Feb 23, 2008, 8:03 AM
Post #1 of 103
Following on from previous threads / discussions about Atmonauti I was wondering if anyone could explain the ‘lift’ phenomenon and whether steep angle flight can produce real lift as claimed by some Atmonaut’s? Apart from the effect of the rig rising off the back, which could be attributed to a number of different things, is there any real hard evidence that such a thing can happen?
To understand the illustrations, it's best to first understand how lift works.
On the left part of the first illustration:
On a 45-degree angle, in a flat body position, less wind will travel across the top of the body. More wind will support the bottom part of the body. Essentially, this will pull your body down quickly.
On the right part of the first illustration:
On the 45-degree, with an arched body position, a flyer has the ability to fight gravity by creating more forward drive. The trick is to try getting as much wind as possible to travel across the top of the body to encourage the lift property. When the momentum picks up, it has more of an affect by dialing in the correct angle and arch.
See the AirPressure.gif illustration: The position is comparible to that of an aircraft wing, if you look at it from the side. Planes lift off of the ground, more because of the wind above the wing than the wind below it.
Sorry Bet Midler, maybe you should rewrite the song.
The arching can be seen through the majority of this video by Marco in Italy:
The rig phenonenon as explained on the deleted facebook thread is this....
When hitting a bit of an angle the gap between the back and the rig is exposed catching air. It pivotes unwards on the attachment points on your body ie... chest strap and hips. Also the rig is lighter than a person is and moves upwards.
Somepeople ie...Tiezzi and his guys, think that this is in itself hard evidence that a human body generates lift.
The other evidence that they push is a picture of someone with thier t shirt gettting blown up while back tracking/atmo'ing....
On thier web site a number of basic diagrams describing lift generated by a wing moving through the atmosphere and then they dirrectly compare hgher and lower angles with the wing and a human body in the air. The conculsion made is that these two modles are directly comparable.
A couple of discrepencies do exists though.
1) the basic calculations for how much an airframe generates are readily available. Add them up(NASA has a good site). Infinitely more drag is produced than lift. The amount is laughable really.
2) Without an independant means of power(a propellor), were not really talking about flight in meaningfull terms. Gliding an extreem push at that
In terms of high and low angles as they relate to how much angular deflection is created and speed, that is very quantifiable. Very interesting as well as they relate to your personal 'wing loading' or BMI(body mass index).
Like your signature block..... can't make a horse surf!!!
I think the model for lift generation holds true for highly loaded wings such as human bodies, the model has been used for long enough and is proven.
there are a couple posed questions which are a bit ambigous... one of which is 'does the human body generate lift'.
Crunch the data, i have. The amount generated is laughable. Some are trying to take the rig moving or t shirts as proof. This falls faily short of being convincing. Dispute the model, dispute the maths and dispute the laws of physics. Its pretty hard to do so.
There is alot of pseudo science being thrown around. Some people are casually using visual evidence to jump to an conclusion without looking at the aerodynamics which are the basis of our undersatnding of the whole field of flight. They are also casually ignoring other aspects which dont support thier conclusion.
I think the term of lift can probably be related to a fairly romantic view of this endeavor. You see it in other sports like climbing, scuba diving and base. None of us are flying, its falling. We arent swimming like fish etc....
I tend to view the forces at play in angle flight and vertical flight in the same manner. We generate more or less drag to create angular deflection to move across the sky. Lift probably isnt an appropraite term.
(This post was edited by fedykin on Feb 23, 2008, 10:49 AM)
Lift, in this scenario, is a relative term. If you are refering to the lift-to-vector speed ratio than yes you're correct. The skydive lasts about the same amount of time as a head down jump. But since flyers are not head down, rather on a 45-degree angle, then there is a difference.
If you are refering to a comparison of flat body or simple tracking than the ground speed is significantly greater. The comparison here can be proved by having flyers fly straight on a 45 without arching their bodies. Then do one where they are arched correctly like a wing. I would expect a difference - if only marginal - still a difference.
Dave, looks like we might be able to have something approaching an intelligent conversation!
Id agree and the overwheming amount of emprical evidence does suggest and prove that the jump does tend to last for a longer period though not for the reasons that some people state ie... lift
I believe and the tunnel evidence will support my hypothesis.
Greater surface area, ceteris paribus(latin for all things being equal, a term we tend to use in economics) means slower fall rate, which in term means longer ride. The larger surface area exposed to the relative wind in tracking, tracing, atmo... whatever means longer jumps. In the tunnel the more movement the higher up someone goes, same thing in the sky ie... stalling to get back up to the formation, double clutching, flicking, whatever you call it.
The fact that it looks like a wing because of the stepper angle does lead one into direct physical comparisons ie... wings and lift. I believe employing logic like this is a bit faulty ie... Mistaking the wood for the trees and vice versa.
The physics at play make lift an impossibility. It's understandable that comparisions are made as we tend to spend so much time around aeroplanes each day and directly associate the two activities, though confusing the variables at play results in comparing apples to armadillo's.
Angular deflection, surface area and drag. I believe these terms are more relevant to the study of human flight. Not lift.
The romantic mindset endures, it is impressive.
But then again, even the Italians amoungt us will appreciate the fact that the unbridled passion and excess of Nero did little to add to Rome's spleandour. I would attribute more positive influence to the detachment Stociism of Marcus Aurelius.
In atmonauti lift is clearly generated, it utilizes the forward speed generated by the angled flight (from 10 - 70 degrees) to promote the movement of air across the "airfoil" whichj is our body in this case, and a low pressure is generated above the skyflyer when done correctly. In frontmonauti the rig not only lifts upwards (incorrectly stated to be due to air entering the space between the back and inner part of the rig causing it to separate), but it ALSO MOVES FORWARDS in the DIRECTION of flight (a clear illustration of the low pressure just above and ahead of the skyflyer's head).
In backmonauti (reverse frontmonauti or backflying) it is common place to see the t-shirt/top lift up and towards the face (if not secured correctly) which again is an illustration of the low pressure zone just above and in front of the face.
In Tandem Atmonauti, the reduced ff speeds are also a clear indication of lift compensating for the effect of gravitational force, WITHOUT the use of a drog.
As with anything in life, if it is done incorrectly the lift is compromised.
Atmonauti is clearly a super fantastic discipline, utilising lift to compensate for the gravitational force, is social, extremely dynamic and easy to get to grips with - in much less time than freeflying, although it also offers challenging moves such as feet first atmo (footmonauti), dynamic transitions, RW etc.
It’s only flying! No need to get defamatory or threatening!
All I wanted was to find out if real lift can be generated (useable lift), in order to prolong flight.
There seems to be two types of argument here.
Fedykins: That the Atmo position in the correct angle creates more surface area, resulting in high pressure on the bottom surface area, slowing the fall rate and the use of angular deflection to produce the forward drive. It’s a matter of shape, body position and angle that allows for extended flight time.
The other arguments: That Atmonauti creates areas of High and low pressure resembling Wing aerodynamics and it is the phenomenon of lift which alows for extended flight time.
Can we stay on topic and not dirty this thread with personal snipes? Thanks.
On that note has there been any real non biased data produced in regards to this topic?
skymama (D 26699)
Feb 24, 2008, 9:56 AM
Post #10 of 103
Dude, atmonauti has a tendency to cause a few subjects of dispute. Some people think it is the same as tracking. "oh..we used to do that in the mid-90's man...it's called tracking".
Whether or not it is a discipline all its own, or lift is possible or not - in which both cases I happen to see it this way -
...either way...it's fun and challenging to maneuver in the angle. Relative work in atmonauti looks money. Transitioning takes A LOT of practice. Smooth docking has a price in jump numbers. Go fly, make it happen, try to create lift, and be creative with it.
In the mark of flying, 45-degree flight has only been experemented. The "tracing" going on at the Nordic Meet and the events that the Italians are putting on are invite-only. The reason for this is that people who practice it regularly are the one's who can do it.
It takes discipline to fly in formation. Get out of a plane and try getting good at it. I still am working on it. In America, it is less popular. Luckily, ZHills gets a lot of Europeans and they like flying the 45. Be safe...Peace....Blue Sky's.
ps....obviously lift is possible however marginal.
(This post was edited by Vertifly on Feb 24, 2008, 10:02 AM)
Here are a couple of interesting things to note when talking Atmonauti vs tracking/freefall:
a) It refers to all angles of flight where lift is being generated (or an attempt is being made at using the body to create lift - whether large or small) in order to compensate for the effect of gravity.
b) In traditional forms of skydiving we utilise the relative wind generated by the gravitational force on our bodies, such as in fs/freefly etc, and we deflect this wind in order to achieve a multitude of stable body positions (in all axis).
c) In all forms of tracking flocks, the relative wind is still from below as we are still in relative freefall, with the wind in our faces and on our chests when tracking face down. The body position is head tilted upwards, hips down, arms behind our shoulders where we cant see them, and we face where we are going.
d) In Atmo, the reverse is true: We position ourselves ahead of the navigator/other atmonauts when setting up, with our heads tilted downwards to the rear (seeking the opposite horizon) and with our arms where we can see them and our midsection, if anything, pushed upwards. The body form is an airfoil in principle.
e) The Frontmonauti set up is everyone ahead of each other (in relation to the ground) when setting up above the rest (on HEAD LEVEL). There is NO relative wind in the face and/or on the chest as in tracking and the relative wind is from the crest of the head towards the feet (as in head down).
f) The opposite is true for backmonauti, where the backmonaut sets up behind the navigator (relative to the ground), with the head tilted backwards, and pushing the hips forwards towards the sky (an arch with the torso), once again seeking the form of an airfoil as with Frontmonauti. The relative wind is in the face and over the chest where the low pressure zone is.
g) Backtracking is where the backtracker lowers the hips, relaxes the arms to the sides/above the torso, faces (with chin down on the chest) the flock setting up behind (in essence an inverted wing shape).
h) In Atmo, as with head down, the arms and legs are mainly for controlling speed (less or more drag), with the head seeking the angle o attack.
i) Freefall is similar in concept to a round parachute.
j) Atmo is similar in concept to a modern day canopy, that does not rely on drag, but flight/glide, and using the angle of incidence/attack to generate the forward speed needed to produce a flow of air over the airfoil, which generates the lift/glide.
Thanks a pretty helpful explanation of the varying positions required to get the 'atmo' effect.
In regards to the similarity of the body and a ram air canopy. Do you think that the two are that similar in relation to the amount of lift achieved? Surely even with even the most efficient ram air wing, the canopy is continually descending unless going through a speed conversion / swoop for instance.
Also, if the two modles are similar is it possible that a flyer could create a similar effect by increasing vertical speed and then converting into drive and possibly greater lift? Body swoop for instance?
I do see the lift argument, but after watching videos of base jumpers for example, going at full tilt, they still only cover a relatively small distance.
Surely deflection is the overriding factor and not lift in relation to greater horizontal distances covered? I hope I’m proved wrong. Its would be fantastic if manipulation of body position and angle could lead to the generation of useable lift.
has anyone got any hard data supporting the lift argument?
I think the term of lift can probably be related to a fairly romantic view of this endeavor. You see it in other sports like climbing, scuba diving and base. None of us are flying, its falling. We arent swimming like fish etc....
Im more inclined to go along with the theory of angular delflection rather than lift in order to produce extended flight time however I wouldnt say were falling.
Falling is a term used to describe something that is pretty much out of control. I would still say that humans are flying as they can choose diferent vectors, if only for a short time and distance.
Not too sure how to awnser that, though yeah i have felt that a bit too
I havent felt the same thing in tracing or tracking, tracking(going fast that is) takes more physical effort when im hiting it. Atmo on your front is pretty relaxed relative to other positions/angles..... hmmmm
Ill take a wild stab and throw a guess out, though itll only be just that. Given that your establishing a drag anchor on your knees, which is relatively biomechanically efficent, and your sticking the angle with your torso, and if the angle is fairly mild, the overall drag is pretty evenly distributed.
Not alot of effort is involved if your not having to move around too much or react to others, then the whole thing is pretty relaxed and effortless.
Comapre this to head down. Even when sticking out a relaxed daffy at a comfortable fall rate, there is a bit more effort and due to the higher airspeed, a bit more force all over the body.
Probably purely psychological, amplified by how much more exertion is used by other positions ie... sit, head down, trace, track....
That is a tough one.... Too much room for speculation!
The rig thingey!- Look at the odd frame that is created by a rig when its worn by a person. When hitting an angle the gap is exposed. This will cause it to move up. It pivots upwards on its connection points ie.... shoulders and hips. The rig weighes less than a person and therefore has a slower fall rate. It will accerate away from the body via the rear bottom edge of the container thus lifting up and forwards.
Does look odd doesnt it! My G4 has got the new lumbar support straps and i do tend to tighen it up a bit so i dont notice it too much. Also when im tracing fast forward, or slidding down on my side to get to an atmo group the riser covers can easily get blasted open. For these reasons i tend to tighten my chest strap up a fair bit, definately dont like the feel of a rig getting slightly 'peeled' off of me!
Thos new micron magnetic riser covers look really interesting, they might be able to hold up under a side slide better than mine.
The counter argument is that for angular deflection to work in this case, it would suggest that the relative wind is from below, creating drag, and deflection for the forward movement.
This is correct for tracking.
However, in Atmo, there is no relative wind to deflect whatsoever from below. There is DEAD AIR below the frontmonaut where there is relative wind in tracking (in the curve created when taking up the airfoil shape above).
With no air from below to deflect, there can be no angular deflection.
Even if like you say a flyer is flying in a very steep angle and the relative wind is hitting the head and shoulders, the air that flows across the bottom of the body from head to toe is still being deflected by that flat surface thus initiating drive. It might seem as though were actually moving great distances relative to another flyer in a similar trajectory, but If we were to look at this from a third point of view, we would probably see that the flyer would be descending allot faster than they are moving forward. This would lead me to believe that it is unlikely that there would be 'dead air' below an atmonaut. Were simply not going fast enough forward for that to be the case.
Isn't it more likely that because of the bend at the hips, the relative wind follows the steep path of the underside of the torso until it reaches the Hip area, where it is momentarily trapped creating an area of high pressure. An 'Angular de arch' of sorts, allowing for slower fall rate? The air would continue to slide off along the legs; this combined with fresh air from below would greatly increase drive, would it not?
Unlike aircraft, which create their own forward drive and have areas of dead air directly beneath the wings, a human is descending at a rapid rate of knots and cannot really hope to achieve this dead air scenario, unless in an extremely steep dive (trace) where the pressure bubble around the body would be the overriding factor. I find it hard to believe that Atmo can achieve this amount of forward drive in order for this to happen, especially when flown in a shallow angle.
I'd personally put the weightlessness effect down to a few things:
1. We are without a doubt descending as slow as we pretty much can when flying in atmonauti because of the angular de arch, creating an area of high pressure which combined with angular deflection allows for efficient energy transfer, and forward movement.
2. The arms and legs being out to the side also create more drag and take some of the weight, this leaves the torso area supported with even less effort.
This slow flight combined with a large amount of longitudinal weight distribution would in my mind give an effect of floating on a bubble of air. However I might be wrong.
Even if genuine lift is being created I doubt that it would be the overriding factor that creates the weightlessness effect. Im sure lift is generated to some small degree, but as Vertifly says, it would probably have a very marginal effect.
Just to make clear this point before the scenario of another flyer flying directly below a frontmonaut rears it head; and how lift probably makes this possible: The steep angle of attack would still allow for a high area of pressure under the hips created by the de arch, this plus the fact the leader is ahead and both flyers are in a staggered formation in relation to the relative wind allows for a frontmonaut to still catch enough air on the front to stay ahead and above the bottom flyer. This sounds a little more reasonable!
We can always look at it from another perspective. If the leader was behind, with the bottom flyer ahead, with both flyers in the same angle, the top flyer, leader, would certainly fall into the burble, would he not? This is especially more apparent in shallow atmo dives.
Surely both scenarios covered here are a little more realistic, and showcase that angular deflection is the most likey reason for forward drive and the ability to position one self seemingly in another flyers burble area?
Soz, dont mean to be a party pooper, but Im having to continue to lean towards fedykins explanation at the moment. I would love your argument to be sound.
(This post was edited by atmonaughty on Feb 25, 2008, 10:39 AM)
Sounds like your internally debating the subject on both sides, i do that a fair bit... feels like having an argument with yourself, odd isnt it!
On the second perspective ill say this. As formation set up and 'no go/burble area'. The angle/zone of disturbed air is typically at the same angle as the angle of movement ie....steep angle, steep burble.
This is why a more aggressive angle can allow people to stack it up with more people and closer + a more aggressive fall rate due to a smaller surface area exposed to the relative wind. The faster fall rate allows heavier people to have more range and get back up.
Steeper angles overall tend to give you a shorter ride due to the higher fall rate. Tracing(Steeper angle) can be incredibly dynamic, really interesting stuff. What is a worthwhile question is WHAT IS OPTIMAL IN RELATION TO BODY WINGLOADING/BMI FOR MAXIMUM HORIZONTAL DISTANCE.
I’ m not in the condition to talk technically about the physics phenomenon , that’ s why I just want to ask for opinion and feedback , posting some concrete example of the fact that I believe that in atmo we generate lift . This having , any way , really clear the aerodynamic lift concept ( exactly the same concept applied to the wing canopies that don’t fall making resistant work , but FLY generating lift).
First consideration would be more as personal sensation when I fly atmonauti in all the different angle (from 45° to 20-15° ) and different speed . What I can fill is no air impact on the body from below ( I really don’t fill to deflect any air from below , as it was happen in track) , and I feel the air on the head , on the shoulders , on the arms and hands (bord of attack) , and on the lateral outside part of the legs (they work as breaks to regulate the speed) …. What I felt really well , is the rig going up and forward ( giving a strange sensation the first time , as do not have anymore the rig on the shoulder …. Luckily is just a sensation ) and I feel a very light body sensation too. The air is coming from the head to the feet , with an inclination of the fluid in relation of the “angle of attack” and speeds of the atmonauts ; with the air coming in this way , is exactly the same air flow as in free fly …. That’s why we can observe atmonauti flying with shape position like in head down ( with daffy , legs close , etc. ) … that’s way we can free-fly in atmo with footmonauts as the free fly stand-up formation ( impossible in track !) . That’s way in atmonauti we built three-dimensional formation flying one on top of the other in head level multi-layer , with flowers and star formation , with person fly tight and close one on top of the other one ( if we was deflecting the air we was not able to fly so close one above the other ). That’s way the tandem atmo with out drogue fly at vertical speed of 170-180 Km/h ( if he was deflecting the air , without drogue will arrive around 300 or more Km/h)
Second consideration : Analysing the flight data , we can assume a vertical speed lower than in all the other know disciplines ( with out any accessory) from 140 to 170 km/h ( … to …. Miles/h ) … an horizontal movement in 10.000 feet of flight altitude , estimate with out wind influence , around 2 miles in a high speed ( as we do in the airshow www.youtube.com/vinsmedia …..).
Already from this two consideration about sensation and datas analysis , I consider that my personal point of view when we talk about atmonauti , is that we are talking about real human “flight” in the real aerodynamics meaning of the term . But I repeat is just a personal very strong opinion and I not pretend to convince somebody with this my arguments. I still believe that the best thing is try it and felt or not what I’m talking. I just want now post some concrete example about what I’m talking , suggest comments from who have possibility to explain in a serious way , if this concrete facts can be related with other different explanation different from the “lift” one . Thanks
Another question is related to the word “trace” “tracing” that Piers Roberts often nominate. Can somebody explicate what it is ? who create it and when ? where the theory , angles explanation ? Where we can found articles and pictures made by his creator about the “Trace” ? Considering that Marco from 2000 define the atmonauti angles (from 45 to 15-20°) , considering that we have see the atmonauti fly from 2000 in all this angles and different speeds ( in free style, following airplanes , in smoke airshow , in big formations , in circulars and varies trajectories , in games , etc. etc. ) , considering also that FAI define from 2003 this following description , I’m really not understand what is this “Trace”: FAI definitions : B-6 Diagonal orientation - “Tracking” is horizontal movement with the torso predominantly horizontal with respect to the ground - “Flock” is horizontal movement with the torso predominantly vertical with respect to the ground - “Atmonauti” is horizontal movement with the torso at an angle between a “track” and a “flock” , but preferred to be close to 45° with respect to the ground. Ceck on http://www.fai.org/parachuting/system/files/artistic_adb_2007.pdf
Can somebody answere this questions in a “concrete” way ! Thanks
Picture n° 1
Tandem atmonauti with 4 way atmo-formation in line In this picture we can observe a tandem atmo with vertical speed of 170 km/h docking in a normal atmo flight formation … we can also observe very well , the rigs going up and FORWARD from the shoulders , INCLUDING THE TANDEM RIG !
Picture n° 2
Atmonauti formation with 4 way flowers , with frontmonauts fly very close above the backmonauts in a link formation , with-out felt any burble zone because of deflected air.
(This post was edited by Ramatos on Feb 26, 2008, 1:14 PM)
not that i just "made up" this user account to help answer my own questions or anything...but i think "tracing" is an art form where one draws rounds the outline of an object/image through what is commonlly known as "tracing paper"
For example, tracing the outline of, hmmm, some images of people tracking with their t-shirts being "sucked over their heads" due to an amazing amount of lift being produced by the magic atmo-lift
The relative wind is from the head towards the feet, in the relative angle in which the atmonaut flies. There is no relative wind from below, as we are not in freefall.
As the air breaks over the crest of the head (first point of contact) it moves over the top airfoil surface at a greater speed than the the air directly across the bottom - creating a low pressure zone above, and a pocket of dead air in the curvature around the chest area due to the form which is taken up by the atmonaut i.e. an airfoil.
A burble does not necessarily need to be ABOVE and abject as you state, rather a burble is always behind the object IN RESPECT TO THE DIRECTION OF TRAVEL.
In the case of atmonauti, if the flight angle is 45 degrees, the burble is at 45 degrees too, directly behind the atmonauts direction of travel, which is why we have NO FLY ZONES in frontomauti and backmonauti.