How do Vortex Generator work on the Kitfox wing? Where to place them? ✈⚙🛩🔧 

Very interesting. Next is a test of a real airplane without VGs, then attach the VGs and test again.

Thanks for sharing your research! Looking forward to your next video.

This is one of the coolest aviation related videos I've seen in a LONG time.

I am a newbie Kitfox pilot and your giving me lots of ideas for future upgrades. Thanks for doing the engineering analysis and design.

I've been waiting for this one. Thanks Alex nicely done

Thanks Alex, cool simulator graphics. Thank you for sharing all of your findings. Very helpful.

I love that you are using engineering data to help solve the VG questions. Great video

I’m really enjoying the content your putting out there, especially the landing gear dampening system you came up with, I can’t imagine how much time you put into that, I think you have a million dollar concept there! Please keep the good stuff coming & be safe out there. Gary…

The engineering aspect of this was fascinating. Thank you for your use of the scientific method.

Excited to see the real world benefit in the next video. i think it will be quite interesting and good to see real world numbers. Great information!

Excellent presentation. Clear progression of the issues, great graphics. 👍

Hey Alex, I have always enjoyed your videos, and the last 2 are exceptional. the content is interesting and very well presented. great to see all the simulations, a great new direction for your channel !

Excellent video ,looking forward to seeing the next video with them mounted on your wing.

Very well done! Love the animations! Finally understand

Great Video, thanks for doing the real world studies and sharing them.

One year later I came across this video. Thank you for the research and time and effort you put into this study. On to the test video!

Great stuff, your graphics are excellent and the content is excellent. Very nice work.

Great explanation! It helped my understanding of VG’s much better at different location. Thank you!

Been watching You for some time, and I must say, This was Your best video ever. BRAVO.

Great video Alex!!!! Love it! Cool animation.... and... interesting information. 🤔👍👍👍

Well done. Outstanding graphics!

Very nice graphics. Was a little confused at first with regard to AOA numbers. I'm used to hearing pitch degrees, but it made sense after all. Thanks !

Itz another "Bell Ringer" Alex. Excellent explanation. 👍😎 Love the landing gear.

Very interesting! Looking forward to the real life test video!

Awesome work!

🔔Placement? Back in 69 when I was on 737s, we did a mod that reduced the number of VGs ahead of the ailerons and also increased their angle. I THINK they were shorter too. Boeing said they were as effective yet increased cruise speed 4 kts. $$$$$ (450 kt airplane @ 30,000 ft). All I remember is knocking them off and gluing new ones on. :-)) This was the same time we were rotating/angling the thrust reverser positions from horizontal pivots to 10/4 oclock ( 2/8) because of exhaust "lift" under the wings. Bare in mind the 737s were a new design only a couple years flying.. You are a "good head" Alex and I appreciate your analytical/ pragmatic thinking.🔔👍 viva la landing gear!

Well Done!!, Thank you sir.

Great Video, nicely conducted experiments.

Great stuff! Smart!

Great video. Thanks !

Excellent!

Very informative video thanks for posting

Great video. I like the way you did your analysis to separate myth from fact. It would be also be good to show the theoretical lift coefficients you were coming up with under the different AOA and VG configurations. It is one thing to see separation but I also want to see what the actual lift will be.

Another great vid!

This is true testing and great info.

Very interesting study!

very good video and very well explained!!!!

Wow you are one smart man!

excellent communication skills.

Alex, you're my hero.

Very nice info, thx u so much bro 👍

Excellent and informative video Alex! One day I’d like to do a simulation with slats installed on a cub wing! Keep it up!

Interesting content. Thanks

Such a great and informative video. I don't own a plane at this time, but was curious exactly why people install VG's and their purpose. Thank you for explaing it to me.

Great work! I am interested in seeing how the VGs affect the drag of the wing

Good info. Keep up the good work.

Love your videos man

Good video, great info; I enjoy the engineering "stuff" as much as the flying... follow-up video will be interesting , thanks👍

Great presentation

Superb explanation...😀

Good explanation and modeling. Nothing on an airplane is without compromise somewhere, however. Leading edge VGs also increase drag throughout the speed spectrum...typically more the further forward you install them. You might want to do a follow up vid and touch on the effects on cruise speed and efficiency.

Alex Great video. On April 12 I installed Pacific NW Aero LLc VGs on my Kitfox STi wing at 5%. The cord is approx. one and three eights thicker at the center than the standard Kitfox wing and Approx. three inches wider front to aft. I had talked to everyone I could about the placement and everyone had different opinions as to where they go. Jerry at Pacific had the kit at 10% , John from Kitfox told me to experiment with the double sided tape but that others had good results at 4%. Jerry also told me after years of VGs placement on other aircraft you would want a wider spacing closer to the fuselage. Jerry also had a guy from Africa with a standard Kitfox wing with good results at 3%, he is still experimenting. Just thought I would share. Keep the videos coming there great. I'll let you know the results of airspeeds on my first flight this spring. Tom

Interesting work, very good video presentation. I, along with many others, await the results of the actual flight testing. When working with the mysterious and sometimes surprising characteristics of boundary layer aerodynamics, I rely on real life results more than theories or simulations. The best method to demonstrate the actual airflow over the wing is with tufting recorded by video. In the Stolspeed website I don't claim a dramatic reduction in stall speed. 3-5kts in most cases. The main benefit of VGs is improved control response at slow speed and softening the stall to a progressive 'mush', allowing safer flight right down to stall speed without the danger of being dropped on suddenly. I tested the Stolspeed VGs at positions from 12% to as far forward as the airfoil allowed. 12% was too far back, 10% was marginal, and anywhere forward of 10% gave the same results. I couldn't find any such 'sweet spot' that some claim. So I settled on 7%, and that has been successful on most aircraft. Some customers have insisted on placing the VGs at 10% because that is what they have heard and read elsewhere, sometimes with disappointing results.... The Kitfox wing is an interesting situation because some previous experience has indicated that farther forward than usual may be more effective..... On the main wing I found no advantage of spacing the VGs any closer than 90mm. The 60mm spacing on the outer portions of the wings was to assist better aileron control and help prevent tip stall on any aircraft so prone. The 7% of chord that I recommend for the placement of Stolspeed VGs is suitable for the practical limit of AofA for most aircraft being 15-16 degrees. Flying beyond that limit means dragging the aircraft with power behind the power curve, and is considerably challenging and somewhat risky for most pilots. Quite a few busted landing gears due to that technique.... I do a lot of STOL landings off-field in outback Australia and don't ever fly behind the power curve.... I find that a glide approach at 1.3Vs right to ground level then an abrupt round-out and hold off, until with stick all the way back and maybe feed in a little bit of power for the highest AofA in flare, to a slow and gentle touchdown. I find this method to be the safest and most dependable, and STOL enough for any practical need. In really remote areas I can't take the risk of flying behind the power curve.... It will be interesting to see how your actual results at 25 degrees matches the simulation. That is very much behind the power curve, and brings in some real challenges. Be aware that if/when the airflow does break away at that AofA, the result will be a very abrupt and dramatic drop, and no way to immediately recover..... If it happens better be right close to the ground..... It'll be interesting to see if you can actually pull a 25 degree AofA with those flaperons at 40 degrees inducing a major forward pitching moment..... I have concerns about flying any of those STOL ops with flaperons at 40 degrees. The simulation shows the flaperon completely stalled, as you would expect at that AofA to the airflow under the wing. I know of several flaperon-equipped aircraft that have come to grief with flaperons at 30 degrees at take-off. The aircraft jumps off the ground at slow speed, then the torque from 100hp starts a roll to the left, the pilot reacts with right stick which puts the left flaperon at even greater AofA causing it to stall, losing lift and increasing drag on that side, pulling that wing back and down and ending in a messy cartwheel..... Once again, I await a thorough video report of the real life flight testing.

Show de bola !!

Wouach.... Thanks ! Good video & explanations. The only thing I have to do is only ...to replace all of them at 3% instead of the actual 7-8% ! I started at 10%, recommended by the VG's producer. Forget it, no effect at all in the stall speed full flaps, not a single knot. I have an Eurofox...

Nice! Now add leading edge slats with the VG’s present. Now that’ll really improve things at 25 degrees AOA!

As a retired Bell Helicopter Director of Research Programs I love your innovative, engineering mind! Chuck

Wish you would have made this video about a year ago. Went with best guest-a-mate on my Avid Magnum placed them @ 6% with little result. Time to redo. Thank you for info, nice meaning you @ Tony’s a wile back. Keep up the vlog, great info.

Makes total sense on more anterior placement as the angle of attack increases the further back the old school of placement @ 7% cord length is no longer in contact with laminar (fast moving) air. I believe the camber on a Just Highlander is greater than the Kitfox yet the top of the wing is similar so intuitively my hope is the calculation would be valid for that aircraft as well... Anyway, Bravo on a great study!

Jerry Barr who is from Burlington, WA, at KBVS, did the testing for Micro Vortex Generators in Anacortes, WA. This testing was extensive on his Super Cub and placement was done for a high angle of attack for STOL competition and also routine or standard flying parameters. He took his flight tests for the STOL and went to the Valdez STOL competition and won it. His were placed at s low percentage of chord, like 5% for the backside of the power curve, and at specific spacing and angles which we see from Micro. For routine flying, they are placed at like 10-12% for just slow speed flying near stall airspeeds. What I was seeing in some of your examples is that they were all spaced at the equal distances apart, and that may be the reason KITFOX said they didn’t work that well. It also depends on the airfoil shape/chord, as well. There are also some placements which very the distance from the leading edge, like closer to 5-6% on the inboard wing flap area, and farther back like 8-10% for the aileron section of the wing. Jerry told me he did like 25-30 test flights for each placement test. If you would like to talk to him, leave a comment. here, and I will his permission to call you. The flow parameters you did looked really great. What fluid dynamics modeling app did you use? Thank you for a great presentation! 🛫😎

Yah got down into the weeds on this one Alex, but I enjoyed it... Thnx, and the next time you're out here in SOFLO (F45) maybe we can meetup???

❤️❤️❤️❤️❤️

I run mine staggered (basically double row that doesn't overlap kind as you showed towards the end), and my 116 sq ft speed wing (RANS) stalls lower than any other speed wings I've heard numbers on. Wasn't what I intended to do originally (long story), but I tried it, and it seemed to work, kept adding them, kept flying slower down to a point. I can touch down sometimes below 40 mph ias, and stalls around 35 in the air. Usual landing speed around 40-42mph which is good for such a tiny wing and a heavy plane. I love VGs! Will be interesting to see what effect you bird has with them (assuming you are installing them?) I think it will bring your stall down at least 3-5mph at high aoa. Maybe more!?

Maybe you could try using some removable adhesive like command strips and try several locations before attaching them permanently.

I'd love to see wind tunnel video with these installed. Those data animations looked a little too good to be true in my opinion. I've no doubt vortex generators work, but that well? hmmm

Ottimo per la mia auto da crono scalata. Ciao

So what would happen in your simulation model if you placed VG's on the wing and on the Flaperon? I'd love to see your simulation model on that?

Alex first u should insert VGs to just upside of the transition zone on airfoil. And dont forget transition point moves upward(leading edge side) when AoA increases. And never use VG's under %10 of chord length. It will cause increase drag and reduce lift.

Very interesting indeed, I did a similar test on the Husky and found a very strange orientation of VGs that worked best on the wing but a more conventional arrangement on the empennage. What software did you use for the flow simulation?

Nice one Alex - looks like a fun CFD session you had there! What airfoil did you use for the CFD model out of interest? - the later KF models use a proprietary airfoil, right? Lastly: In the 25°AoA examples, do you think the flow separation over the top of the flaperon profile is accurately illustrating the cause for the reduced roll authority tendency that flaperons are generally known for, when in the flap-extended position? Hey - aeronautical engineering is every bit as interesting as the flying - keep up the great work!

Yeh to the Flying Cowboys.

By preventing the friction caused by the effect of the movement, a gap can be provided between the surface and the air with the coating made by using composite materials, thanks to the frequency that varies according to the measured parameters. However, if the spiral rotation effect can be achieved, as the speed of the flying vehicle increases, the increase in the number of particles per unit square will increase the pressure on the surface, so it can gain continuous acceleration. If we consider it as the minimum friction in the vacuum of space. Physically, the greater the density of matter in an area, the greater the friction. The interactions of atoms with each other at certain speeds are variable. I know it's a little confusing. You can exemplify this as how a drill bit drills through solids.

Which software did you use for the analysis?

Cool vid, I like the approach, btw, you know that there is a way to figure this out, right? Basically you run the model wing in a “wind tunnel” and setting a given airspeed, then you see where the separation occurred at a given (alpha) usually with a vizflow fluid. You then place the VG, 5% before the separation occurs. The problem is leveraging a RIIBBLET airfoil, there is no reliable wind tunnel data for them. The problem with them is that there is some hysteresis happening at those AOA and airspeeds. How I would test it, place a camera looking at 30% of the wing span (measured from the root) please your VGs and spray vizflow on the area, go do some stalls with and without and report back with those videos...

Hey. Do you know the name of the wing profile that is used on the Kitfox STI?

Digging the nerdy stuff Alex. Great addition. Were you able to model the stall itself? Just wondering if...if it propagates in a predictable and repeatable way if you could find the most critical AoA/speed then find the ideal cord % to nail that

Well done. Thanks . Could you run a simulation for the sti wing.

Just learning about these. I have a question on how these would effect say a car with the airfoil upside down from a plane ( sprint car) 5ft x 5ft wing. Would these help improve downforce and effectiveness as well as aid in drag reduction since the air flow would technically be hitting the rollcage/driver at 20 to 30 degrees of attack

At the spacing you suggested, watch out for a vicious stall. (60mm for outer third 90mm for mid length and120mm on the inner third, rule of thumb approximately) also they will increase low speed control,not don't know the effects on the kf setup, looking at your simulation vg's on the flaperon might be a idea worth looking at.

Nice! You should get in touch with Mike Patey (Draco Builder) he is doing a new project and your Vortex Generator Informations might come in handy ... and you might get some props :-)

I found it very informative here about vg,but anyway whats the software for the animation ? Thanks cheers 🍻🍻

1:36 pls flip the smoke image

Excellent video bud. I bought the Stolspeed VG.s and Ive been looking for a video like yours that actually explains the VG positioning with some backed up engineering data. I have a piper Tripacer. Different wing but I'm sure will have similar results to your kitfox. Well done. BTW was that 3 degrees to the highest point of your VG or to the beginning of the VG ?

I'm switching my answer from Backcountry flying to Aviation engineering

This was a very thoughful video. It added valuable lesson that cleared my doubts on vortex generators but still. Is there a suitable formula to determine a favorable position and angle to place the vortex generator on the wing?

Thanks for the video ! Is it ANSYS you used for the CFD ? or which software was it ? thanks

Thank you for this video! Could you explain the reason why they need to be twisted? 👍

Try putting VGs on the top of the flapperons and see if that helps!

Thanks for the video Alex. And i would like to know that, what software you are using for this flow analysis.?

nice, which software do you use for your cfd ?

Hello Alex, nice informative video. What is the software that you used to run the simulations? I have a few things that I want to thinker with. Thank you.

Lmao, “...and paint them! Don’t be lazy! Make them look good.” 😂

Great analysis! What software are you using? Can you report on the difference in AOA and CoLift at stall was for none vs. 3%? And how about CoDrag gains at cruise for the optimal VG configuration?

Awesome video. As you are simulating have you thought about using biomimicry like hump back whale tubercles to see what results you might get??? (just for fun)!!!

what CFD did you use for the simulations?

It looks like flow separation over the aileron... If it matters, little VG's for them?

This is a great analysis; good to see some myths being busted. What CFD program were you using here?

Hi Alessio, grazie, great video. I had no idea that the little wedges would do that. Any idea at 0.85 Mach what would happen? I am in Geneva, Svizzera. Dove sei, tu ?

VGs on the flaperons would be interesting .

What cfd application are you using?