Basic Design Theory and Aerodynamics behind Flying Wings and Tailless Aircraft (Part 1)

[@BenjaminWagner-y8p]

Excellent video GabeFPV. You pretty much covered the key points of 2 years worth of aerospace coursework in just the right amount of detail while stringing together a great narrative. Good slides too. I feel like I could go back and pass my intro to aerospace final with flying colors😂. (A long time ago for me)

[@brucematthews6417]

Very well explained. Good level of detail without burying us in math. I'm looking forward to the next part.

[@Tensho_C]

finally an in-depth video on unconventional wing designs. been looking for one since the nasa prandtl project came to my attention

[@zipped1214]

Current Aerospace Engineering student here (undergrad), and I loved this video!

[@antrygrevok6440]

Incredible amount of help you've given us, in this.. Couple of gifts for you, ( hopefully ), from an autistic who's spent a few years thinking on aircraft-design, & tried working through Raymer's university-textbook ( until the damn carelessness in his work stopped me: sometimes his explanations aren't clear, & his books all seem to need much more rigorous copy-editing!! *don't* allow mistakes into textbooks, eh? ) 1. Please, *PLEASE* try Julia with Pluto, instead of spreadsheets: You can make your work be compounding-capability in ways that spreadsheets sabotage.. ( I intend that all my aircraft-design stuff be able to generate variant-aircraft through calculating everything, just with some parameter-changes, & Julia+Pluto's core to that. Spreadsheets constrain one's work much more, the Julia/Pluto combination is much more parametric/dimensional/live ) 2. given that there is a portion of any real ( full-sized ) aircraft which is likely *usually* turbulent-boundary-layer, consider doing the golf-ball dimples thing, to that portion of the surface, to energize the boundary-layer a bit ( there are 2 competetion-level golf-balls, apparently, & they've got different dimples-patterns: 1 is all the same, the other has some-larger/some-smaller. I *think* the dimples need to be proportioned to either the Re or to the dimension of the object, but don't know which, yet, or if both make-difference.. ) 3. Please consider doing experiments re aircraft icing, with a boat hull coating called Silic One, which is a silicone-silane anti-fouling.. If it makes it impossible for ice to accumulate onto a surface, it may be a significant safety-investment for some aircraft.. ( I suspect that the blown-wing with aluminum in it, in the ATR-72 might have been part of the problem: blown surfaces tend to be colder, & having a prop blowing an aluminum-wing, or partially-alu-skinned-wing, seems to me like an icing-suicide-machine.. I don't know how long it'll take for the accident-investigators to report, so may have to wait a few years to know if this insight is right ) 4. I don't understand why flying-wing tankers aren't the normal ( just a random opinion of mine, for the last few years ). You can refuel more aircraft behind the thing, through more spanwise drogues, AND you waste less fuel staying in the air, while doing the work? Seems win-win, to me.. 5. Please consider trying fractions, instead of percentages, in your work: Nature seems to work more that way. ( e.g. natural ocean waves, that aren't, through shelving seafloor, becoming breakers, have a 1/7 ratio of height to length ) You said the optimal change from lift to negative-lift is around 70%, I suspect that it's either 2/3, or it's in a range ( due to specific-configuration ) between 2/3 .. 3/4. Once I realized that for sailboat & aircraft design ( both are related, & the lessons learned in each often do improve one's competence in the other, please consider "Principles of Yacht Design" to be the basic-text for it, & the North Sails textbook to be the pinnacle of sail-design books ), the fractions-orientation simplifies/clarifies much.. Like when I realized that the NASA recommendation for quiet operation, to keep prop-tip-speed down to 0.6 Mach was *actually*: the upper-surface of the prop has airflow around 4/3 of the prop-blade-speed, & 4/3 * 0.6 == 0.8, so you're getting close to transonic, then.. THEN it made much more sense, see? ( having a number where it's actually the interaction of 2 distinct fractions, if you know the basis-fractions, then it can make much more intution-sense, and THAT is one's designing-instinct: one's intuition. Get it right, consistently! : ) Or, another e.g.: make a yacht-rudder a symmetrical NACA foil of 1/8, aka 12.5% chord/thickness.. but if you want a low-drag foil? go to 1/12. Why is so-simple a thing important? The difference between a displacement-mode monohull & a faster-than-displacement-mode trimaran means that the optimal rudder-thickness may be thinner, for the trimaran, right? This hands me the exact range to try: 1/8 .. 1/12. I already KNOW the right-answer's within that range! ( : --- Please identify for us the textbooks you recommend, for us to learn these things *properly*. I'm already presuming that Doug McLean's Aerodynamics ( arguing from the actual physics, or something like that ) is the proper aerodynamics book to rely on ( he's got an IMPORTANT video kzbin.info/www/bejne/h3ymfGeif7GEfrc ) & that Snorri Gudmundsson's General Aviation book is the book to replace Daniel Raymer's one.. ( please correct me if I'm wrong ) but that still leaves massive gaps in one's learning, doesn't it? Please identify the dimensions-of-knowledge, & the specific self-learning textbooks you recommend in each, not as a reply to me, but rather as the text-underneath your videos, so that everyone readily sees that! Also, please make a playlist for these videos, so it *as a set* can be shared.. Subscribed, upvoted, & I wish I had the mental-firepower to work directly with this, as you do, & I wish I could hire you, to help me make my imaginings actualize.. ( multiple kinds of aircraft, arrays-of-each in different scales/sizes, bushplanes being 1 of those kinds ) Perhaps karma will change, perhaps not: either way, learning results, right? Either way, Salut, Namaste, Kaizen, & Gratitude for your helping us! _ /\ _

[@DC_DC_DC_DC]

Wow !

[@gian.4388]

On why there's no flying wing tankers: money. The cost of the project would far outweighed the benefits given current tankers do just fine as is

[@hu5116]

Hey Gabe, this was absolutely EXCELLENT! I’ve been watching a lot of flying wing videos of late due to a pending interest in trying out a related blended wing body design, and yours is absolutely the best! (At least for us engineers ;-). I very much look forward to seeing part 2 on stability, as this very much is “the rest of the story”. Thanks so much!

[@veloxsouth]

Excellent video and explanations. I'm looking forward to more on stability.

[@gabefpv]

Almost finished with the stability portion of the next one.

[@veloxsouth]

@@gabefpv thank you so much

[@unknown_person_777]

u teach better than my professor

[@mykolakhrystenko2886]

Thank You for your effort putting all this information in the video! Waiting for the next part!

[@mtsAlencc]

Very happy I came across this video. Thanks for all the clear explanations.

[@paragjiwtani]

The amount of knowledge crammed into 23 minutes is insane! Can't wait for the next part.

[@captarmour]

Love this video! Flying wings and close coupled canards get me really excited. When I started playing around with making flying wing foam gliders to test airfoils I found that when I would hand toss a symmetrical tailless wing she would climb hard at high speed and then as she slowed down she would lower her nose and find her trimmed speed. Then I would reshape the LE to give some positive camber and with the same force throw(launch) she would tuck hard until I retrimmed her by moving the cg way back. she would fly almost level at high speed but as she slowed she would gradually nose up into a stall. I got the longest glide with a symmetrical LE and just enough positive TE camber so that she would barely climb with a high speed toss and maintain almost level flight while decelerating before lowering her nose at slow speeds. I think what I'm seeing is the wing wants to follow the camber. I came across a "self incidence wing" which if I remember correctly had only about 1% camber which maintains a somewhat constant AoA over a range of speeds. I think it was a 1410 airfoil.

[@gabefpv]

Awesome man. I've also had several stable designs and flights with symmetrical foils, just making up the stability with more significant sweep/twist/taper

[@jayfeaver8243]

Nice effort on the video! You did a great job of summarizing and presenting. I really hope you keep going and look forward to watching the next ones. 😊

[@AerialWaviator]

Fantastic video. Interested seeing more of your design process as you worked through creating and building a flying wing. This looking to be the start of a nice mini-series on aerodynamics and design.

[@Zoey_the_Rat]

Nice vid! I'm religiously opposed to flying wings, especially planks after working on them for a while, but they're still cool marvels of aerodynamics

[@nuttyDesignAndFab]

big brain stuff! understood maybe 1/2 of what you said. looking forward to pt 2 :D

[@AstroCharlie]

This is an awesome video! I love the engineering level deep dive on flying wing theory!

[@IsaacKuo]

So informative! A crazy design challenge could be to design a VTOL drone which purposefully spins for take off and landing. The only two moving parts are props below the wingtips. With one prop going forward and the other in reverse, the wing is twisted for positive angle of attack. Alternatively, the props could be attached to flaperons, to similar effect. No need for a launch catapult or runway, and basically no compromises on horizontal flight performance. Spinning in place gives the benefits of a long runway without the runway.

[@gabefpv]

This sounds interesting. Are you thinking about something like this? kzbin.info/www/bejne/bXurYpKQgLtqqpYsi=_uxspg2Embj-Ke6I

[@IsaacKuo]

​@@gabefpv I'm thinking something simpler - more like ProjectAir's monocopter. That was the "Simplest Helicopter Ever" - just a wing and a single prop to set it spinning. Only one moving part. However, a monocopter can only fly like a helicopter. It can't transition to airplane-like horizontal flight because its prop is positioned to spin it. To transition, you want two props at opposite wingtips. That way, it's possible to fly like a monocopter by reversing one prop, and it's also possible to transition to horizontal flight by pushing forward with both props. Compared to a normal flying wing, you don't need a catapult or long runway. You get the benefits of a long runway but instead of landing gear you just spin in place on a bump at the center of mass.

[@johntenhave1]

Great Video with excellent graphic illustrations. I learnt a lot from your excellent presentation. It will take a couple of viewings to understand it all but that is a good thing and refreshingly different from the once over lightly skims that so often come our way. keep up thee good work! Further explanation of how aerodynamic twist works would be very helpful.

[@gabefpv]

Glad it was helpful!

[@TheQuantumFreak]

Excellent work man, took notes on this one.

[@BoonOhm]

Very good video. I need more content like this!!!

[@gabefpv]

Thanks, appreciate this!

[@CarlosChavez-gs1ld]

Well done, good pace, not for newbies.

[@PaulBreed]

Awesome video...just exactly the right level of technical detail. Eagerly await the next chapter... I'd love to talk with you about a project. Specifically I'd like your thoughts on the difference between designs for best L/D which pradalt does well and minimum power flight and how one might change the flying wing optimization to minimize power (CL/Cd)^(3/2) Best way to contact me is unrocket on what was the bird app.

[@gabefpv]

Prandtl's BSLD is best for high L/D as it aims to minimizes induced drag by producing a lift distribution that is near optimal for a given AR. Mathematically, the BSLD is ~13% more efficient that the ESLD (it also needs a bigger wingspan. If span is restricted, ELSD is your go to). BSLD will give minimum drag under no span constraints. I dug around in my sources list and this may be helpful for you - this is Al Bowers himself: kzbin.info/www/bejne/rV7HnGSEpbuBhKs (~15:30-21:00)

[@bellajbadr]

Damn, this video is insane. Thinks Bro!

[@gabefpv]

Thank you man!

[@FlavioSantos-uw1mr]

Hey thanks a lot! I am working on an autonomous drone for data collection at variable altitudes, the initial plan was a flying wing but some difficulties in balancing made me choose a more traditional model, at least until the software is developed enough to control the instability of the aircraft in flight, as my area is physics not engineering I knew how it worked but I had no background on how to make it work for my particular purpose, this video made me rethink and revert the model back to the original plan as it was more efficient than the aerodynamic abomination that I'm using now, a brick with wings and a turbine strapped to its back would be a good description of what I've created

[@gabefpv]

Higher altitude means more severe wind and turbulence, so you need a very stable plane. I wouldn’t use a flying wing for this

[@FlavioSantos-uw1mr]

@@gabefpv The altitudes shouldn't be too high but I'll keep instability in mind.

[@sashgorokhov]

Very timely video. I am currently designing wing uav under 100g auw.

[@stratos2]

I had never heard of the prandtl lift distribution before, that is really interesting! Could you perhaps put yot sources into the video description, I would love to read up more on this.

[@gabefpv]

I just tossed links to several of the research papers and resources used for my designs in the description. The first two papers are key.

[@StarkPhils]

This is really good! Well done!

[@marcobrandao3468]

O melhor trabalho sobre está configuração que já encontrei. Gostaria da indicação de literatura útil para o desenvolvimento de aeronaves deste tipo.

[@KlingbergWingMkII]

Actually it is very easy to decouple roll and yaw. Reduce the dihedral. Usually 0 to -2 degrees of dihedral does the trick The resulting spiral instability is of a very long period and easily controlled by the pilot. The main point of your video should be that we really don't know much about flying wings compared to regular aircraft and that the design of them should be approached with great caution, lest that person get a Dunning-Kruger award.

[@gabefpv]

I’d like to study the effect of this method of decoupling on any proverse yawing conditions. Curious if this would nullify the proverse yawing effects or even flip the resultant vector back to that of an adverse yawing condition.

[@tomdoly1918]

Thanks a lot for sharing all this .

Thank you for the excellent video. In a future video, could you perhaps explain in detail the effect of low aspect ratio on flying wings? Barnaby Wainfan has really intrigued me with this actually old concept, but there isn't much to read on the subject. Thank you, and keep it up!

[@gabefpv]

Great suggestion. Will add this topic into one of the next videos

[@VeerJoshi-j6c]

Real cool video, looking forward to the next installment of this series. I am an undergraduate in mechanical engineering and a part of a student aero design team. I see that you also use star CCM for your sims.

[@gabefpv]

Thanks man. I started the DBF team at our uni too, maybe I’ll make another quick vid on whatever notes I have from aircraft design and payload/structure optimization

[@jimhalpert3180]

Great video! We recently established our team as well, however we compete in SAE instead of AIAA.

[@c.l.3806]

Hello Im an Inventor invented a fishtail propulsion for the flying wing. Instead of an reflexed airfoil , tandem airfoils are used. One big front airfoil is the fish body. And the small airfoil behind is the fish tail fin. The tail fin is working like a slotted flap And it's producing thrust like a propeller. It decreases drag of the big body front wing with boundary layer suction technic. Im searching for people interested in my inventions. I believe fishtail propulsion is a very efficient flying technic.

[@andik.4235]

Well done!

[@emanueleungaro4277]

1:20 Most watching have an idea of what is multicalcualte calculus and low speed aereo dynamics sure go ahead

[@ancien_pauvre]

Thanks a lot for sharing this !

[@1KosovoJeSrbija1]

Can you cover the advantages and dissadvantages of a canard configuration? Is it true that it allows all aerodynamic surfaces to be lifting bodies and being stable?

[@gabefpv]

Sure, I’d love to. Stay tuned.

[@1KosovoJeSrbija1]

@@gabefpv thank you very much

[@lizhikai5587]

Well organized explanation! Thanks for making delicate diagrams and sharing knowledge with us. However, I have 2 questions about airfoil Cm, and one question about the span loading. 1) How did you calculate the Cm of the airfoil? My result of Cm indicates an positive (d Cm/d \alpha) for MH61 using xfoil. In practice, the CG still needs to be situated about 4%MAC in front of NP to get the overall (d CM / d \alpha)

[@alexandrpetrov1110]

Basic Design Theory and Aerodynamics behind Flying Wings and Tailless

[@HitAndMissLab]

do a video on forward swept wings.

[@mostowitz84]

Currently designing my own personal flying wing. Interested to see what comes next. Could you please reference the software packages you used along the way.

[@gabefpv]

Sure, mainly XFLR5, Matlab, Star-CCM+

[@waywardscythe3358]

Ayy I'd recognize a soccer ball carrying plane anywhere now

[@free_spirit1]

3:28 People always say this, but I'm never exactly sure why this would be so uncomfortable? Passengers also sit 30m from the center of pitch but that's not too uncomfortable. Is roll acceleration really that much stronger compared to that of pitching? Edit: timestamp

[@gabefpv]

Not sure about commercial body rates, but I can tell you that since one wing will be going up and the other down, one side in a roll will be 'floating' and the other side will feel 'heavy'. Since a plane is moving forward and pitching results in centrifugal acceleration (think the plane drawing a vertical circle in the sky) into your seat at any location on the plane, no-one's experiencing negative g's, or at least that's how I think about it. You would be correct if the plane was stationary - the back of the plane would feel floaty and the front heavy.

[@gabefpv]

@@free_spirit1 also 16:30 here kzbin.info/www/bejne/p4XbfI18f6qMq68si=WlU8B4F4lCMM_vdf

[@free_spirit1]

@@gabefpv Thanks man!

[@andreyl2705]

awesome)

[@tylerjohnson4]

Im in high school in AP research class and I want to research something in aerospace engineering, but im not super farmilerilar with everything? Got any ideas or topics I should look at or advice? Thanks

[@gabefpv]

Unsure what kind of research this is, but it could be fun to look into how turbojets work!

[@blackend00]

so if the design of a wing with a variable sweep angle and length and dihedral angle , maybe it can have a twist but didnt implement that yet, would the lift of such a wing where every time any of those variable can be changed for diffenrt situation can be simulated ? or have any benfits to begin with ?

[@gabefpv]

Variable length would be a massive challenge by itself

[@blackend00]

@@gabefpv so do you think i should keep working on this or its just not useful or will be have any benfits to have such a wing , the idea is to have it on small airplanes or jetpacks , thats for the long run, for short objective is to make it work on a rc model.

[@captarmour]

Does anyone put the elevators outboard of the ailerons? This would morph the wash-out from maximum at min speeds to wash-in in a dive! With ailerons on the inner 2/3 of half span the down going ailerons would move the vortex inboard producing proverse yaw in turns. What do you think.

[@gabefpv]

My very first wing (0:30-0:36, 23:05) did exactly this. I decoupled the roll and pitch with the inboard and outboard 'elevons', and also tried out differential yaw (right side controls deflect opposite of eachother, left hand don't deflect. The math was involved, but it was effective). I'm sure the proverse effect was decreased due to winglet effects on the lift distribution. Winglets are kinda countering to chasing proverse yaw in a wing.

[@captarmour]

Thanks for your reply means a lot to me. I went back to your vid and saw the wings at 0.30, 0.36 and 23.05! Very nice wings! I'm thinking the winglets would make a difference. I do like the idea of the elevators providing the amount of washout needed when reflexed for slower flight and not increasing drag at high speed as less 'reflex' would be needed. On another note, you mentioned 30⁰ sweep, is that because of handling problems due spanwise flow at high sweep angles? On still another note, my interest in swept wings is because I have noticed that swept wings transition in and out of Ground Effect with no pitching problems. My first WIG RC I left the all moving close coupled canards loose for high speed taxi tests and noticed that they pointed straight down. This made me realise in strong GE the high press under the wing produced a strong vertical flow at the LE! Thanks again, keep up the good work!

[@Uhhhhh-b1l]

Anytips for future aerospace engineering students?! I have a background in aviation maintenance and I’m learning about poweplants right now as we speak. I’m thinking of heading into general aviation while I stay in school to eventually transfer into a university:) anything helps !!

[@gabefpv]

General Aviation or Aerospace Engineering in college after A&P school? Aviation is geared much more towards pilots, and AE is much more engineering than flying. Start building a good understanding of calculus and multi variable calculus, and you’ll learn the rest of the theory in school

[@Uhhhhh-b1l]

@@gabefpv I want to do aerospace engineering and work on rocket engines but rn with my credentials I can work on airplanes and repair then as my main source of income. I plan on going through a cc and transferring

[@ninjax4909]

where next video? :(

[@gabefpv]

Pushing to get this out tonight or tomorrow.

[@6227836jschulz]

Hi, I hope you are aware of Sam Sheppard's (RIP) flying wing: kzbin.info/www/bejne/l4SnZ2ygmc5leacsi=kV9TkZgjqd1UjN_R. I recreated the plane according to his instructions at 8:13 in his video and added a flat body section in the middle to fit a 4S 21700 pack and the electronics. It flies great with FPV and an F-405 wing running Arduplane. I am very interested in the construction part of your build. Please keep it going. 😁 Thank you!

[@keithwalker6892]

What is wing NACA on ATR Aircraft

[@gabefpv]

airfoiltools.com/airfoil/details?airfoil=atr72sm-il

[@cristian-scd]

Gabriel, it's a well put video explaining flying wing principles. I'm a fun of unconventional planes especially flying wings. I've seen your wing at the beginning of the video and I thought the one I'm working on now damn I've copied from you - but is almost exact shape 😀 . My wing would have enlarged elevons at the tip, so change the twist of the wing in some range. I'm still struggle to figure out size of the elevon at the tip. In basics is to maintain a fairly constant lift distribution by controlling aoa and the twist ... as a hobbiest experiment Can I ask Is it possible to share to me the Pankin twist excel sheet that you have ? There is one made by Curtis S. but i think yours is much better. ... and waiting for the second video Thanks,

[@gabefpv]

Google Sheets messes up all the plots but the calcs are there in the description if you'd like. Standby for me figuring out how to share a true excel sheet

[@cristian-scd]

@@gabefpv The graph does not work propperly indeed but the rest is just fine. Thanks for sharing. I would need some help to ensure my XFLR analysis is correct, I would like to ask if you could make hlf hour available to talk ( may be share screen ) ?

[@alterego2421]

have u ever heard from the nasa prandtl d wing? insanely interesting pdf online also nice presentation from Albion Bowers on yt

[@alterego2421]

yea u have xD nice

[@gabefpv]

Haha yessir, I have his paper on my desk from this video still

[@alterego2421]

@@gabefpv Im building my own prandtl d wing rn with 3d printing rips and i can see why engineers dont like to work with flying wings xD the lay out is beyond tight to get everything in the body

[@alterego2421]

@@gabefpv Also ive built one from balsa wood before freehandcutting all the rips - it flew but only by force xD I moved the cg foward by like 10cm to get her somewhat stable because i couldnt cut the reflex airfoils by hand. Now with 3d printing I can get 0.1mm tolerances what a bliss 😍.

[@gabefpv]

What’s the span of this thing? I’ve been designing and flying little guys 100% 3d printed with a span of 1-1.5m

[@CptPorkster]

Monke SMASH

[@artemplatov1982]

links not working

[@gabefpv]

Working now.

[@noorik8778]

Как упоковать все знания об аэродинамике в одно видео, начиная с основных смыслов?

[@barenekid9695]

Prandtl DIED over a century ago. The wing only Craze pretty well ended by the 50's. With a history of failures. Basic attraction currently is in lower Radar profile. However Only processor controlled aero aids keep the current b2 airborne.

[@gabefpv]

I may add that almost all fighters are inherently unstable too, FCS/FBW and SAS's are a work of art