Aeroflexible Aerodynamics
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- เผยแพร่เมื่อ 18 ต.ค. 2024
- Selfactuated Wing for advanced Flight. Movie which was presented on the Hannover Messe 2013 first. Who describes the advancement of aeroflexible surface in comparison of a rigid surface, operating in an aerodynamic context.
You may produce more lift but what about the drag
suprisingly about 10%-20% less drag in all wing prototypes. Soon there will come a video about all measuring results
@@felixschallercom That is really strange.
Can be explored via simulations.
@@aeroraheem It’s not strange because at higher angle of attack airfoil is experiencing increase in turbulent flow behind the wing and ultimately as the AoA is increasing the wing will stall which is associated with the huge increase in drag and loss of lift.
By applying featherlike structure the turbulence over and behind the wing is decreasing and the wind flow over the wing becomes more laminar and consequently the drag is reduced and the lift is increased.
There will be less turbulence (air disturbance)
Contrary to the responses below I think this is a wonderful idea inspired by nature. The drag increase during cruise conditions will be minimal as the acetate flaps will be lying flat over the wing surface, contributing little to extra skin friction and pressure drag. These things really coming to play during high instantaneous angle of attack manoeuvres, where they create pockets of smaller separation rather than large scale energetic vortices. I'd say this is worth pursuing. Keep at it.
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I hear what your saying, but it seems to me that the acetate 'flaps' are interrupting the turbulence that forms during the change to a high attack angle, so actually preventing a complete stall.
I have been into hornithopters for a year, but whatching this video really opened my eyes. You gave me a lot to think about, because wing bird motion is not everything. Thanks!
It does seems to address the gap between our machines and how birds have evolved, clearly you are after something big here. Cheers!
Wow fascinating!! Thanks for posting. Nature has a way of coming up with such smart solutions 👌
This was so informative. Definitely deserves more views and like.
Seriously that is amazing, would never have considered this. I fly rc planes and will try this out. Thanks
This is pretty good stuff. You guys are into something big. I knew there was a reason for feathers.
Yeah my fruit bat was telling me that the other night.!
Neat idea... more wind tunnel tests!
Man, great video. Your last experiment that shows the difference with the turbulent air flow is very interesting !
It seems that the KFm2 airfoil also performs astonishingly well at high angles of attack.
Excellent study. I think flexible wing that changes shape will be the future that will open all kinds of possibilities. We maybe limited by materials to build flexible wings but I am sure that problem will be solved very soon.
This video doesn't show the cycling pattern of the actual model just a stall, but the main issue is that the model is trimmed with too much positive pitch reaction, the CG is too far forwards, making the model overly sensitive to speed. Most radio control gliders are trimmed with just a hint of positive stability: if put in a shallow dive (about 5 degrees), it should take 2 to 3 seconds to level out, with no visible pitch cycling. Wing camber can be adjusted by moving the entire trailing edge (flaps and ailerons) up (reflex) or down (camber). If using a powered model, then throttle to elevator mixing is used to prevent unwanted pitching moments.
Hi, thanks for the remarks. over-pitching is made by purpose to create steep angle of attack and thus to bring the airfoil into stall.
That's fascinating. I wonder about added weight, esp on a free flight model.
Thaks for scharing such a great idea .Do you have any publish paper about the subject?
I am still gathering results... it will be published herer then: www.researchgate.net/project/Aeroflexible-Aerodynamics
This is really interesting! The wing is way less likely to stall. Do you know how the lift and drag compare to the standard wing as AoA changes?
So its like an SAS or stability enhancer. I could use this for my Aerodynamic Assignment. Amazing. thanks for the vid.
I am going to use this idea for my science fair project with a wind tunnel.
Could you tell me what material you used for the "feathers"?
Thanks!
i think any material will work as longs its light and rigid
Mylar ?
im adding this to my Micro Raptor model !
The plane shot up in the first instance because of a poor elevator trim. the second instance had the added weight of the plastic and therefore moved your C.G. forwards (also because of the "dirty" wing, the lift is decreased. The idea of these feathers or whatever you call them is interesting but a far more economical solution already exists: adjust your elevator.... What you are doing only increases the wake drag....
I thought so too, but actually, that's not quite accurate. I have just done an experiment of my own with the compliant surface elements. I used one of my Discus Launched Gliders. The performance increase was noticeable. It was really cool. Have a look on my channel.
That's superb man!....are you able to delay the wing from stalling because you reduce the AOA at the trailing edge by moving it closer to the airflow separation region ?
Fantastic... ! :)
Super !!! Bravo .!!!
Regards PP.
Brilliant
Bro. You are genius. 👍
Wow, that is amazing
This is amazing
Amazing!
you'd have a sweet glide if you just fix the C.G. and incidence angle without having to add such features, also these flexible fixtures would decrease lift in such situations.
we have made wind-tunnel tests which can proove, that the airfoil gains plus 20% up to 40% more lift (depending on which Type of Surface or Profile you use)
Amazing !!!
Very interesting results
Doesnt it affect the efficiency in normal flight regime ?
So. Like feathers?
interesting, so the non-flight feathers are actually playing a role in flight stabilisation
feather or scales adopt dynamically to the surrounding stream mechanically to fill a mathematical/mechanical insufficiency in the physical solution of the fluid. feathers therefore glue or attach to the fluid streamlines. if a flow separation happens (reverse flow) the scales or feathers lift up to avoid the detachment of low pressure into vortices.
Simply: Dynamic lift happens because it's an unfinished vortex. The wing flies inside this half vortex. if air/fluid can finalize the vortex it detaches and stall happens.
@@felixschallercom Ok, so the essential part in all of that will be the birds own nerves and ability to feel what is happening? That allows it to take advantage of a range of flight characteristics that it discovers as it flies more and more. Are you using AI? Do you think you can get the AI to do something like that soon as it gets better and better?
And thanks for the explanation :)
Try this video on "how aircraft fly!!" How does an Aircraft fly ? : Flight lift theory explained (The Aerodynamics of flight )
Very intresting facts! 😃
That is an amazing concept explanation. I have been thinking of doing this and you already did it. I learnt from your video.
May be we can do some collaborative work in the near future. Right now I just do simulation on airfoils and could be a better thing to do in simulations.
Sure, why not?
@@felixschallercom May be we could setup a meeting to talk more. I have seen your website contact, felixschaller.com/index.php/contact
Am I Correct with the address of website?
Do you reply to comments?
yes, sometimes - if they have related content ;)
Agora é só encher os carros e avioes de penas e vamos dar um salto evolutivo kkk
The last test in wing tunnel is cheating.
The strings are attached at different points.
The new one has strings very close to attack edge which makes gravity stabilization.
In the traditional wing model the string is attached near the center of aerodynamic forces. That makes it unstable. Unstability is caused by moving of aerodynamic forces vector back and forth between 1/3 to 1/2 of the wing depending on angle of attack.
The idea of moving parts on the wing may be good but cheating on demonstration is very bad idea.
+Romek Zyx I don't think you are right - if you look carefully I think you will see that the attachment points are close to the leading edge in both cases. I am not sure what the bits of red ribbon are for but that is not where the attachment is in the classic case.
sorry that's wrong. it's rather the perspective that cheats ;D ...there is another video in my channel which shows it in more detail: th-cam.com/video/ubXz4SnrnDE/w-d-xo.html
Alright, Da Vinci award
Are you sure the improved flight characteristics is cause by your active profile rather than simply added mass countering the lift? Because i sense every little flappy thing fluttering making less efficent profile. Every movement is loss of energy man
Now thinking back, correcting the plane by pushing nose causes drag too. But i still doubt this one
@@anttitheinternetguy3213 I was skeptical too. But i just did a similar experiment with compliant surface elements, and had good success. Mine were not nearly as complex as his, but the stall recovery and glide ratio were still noticeably improved. have a look on my channel. :)
3:18
The authors have two wrong scientific approaches: researching the creation of Lift force and Low pressure at upper side of the wing, relative to the ground surface and Earth. I explain the aerodynamic cavitation and existence of Lee side aerocavern, and creation of Aerodynamic force.
existence of "Caverns" (resp. areas of lower pressure) is not an explaination it just provides an observation, but not a reason for their existence... traditional aerodynamics explain low pressure by bernoulli: higher speed = low pressure - but this is incorrect because of a missing energy potential finally bernoulli (aka. potential theory) would lead to the fact that forces equilibrate and lift is zero.
@@felixschallercom I send you an email at felixschaller
@@vlatkopopovski2685 ok, didn't saw it yet, meanwhile rarely check my emails, though. i'll check back. in case send it again...
@@felixschallercom When a solid body in fluid is displaced, in its previous place in a moment, in a small time lag that cannot be measured, there is/was a "cavern in the fluid".
The body moving through the atmosphere pushes and swept out the air along the way and creates an aerocaverne - a zone with subatmospheric pressure on it backside.
Lift is not upforce! In the dictionary, Lift means pick up and move to a different position. In aerodynamics, Lifting is a lateral moving, Lift is component of the aerodynamic force that "displaces" an object from the line of air flow.
This lacks the controls needed to prove anything. Wind tunnel tests are done by taking lift, drag and pitching moment measurement in a turbulence & velocity controlled airflow. Oh & temperature & pressure measurement to determine Re for each test. Letting a section of wing flop around wildly in an uncontrolled flow from a fan & not taking any calibrated measurements proves nothing at all.
Look, it is well established that a slightly rough surface or tabulator spars or wire trips the boundary layer into early transition & this help the boundary layer remained attached at mush lower Re higher angles of attack & removes stall hysteresis. Yes feathers can provide these benefits. But you don't get something for nothing. Doing the above destroys laminar boundary layer & therefore increases skin drag.
Putting a free flight model out of glide equilibrium in such an uncontrolled way proves nothing. If you are going to do an experiment like that, every flight glide test must be disturbed exactly the same, otherwise you can't tell if it is your surface feathers or variations in pitch, velocity, temperature/viscosity, flow turbulence etc are the cause of observed behavioural differences.
If you want to make a statement about such things, reference a real study on the subject, to which you can still attach this entertainment video.
Showing feathers flop about in deep stall doesn't say much really, however, the idea the feather movement might modify surface curve in a way that maintains a smoother free flow near to stall transition, isn't so band of an idea IMO. We just need better data than provided here. It is known that leading edge slats & fowler flaps essentially help with this, though they don't work in quite this way either.
Hi Ken I appreachiate your concerns. But i have no Idea about the intention, except establishing the state of the art. You mainly repeat common aerodynamic myths like "turbulence increases skin drag". This is only correct for rigid and smooth surfaces (as ironically most aerodynamic bodies made by man are). The reason is the rigid doundary condition they produce. If wou watched this channel carefully then you may have seen other videos which debunk all your concerns. This surface indeed produces a lower drag and lift. This Video: th-cam.com/video/bhSytBec-dM/w-d-xo.html shows some of the measurements. And the other Videos explain - why.
@@felixschallercom I am only commenting on this video which has no measurements & no controlled conditions. These ate both prerequisites to determine anything in engineering. Nothing in this video proves anything at all. This is the only video by you that I have come across & there is no attempted scientific or engineering approach taken here. That is the main point I open with, because it means that no valid conclusions can be made from what you show. Turbulent boundary layer does indeed produce higher drag than a laminar flow boundary layer. However, there is an advantage to tripping early transition of the boundary layer to turbulence in that it tends to then detach and reattach much more predictably with little if any hysteresis. This is advantageous in say the ability to control gliding descent angle of landing. You can safely push a wing CL above it's sink trim for a slow but steep descent if you want to shorten the landing. That is a better strategy than reducing height early, as the latter produces greater air speed within the ground effect where there is much less drag & as descent rate is tied to drag, The plane will tend to float & over shoot the landing unless you touch down with excess airspeed which risks a bounce & stall which can end in disaster. So, landing safety is a good case for none laminar flow. This is all very well established aerodynamic facts. No myths here.
@@kenwebster5053 i am sorry to say, you are wrong. I have measured it in a wind tunnel and i have plenty of witnesses with aerodynamic PhD. The thing is simple if you deal with rigid objects, aerodynamics behave as you describe. There are those concepts you mention that try to explain it. But tose models only work in a very limited boundary and context of rigid objects. why, because I am keen to say they are wrong from the bottom up. the problem is a misconception of the energy conservation in the bernoulli law. aerodynamics does not behave like rigid body dnamics. turbulence is a solution to solve the energy conservation in fluids correctly - and that's why turbulence DOES in fact reduce drag if the eddies can kept small. large eddies are the ones who produce the drag on smooth and rigit surfaces, because they absorb linear momentum into angular momentum of the eddies. They in particular occur easily there because the surface does not interact with the fluid. Instead all creatures in nature have a rough surface with reason, because these surfaces reduce surface drag by small eddies they act as ball bearings in the boundary layer...
@@felixschallercom Well how is anyone to know you measured anything or did any controlled testing at all when you give no hint or explanation of that & all you show uncontrolled, unmeasured free flight showing a model plane responding normally to nonequilibrium flight dynamics & making assertions not supported by the video evidence just like an uninformed person might do?
@@kenwebster5053 ... well that's why there are other videos in the channel where eveybody can make himself an impression about the evidence
.com invented nothing... windtunnel joke..
also kf airfoils proved nothing yet. it s just convenient for lazy cheap rc plane builder.
hahaha :D