but this was so simplistic, I wish they had put your product through its paces more completely. Can it do farfield flow and pressure gradients as well as streamlines? Is there a limitation to Reynolds Number? Can it do studies at mach numbers in high subsonic region?
@@gendaminoru3195 To be fair, if you're starting by explaining (so clearly!) that a wing has something called stall which relates to angle-of-attack which relates to flow separation... moving onto the notion of flow regimes and Reynolds scaling is not gonna fit well in your first 10mins of video! From memory those topics are at least a few weeks apart even in a good under-grad course! Awesome Work Dark Aero folks, keep it going:)
@@DarkAeroInc I've watched a few of your vids now and all round well done. There's probably be a few things I'd do differently but they'd be preference not technical. On this one I'd go into more detail of stalls because stalls are an issue after the Max-8 but that wasn't the purpose of the video. Overall this is a very good collection of "how to go about getting an aircraft built." Project management and component & material selection are 2 of the most misunderstood tasks across the entire engineering field. 👍👍🦘🦘🦘🦘🦘
Love it. Going to use this video with my flight school students. Concept was very well explained visually. Be great to see with flaps / gear, and also the split rudder, as you mentioned in another comment!
Thank you David! We tried to keep the explanation at an introductory level so it would be suited for to broad audience. CFD is such a cool tool for showing aero effects visually! We are planning to show more in future videos. :)
Jesse, thank you for watching and for the comment! The question of wingtips was brought up in an earlier comment so just copying and pasting what we replied with there. Properly designed winglets would reduce induced drag. A similar result could be achieved by adding extra wingspan or something like a sheared wingtip which we would probably implement before a winglet. Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. At our cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. They start to have more benefit in a high altitude economy cruise scenario though.
Awesome, keep making videos showing neat uses of tech and ones like this that show how you get confidence in parts of your design. Very useful for students to see how engineering processes can be applied in real life
Great video! Would love to see more tech analysis like this... A few numbers on angle of attack and airspeed for the images you showed would be great to help understand the nuance of your decision making.
You asked for suggestions for future video topics, so I'd suggest making a video that focusses on your secret sauce- the extensive use of carbon fiber. What are its plus and minuses? Questions I have: how do you deal with sun exposure? does it interfere with radio communications? how do you make repairs? is it possible that you've made it so light that it will be too sensitive to turbulence?
Tom Busey thank you for watching and thank you for the video suggestion! I like the idea of videos going over carbon fiber in more detail since it is such a big portion of our airframe. This is one we have been talking about doing but it will definitely be a couple of videos because there is a lot to cover. Just to address your questions quickly before we get to making those videos, the big advantages of carbon fiber are its light weight, strength, stiffness, and ability to be formed into complex aerodynamically clean shapes. The main disadvantage is it’s cost. We deal with sun exposure by covering it with paint or UV blocking clear coat. Carbon fiber is opaque to radio waves so external antennas are required. We built the canopy fairing from fiberglass so it can house our antennas since fiberglass is radio wave transparent. Repairs can be made but the repair procedure will depend on the location and extent off damage. We’ve built the airplane light but we’ve also kept the wing area relatively small which puts the wing loading in a range that will prevent the airplane from being overly sensitive to turbulence.
Glad I stumbled across this channel, great content! I’d like to know more about how you’ve designed the structural components on a general level, especially considerations for fatigue. Coming from this background it intrigues me.
Austin Ekenstam thank you! Glad you are enjoying the content! Based off some of the questions we have received, we have been talking about making some videos going over designing/building/testing structures with composites.
I think most people whould be surprised at just how easy it is to make just about anything fly hehe. Just applying some rough, well explored design characteristics pretty much guarantees a plain will fly. How WELL it will fly is a matter of finer study
Are you able to do the same thing with flaps extended and ailerons deflected? How about the horizontal stabilizer with elevator deflection? What a cool tool. I love all the technology you guys are implementing in this build.
Thanks for checking out the video Marty! Yes, we can simulate control surface deflection. This might be interesting to show! We were thinking of sharing something like the split rudder sim as a follow up to our split rudder video.
Thanks for the terrific video. I would be interested in how you sized the horizontal and vertical stabs as well as the rudder, given that they all look quite small, especially the rudder. Spin recovery is a frequent problem area for new light aircraft. I would be interested to also see the same software show airflow during a yawed stall.
Here is a simple truth. No light sport aircraft etc has problems with spin recovery. Rather poor pilots have problems with spin recovery requiring massive empenages to more adequately cover their ***** lack of situational awareness**** at LOW altitude when flying SLOW. What this means is that Light sport pilots react too late because most of the crashes happen due to low speed too LOW to ground and therefore have insufficient time to recover with the perfectly adequate empenage. Instead of blaming oblivious pilots, empenages are being blamed. Empenages, by calculation are all massively oversize for spin recovery. Empenage sizing by calculation, is entirely dependent upon LOW speed landing/TO conditions for cross wind and rotation/max alpha correction. Empenage problems for spin recovery are PLACEMENT/Blanketing of wing/fuselage on said rudder/elevator, not size. How do you size them? Tail Volume Coefficients which tie directly into your neutral point and static margin calculations at different alphas for the moment of the airfoil. Rotation moment required which comes down to mass of aircraft, and landing gear distance from CG. This aircraft in question will have a relatively high VR on a ~medium length runway instead of like a STOL plane who must use the extra velocity from the propeller slipstream to rotate. Gets back to propeller selection for CRUISE, or do you select for more thrust on Takeoff? Not a simple answer, but an answer. With such a light aircraft, rudder, elevator forces even with their design should be low. Why you do not generally speaking see their design as the aircraft increases in size.
That’s great you guys are building an airplane from scratch! But I do have questions regarding the control of stall progression and spin resistance. Why do you not use aerodynamic features such as a leading-edge cuff, a dogtooth, or leading-edge root extension or fillet? Another great design feature is found on the Questair Venture that incorporates a single outboard-droop segment together with a small slot for spin resistance. Also, have you tested spin resistance with a dorsal fin added in front of the vertical stabilizer? Remember "Safety first, speed second."
Thank you, it is something I was waiting for. :) As Jordan Reimer, I'm also interested in the pre-calculation and structural analysis of a part (e.g. wing, gear strut). How the loads are defined, what is the factor of safety, do you use static, dynamic or fatigue approach? Can't wait to see something like that! :)
These are all good topics to discuss! A lot of the exact numbers we keep proprietary because we don't wan't builders to test the safety margins but it is still possible to show the concepts and approach to structural analysis in a future video. We have done a few unique things structurally that have sparked some discussion so we are definitely planning on covering this more.
@@DarkAeroInc Yes sure, and the exact numbers are part of your intellectual property! Indeed, the concept and the approach is the thing I am interested in the most! Can't wait to see! :)
Do the results gained from CFD then go into time response and handling qualities analysis? Are there certain handling quality requirements that DarkAero must satisfy from a regulatory perspective? I would assume that would be the case to be able to qualify for certain type ratings, but maybe not with experimental aircraft? I'm a senior in aerospace with interest in flight dynamics and controls type of stuff so I am just curious how the regulations and other polices come into the requirements/design of the aircraft. Keep up the good work!
In general, experimental aircraft are not required to meet the same standards and policies for design and manufacturing as certified aircraft but we still follow them as much as possible. For flight control and handling we follow FAR Part 23. An example of where we might deviate would be our use of a non-certified engine.
Just discovering the channel. Seems interesting. Thx a lot for all this sharing 😊. Please, is it possible to have a video of how you analyse wing - propeller slipstream - fuselage interaction effects in the aerodynamic of the wing (lift, drag, stall angle of attack?)
What were your main resources and past projects that you used to draw the relevant equations necessary for flight calculations? And are these used for a specific purpose, or to check and verify the results from CFD?
It would increase the high angle lift and increase the stall angle. It would also increase the drag. So, it's a trade of depending on what the aeroplane is being designed for.
Nice job of keeping it straightforward and understandable with good editing. Question: Any consideration of the wing tip vortices effect? And was any consideration given to adding winglets to the wing? Also, very interested in the answer to Marty G's questions. Great job!
Thank you Mark! The wing tip vortices are really minimal at our cruise condition which is the first wing simulation shown. The vortices get larger at higher angle of attack but realistically the airplane won't spend much time operating at high angle of attack. We have considered doing something like a winglet but the design we were thinking of would be more like a wingtip fence near the trailing edge of the aileron tip. Something like a mini version what you see on the A380 wingtip. It might be fun design area to iterate on down the road.
DarkAero, Inc I was also wondering about using winglets to address the vortex issue in both the area of high speed, high angle of attack but more importantly in low speed stall conditions around landings and takeoffs. I’m not sure what your predicted stall speed (VS1) is but I would imagine it is higher than many entry level and Kit planes which would add to complexity thus classifying it as a more complex plane to fly. I certainly don’t want to see the DarkAero 1 get the reputation as a pilot killer like the Evolution IV got labeled-which was a key factor in sinking that' company when liability insurance became all but impossible for the company to get and keep. Low speed stall characteristics can have a really huge effect on the short and long term viability of not just the airframe and wing design but also that of your company. Using winglets sooner rather than later might actually improve your business case as mitigate risk up front.
Before installing VG's, we would work on a more advanced flap design with higher lift increment. VG's would disrupt the laminar flow on the wing and increase drag throughout the entire flight envelope.
Once again, another nice video. Great job reducing complex concepts to easy-to-understand explanations. As a result of the CFD analysis, do you have predicted stick force plots yet that you would be willing to share?
Thank you Tom! We haven't done a stick force plot yet but hinge moments are obtainable from the CFD. We do have the ability to tune the stick force a bit by adjusting the mechanical advantage in the control system. We are using FAR Part 23 as our guidelines.
I have always wondered why spoilers aren't used in place of ailerons because they would cancel out most of the the need for rudder input in a turn! Why wouldn't they be better?
Thank you! Good to hear of a fellow Onshape user! Definitely recommend checking out SimScale too. We'll try to include some more discussion on flight loads in a future video. Any particular flight loads you are interested in?
Yes it would be cool to see the simulation conditions and how you came up with them. I’m really excited and inspired by your guys’ journey to building one of the fastest plane in its class! It was also a pleasure meeting you all at EAA last year. Keep up the great work!
Interesting to see visually how the wingtip vortex increases with AOA. Would the induced drag from this vortex be significantly reduced with the addition of a winglet, enough to be worthwhile on this wing? I'd also love to see what kind of effect on airflow separation would occur with the addition of vortex generators, and how that would affect stall speed.
Good eye noticing the wingtip vortices! Properly designed winglets would reduce induced drag. A similar result could be achieved by adding extra wingspan or something like a sheared wingtip which we would probably implement before a winglet. Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. At our cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. They start to have more benefit in a high altitude economy cruise scenario though. Thank you for watching!
CFD is an amazing tool. With its fairly high wing loading, do you anticipate the DA1 absolute and service ceilings being close together? Is it possible to anticipate through design tools and wind tunnel work the kind of incipient stall indication the aircraft will give, eg tail buffet or wing buffet?
Good questions Lew! Our service ceiling is currently 20,000 ft but this is mainly because UL Power only publishes engine performance data up to 20,000 ft. The absolute ceiling will be higher than this but we haven't made any hard claims about it without the engine performance data. The "feel" of the stall is a little trickier to measure through CFD but you can look at how airflow over the wing contacts the rest of the airframe. Tail buffet would be from the horizontal stabilizer flying through turbulent separated air shed from the root of the wing. We do see this effect in our CFD results so a tail buffet is expected. Hopefully we see this in flight testing. Thank you for watching!
While we didn't do any sphere simulations, there are a lot of publicly viewable sphere sims run under all sorts of different flow conditions in SimScale's community accounts. Your point about whether or not to trust the results is valid though and there are methods that can be used to determine if the results are reasonable. The underlying computational models are well proven but they do have their limitations. It's important to use the correct simulation model to analyze the particular flight conditions. For example, certain models are better at handling laminar vs turbulent or compressible vs incompressible so it's important to have an understanding of your flow conditions upfront. The mesh size and type is also important to get right. It's possible to run the same model with different mesh densities to get an idea of if your results are converging towards a solution. Another variable is the number of computational iterations and the residual error in the solution. CFD programs (SimScale included) can output residual error and give an indication of the convergence and stability of a solution. Once you have a result it's good to have some physical expected results like wind tunnel testing to compare it to as a cross check.
@@DarkAeroInc could you try a sphere? perhaps a couple of different sizes and simulation resolutions. It's a simple object and has a combination of aerodynamic and turbulent forms so it might be very telling. What I found to be the case, certainly for x-flow is that any half decent understanding of what makes an aerodynamic shape is vastly more precise than a simulation. If that is the case, you can save a lot of time by skipping all sims, knowing they will only mislead you with a false sense of rigor.
@@DarkAeroInc and should it give roughly meaningful numbers, you could try adding golf dimples to a sphere which I expect will give a second tier understanding of the efficacy of the tool so you can know when and when not to consult it.
I just watched your latest video and am very impressed with your stall computer calculations and software. I am building a Cozy Mk 4 and got to meet you at Airventure 2018. I’m curious if you are able with the software to anticipate the effects of the prop wash on the flight characteristics?
Thank you Mike! SimScale can do transient analysis like prop wash. We are thinking of showing this in a future video because the results are pretty interesting.
Awesome! Best airplane-building videos ever! I'm just curious about why there was no wing tip design for DarkAreo 1? Is it unnecessary or for some other reasons based on the CFD results?
It would be interesting to run WWII fighters (WITH the propeller spiral effects on the wings) in this system, because if the FW-190A at 45 lbs/sq foot has a smaller low speed sustained radius, and a faster sustained rate of turn than the Spitfire Mk IX at 30 lbs(!), and gains on it at any speed below 200 mph, then there is something wrong with our understanding of the physics. Pierre Clostermann (18 kills), the only WWII Western Allied pilot trusted to do technical conferences on German aircrafts to other pilots (he had studied engineering at Caltech), and an obsessive watcher of thousands of gun camera films, said the notion of the Spitfire out-turning at low sustained speed the FW-190A "Is a good joke", and Johnny Johnson, top Spitfire ace at 36 kills, concurred in a post war article. I believe the root cause of this is a web of leverages internal to the aircraft, putting in play the nose length among other things. See my channel for more details.
nothing in simulation on the INTERFERENCE DRAG between wing and fuselage at high angles of attack? what is the behavior of the plane (or half of the plane?)
Nice video! I was wondering whether you by any chance know the reason why the initial flow separation occurs where it does (about 1/4 semi-span), instead of closer to the root?
Thank you! This is an excellent question. The wing uses different airfoils at the root and tip to achieve a progressive stall. The tip airfoil stalls a few degrees after the root airfoil. If the wing was a straight "hershey bar" shape it would probably stall right at the root first. The taper of the wing adds in another variable that pushes the initial stall outboard. For the particular family of airfoils we are using, a section with a shorter chord tends to stall sooner than a longer chord. It is the combined effect of the different airfoils and the taper of the wing that drives the initial stall location. The start location is acceptable since it is inboard away from the ailerons.
@@DarkAeroInc Thank you for your explanation. Very clear. My guess is the fuselage wing junction would also have an effect and move it back inwards or just enlarge the separation area slightly? Of course you did not include the fuselage, for explanation purposes, very understandable.
Just came across your project! I wish you success with it. The one thing that came to my mind was the natural progression to stalling, which the aeroplane wil have to demonstrate in a flight test regime... spinning! Have you considered spin recovery when designing your tail surfaces (esp split rudder)and fuselage on the CFD?
Is there a reason you guys chose such straight lines in the design of the aircraft? It doesn't seem to have any flowing lines in the design at all and I'm wondering if this was a design consideration to simplify production at the expense of appearance?
Thanks for sharing a superb explanation! Are you guys intendind a parachute device installation? When the nice bird will have a maiden flight and date of availabke sales kit! Thans again. I am a sport pilot from Brazil
How was the decision made, not to incorporate winglets [of some sort] . There is a lot of energy slipping off the wing tips, making that tornado, clearly seen in the cfd sim. Guys a sharp as you seem to be, must have considered this.......
John, thank you for watching and good question! Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. A cruise angle of attack is shown at 4:12-4:20 in the video and you can see the wingtip vortices are pretty minimal here. For our target cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. Winglets would start to provide more benefit at higher angles of attack such as in a high altitude economy cruise scenario. The conditions shown in the sim with larger wingtip vortices are near to stall. The aircraft spends little time operating at these angles of attack so we would not add winglets to try to optimize around that target.
You are overvaluating winglets. They are not a magic answer, merely a way of increasing aspect ratio without much increasing stress on the wing. As Darkaero said they provide benefit but are not always worth the added weight and cost.
The progressive stall is achieved by using different airfoils for the root and the tip. Basically the root section stalls a few degrees sooner than the tip section. The specific sections are proprietary. Thank you for watching!
Hey darkaero team. Thanks for sharing. Amazing work you are doing. May I ask you why you are designing all wing and rudder/stabilator surface tips with sharp edges iso round out every tip? All the large airliners are going to smooth round wing tips...
Any concerns about turbulent air off main wing affect rear stabilizer lift? Visually the rear stab appears low and in line with wing. I am sure your CFD tested for that
Can you show the split rudder in simulation ! and what have you done that the stall is occurring on the root side of the wing first ... and why you haven't narrowed the body at the wing ... Please answer...
I really enjoy your channel and what you brothers have and will accomplish. I was wondering if you guys had the time to create your aircraft for us wish to be pilots in Microsofts Flight Sim 2020. I'm a 61 year old man suffering from 4th stage chronic kidney failure but really enjoy what you guys are doing. I would love to add to my fantasy the joy of flying your aircraft. Is it or will it ever be available in flight sims so that I can fulfill my fantasy? Thanks in advance for all you do.
For this particular analysis we didn't simulate prop wash because we were focusing on the wing and it would add unnecessary complexity and computation time to the simulation. The prop wash does have an effect on flow though, especially at the root of the wing. It is important to have a wing that stalls in a favorable manner both power on and power off so the model without prop wash is still valuable. We are thinking of sharing a simulation with prop wash in a future video because these effects are pretty interesting to see. Thank you for watching!
Are you able to go into specifics about how you were able to optimize stall characteristics? I'm guessing that you used wing twist (slightly less incidence as you approach the wingtip) to force the inner portion of the wing to stall first, but i could be wrong??
I’m not even there but I know it will fly. There were a ton of working aircraft built prior to fully understanding the principles used. Heres what you need: Enough power Wings employing Bernoulli’s principle Enough induced drag Weight and balance within reason Sufficient control surface area Your airplane will fly. I just hope you don’t try to leave the carbon fiber visible. There shouldn’t be any ultraviolet light allowed to contact structural carbon fiber. There are also some conducive complications with carbon fiber. I haven’t heard how you intend to deal with static electricity generated in flight (there’s a lot).
They will be different if you include the aircraft fuselage, but if you move your symmetry plane to the centerline of the aircraft then there will be no difference with a half or full geometry. The CFD run time will however be around half. That's assuming that you have no yaw angle.
If i understand this correctly, as someone who knows very little about aerodynamics, the tips of the wings need to be able to support the weight of the aircraft alone otherwise in a progressive stall the wings could break as the lift from the root outward decreases ?
Not really support all the weight. We want the stall to be be both predictable and controllable. Imagine the opposite, that's called "tip stall". Tip stall, when it happens, is not perfectly symmetrical. Actually, one wing will lost a bit more lift than the other at the tip, which creates a momentum that can tip the airplane over very quickly.
How much attention did you folks pay to achieving laminar flow in the wings or fuselage? I ask as it seems to be something prioritized in some new plane designs.
Interesting video! With carbon fiber you guys could have designed a wing of virtually any shape or a combination of wing designs. How did you settle on design choice?
Did you have control over all the parameters of your CFD simulations? Results can vary a lot, especially when the flow is not laminar. Also, it's easy to think that as the result looks good and realistic, the sim must be close to reality. Unfortunately, that's often not the case. Anyway, I assume you applied well know rules to design a wing that won't tip stall (like negativ twist for example), so there shouldn't be any unexpected stall problems
This simulation is on a clean wing, can you apply the same simulation with flaps lowered? Flaps would change what part of the wing stalls first, could a stall then develop closer to the area of the aileron? This is why a split-angled wing is being used on the newer Cirrus and Kodiak.
Modern designs make me shake my head but mainly because I'm old - my bum on the spar/COG always feels correct but yours, looks like I will fall off the back of the wing! lol
How do you collate the results that you get from CFD and wind tunnel? I'm wondering if you used dimensional analysis and based the results (Flight Characteristics) from your wind tunnel testing and CFD is used for confirmation of such results. Thanks
Very interesting video. Do the wingtip vortices play into the tip of the wing retaining lift longer? I've been wondering why wing designs don't contain those to avoid the extra drag.
Nice vlog as usual. I might be an amateur but here is a Question. Why did you design the position of the seats side by side and not in line (front and back) of the fuselage? More aero efficient and speed if you had a narrow body!
Dave, thanks for watching and the question. You're correct that the aircraft could have been even more aerodynamically efficient if we had opted for front and back seating. However, side-by-side seating is a more enjoyable flying experience. Additionally, the engine is also already nearly as wide as two people sitting side-by-side.
Awesome Video. But wathcing this turn me a question. Creating a stall configuration on the root of the wing, how does it affect the elevator? There is no risk in losing autority of the elevator in a stall? Thanks from Brazil!
Would you consider releasing an STL for us to print a desk model of at home? Love to have one of these on my shelf, since a grad student budget won't allow the real thing for a while.
Since there is a certain amount of intellectual property tied up in the CAD we haven't released any of it. At some point we might come up with an abstracted file for 3D printing. :)
Looks very promising :-) Did you also use SimScale for estimating performance figures? How confident do you think you can be about speed and range predictions?
Yes! We have both forward and aft baggage compartments. The forward compartment sits in between the firewall and instrument panel is divided into left and right sides. Each side can fit a soft carry-on size bag or backpack. The aft compartment is larger and can fit items like duffel bags. Total capacity for cargo is around 100lbs provided it is loaded within the center of gravity envelope. This isn't too difficult with the compartments divided up forward and aft.
Awesome content! Thank you! Are you familiar with the prandtl wing? Also, some flight Sims like x plane do calculate the forces applying to an airframe. Do you know whether they use fluid dynamics or just tables?
Neither. They create a force model based on the geometry. Each element (wing, fuselage, tail etc) has a lift and drag and a physical location which is used to find the body force and moments for different angles of attacks. The accuracy of the approximation depends on the complexity of the mathematical model but its a world away from CFD.
GA aircraft not certified for known ice should NEVER proceed into it. The reality’s is the current fleet has accidentally and intentionally ventured into these deadly ( for uncertified aircraft) conditions. Has any predictions been made for how well this critical wing would do under those conditions?
![Kodak Black - Sharp Vibes [Official Music Video]](http://i.ytimg.com/vi/oEV0OoLJeIs/mqdefault.jpg)
Great video! We are very happy to working with such an incredible company like DarkAero!
Happy to work with you as well!
Can’t wait to show my class this. Probably one of the best videos showing stall and the disruption of air.
Nice stall analysis with the soft. Congrats ALL !!!
but this was so simplistic, I wish they had put your product through its paces more completely. Can it do farfield flow and pressure gradients as well as streamlines? Is there a limitation to Reynolds Number? Can it do studies at mach numbers in high subsonic region?
@@gendaminoru3195 To be fair, if you're starting by explaining (so clearly!) that a wing has something called stall which relates to angle-of-attack which relates to flow separation... moving onto the notion of flow regimes and Reynolds scaling is not gonna fit well in your first 10mins of video! From memory those topics are at least a few weeks apart even in a good under-grad course! Awesome Work Dark Aero folks, keep it going:)
While my specialty is structures, these videos warm my engineering heart.
😊Thank you for watching! What sort of structures do you specialize in?
@@DarkAeroInc Buildings.
@@DarkAeroInc I've watched a few of your vids now and all round well done. There's probably be a few things I'd do differently but they'd be preference not technical. On this one I'd go into more detail of stalls because stalls are an issue after the Max-8 but that wasn't the purpose of the video. Overall this is a very good collection of "how to go about getting an aircraft built." Project management and component & material selection are 2 of the most misunderstood tasks across the entire engineering field.
👍👍🦘🦘🦘🦘🦘
Love it. Going to use this video with my flight school students. Concept was very well explained visually. Be great to see with flaps / gear, and also the split rudder, as you mentioned in another comment!
Thank you David! We tried to keep the explanation at an introductory level so it would be suited for to broad audience. CFD is such a cool tool for showing aero effects visually! We are planning to show more in future videos. :)
@@DarkAeroInc I'd be interested in seeing what effect the flaps have on airflow. Thanks.
It’s really cool to see the wingtip vortices depicted as angle of attack increases. Have you considered adding winglets?
Jesse, thank you for watching and for the comment! The question of wingtips was brought up in an earlier comment so just copying and pasting what we replied with there. Properly designed winglets would reduce induced drag. A similar result could be achieved by adding extra wingspan or something like a sheared wingtip which we would probably implement before a winglet. Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. At our cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. They start to have more benefit in a high altitude economy cruise scenario though.
It's extremely impressive to see how understandable you are and how simple you actually make something quite technical sound. Very well done 👏
Awesome, keep making videos showing neat uses of tech and ones like this that show how you get confidence in parts of your design. Very useful for students to see how engineering processes can be applied in real life
Thank you for watching! We have a lot of future videos planned. Happy to hear they are useful/helpful to students! :)
The answer should be "We know it will fly because it's bad ass" Awesome workmanship guys!
Terry, thank you for watching and the kind words! 🚀
Great video! Would love to see more tech analysis like this... A few numbers on angle of attack and airspeed for the images you showed would be great to help understand the nuance of your decision making.
Wow this is such an incredible video!! Thanks for the clear explanation!! Can't wait to see the aircraft fly!!
Glad you enjoyed it! Thank you for watching! We are excited to get it flying. :)
You asked for suggestions for future video topics, so I'd suggest making a video that focusses on your secret sauce- the extensive use of carbon fiber. What are its plus and minuses? Questions I have: how do you deal with sun exposure? does it interfere with radio communications? how do you make repairs? is it possible that you've made it so light that it will be too sensitive to turbulence?
Tom Busey thank you for watching and thank you for the video suggestion! I like the idea of videos going over carbon fiber in more detail since it is such a big portion of our airframe. This is one we have been talking about doing but it will definitely be a couple of videos because there is a lot to cover. Just to address your questions quickly before we get to making those videos, the big advantages of carbon fiber are its light weight, strength, stiffness, and ability to be formed into complex aerodynamically clean shapes. The main disadvantage is it’s cost. We deal with sun exposure by covering it with paint or UV blocking clear coat. Carbon fiber is opaque to radio waves so external antennas are required. We built the canopy fairing from fiberglass so it can house our antennas since fiberglass is radio wave transparent. Repairs can be made but the repair procedure will depend on the location and extent off damage. We’ve built the airplane light but we’ve also kept the wing area relatively small which puts the wing loading in a range that will prevent the airplane from being overly sensitive to turbulence.
I love these analysis videos. More CFD please!
This is great. Please do more in-depth engineering content!
Glad I stumbled across this channel, great content! I’d like to know more about how you’ve designed the structural components on a general level, especially considerations for fatigue. Coming from this background it intrigues me.
Austin Ekenstam thank you! Glad you are enjoying the content! Based off some of the questions we have received, we have been talking about making some videos going over designing/building/testing structures with composites.
Love the project. Love the team. Love learning.
This is gold.
An area of interest for CFD is the wing root fuselage interaction. The high pressure gradient can cause big separation events...
I think most people whould be surprised at just how easy it is to make just about anything fly hehe. Just applying some rough, well explored design characteristics pretty much guarantees a plain will fly. How WELL it will fly is a matter of finer study
Are you able to do the same thing with flaps extended and ailerons deflected? How about the horizontal stabilizer with elevator deflection? What a cool tool. I love all the technology you guys are implementing in this build.
Thanks for checking out the video Marty! Yes, we can simulate control surface deflection. This might be interesting to show! We were thinking of sharing something like the split rudder sim as a follow up to our split rudder video.
@@DarkAeroInc This would be an interesting video.
Thanks for the terrific video. I would be interested in how you sized the horizontal and vertical stabs as well as the rudder, given that they all look quite small, especially the rudder. Spin recovery is a frequent problem area for new light aircraft. I would be interested to also see the same software show airflow during a yawed stall.
Here is a simple truth. No light sport aircraft etc has problems with spin recovery. Rather poor pilots have problems with spin recovery requiring massive empenages to more adequately cover their ***** lack of situational awareness**** at LOW altitude when flying SLOW. What this means is that Light sport pilots react too late because most of the crashes happen due to low speed too LOW to ground and therefore have insufficient time to recover with the perfectly adequate empenage. Instead of blaming oblivious pilots, empenages are being blamed. Empenages, by calculation are all massively oversize for spin recovery. Empenage sizing by calculation, is entirely dependent upon LOW speed landing/TO conditions for cross wind and rotation/max alpha correction. Empenage problems for spin recovery are PLACEMENT/Blanketing of wing/fuselage on said rudder/elevator, not size.
How do you size them? Tail Volume Coefficients which tie directly into your neutral point and static margin calculations at different alphas for the moment of the airfoil. Rotation moment required which comes down to mass of aircraft, and landing gear distance from CG. This aircraft in question will have a relatively high VR on a ~medium length runway instead of like a STOL plane who must use the extra velocity from the propeller slipstream to rotate. Gets back to propeller selection for CRUISE, or do you select for more thrust on Takeoff? Not a simple answer, but an answer. With such a light aircraft, rudder, elevator forces even with their design should be low. Why you do not generally speaking see their design as the aircraft increases in size.
That’s great you guys are building an airplane from scratch! But I do have questions regarding the control of stall progression and spin resistance. Why do you not use aerodynamic features such as a leading-edge cuff, a dogtooth, or leading-edge root extension or fillet? Another great design feature is found on the Questair Venture that incorporates a single outboard-droop segment together with a small slot for spin resistance. Also, have you tested spin resistance with a dorsal fin added in front of the vertical stabilizer?
Remember "Safety first, speed second."
All of those items can be added later. The features on the Questair Venture were absent originally.
Thank you, it is something I was waiting for. :) As Jordan Reimer, I'm also interested in the pre-calculation and structural analysis of a part (e.g. wing, gear strut). How the loads are defined, what is the factor of safety, do you use static, dynamic or fatigue approach? Can't wait to see something like that! :)
These are all good topics to discuss! A lot of the exact numbers we keep proprietary because we don't wan't builders to test the safety margins but it is still possible to show the concepts and approach to structural analysis in a future video. We have done a few unique things structurally that have sparked some discussion so we are definitely planning on covering this more.
@@DarkAeroInc Yes sure, and the exact numbers are part of your intellectual property! Indeed, the concept and the approach is the thing I am interested in the most! Can't wait to see! :)
Glad to see you here Jani! ;-)
Do the results gained from CFD then go into time response and handling qualities analysis? Are there certain handling quality requirements that DarkAero must satisfy from a regulatory perspective? I would assume that would be the case to be able to qualify for certain type ratings, but maybe not with experimental aircraft? I'm a senior in aerospace with interest in flight dynamics and controls type of stuff so I am just curious how the regulations and other polices come into the requirements/design of the aircraft. Keep up the good work!
In general, experimental aircraft are not required to meet the same standards and policies for design and manufacturing as certified aircraft but we still follow them as much as possible. For flight control and handling we follow FAR Part 23. An example of where we might deviate would be our use of a non-certified engine.
i can't wait to see it lift :)
Just discovering the channel.
Seems interesting. Thx a lot for all this sharing 😊.
Please, is it possible to have a video of how you analyse wing - propeller slipstream - fuselage interaction effects in the aerodynamic of the wing (lift, drag, stall angle of attack?)
Could you go deeper into the equations you used for DarkAero? Thanks.
What were your main resources and past projects that you used to draw the relevant equations necessary for flight calculations?
And are these used for a specific purpose, or to check and verify the results from CFD?
Would love to see what the addition of vortex generators does to your wing design.
It would increase the high angle lift and increase the stall angle. It would also increase the drag. So, it's a trade of depending on what the aeroplane is being designed for.
I'm going to focus my final degree diseration on a CFD analysis. I hope to obtain results as perfect as yours haha. Nice to see that streamlines !!!
Looks like it will be suitable to make high banked turns at 50 foot off the deck.
Perhaps over the Nevada desert? 😏
Nice job of keeping it straightforward and understandable with good editing. Question: Any consideration of the wing tip vortices effect? And was any consideration given to adding winglets to the wing? Also, very interested in the answer to Marty G's questions. Great job!
Thank you Mark! The wing tip vortices are really minimal at our cruise condition which is the first wing simulation shown. The vortices get larger at higher angle of attack but realistically the airplane won't spend much time operating at high angle of attack. We have considered doing something like a winglet but the design we were thinking of would be more like a wingtip fence near the trailing edge of the aileron tip. Something like a mini version what you see on the A380 wingtip. It might be fun design area to iterate on down the road.
DarkAero, Inc I was also wondering about using winglets to address the vortex issue in both the area of high speed, high angle of attack but more importantly in low speed stall conditions around landings and takeoffs. I’m not sure what your predicted stall speed (VS1) is but I would imagine it is higher than many entry level and Kit planes which would add to complexity thus classifying it as a more complex plane to fly. I certainly don’t want to see the DarkAero 1 get the reputation as a pilot killer like the Evolution IV got labeled-which was a key factor in sinking that' company when liability insurance became all but impossible for the company to get and keep. Low speed stall characteristics can have a really huge effect on the short and long term viability of not just the airframe and wing design but also that of your company. Using winglets sooner rather than later might actually improve your business case as mitigate risk up front.
@@DarkAeroInc Good answer, thanks.
Great video!
Why not add vortex generators to induce turbulence on the air flow so at higher angle of attacks the airflow remains attached to the wing?
Before installing VG's, we would work on a more advanced flap design with higher lift increment. VG's would disrupt the laminar flow on the wing and increase drag throughout the entire flight envelope.
This video is so cool!
thanks for this video.
It soo reminds me of a sleek sailplane and looks to be smooth in the stall ,instead of whippy
Once again, another nice video. Great job reducing complex concepts to easy-to-understand explanations. As a result of the CFD analysis, do you have predicted stick force plots yet that you would be willing to share?
Thank you Tom! We haven't done a stick force plot yet but hinge moments are obtainable from the CFD. We do have the ability to tune the stick force a bit by adjusting the mechanical advantage in the control system. We are using FAR Part 23 as our guidelines.
I have always wondered why spoilers aren't used in place of ailerons because they would cancel out most of the the need for rudder input in a turn! Why wouldn't they be better?
Can you show us the calculation/simulation for flight loads. great vid on CFD. I use OnShape but new to SimScale
Thank you! Good to hear of a fellow Onshape user! Definitely recommend checking out SimScale too. We'll try to include some more discussion on flight loads in a future video. Any particular flight loads you are interested in?
@@DarkAeroInc I am interested in the stress in the fuselage under normal flight loads and under higher G. Sweet looking plane great vids!!!
Yes it would be cool to see the simulation conditions and how you came up with them. I’m really excited and inspired by your guys’ journey to building one of the fastest plane in its class! It was also a pleasure meeting you all at EAA last year. Keep up the great work!
Interesting to see visually how the wingtip vortex increases with AOA. Would the induced drag from this vortex be significantly reduced with the addition of a winglet, enough to be worthwhile on this wing? I'd also love to see what kind of effect on airflow separation would occur with the addition of vortex generators, and how that would affect stall speed.
Good eye noticing the wingtip vortices! Properly designed winglets would reduce induced drag. A similar result could be achieved by adding extra wingspan or something like a sheared wingtip which we would probably implement before a winglet. Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. At our cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. They start to have more benefit in a high altitude economy cruise scenario though. Thank you for watching!
Is the wingtip squared off or rounded? Would an upturned tapered wing add benefits similar to the SR22?
CFD is an amazing tool.
With its fairly high wing loading, do you anticipate the DA1 absolute and service ceilings being close together?
Is it possible to anticipate through design tools and wind tunnel work the kind of incipient stall indication the aircraft will give, eg tail buffet or wing buffet?
Good questions Lew! Our service ceiling is currently 20,000 ft but this is mainly because UL Power only publishes engine performance data up to 20,000 ft. The absolute ceiling will be higher than this but we haven't made any hard claims about it without the engine performance data.
The "feel" of the stall is a little trickier to measure through CFD but you can look at how airflow over the wing contacts the rest of the airframe. Tail buffet would be from the horizontal stabilizer flying through turbulent separated air shed from the root of the wing. We do see this effect in our CFD results so a tail buffet is expected. Hopefully we see this in flight testing.
Thank you for watching!
Try calculating the drag coefficient of a sphere with the software as a gauge if you can trust it to any degree.
While we didn't do any sphere simulations, there are a lot of publicly viewable sphere sims run under all sorts of different flow conditions in SimScale's community accounts. Your point about whether or not to trust the results is valid though and there are methods that can be used to determine if the results are reasonable. The underlying computational models are well proven but they do have their limitations. It's important to use the correct simulation model to analyze the particular flight conditions. For example, certain models are better at handling laminar vs turbulent or compressible vs incompressible so it's important to have an understanding of your flow conditions upfront. The mesh size and type is also important to get right. It's possible to run the same model with different mesh densities to get an idea of if your results are converging towards a solution. Another variable is the number of computational iterations and the residual error in the solution. CFD programs (SimScale included) can output residual error and give an indication of the convergence and stability of a solution. Once you have a result it's good to have some physical expected results like wind tunnel testing to compare it to as a cross check.
@@DarkAeroInc could you try a sphere? perhaps a couple of different sizes and simulation resolutions. It's a simple object and has a combination of aerodynamic and turbulent forms so it might be very telling. What I found to be the case, certainly for x-flow is that any half decent understanding of what makes an aerodynamic shape is vastly more precise than a simulation. If that is the case, you can save a lot of time by skipping all sims, knowing they will only mislead you with a false sense of rigor.
@@DarkAeroInc and should it give roughly meaningful numbers, you could try adding golf dimples to a sphere which I expect will give a second tier understanding of the efficacy of the tool so you can know when and when not to consult it.
I just watched your latest video and am very impressed with your stall computer calculations and software. I am building a Cozy Mk 4 and got to meet you at Airventure 2018. I’m curious if you are able with the software to anticipate the effects of the prop wash on the flight characteristics?
Thank you Mike! SimScale can do transient analysis like prop wash. We are thinking of showing this in a future video because the results are pretty interesting.
DarkAero, Inc oh cool I’ll look forward to that. Thanks
Awesome! Best airplane-building videos ever! I'm just curious about why there was no wing tip design for DarkAreo 1? Is it unnecessary or for some other reasons based on the CFD results?
It would be interesting to run WWII fighters (WITH the propeller spiral effects on the wings) in this system, because if the FW-190A at 45 lbs/sq foot has a smaller low speed sustained radius, and a faster sustained rate of turn than the Spitfire Mk IX at 30 lbs(!), and gains on it at any speed below 200 mph, then there is something wrong with our understanding of the physics. Pierre Clostermann (18 kills), the only WWII Western Allied pilot trusted to do technical conferences on German aircrafts to other pilots (he had studied engineering at Caltech), and an obsessive watcher of thousands of gun camera films, said the notion of the Spitfire out-turning at low sustained speed the FW-190A "Is a good joke", and Johnny Johnson, top Spitfire ace at 36 kills, concurred in a post war article. I believe the root cause of this is a web of leverages internal to the aircraft, putting in play the nose length among other things. See my channel for more details.
Why that wing haven´t some more sophisticated end, like winglet or so for reducing drag?
nothing in simulation on the INTERFERENCE DRAG between wing and fuselage at high angles of attack? what is the behavior of the plane (or half of the plane?)
Nice video! I was wondering whether you by any chance know the reason why the initial flow separation occurs where it does (about 1/4 semi-span), instead of closer to the root?
Thank you! This is an excellent question. The wing uses different airfoils at the root and tip to achieve a progressive stall. The tip airfoil stalls a few degrees after the root airfoil. If the wing was a straight "hershey bar" shape it would probably stall right at the root first. The taper of the wing adds in another variable that pushes the initial stall outboard. For the particular family of airfoils we are using, a section with a shorter chord tends to stall sooner than a longer chord. It is the combined effect of the different airfoils and the taper of the wing that drives the initial stall location. The start location is acceptable since it is inboard away from the ailerons.
Interesting, so it’s not washout, but airfoil shape/chord span wise difference?
@@DarkAeroInc Thank you for your explanation. Very clear. My guess is the fuselage wing junction would also have an effect and move it back inwards or just enlarge the separation area slightly? Of course you did not include the fuselage, for explanation purposes, very understandable.
Very cool video, do you have any videos for structural analysis on the dark aero?
Just came across your project! I wish you success with it. The one thing that came to my mind was the natural progression to stalling, which the aeroplane wil have to demonstrate in a flight test regime... spinning! Have you considered spin recovery when designing your tail surfaces (esp split rudder)and fuselage on the CFD?
Is there a reason you guys chose such straight lines in the design of the aircraft? It doesn't seem to have any flowing lines in the design at all and I'm wondering if this was a design consideration to simplify production at the expense of appearance?
Thanks for sharing a superb explanation! Are you guys intendind a parachute device installation? When the nice bird will have a maiden flight and date of availabke sales kit! Thans again. I am a sport pilot from Brazil
Nice one guys!
Thank you!
Nice explation. Thank you.
Thank you for watching!
How was the decision made, not to incorporate winglets [of some sort] . There is a lot of energy slipping off the wing tips, making that tornado, clearly seen in the cfd sim. Guys a sharp as you seem to be, must have considered this.......
John, thank you for watching and good question! Our wing is optimized for high speed cruise and at this operating condition the induced drag is pretty low, around 5-7% of the total drag. A cruise angle of attack is shown at 4:12-4:20 in the video and you can see the wingtip vortices are pretty minimal here. For our target cruise conditions, adding winglets would reduce induced drag but would increase parasitic drag by a similar increment so the net result is close to neutral. Winglets would start to provide more benefit at higher angles of attack such as in a high altitude economy cruise scenario. The conditions shown in the sim with larger wingtip vortices are near to stall. The aircraft spends little time operating at these angles of attack so we would not add winglets to try to optimize around that target.
You are overvaluating winglets. They are not a magic answer, merely a way of increasing aspect ratio without much increasing stress on the wing. As Darkaero said they provide benefit but are not always worth the added weight and cost.
Very interesting. Will elevator authority be an issue in a stall because it is in the slip stream of the wing?
Are your tools able to simulate how the aircraft will recover from a spin?
Very nice! I have a question: Why the stall starts at the root and progresses toward the tip? which airfoils you are using?
The progressive stall is achieved by using different airfoils for the root and the tip. Basically the root section stalls a few degrees sooner than the tip section. The specific sections are proprietary. Thank you for watching!
Hey darkaero team. Thanks for sharing. Amazing work you are doing. May I ask you why you are designing all wing and rudder/stabilator surface tips with sharp edges iso round out every tip? All the large airliners are going to smooth round wing tips...
great work.please keep making great content
A-6M ZERO thank you for watching! Glad you liked it!
@@DarkAeroInc i also making a twin engine by my own.my team is me keep up bro
I agree with gsmac 1969: Winglet?
Any plans for a scale RC model? For those of us without a pilot license and deep pockets.
Does the simulation behave different at different scales?
Any concerns about turbulent air off main wing affect rear stabilizer lift? Visually the rear stab appears low and in line with wing. I am sure your CFD tested for that
Can you show the split rudder in simulation !
and what have you done that the stall is occurring on the root side of the wing first ...
and why you haven't narrowed the body at the wing ...
Please answer...
I really enjoy your channel and what you brothers have and will accomplish. I was wondering if you guys had the time to create your aircraft for us wish to be pilots in Microsofts Flight Sim 2020. I'm a 61 year old man suffering from 4th stage chronic kidney failure but really enjoy what you guys are doing. I would love to add to my fantasy the joy of flying your aircraft. Is it or will it ever be available in flight sims so that I can fulfill my fantasy? Thanks in advance for all you do.
Do you simulate prop wash?
For this particular analysis we didn't simulate prop wash because we were focusing on the wing and it would add unnecessary complexity and computation time to the simulation. The prop wash does have an effect on flow though, especially at the root of the wing. It is important to have a wing that stalls in a favorable manner both power on and power off so the model without prop wash is still valuable. We are thinking of sharing a simulation with prop wash in a future video because these effects are pretty interesting to see. Thank you for watching!
Are you able to go into specifics about how you were able to optimize stall characteristics? I'm guessing that you used wing twist (slightly less incidence as you approach the wingtip) to force the inner portion of the wing to stall first, but i could be wrong??
Winglets? Why you don’t use any a swept back wingtips like b787
What NACA airfoil are you using or did you design, or have designed, a unique airfoil for the Dark Aero?
Have you guys done any small scale testing? If not I'd be interested in 3d printing a small scale rc model. :)
I’m not even there but I know it will fly. There were a ton of working aircraft built prior to fully understanding the principles used. Heres what you need:
Enough power
Wings employing Bernoulli’s principle
Enough induced drag
Weight and balance within reason
Sufficient control surface area
Your airplane will fly.
I just hope you don’t try to leave the carbon fiber visible. There shouldn’t be any ultraviolet light allowed to contact structural carbon fiber. There are also some conducive complications with carbon fiber. I haven’t heard how you intend to deal with static electricity generated in flight (there’s a lot).
is the drag and lift coefficient the same when you analyse half of the geometry vs all of it?
They will be different if you include the aircraft fuselage, but if you move your symmetry plane to the centerline of the aircraft then there will be no difference with a half or full geometry. The CFD run time will however be around half. That's assuming that you have no yaw angle.
If i understand this correctly, as someone who knows very little about aerodynamics, the tips of the wings need to be able to support the weight of the aircraft alone otherwise in a progressive stall the wings could break as the lift from the root outward decreases ?
Not really support all the weight. We want the stall to be be both predictable and controllable.
Imagine the opposite, that's called "tip stall". Tip stall, when it happens, is not perfectly symmetrical. Actually, one wing will lost a bit more lift than the other at the tip, which creates a momentum that can tip the airplane over very quickly.
How much attention did you folks pay to achieving laminar flow in the wings or fuselage? I ask as it seems to be something prioritized in some new plane designs.
Super interesting!
Interesting video! With carbon fiber you guys could have designed a wing of virtually any shape or a combination of wing designs. How did you settle on design choice?
Did you have control over all the parameters of your CFD simulations? Results can vary a lot, especially when the flow is not laminar. Also, it's easy to think that as the result looks good and realistic, the sim must be close to reality. Unfortunately, that's often not the case.
Anyway, I assume you applied well know rules to design a wing that won't tip stall (like negativ twist for example), so there shouldn't be any unexpected stall problems
Just curious......if your test pilot needs to egress the aircraft how’s he going to do that with that forward opening canopy ?
Wondering how closely your hand calculations correlated to the wing CFD.
Hey! Why no rakes or winglets at the tips of the wings?
Nice computer simulation! Looks like it needs some winglets
Which airfoil was used on the wing?
I expected to hear the term 'finite element analysis' but never did. Any idea who will do the first flight?
This simulation is on a clean wing, can you apply the same simulation with flaps lowered? Flaps would change what part of the wing stalls first, could a stall then develop closer to the area of the aileron? This is why a split-angled wing is being used on the newer Cirrus and Kodiak.
Modern designs make me shake my head but mainly because I'm old - my bum on the spar/COG always feels correct but yours, looks like I will fall off the back of the wing! lol
That's not a matter of vintage - it's the result of a large engine in a small single-seat aircraft.
How do you collate the results that you get from CFD and wind tunnel? I'm wondering if you used dimensional analysis and based the results (Flight Characteristics) from your wind tunnel testing and CFD is used for confirmation of such results. Thanks
Very interesting video. Do the wingtip vortices play into the tip of the wing retaining lift longer? I've been wondering why wing designs don't contain those to avoid the extra drag.
Because wing tip vortices are an inherent part of lift. They can be moved or reduced but that lead to a much more complex wing tip shape.
I guess I am s'prised you have such a high AR vertical with no dorsal... Spin Recovery??
What aerofoil are you using on this plane? Are you considering some winglets to help reduce the wingtip vortices?
Nice vlog as usual. I might be an amateur but here is a Question. Why did you design the position of the seats side by side and not in line (front and back) of the fuselage? More aero efficient and speed if you had a narrow body!
Dave, thanks for watching and the question. You're correct that the aircraft could have been even more aerodynamically efficient if we had opted for front and back seating. However, side-by-side seating is a more enjoyable flying experience. Additionally, the engine is also already nearly as wide as two people sitting side-by-side.
Awesome Video. But wathcing this turn me a question. Creating a stall configuration on the root of the wing, how does it affect the elevator? There is no risk in losing autority of the elevator in a stall? Thanks from Brazil!
The elevator is on the tail, isn't it?
Would you consider releasing an STL for us to print a desk model of at home? Love to have one of these on my shelf, since a grad student budget won't allow the real thing for a while.
Since there is a certain amount of intellectual property tied up in the CAD we haven't released any of it. At some point we might come up with an abstracted file for 3D printing. :)
The wing profile looks laminar flow. Is this the case?
So, what was the critical (stall) AoA according to the CFD?
Are vortex generators useful in this scenario?
Who will be the test pilot?
What was the process to design the required wing??
Looks very promising :-)
Did you also use SimScale for estimating performance figures?
How confident do you think you can be about speed and range predictions?
Good question. This is where the CFD specialists get nervous about results.
will it have any storage space ?
Yes! We have both forward and aft baggage compartments. The forward compartment sits in between the firewall and instrument panel is divided into left and right sides. Each side can fit a soft carry-on size bag or backpack. The aft compartment is larger and can fit items like duffel bags. Total capacity for cargo is around 100lbs provided it is loaded within the center of gravity envelope. This isn't too difficult with the compartments divided up forward and aft.
Awesome content! Thank you!
Are you familiar with the prandtl wing?
Also, some flight Sims like x plane do calculate the forces applying to an airframe. Do you know whether they use fluid dynamics or just tables?
Neither. They create a force model based on the geometry. Each element (wing, fuselage, tail etc) has a lift and drag and a physical location which is used to find the body force and moments for different angles of attacks. The accuracy of the approximation depends on the complexity of the mathematical model but its a world away from CFD.
What are your thoughts on the wingtip vortices?
GA aircraft not certified for known ice should NEVER proceed into it. The reality’s is the current fleet has accidentally and intentionally ventured into these deadly ( for uncertified aircraft) conditions. Has any predictions been made for how well this critical wing would do under those conditions?