Drone Design #1 - Selecting an Airfoil
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- Опубліковано 28 лип 2024
- For part 2, check this link: • Drone design #2: 3D Fl...
Drone types
Rotary wings, quadcopters, for example, use the vertical thrust of the propellers to keep the drone in the air. A fixed-wing drone, however, relies on conventional wings to generate the required lift, just like an aeroplane as it travels through the air. In most cases, this setup eliminates any hovering capabilities, but it greatly increases efficiency, giving you much longer flight times.
Fixed wing drones come in many shapes & designs. Some look just like minified aeroplanes, with a propeller at the front, a fuselage in the middle with a long slender wing at both sides and a tail with vertical and horizontal flaps. Blended wings, on the other hand, look very futuristic, with fuselage and wings morphed into a single piece, without any tail at all.
Airfoil basics
Whichever design you go for, you’ll need to choose some kind of wing section, called an airfoil, to generate lift. In more advanced designs, the size or even the shape of this airfoil can change along the width of the wing, but it’s always a good starting point to do some basic hand calculations first.
Let’s start with naming the basic parts of an airfoil. At the front, you have the leading edge, at the back you have the trailing edge. They are connected via the upper surface, also called the suction surface, and the lower surface also called the pressure surface.
The chord is the straight line connecting the leading & trailing edge. The camber line, on the other hand, runs nicely in between the upper and lower surface, showing the centre line of the wing.
The angle of attack is the angle between the chord and the relative wind direction. The relative wind is not only composed of the wind vector but also the velocity of the drone itself.
Lift and drag
Essential to airfoils is how much lift & drag they generate. Lift is the vertical force perpendicular to the relative wind direction. Drag is the horizontal force along the wind direction. These vary in function of the angle of attack. There is a great website called www.airfoiltools.com/ that provides you with tons of data on different airfoils. To understand drag & lift curves, let’s illustrate this using a symmetric airfoil, where upper and lower surface are identical. An example is the NACA0012.
At zero angle of attack, the lift is zero as well. There is only drag. As soon as the airfoil rotates its nose into the air, creating a positive angle of attack, it starts generating lift. The bigger the angle of attack, the larger the lift. Beyond a certain critical angle of attack though, the lift will start to decrease again. This operating region beyond the critical angle of attack is called aerodynamic stall and is caused by a separating flow at the suction surface of the airfoil. Trying to pull up too fast during take-off, for example, is a typical scenario in which planes can go into the stall, lose lift and risk crashing.
Another effect of increasing the angle of attack is the increase in aerodynamic drag, which could cancel out the positive effect of lift. To find the sweet spot, we can use the lift-over-drag curve, which plots the ratio of lift over drag in function of the angle of attack. The NACA0012, in this case, reaches its maximum efficiency at an angle of attack of around 8°. At this point, the lift generated by the wing is 80 times bigger than the aerodynamic drag!
This is not the best you can get through. In contrast to symmetric wings, asymmetric wings sacrifice performance at negative angles of attack to generate more lift and less drag at positive angles of attack or even at zero degrees. With airfoil tools, you can easily compare two different airfoils, like the symmetric NACA0012 versus the asymmetric NACA6412. You’ll see that the NACA6412 peaks at a lift over drag ratio of over 140!
As you may have noticed in these curves, lift and drag are expressed as coefficients Cl and Cd, rather than the real lift and drag force. This makes it easier to compare different airfoils, irrespective of their size. The coefficients are calculated by dividing the lift or drag per width of the airfoil by the product of stagnation pressure and the chord length.
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The AirShaper videos cover the basics of aerodynamics (aerodynamic drag, drag & lift coefficients, boundary layer theory, flow separation, reynolds number...), simulation aspects (computational fluid dynamics, CFD meshing, ...) and aerodynamic testing (wind tunnel testing, flow visualization, ...).
We then use those basics to explain the aerodynamics of (race) cars (aerodynamic efficiency of electric vehicles, aerodynamic drag, downforce, aero maps, formula one aerodynamics, ...), drones and airplanes (propellers, airfoils, electric aviation, eVTOLS, ...), motorcycles (wind buffeting, motogp aerodynamics, ...) and more!
For more information, visit www.airshaper.com - Наука та технологія
This is a very comprehensive video. One that includes practicality of the topics and not just the theory of terms! Thank you for creating this video and the channel as well!
Thank you very much! And all tips appreciated!
Thank you. Just opened solid works and ready to start when I realized after all this drone flying I have no clue about aerodynamics. This was a good starter!
Thanks, I'm glad the video provided you with a first introduction :)
I just stumbled onto this video and I'm stunned how perfect it is. Good job :)
Excellent information. I found it very easy to understand. I appreciate that you provided the math. It really helped to understand the underlying formula so I can tinker with different hypothetical designs before deciding on a few prototypes. Thanks very much!
Thanks a lot Mike, I hope this takes you to the next step in your design!!
This is amazing. Thanks for uploading this video.
Hi Bello, thank you very much for the kind response! I'm glad you liked it, and I hope you like the second part as well (and our other videos on airplane aerodynamics). Enjoy!
Excellent presentation. Thanks for sharing
Thanks a lot!
Really good Explanation!
Thanks Ansh!
Really good video on the topic. Little tip: If you mention a website in the video, you should also link it somewhere!
Hi, thanks for the compliment and for the tip! I must have forgotten! I'll add it ASAP!
@@AirShaper Air you are such a dude. Brilliant video and you are still open to constructive criticism...REALLY impressed, thank you beautifully done...
@@peterkay7458 Thanks a lot Peter!!
Also I subscribed, you legend
Hi Saber, thanks a lot for the nice compliment, a nice way to start the week here :) I hope you'll like the upcoming videos as well!
Thank you sir
Thank you for the feedback as well!
Kind regards,
The AirShaper-Team
Please make a video for rotor craft frame design and structure calculation ❤
Hi! Very good and informative videos.
I find it very sad that you are so underated. Deserve millions of views.
Hi Arjun,
thanks for the very nice feedback!!
If you have any tips on how we can grow the channel, please do let us know (specific forums on drones, Facebook groups, ...) - all help appreciated!
@@AirShaper I recommend you to collab with big youtubers like Zack, as he is the one who brought me here.
@@ArjunSingh_11 We will surely continue along that track - the collaboration with Zack has been supercool!
Perhaps explained properly ❤
1/2*rho*v^2 is not the stagnation pressure. It's the dynamic pressure.
Hi Stefan, you are right, it is the dynamic pressure. We're a bit too used to working with relative pressure difference so we forget to add the static pressure, our apologies!
AirShaper All good. Thanks for the video
It is a good video but i find selecting an airfoil as a first thing in the design process wrong. Airfoil selection can really be a late phase in design of a fixed wing vehicle. In drone design apart from cL/cD characterstics, coefficients of moment characteristics will matter more. If you are not in the last design phase, trying to optimize airfoil for optimum lift/drag without even having a planar and 3d profile yet will prove wrong. As an example, a thick or simple airfoil that still can get the jobe done will prove usefull in terms of manufacturing and extra size inside wing we can use for a lot of things.
I agree with this. Also the 3d shape of the wing plays a significant role in the final aerodynamics. Also, you can't select an airfoil without knowing an estimated trim condition and flight Re. And you can't know that until you've performed high-level trade studies
I agree that the video perhaps wrongfully implies this is a sequential process. In reality, it is like you say, you need to iterate between various aspects. At least we hope we gave good hints for a first shot.
What airfoil would you suggest for aThe tecnam p2012 RC model?
Sir I am an aeronautical engineer. Which designing software do you prefer for me for today aeronautical field. I really learned a lot of things by your videos.
If it needs to be free, FreeCAD and blender are very good options. Www.gliderplanedesign.com is also nice to play with plane settings.
this is a good video. though I'm currently having a hard time selecting an airfoil for my fixed-wing drone. can you help me?
Hi James, indeed, it's not an easy task!! Best to start with your payload & estimated weight requirements to obtain a required lift value. Keep in mind that when going from 2D to 3D, you loose quite a lot of lifting power due to the non-infinite wingspan. So be sure to run a full 3D sim at some point as well! And if the choice of airfoil is too complex, start with a common profile that you find on other drones (google will quickly show interesting references). The special profiles are for later on, once you've run prototype tests and/or need to upgrade your design later on.
@@AirShaper Thank you so much. makes a lot of sense
Please i need help how can i contact with you
Great video! Can you provide the link where you discuss the Reynolds number? You referred to this terminology but I can't find the video which discuss this. Thanks!
This should be the one: ua-cam.com/video/sV8l8xd4MEQ/v-deo.html
Hello Buddy, You explained it very well.
I'm an undergrad student and I'm supposed to design a fixed wing vtol with 2 hours flight time and 2 kg payload carrying capacity, so which airfoil you would suggest to achieve these milestones?
I suggest you to browse airfoiltools.com to look around, look for efficient profiles for your specific Reynolds number. And keep in mind that when going from 2D to 3D you can lose a lot of lift due to the finite wingspan. So do check for correction factors for this befote you size the wing (you can find some in Joseph Katz's 'race car aerodynamics' book).
Hii, I'm Shivam Tadwalkar from India. I'm also supposed to design a VToL aircraft. Can you please help me with that? If you have made your project.
static not stagnation pressure in the denominator of the coeffs
No. it is stagnation pressure
Can you share a resource about vertical takeoff fixed wing vehicles. Do you have a site or an article video?
Thank you.
Hi Omeroglu,
we've worked on senseFly drones, which are somewhat different, as you through them into the air to launch:
airshaper.com/cases/sense-fly-increasing-drone-flight-time
I wouldn't know of any specific site or video on this, but there must be plenty out there! On researchgate for example, you'll probably find the more technical resources.
hi, im an engineering student and i m making a drone whose function is to carry an attachment that will throw a ball to a particular place at some height , i searched about drones , and i got to know that copters that lift more weight are difficult and too costlier to develop, so my q is can i opt for fixed wing to perform the same operation, whats your opinion?
Fixed wing drones can indeed carry more weight in some cases, but they need speed to have the wings generate lift. So it could be necessary to launch the drone using a catapult for example (this is quite common)
@@AirShaper can you explain in detail in which cases it can lift more weight and do i need to launch it from catapult even if i have a runway long enough?
If you have a large runway, you may not need a catapult. The ground effect (wings generate more lift when close to the ground) will make take off easier. So it comes down to selecting an airfoil and a required velocity to get enough lift!
I’m currently doing A Level Design Tech and part of my coursework is to design something of our choice this will involve Low fidelity and medium fidelity prototyping of some sort. Do you think it is possible for me to design an aerofoil or something? I want it to link to aerospace Engineering. Do you have any ideas on what I could do?
Dear Prashant,
airfoil design does require fairly high fidelity, especially if you are looking at 3D flow (which can vary greatly from 2D flow) and/or separation locations. Perhaps the flow around a drone bodywork could be interesting for you to study? (check our second video on drone design)
@@AirShaper Thank you for your fast reply and as a matter of fact it helped me a lot. I’m going to design and build a budget remote controlled drone targeted towards those who can’t use it due to money. Outside of your second video on drones is there anything else you could help me with?
@@Prashant-pm7iz Perhaps it could also be useful to check this article:
airshaper.com/cases/sense-fly-increasing-drone-flight-time
That would be about it in terms of what I can think of to help!
@@AirShaper Thanks mate, I appreciate it.
Hi sir
I am an Aeronautical student doing my undergraduates .I am interested in designing drones but I don't have any proper guidance of doing it done .Can you say me what to do exactly to learn to design and what are the things I need to mainly look after for getting it done .
Waiting for your reply
Hi Viswak, there is a lot to be learned by just starting to build your own, using parts from hobbyking for example (if budget permits it). Setting up controllers and so on, will make you learn a lot! Apart from that, perhaps it could help you focus to decide on whether you want to go for vertical propeller drones, or fixed-wing like drones (in the latter case, you may want to focus more on general aviation theory). Good luck!
Thanks for your reply .It was very useful but I have one question what are the open source software for programming and designing drones We can get which is best .
Waiting for your reply
@@hurtlessstatus3414 Maybe you could have a look at this one: aero.go.usu.edu/machup/
Thanks a lot it is very useful
@@hurtlessstatus3414 Most welcome!
Which airfoil to use in 1045 propeller in typical quadcopters?
Hi Ayush,
I wouldn't be able to answer thay without proper research I'm afraid!
@@AirShaper Can you guide me where I can find that? I need that data for 1045 prop and 1047 prop.
I wouldn'y know Ayush. Perhaps search hobby forums?
Hi Wouter
Am a Mechanical Engineering Student planning to do my Undergraduate thesis On Unmanned Aerial Vehicle could you suggest some books and website where i can start from scratch to build a UAV and all the basic concepts in aerodynamics to understand in a much detailed manner.
waiting for your reply
Hi Balaji,
That sounds like a great subject for your thesis!
I don't have a UAV building book top of mind but a website/tool I might suggest would be our new partner CAESES
www.caeses.com/news/2019/caeses-and-airshaper-for-aerodynamic-glider-design/?fbclid=IwAR00DeJipokLyk-gWZYrXALZs14Djr2HO79TgUpuqGHAGLs0yJqviJyL3lk
They are about to launch a glider design web app. It will have a short preliminary analysis within the tool and also an easy export to AirShaper button for a full 3D flow analysis. It will also have options for other types of designs.
A book you might be interested in about the basics of CFD is: Fluid Mechanics by Frank M. White.
For other questions, make sure to check out our other videos or let us know, we can answer them or maybe even make a video about them!
Kind regards,
The AirShaper Team
@@AirShaper the same thing happened with me I need to start in my graduation project and I need a practical approach to design a drone not theoretical one.
Thanks anyway for your valuable information. And keep up the good work.
Can airshaper provide CFD analysis for wing ground effect? Can it determine the center of pressure shift with respect to percentage of height to chord ratio. Thanks
Yes we can study ground effect with AirShaper and assess the effects on the pressure pattern / center. Feel free to mail me at wouter@airshaper.com to discuss your project!
Do you know any hooks to teach designing airfoil? I need to learn to design airfoil wings but I have no knowledge. If you let me know what are the books I need to buy I thank you
I would recommend airfoiltools.com, and of course a quick google search will yield many relevant books. Depends on the application (low or higj speed, size, ...).
@@AirShaper thank you so much. I need to design and build a wing similar to jet man. I asked many universities but none willing to help. So I need to do it myself. Any other useful information if you can give me? I guess since the wing has no tail the lower chamber design should be upward. I need to calculate a wing 120cm of chord for speed minimum of 200km per hour.
@@noneNone-mw1px I wouldn't wait too long before moving to 3D, as the person will have a huge impact on the airflow! In terms of airfoil selection, indeed you'll want one that is relatively stable (the "torque" or "moment" will be important), with a gradual stall angle.
@@AirShaper yes true I need an stable airfoil with highlift efficiency. In my investigation I found that for delta wing with no vertical stabilizer the best airfoil to have upward lower chamber. So do you have any idea where and how should I start? Universities are really very disappointing. Either they do not know or they' do not want to help
@@noneNone-mw1px This would also be beyond my knowledge, but I think you should look for "self balancing/stabilizing wing or airfoil".
Hi Wouter, my name is Angelo Conte and I'm an aerospace engineer who has working on the designing of propeller for a multirotor. I would like to ask you a question: suppose that I want to design a propeller (10 inches of diameter and 4 for pitch). What approach do you can suggest me to analyze the blade of propeller near the hub in hovering condition, where the Reynolds number is very very low and the beta angle is about 30 degrees? I thought to use xfoil with viscous analysis but in that condition the convergence of solution is never reached. Thank you in advance and my compliments for your videos. Great job. Ciao
Hi! Indeed in those conditions flow is quite tricky, as it's a very 3D flow:
air doesn't just flow over the cross section of the airfoil, but also transversal to it. So an approximation with 2D simulations can be a bit tricky.
If you're handy, I'd suggest to set up a cyclic 3D simulation, with either:
- real moving geometry (sliding mesh)
- virtual rotation (MRF - moving reference frame)
- tangential velocity condition
All of these can be done in OpenFOAM, if you like!
Sir make more vedios
Hi Mohit, we're working hard on that one! We have a video coming up on the Air Race E, would that interest you?
Great explanation , but use more Diagrams !
Hi Robert, thanks for the compliment and the honest feedback!! In our most recent videos, we do try to include more diagrams. Also, there's a sequel to this video, I hope that one at least fills some of the holes for you? (Drone design #2)
I study in 7th standard but I interested in mechanism of vehicles
Hi Vicky, if you're interested in mechanisms of vehicles, then "mechanical engineering" channels on UA-cam should be interesting for you! We also have some videos on Porsches and so on, if you like :)
Why don't Airlines' use vortex generators to prevent drag, just like race cars & high performance cars use vortex generators to create downforce? Ok I just searched on google, that they do, after I actually typed the comment. I know i can delete it but I won't.
Hi Car Guy, indeed, they do apply it in some cases on airplanes too :) Often to postpone the stall-point, allowing for higher angles of attack.
AirShaper thank you, u're a great teacher. I understand 98%, despite my age. I'm 13, and I repeated this exquisite tutorial 2 or 3 times and understood more and more. Really appreciate your tutorials, tomorrow is the time to understand your second tutorial of this playlist and really appreciate your immediate response to my question, unlike most mainstream UA-camrs. You are top class Mr. Remmerie, a great explainer and I just subscribed to you today. You deserve more views & subscriptions. But It's crazy how people don't wanna learn and get knowledgeable. This is why we, students& future entrepreneurs have a great advantage, since most spend time watching cats play with cottonballs on UA-cam.
Thank you again ✌😀
higher Alpha = quicker & higher lift, right?
@@reeshadmuntasir5203 Initially, increasing angle of attack will increase lift without increasing drag much. So if you're looking for more downforce, that's a quick win. For for higher angles of attack, the increase in drag becomes significant and even the lift increase can reverse (the stall point). And if you're going for straight line speed, then you typically want to reduce downforce so you can reduce drag as well.
@AirShaper, but downforce is the opposite of lift, how's that an advantage
I have to search in english because there isnt anything in spanish.
Hi Rai, my Spanish would not be very useful in a video :) So I have to stick to English :)
Iam frome sudan iwant learn about air but idont know english
Dear, I would suggest to use a translator on the description below the video - most of the information is in there!
Don't remove the beard, it looks nice on you
I removed it in part 2, got bad feedback, grew it back and kept it ever since :)