control systems you'd better understand what slow or sudden changes in a process variables might imply.

Keeping flying in circles as free flight sailplanes do, means relatively slow transitions upwind/downwind, while the plane is continuously sinking related to the air mass it's flying in, transferring potential energy difference from high to low altitude into kinetic energy, which means airspeed.
This case can be considered being close to a steady state condition with minimal disturbances apart from the fact that in windy conditions you might need to travel or to run across the country in order to get your plane back, because the moving "sea of air" may take it away from your sight.

Since most people don't think it's so funny keeping searching for their planes, they prefer to control them instead, thereby subjecting them to sudden aerodynamic forces, which may result in sudden unexpected outcomes.

:)

[admodesi]

BTW some of my indoor models will fly outdoors in reasonable winds....it's the well trimmed free flight models that work best and that's because they're not subject to (ground referenced) piloting errors ;).

Steve

Well said! LOL ...sound like some of these people need to vist the Dynamic-Soaring forum. Or even better try dynamic-soaring.

IMHO the term "down-wind turn" is an excuse bad RC pilots use to crash! :p I fly full-size as well and it is not an issue.

[Tom Harper]

FF2,

About a year ago Carl Moore and I rigged up some crude sensors and made flights to examine forces in the down wind turn. We selected days with winds above 35MPH. The model was flown upwind and the throttle retarded until the model was standing still with respect to the ground. So, the windspeed and the model speed were equal and opposite. The model was then quickly turned 180 degrees.

The plot, from the sensor data, showed that as the model turned the velocity of travel over the ground was related to the sine of the heading. Velocity over the ground was a smooth sinusoidal plot from 0 to twice the wind speed. There was no distortion due to acceleration. So the model was in equilibrium with the flow of the air mass. However, there was a dramatic loss of altitude. Dramatic in the sense that it was much greater than the same turn performed in calm air.

When the plot was posted on this forum the comments ranged from "that's neat" to "you guys don't know what you're doing". The usual stuff. All true to some extent. It was obvious that our instrumentation was not sufficient for the task. But, the model did lose altitude.

So, for the last year we have been working on better instrumentation. Actually this is a by product of a more serious effort. Should have some new plots by this summer.

I used to have opinions on this topic, but I have abandoned them. I'd just like to see the discussion based on actual data.

Tom

[David A Ramsey]

Only problem with the downwind turn is lack of altitude and power management... and forgeting that the elevator controls speed.

[funfly2]

FF2,

About a year ago Carl Moore and I rigged up some crude sensors and made flights to examine forces in the down wind turn. We selected days with winds above 35MPH. The model was flown upwind and the throttle retarded until the model was standing still with respect to the ground. So, the windspeed and the model speed were equal and opposite. The model was then quickly turned 180 degrees.

The plot, from the sensor data, showed that as the model turned the velocity of travel over the ground was related to the sine of the heading. Velocity over the ground was a smooth sinusoidal plot from 0 to twice the wind speed. There was no distortion due to acceleration. So the model was in equilibrium with the flow of the air mass. However, there was a dramatic loss of altitude. Dramatic in the sense that it was much greater than the same turn performed in calm air.

When the plot was posted on this forum the comments ranged from "that's neat" to "you guys don't know what you're doing". The usual stuff. All true to some extent. It was obvious that our instrumentation was not sufficient for the task. But, the model did lose altitude.

So, for the last year we have been working on better instrumentation. Actually this is a by product of a more serious effort. Should have some new plots by this summer.

I used to have opinions on this topic, but I have abandoned them. I'd just like to see the discussion based on actual data.

Tom
Thanks for sharing your tests, they are quite interesting.
Didn’t know about them at all and I can imagine what you’ve heard from some self-appointed “experts” here...

The plane loses altitude in order to keep airspeed, which would be lost if the pilot tried to keep it by applying elevator during the transition from upwind to downwind.

:)

[JetPlaneFlyer]

However, there was a dramatic loss of altitude. Dramatic in the sense that it was much greater than the same turn performed in calm air.

Tom,

Obviously any aircraft that performs a tight turn will have to either have extra power applied, or dive, to maintain airspeed (due to the extra induced drag generated in the turn)... This effect should be the same regardless of wind.

How did you measure loss of altitude?... Visually or with onboard instruments?

I'm wondering if the perceived greater loss of altitude could perhaps be down to the fact that the model turning in the wind would have been moving rapidly downwind which would make accurate visual altitude estimate impossible.

The other obvious variable is pilot control input. Relying only on the pilot to put in exactly the same control deflection and hold it for exactly the same time despite the different visual cues he receives from the model, would make the experiment invalid. I assume you had some way to ensure this was absolutely constant... Something programmed into the transmitter perhaps?

I'd like to think don’t have an 'opinion' on this either, just an understanding of basic physics.

[Tom Harper]

Jet,

Altitude, elevator position and airspeed were tracked by an Eagletree data logger. Speed over the ground was tracked by GPS.

Flights were made in calm air and the results compared to those in high wind. The sample rate was too slow for conclusive results. The present system has a 5 Hz sample rate which should do better. I can add a MSP430f169 processor to control the turn.

I am an engineer so I do not claim to understand the basic physics. However, I do know how to record and evaluate data.

The topic of this thread is psuedo-science. That term is generally applied to fraud. I don't think there is fraud involved when we draw wrong conclusions from our observations. After all, science is just rationalizing observations.

Psuedo-science usually results from rationalizing a conclusion based on incomplete data. In that case the theory may be correct and the conclusion still be invalid. Whether or not it's fraud depends on the motives of the presenter. For most of us it is just ignorance - which can be cured by data!

Tom

[HugePanic]

did you respect the fact that the windspeed is NOT equal at all heights???

at ground level it's much smaler than in 50m (90ft) height....

if the plane goes down 1meter in turn (due to incresed drag due to aileron/elevator usage) it might loose another 2meters due to the smaller windspeed...

[Tom Harper]

Huge,

Good point, it all comes under the heading of incomplete data.

Tom

[mlbco]

F2F,

More data for you to ponder:

http://www.rcgroups.com/forums/showthread.php?p=5691159#post5691159

Steve

[Tom Harper]

Steve,

Looks like a NW prevailing wind with 5 kt gusts.

That airplane is nicely on station in the circle.

Tom

[mlbco]

F2F,

Here is one more test case to try your theories against:

Forget about aircraft and consider a car on a treadmill. The treadmill moves at a steady 40mph and the car's throttle is controlled to maintain 40 mph on the speedometer. You are driving the car using RC controls and you maneuver on the treadmill as aggressively as you like (no steady turns required). From your point of view the car sometimes appears motionless when the treadmill speed cancels the car's speed. Does your theory predict that the car will rise off the treadmill to convert the "lost" kinetic energy into potential energy?

Steve

[biber]

I'm a self anounced expert in turning aircraft! :p

Most of the fullsize gliding I do (mostly thermaling and aerobatics) involves a vast amount of turning,
aswell as my modeling activities do, since F5D is all about flying in circles,
including sudden and very sharp turning.

ff2, you can call Vinny a troll for many reasons, but not because he would be wrong on this threads topic.
Your observations (are there any?) don't match mine and don't match the observations of the great majority of professional observers in science and avaition.

I take it the Vintage way, theory enables predictions of how something will behave.
in the realms to where the theory applies, it just works and I'm happy with it.

What i can't wrap my mind around is just, how you misuse and mix up everything,
so that (otherwise valid) theories loose applicability,
then come to conclusions that are not to be observed in nature
and claim that all the others have it wrong.

Don't let it get you irritated, when we continue to do it the old engineering way and even get it all working.
Just dream on.

biber

[vintage1]

If a theory, or an application of a theory doesn't agree with observations, then either the theory is wrong, or its being misapplied.

Boats going downstream do not sink, and boats going upstream do not rise out of the water. Ergo the kinetic energy with respect to the bank, is not reflected in a change in potential energy of the boat, with respect to the bank.

So something is awry.

It is only by selecting the sun as the center of the solar system, that the mathematics of planetary motions became simple enough to be calcualable: it is as true to say that the sun goes round the earth and planets, as to say the earth and planets go round the sun. It just makes the maths a lot easier if you take the latter view..

And that led to Newtons prinicipa, which in the end decided the really simplest thing was to say that all rotated round a common center of gravity, but the sun being much more massive, that was pretty much the sun's center anyway. That's the most simple and accurate way to picture it. Is it the case though? only in men's minds.

Einstein produced another view, that was even more accurate but rather harder to calculate..did that make it 'more real' ? I can't say.

Stuff works, or it doesn't. More, or less, accurately. If it works accurately its a good theorem and a useful one. That's all.

I've no problem with someone saying 'watch those downwind turns: you should make em faster and wider than you would think they need to be'

I do have issue with someone trotting out half understood physics to explain why its not a problem of perception though.

Its a bit like the apocryphal tale of the man who led a S American tribe out of deep jungle to a clearing where trees were being felled, and showed them the peple working' Why are they all so small? ' he was asked..and realised that in the jungle, it is not possible to see more than a few yards in any direction, and perspective simply wasn't in the understanding.

[funfly2]

If a theory, or an application of a theory doesn't agree with observations, then either the theory is wrong, or its being misapplied.

Boats going downstream do not sink, and boats going upstream do not rise out of the water.
...
Oh, I like this one, especially as it comes from an "expert".
Boats don't need water running to keep afloat, whereas planes need airspeed to keep airborne.
If a boat stops moving through the water it doesn't sink because of that, if a plane stops moving through the air it does sink.



F2F,

Here is one more test case to try your theories against:

Forget about aircraft and consider a car on a treadmill. The treadmill moves at a steady 40mph and the car's throttle is controlled to maintain 40 mph on the speedometer. You are driving the car using RC controls and you maneuver on the treadmill as aggressively as you like (no steady turns required). From your point of view the car sometimes appears motionless when the treadmill speed cancels the car's speed. Does your theory predict that the car will rise off the treadmill to convert the "lost" kinetic energy into potential energy?

SteveThe same answer applies here.
The car doesn't need airspeed to keep its "altitude" over the treadmill.
Anyway, if you keep the car's speed at 40mph on the treadmill and suddenly make a 90 deg turn, the car's forward speed over the treadmill would be reduced, it would also be pushed sideways and possibly roll over.

.

[funfly2]

I'm a self anounced expert in turning aircraft! :p

Most of the fullsize gliding I do (mostly thermaling and aerobatics) involves a vast amount of turning,
aswell as my modeling activities do, since F5D is all about flying in circles,
including sudden and very sharp turning.
...
biberNow we all know that planes may indeed make sharp turns and aerobatics without falling out off the sky.
Thanks biber for enlighten us.

I just don't think you're suggesting that you always maintain your altitude and airspeed during your acrobatics…

Underbar.

:cool:

[biber]

It's glider aerobatics and thus either airspeed or altitude vary or both of them.
During thermaling airspeed is pretty constant, however.

In case of the F5D stuff you can consider it to be at constant altitude, with acceleration on the straights and deceleration in the turns.

in any case, what you describe is not getting observed.

biber

[Roj]

Wow - i've been away from these forums for ages, and return to see the same old pseudo-science reinventing itself.
V1 I admire your patience...

As tempted as i am, i'm not going to be dragged into this debate. It's like trying to argue that the world is spherical to someone who's religion says it is flat. Debate is futile.

Anyway, if you keep the car's speed at 40mph on the treadmill and suddenly make a 90 deg turn, the car's forward speed over the treadmill would be reduced, it would also be pushed sideways and possibly roll over.

ff2 - Stay calm, and just promise to consider the possibility that the rest of the world might be right, and that you might be wrong.

There are plenty of basic texts on simple relativity and velocity vectors etc.
Read them.
When (not if) you finally realize why the speed of the treadmill is irrelevent in the above example, post back and report.

[deh6]

Back to vintage1's original, excellent post--

If you can find the following book it is a quite thought provoking piece that looks at the how scientific fact is socially constructed. The book is out of print and hard to find, though a university inter-library system should turn up a copy. It was written in 1935, but not translated to English until 1979 so the work was overlooked. It is short and fascinating to read. He sort of turns things around, building a case that facts are a result of a way of thinking about something (he uses the development of the Wasserman blood test and traces the changing of the concepts and facts of regarding syphillus).

Fleck, L. (1935/1979). Genesis and Development of Scientific Fact (Fred Bradley, Thaddeus J. Trenn, Trans.). (1981 ed.) Chicago, IL: The University of Chicago Press.

There is a lot of overlap with the ideas Kuhn (this is the guy that coined the term "paradigm shift") expressed in his work (e.g. Stucture of Scientific Revolutions (1962), The Nature of Scientific Revolutions (1970)). Bruno Latour is a more recent author has a number of books in this area. He makes some arresting statements, my favorite (paraphrased) is that nature is not what determines the outcome of an experiment, but it is the experiment (and the thinking behind it) that results in people agreeing on what is a law of nature.

This is rather primal stuff, but then this forum is about modeling science this thread focuses on the science aspect.

And,...there seems to be nothing that gets the juices up faster with modelers than a discussion of downwind/upwind turns.

[Tom Harper]

You might also try "Posterior Analytics" by Aristotle.

Tom

[AndyOne]

Hummm, he was Greek wasn't he!

Andy.

[vintage1]

I had forgotten Thomas Kuhn: I think the whole trend starts with Karl Popper, and the others mentioned added to and helped redefine the scope of what science actually is.

Popper clearly states that his ideas arose out of a deep dissatisfaction with some of what was being called 'science' when he began his thinking: In particular Freudian psychology, a 'science' that he felt was not subject to refutation and proper testing.


Its always important to get back to first principles when you have problems with theories and suchlike: Quantum physics is in a similar position - we tend to think in terms of the actual reality of things like gravity, electrons, force, energy, motion and the like. Its very imporatant when pushing the boundaries to remember that these are only notions, notions of invisible things that 'if they existed' would 'fit the facts' (save the data).

In my more mystical moments, I tend to regard the whole world of experience like that: merely a notion that 'saves the data'..after all, the only evidence we have of the existence of anything is our experience, and that itself is (neurologically) filtered through an 'array of preconceptions'.

There is plenty of evidence that if that array gets screwed people end up in a completely different (subjective) world..our only experience of Time is via memory. If that gets wrecked - as in dementia - the person affected lives in a completely different time reality. The old person will solemnly assure you that they have just been 'walking with their dog' despite the fact that the dog has been dead some 30 years..all intervening memory having been wiped, that is the reaility of the situation, to them.

The frightening thing is that the world of 'facts' are only 'facts' because we all see them in similar terms.

It's not even Heisenberg that stands in the way, there is a greater Uncertainty Principle involved: that of our own perceptions and interpretations.

This shows up in two ways when flying model aircraft, in a more or less trivial fashion. The phenomenon of 'aileron reversal' when the model flie s towards you, and the 'downwind turn'

People whose preconceptions cannot cope with the relocation of frame of reference in the first case, from a 'behind the model' prespective to an 'in front of' the model perspectve will naturally push the sticks the wrong way.

In the case of the downwind turn its translation to a frame of reference that is speeding downwind that causes the problem.

Mutatis mutandis in the end there is not real difference between concocting grandiose theories of epcyclic complexity, and going with the moving reference frame. But as with Newton, the math gets far simpler if you simply translate the frame of perceptual (and inertial) reference to the moving air mass, and then all the maths gets simpler.

I've noticed the same problem with driving: Very few people can do the sort of double second differential equations in their heads as it were to work out how hard to brake to avoid e.g. hitting a car slowing in front. A fact that leads to many a motorway pileup as they over or underestimate the time.

Also shooting: people who can snap a clay out of the air every time at a fixed range and velocity, can't hit a speeding pigeon at all. When walking with some shooting friends I asked what the muzzle velocity was and calculated that a 40mph pigeon at 50 meters needed about a 6-10ft lead, plus a fair amount of drop allowance from a typical shotgun. Highly counterintuitive.

It's probably no coincidence that former F1 world champion car racer Ja
ckie Stewart, is also a crack shot, and suffered from dyslexia. My bet is his brain works in a way more suited to complex analysis of differential equations, rather than reading and writing...;)

At the philosophical level, we find that Science has had its best results when by a stroke of the pen, it relocates itself from one frame to another. Kuhn's 'paradigm shift' is the buzz word for this.

However that is not what most people WANT to do. They want a 'one size fits all' absolute frame of reference. Its easier to handle. So people are taught in terms of absolute Truth, and if you want a system based on Absolute Truth, you will inevitably end up with some sort of supernatural component, some Absolute that is the prime something or other in the universe.

Its my beliefe that the greatest advances in 20th century philosophy have been in deciding more or less completely, that whilst there may well be some sort of absolute something underlying the complexity of everything, we cannot actually ever hope to discover what it is. Opportunities for alternatives will always exist. Largely because we, as thinking beings, do not stand outside of the world like gods: we cannot ever stand on ground that is not part of our preconceptions.

Of course you CAN say, if you like, that our intellectual abilities are entirely outside the universe: consciousness is 'spiritual' and so on..but all that does is to transfer the ultimate problem to some extra-physical plane: Not solve it. I think - and its hard to tell - that this is the essence of Kant's 'critique of pure reason'. I also belive (my maths isn't up to the formal proofs) that Godel's incompleteness theorem* is in the same league.

In the end, the answers you come up with depend on what you assume to be self evident a-priori fact before you start doing the analysis.

Whether you place your model in a ground based frame or in its own air based frame, in this case.

Either can be made to work, but some are more simple than others.

What you cannot do, hwoever, is use relative analytic systems (Newtonian mechanics) refereced to an absolute frame, and get the right answer. That is falling between two stools with a vengeanace, and will result in splintered balsa every time..

* As I understad it, the essence of Godel's theorem, is that no formal mathematical theorem that actually does something useful, other then - say- that if something is true, its true - must necessarily have in its core some assumption that is self evidently true, but canot be proved to be so within the theorem itself. To me that implies that no theory can be constructed about the world without making some or other - or many - unprovable assumptions about the world before you start. If I read Kant aright, he was saying the same sort of thing: space and time are not inherent properties of the world, they are inherent properties of the way we think about it . A subtle, but very important distinction.

[Brandano]

At the end of the day it all reduces to "Cogito, ergo sum". Everything else is an assumption.

[Odysis]

At the end of the day it all reduces to "Cogito, ergo sum". Everything else is an assumption.

Wow Latin changes with the years... It was "Bibo, ergo sum" when I learnt it :p