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bearfoil
27th Aug 2010, 19:25
Please forgive me, I can't help myself, and this has been done to death.

I've been flying a very long while, even used to make good money doing it. More than the joy of flying away from a sunrise in a pink/orange hued cockpit as the Sun climbs.......

I can't not stare at the wing in flight, unless it's swept, that gives one a sore neck.

Years ago after flogging the Bernoulli debate to the verge of nausea, I came up with a proof which led to a sought for patent. After I had only spent 7,000 in 1992 dollars was I to find out that a man named Frank Garza owned the (then expired) patent.

Briefly, (or google Garza), replace the tail boom of a helicopter with a wing. Say a chocolate bar Piper constant chord draggy dinosaur. On a spar, the wing can change AoA relative to the downflow of the Main Rotor Wash. It replaces the Tail Rotor assembly, saves all the energy lost in transmission and gearing, not to mention almost no maintenance, and of course requires no "Watch your Top Knot, Jose".

Won't work? Oh yes it does. You've just not recognized it. I have a working model, proprietary of course, and have improved Mr. Garza's work perhaps five fold. (Never been too shy). I've added some captured energy, and included some nice unprotected NASA work I saw At Moffett. The Patent Applied For sits on my Attorney's desk, I'm out 15,000 dollars, and need an expensive proof/model built.

This new thing, I'm rather proud of it, and now my attorney will do the rest of the work on credit, see, he flew Helicopters in the Air Force, and he is my biggest fan.

I don't know if this is Modworthy, but I don't want to clutter up the 447 thread discussing making money. (If anyone brings up NOTAR, you don't understand the concept, or you are not a pilot).

bearfoil

henra
27th Aug 2010, 20:11
Hi Bearfoil,

This is an interesting approach and to a small extent some Heli manufacturers have included the basic idea behind in their Heli's.
AW uses stringers on one side of the tail boom to generate some lateral 'Lift' to counter the torque. The same applies to MD with their NOTAR's.

As a sole means of countering torque, I don't know jow big that 'wing' would have to be, I'm afraid, it would have to be huge.
How big does it have to be on your model ?

The next problem could be the dynamics of the downwash, especially if gusts spoil it. Will it be possible to keep it reasonably steady with this measure alone ?


regards,

henra

bearfoil
27th Aug 2010, 20:47
Hey! Since it is "vectored thrust", it is in the high speed realm of response. The directional control is quite authoritative. The actual size of the wing is unknown to me, my mission as of now is to present a model with my formal application. Have you been involved with patent work? It's an education. Did you know the Patent Office has no care whether the idea "works" or not? It only has to be new, not what's called "prior art".

I'm trying to think of something flying that uses Garza. There is a flying "Dish" that uses downwash as directional control, it may actually have appeared here, but in JetBlast!

in short, I left Bernoulli behind, I hope you don't think me arrogant, but Bernoulli was a genius in Fluid mechanics, and within a pipe, at that. If he had ever seen an a/c, (he didn't of course) I like to think he would be confused as to the aeronautical application. He applies in ground effect and up to 272 knots (arguably) but without AoA and a view of work that is lost on (some of) his adherents, (I am not one), his work is inapplicable to modern aeronautics. His theories are used to easily explain Lift to the beginner, but Nature doesn't allow a vacuum, (ever), and the real work is done on the bottom, not the top.

For the most part, NOTAR is "COANDA".It is first generation, and again, don't think me presumptuous, it works fine. I saw pictures of a groundy who walked into a tail rotor aboard ship. Except for the Mains, a helicopter is quite safe with NOTAR, how many lives and maintenance/parts has it saved? I'd like to see the numbers.

Briefly, Who hasn't heard/given the lecture? Each molecule of air travels either over or under the "airfoil". The top molecule has further to go and less time to get there, fewer molecules mean less pressure on the top, the wing "pulls" the a/c "up".

There are two fallacies in the opening gambit. First, it is in no way necessary (or even likely) the two bespoke molecules reach the trailing edge at "the same time".
Second, Nature does not allow "Pull" or "Suck". It is a fallacy of the first order as my first chem prof explained. "When you think you see a Vacuum, you don't, you just don't see the "Push".

cheers!

ChristiaanJ
27th Aug 2010, 21:26
I googled Frank Garza, but all I got was baseball players and suchlike.
Any more specific links?

CJ

bearfoil
27th Aug 2010, 21:33
US Patent4462559

Google Garza, helicopter control, or Lateral control of helicopters. I never did see drawings, actually and come to think of it, his designs had ailerons on the wing.You know, I may have been too hasty re: Garza's work, his patent describes a complexity nonexistent in my proposal (not that that is a bad thing). I may be in lock yet with the original. Y'all are sworn to silence, Hear?

bear:O

henra
27th Aug 2010, 21:34
His theories are used to easily explain Lift to the beginner, but Nature doesn't allow a vacuum, (ever), and the real work is done on the bottom, not the top.

Hi Bearfoil,
That's where I tend to disagree.
If you take a very asymmetrical Wing e.g. a NACA 4312.
The lower side is still slightly convex.
Yet the airfoil has a lift coefficient of 0.3 ! at Alpha = 0°.
I see no other explanation for this than the fact that a low presssure on the upper side creates a 'suction' force on the foil.
And that has nothing to to with Ground effect as Alpha is 0 and thus no compression takes place on the lower side.

When Ground effect takes over you will notice that by a shifting of the center of lift from the quarter chord line towards the mid chord line.
When you have only ground effect the center of lift of a flat plat with AoA will be at 50% chord.
Convex or concave shape of the plate will shift the center of pressure / lift according to the local velocities, i.e. crossection.
Which can btw. also be explained by Bernoulli. I have to confess I'm a believer in Bernoulli as long as no one comes up with a better explanation.

bearfoil
27th Aug 2010, 21:53
henra

I've discussed this with many folks, and frankly neither approach is completely "correct" Only insofar as one rejects the other completely, and it is a fascinating discussion.

A "Fat wing" with 0 AoA may of course produce a "suction", but as above, and I believe this is an important and pivotal point, there cannot be a "suction" absent a "push". Picky? No. Accelerate the fatty to whatever velocity you like, the wing will not leave the ground. Not because it's a mystery, but because the mechanism of Flight is done a disservice by disallowing the underwing "pressure".(NOT Ground effect, that is for later, and it too is not mysterious).

Wait, you say, eventually the wing will have plenty of suction at "X" knots! No, it won't, the "center of lift is changing" and will constantly lower the LE to balance the "Suction". If you try to overcome this aftward drift of CL, you are pretending to be the Tail, with its downward (increase, actually) effect on AoA. The wing by itself will constantly compensate for what is claimed is lift, by biting less air.(decreasing) AoA.There is no airfoil that will produce lift without an AoA. This is why Flying wings are hideous without FBW. Same, Harrier.

I think it was Glenn Edwards who said, after the wing crashlanded and caught fire, at Muroc. "I wish they hadn't put the f*****g fire out" It was prophetic, the wing eventually killed him. That is why "Edwards" AFB. Why "Muroc"? The only people living on site when the AAC set up shop were named Corum, Muroc, backwards.

Christiaan?

ChristiaanJ
27th Aug 2010, 22:18
Thanks, just found Garza.
Will read that in peace tomorrow, past midnight here now !

CJ

MrBernoulli
27th Aug 2010, 22:48
Never was a plumber. All lies! :E

bearfoil
27th Aug 2010, 22:53
Neither was he, and I did not know he had progeny! :ok:

Brian Abraham
28th Aug 2010, 01:10
Love to see a drawing of what you propose bear. I think I have a picture in my head, but fail to see how the idea would work when the tail is devoid of downwash ie autorotation as one example - downwash changes to upwash. I'm sure you have it worked out, hence the request for a drawing.

bearfoil
28th Aug 2010, 01:22
Brian Abraham

You have the big picture, try the small one. You don't get a tail, nor do you get a Fuselage. I'm in the tunnel at Moffett, the wing is mounted to "nothing", with only brainpower to envision a perfect response (retaliation) to each packet of energy.
You want a fatty, or a razor blade? I like things backwards, let me see it then I'll figure it out,

Oh, and no swing wing either Aardvark. Here: Only one wing, no taper, constant chord, mounted to an invisible spar that moves back with the aftward movement of Cl and its corollary. All the impinging energy is conserved, the weight of the wing is supported at all times by an invisible spar that can rotate with the chord of the wing, (but it won't, as you'll see,) and is ready at all times to "Lift" the invisible Fuselage, but it won't, etc. You can add drag if you like, it won't matter, it will always be counted invisibly. Increase the speed of the airstream all you wish, you cannot have "Lift" until there is an angle of Attack, positive or negative, all the same to our structure. If for one millisecond the system allows an AoA, it would be very bad, things would disintegrate quickly. Again, as above, the flying wing is nibbling at disaster every second of flight, it is phenomenal that humans could control it at all.

The only redeeming trait of the flying wing is that its angle of attack envelope is narrow, the wing can hardly go out of control over the top, but it will, if the hapless pilot is lucky. What the wing truly wants to do is reverse positive AoA for negative in hundredths of a second, it explodes from flutter. That's the un lucky scenario. I hope I haven't spit out the constraints of the theory and put you off.

Very basically, along with theoretically, I am trying to demonstrate that as the Cl moves aft, its bottom component (push) is directly under the top component, the "Suck", and the wing will not produce the desired effect per Bernoulli. The upward movement of the after portion will be met with a downward movement of the forward portion. Leading edge drops, and the wing will actually move down, That is not what we want, we want flight, and that takes a more complicated combination of surfaces. The "dropping wing has an AoA". By demonstrating how what is taught is actually theoretically opposite to the effect assumed, I think AoA is a better way to teach flight, from pushback to cocktails. With Bernoulli, students make a leap past some fundamentals, sometimes for a career.

bearfoil

henra
28th Aug 2010, 09:04
A "Fat wing" with 0 AoA may of course produce a "suction", but as above, and I believe this is an important and pivotal point, there cannot be a "suction" absent a "push".
Hi Bearfoil,
I absolutely agree and so does Bernoulli:
There is a push.
In static air, a push is performed on the wing with 10^5 Pa from all sides (at Sea Level).
Now that the wing is moving through the air, Bernoulli says, that there is still a push of 10^5 Pa.
And now comes what I falsely quoted as 'suction' :
On the upper side, the static push has dropped below 10^5 Pa.
That is due to the sum of static + dynamic pressure being constant.
The air has been accelerated above the wing, because at the end of the chord the air wants to merge again at the same point where it separated in front of the wing. Otherwise you would get a 'hole' in the air at the end of the chord on the upper side.
The profile of the speed of the air above the wing depends on viscosity of the air.


Very basically, along with theoretically, I am trying to demonstrate that as the Cl moves aft, its bottom component (push) is directly under the top component, the "Suck", and the wing will not produce the desired effect per Bernoulli. The upward movement of the after portion will be met with a downward movement of the forward portion.

I have to disagree.
And so does NACA:
If you look at the moment coefficient around the Quarter Chord line of an airfoil in free air, you will see that it is roughly the aerodynamic center, i.e. the axis around where a chnage in Alpha does not increase the pitch up moment.
If you take the mid chord, the moment coefficient is hugely positive, i.e. any posiitive change in Alpha increases further dramatically the pitch up moment of the foil around this axis. It won't stabilize.
Putting the axis of rotation (in a plane that would be the Cg) in front of the aerodynaimc center (which is for most foils close to the 25% chord calculated from the LE) is the basic priciple of aerodynamic stability as the tail fin is pushing slightly down and equalizing the moment of the Cg.
As the tail fin is excerting a mostly linear force (due to working closer to Alpha = 0 than the wing which has an incidence) the Cg in front of the aerodynamic center causes a negative moment coefficient, i.e. with an increasing Alpha, the pitch up moment on the main wing reduces more than the down force on the tail.
Edit: Flying Wings achieve this with an S- shaped foil, where the TE section provides the downforce.
/Edit
That's basically how the plane stabilizes itself

bearfoil
28th Aug 2010, 12:31
henra

Your last paragraph describes precisely what I want to convey, with one exception, and in this exception is where not Bernoulli stumbles, but the blunder every (well, more than a few) teachers of Bernoulli make, as I did, until I grokked the flaw. Perhaps due to impatience, where the Jedi draws the little picture for Paduan, an assumption is made that "Lift is here, and the wing lifts the plane". No, it doesn't. Without the tail, it nose dives into the dirt.

I don't start with the little drawing of the complete a/c. As simple as it presents, it almost invariably confuses the learner, as it did me once, causing a resentment against the genius behind the equations, and an irritation with Hank, a classic old school Captain with a now gone A/L.

The "lift is here" and because our wing is suspended in space in a make believe wind tunnel, attached to invisible spars that rotate, and with no taper, a constant chord, and a reasonably exaggerated chord (fat), I don't want anyone to say: "and the airplane climbs and all is right with my world".

I want to hear, "The leading edge will drop, and the ugly lonely wing will dive for the deck.When I hear that, then I "attach" the fuselage, and move on to the next discussion. I firmly believe that one does not teach one to fly.

One teaches one to learn how to fly.

bear

bearfoil
28th Aug 2010, 14:16
Brian Abraham

Holy crap. I just tumbled to the fact you asked about the heli and I gave you Bernoulli.

What a dunce! I hope you forgive my inattention. A picture is forthcoming. The tail boom replacement is not actually a "wing" at all, it is more a "Vane". The length of the tail, and pivoting about its spanwise center line. It grabs a gob of downwash, and I consider it "Vectored Thrust" rather than lift. It articulates through a simple hydraulic ramset that will change its bite through ~60 degrees.

Autorotation is unexplored as yet, Do you have any ideas? I'll cut you in for a percentage!!

bearfoil

henra
28th Aug 2010, 17:23
No, it doesn't. Without the tail, it nose dives into the dirt.

Hi Bearfoil,
Fully agreed !
The Cg of the whole thing should be in front of the center of Lift of the wing, thus creating a perfect Lawn Dart.
I think we some times have just misunderstandings concerning the way how we describe things....

regards,
henra

AerocatS2A
29th Aug 2010, 10:17
The air has been accelerated above the wing, because at the end of the chord the air wants to merge again at the same point where it separated in front of the wing. Otherwise you would get a 'hole' in the air at the end of the chord on the upper side.
The profile of the speed of the air above the wing depends on viscosity of the air.
There is nothing wrong with using Bernoulli to explain or calculate lift. If you measure the velocity of airflow around a wing section, Bernoulli will accurately predict the pressure differential. What is wrong with the typical Bernoulli explanation is what I've bolded in your quote. The air doesn't meet at the same point, if it did that there wouldn't be enough of a velocity difference to account for the lift. The velocity of the air going over the top vastly out strips that of the air around the bottom and the air over the top beats the air it separated from at the leading edge.

So to summarise, Bernoulli accurately predicts lift from the variation in velocity around a wing, but the "air over the top must meet the air across the bottom at the same point it separated" is wrong.

On the other hand, the typical "deflection" of air theory completely ignores the importance of the shape of the top surface of the wing in accelerating the air mass.

Newton and Bernoulli are both correct, they are both different ways of measuring the same thing. In simple terms lift is produced because the shape of the wing along with the angle of attack of the wing causes the air mass to be accelerated downward. Bernoulli accurately predicts pressure differential and therefore lift from the difference in velocities around the wing, Newton accurately predicts lift in terms of air being accelerated downward. So Bernoulli and Newton are both correct but the typical explanations of lift using Bernoulli and Newton are both wrong in important aspects.

bearfoil
29th Aug 2010, 13:48
AerocatS2A

I said it differently above, but using two good (but different) tools for the same task is acceptable, and there is no argument anywhere to be found. Like in many other pursuits, the experts get where they are by employing many different processes; even when using one is fine. The theoretical approach can appear wrong when it isn't, it's utility is elegant when used to build a foundation.

In problem solving groups, I have heard (and used) the expression, "Let's look at this a different way", or, "Let's unwind this tangle, and start over with a different method."

I like Newton for air handling that is "complex", because it is simple in that domain.
Bernoulli is a complex way of understanding something straightforward imo.

One can get bogged down in the math, and the simple equations are my friend.

The "all-flying tail" can be a flat slab, the nuance is on the top, the basic work is on the bottom.

bearfoil Are you Grumman or Pitts?

henra
29th Aug 2010, 20:00
The air doesn't meet at the same point, if it did that there wouldn't be enough of a velocity difference to account for the lift. The velocity of the air going over the top vastly out strips that of the air around the bottom and the air over the top beats the air it separated from at the leading edge.


Aerocat,

<Deleted: Should have read your post correctly !! >

Edit2:
Or are you referring to the circulation model ?
/Edit2
Edit3:
I re-read your post, should have done that earlier:
You are referring to the circulation model.
OK, that is one of the valid explanations for the Lift of a wing
/Edit3

<deleted, explanation above >
With Newton I'm OK.
Edit:
It's a combination of Newton and Bernoulli, the proportion depending of the shape of the foil.
Thick Profile with steep TE => Lots of Newton
S-Shaped profile (flying wing) => very little Newton.
/Edit

bearfoil
29th Aug 2010, 20:32
Professor, Professor! Me ME.

"bearfoil, Please, give some one else a chance, be patient!!"

rats, rats, rats.

Professor? Fine bearfoil.

Well, the molecules do split up at the LE, that much we know. Let's assign Red uniforms to the Top ones, and Blue uniforms to the bottom ones. The Red ones start thinking... "Where's everybody going?", The Blues, "Damn, it's getting crowded again, I should get here earlier."

There is absolutely no chance the two molecules at the LE will ever meet, at least not in this time frame. There is no Necessity, and virtually no chance.

The Reds speed up and shift their heading toward the tip. The Blues stay on heading and meet other Reds, ones who started inboard from the first Red. There is a new color beyond the trailing edge, Purple, and it is very turbulent. The cost of upsetting the still air to make it work is basically a fashion statement. I've actually seen this done, and it is spectacular. On to the "Winglet?" There is a hint watching any modern jet make water cones behind its leading edges, (When it's rockin and rollin with nimble changes in direction).teeny at the Front, expanding as it is left behind. The tip of the cone can't be that different from the wake behind? There isn't time. Dead give away. So really high pressure at the LE, lessening as it travels oer the surface? The Red uniform has to stick close to the aluminum to have a chance at meeting his LE compadre. What's the ODDS? Long, real long.

bear

henra
30th Aug 2010, 07:25
Bearfoil,

I have to admit I always had difficulties with the circulation model at AoA = 0 for an asymmetrical foil like e.g. NACA4312.
It's clear if we have a high AoA where the air on the lower side is decellerated. In that case we get a flow around the TE which tries to 'fill the void'.
To stay in your very nice example like in real life the molecules want to have equal space around them. I.e. they alway try to go there where the density is lower, i.e. where there seems to be a void.
That is what you see in animations of the circulation model.
If you now take a semi- symmetrical Profile at Alpha = 0, you don't have a decelleration. You only have less acceleration on the lower side than on the upper side. And that is a case where I don't really see a significant equalising flow from Upper to lower side at the TE. I see more or less just the added vertical speed component which gives the Newton Part of the Lift.
From my point of view the circulation only becomes really relevant at certain AoA. For very low AoA I tend to consider in negligeable,
Would be interesting to make such a simulation in coloured water for different AoA's to see when the effect really kicks in.

Very interesting discussion !
Thanks for the thread !

regards,

henra

bearfoil
30th Aug 2010, 10:33
henra

It is after all, all circulation. The descriptor (Bernoulli) at 0A is negligible. That is the problem I have with it. Volume (circulation) is only drag until the LE rises relative to flow, (for all intents and purposes).

A mental image I use is that the wing is an expensive air compressor. Blow on your hand, there is a rise in Pressure. It isn't contained, and nothing happens to imitate actual work. That is why, to me, Ground effect is a critical concept for the novice, one uses it (instinctively, one hopes), for a lifetime. The deck is a dynamic "container", and gives a freebie in "Lift".
Another is that I present the a/c at speed as a ski boat, "Planing" on the dense water, oblivious to the "top" of the "wing". I have set up a complicated model in the tunnel that is two "layers", a dense lower layer, and a very LP "Upper". If separated successfully, the "wing" needs no incidence at all, it rises magically.

Well, Newton is my preference. I've seen diagrams of Bernoulli with thousands of little arrows, but in the time it takes to get anything out of it, Goose has kicked the tires while Mav lights the fires, and they are heading downtown for a knife fight.
Newton would have loved to fly, but other pilots might have avoided him, that is another thread, (for the National Enquirer). Or The Guardian.

it has been fun, take care.

bear

AerocatS2A
30th Aug 2010, 11:40
Edit:
It's a combination of Newton and Bernoulli, the proportion depending of the shape of the foil.
Thick Profile with steep TE => Lots of Newton
S-Shaped profile (flying wing) => very little Newton.
/Edit
That is not quite correct, It is ALL Bernoulli AND it is ALL Newton. The classical rules of physics don't apply in half measures, they are both different measurements of the same thing. Take any wing of any shape and you will be able to account for ALL of the lift by measuring velocity and pressure around the wing (Bernoulli) and you'll be able to account for ALL of the lift by measuring the downward acceleration of air, they are not mutually exclusive.

henra
1st Sep 2010, 22:27
Aerocat, (Bearfoil)

I really have to work on the way I describe things!! :{
I had the same misunderstandings with Bearfoil, so I derive it's got to be me who is messing the descriptions up! (obviously badly:})
Btw. I re-read my own stuff and it is indeed misleading.

Sure Newton and Bernoulli are two equally valid ways of calculating the Lift. Both will deliver Lift as a result, that is the complete Lift, not additional. Sorry for bad explanation, will have to work on that...