How Good Are Stepped (KF) Airfoils Actually?

[@_BL4CKB1RD_]

Remember, I’m not an expert on this subject so I probably got some facts wrong in this video.

[@ZapTeam]

Please make some rc models

[@_BL4CKB1RD_]

@@ZapTeamis this not remote control?

[@ZapTeam]

@@_BL4CKB1RD_ Issa glider

[@ZapTeam]

@@_BL4CKB1RD_ no radio controlling

[@ZapTeam]

@@_BL4CKB1RD_ nm I saw ur flying wing build

[@ryderphillips4464]

My dad showed me this airfoil in the70's. It was thought to be stall proof in a canard way. The rolling air in the gap would push the nose down just before stall speed.

[@_BL4CKB1RD_]

That's very interesting.

[@realreal3070]

THIS GUY IS SO UNDERRATED BRO

[@ralphbronzin9721]

Great little experiment, definately something nobody has ever thought of. Maybe for more consistancy, you could simply run wind tunnel tests on the two standalone wings and compare the lift and drag data. If you don't have that, then it's always a great idea to find an excuse to build another airplane. Good work!

[@_BL4CKB1RD_]

Originally, I meant to use a bungee launching system to help with consistency, but it never worked, so this was my Plan B.

[@emily36130]

Interesting video. Afaik KF airfoils have lower performance than regular airfoils, but compared to an airfoil made from bent foamboard the difference should be minimal. The main advantage of them for RC planes is that they're incredibly easy to build by just glueing two or three sheets of foam on top of each other and then sanding the leading edge into an airfoil shape. At least for the depron we get here in Europe that doesn't have paper on it, I don't have experience with dollar tree foamboard.

[@dudermcgavin]

This Guy could make The D.M.V. Exciting!

[@Thehamster12]

Bro is the goat

[@Silvan-re1og]

This could be a great slope glider or if the Wings are bigger it would be a probably good thermal glider

[@BrainDeadEngineering]

I very enjoyed this ! rock on !

[@_BL4CKB1RD_]

Thanks, you too!

[@pacificWebsurfer]

good work for consistent air, best to try in dead calm (often best early morning or dusk), and possibly more effective to tow the glider and release by flying off a tow ring on a consistent length of line, on a big field, and timing the flight from release - preferably in a straight line, because turns induce drag that supposes equal speed for both if max distance is the comparison, otherwise you will be comparing "hang time" as the measurement fwiw, v tails look good, but they don't steer as well as rudder / elevator

[@_BL4CKB1RD_]

Gotcha👍

[@Elnufo]

The Duck is on the leftmost edge of the Screen, sitting in a plant. Can be seen from 3:44 to 3:48. And thank you for 8:39 i havent been franced in a while 😂

[@SvenGray-hx5to]

I think KF airfoils are great in the RC field as a static wing shape. Modern commercial aircraft can modify wing shape via slates and flaps. Great video!

[@torri7062]

Hi! It's the pressure diferential which accelerates air above, and not the opposite (as you said). With some angle of attack is more intuitive. The air coming towards the wing is forced to go downwards (downwash) so more air is concentrated. In the upper part there is much less air, so pressure decreases. A consecuence of this is the acceleration of the fluid, but the acceleration of the fluid IS NOT THE CAUSE. There are NASA documents you can easily search proving wrong the Bernoulli's theory for airfoils, which is logical, cause Bernoulli made his theory for uncopressible fluids like water, not air. Great video, awesome

[@_BL4CKB1RD_]

Alright thank you for letting me know. I know I’m no expert on this subject, but how does the pressure differential arise in the first place then? (Also, air is compressible only past 0.3 Mach, at these extremely slow speeds, we can follow Bernoulli’s principle)

[@torri7062]

It is easy to see when there is some angle of attack. In the underside the air accumulates (more pressure) and it is forced to go downwards, while in the upper part, there is much less air, therefore less pressure and the air above is sucked

[@_BL4CKB1RD_]

@@torri7062 that wouldn’t make total sense for no angle of attack, since all the air is streamlined. I believe you are thinking of Newton’s third law, where each action has an equal and opposite reaction. When the air hits the bottom surface of a wing, and deflects downwards, the resulting force of that contributes to the wing lifting upwards. There is no one way a wing produces lift, but a combination of various principles.

[@patrickradcliffe3837]

So a few things that will make things easier and more consistant. A bungee launcher will give consistant launches. Also measure your steps and pace off the distance instead of the tape measure dance. In your next test try the Klein-Foggel airfoil with the step on the bottom I think you'll be pleasantly surprised at how much better ot does then the step on the top.

[@_BL4CKB1RD_]

Thanks for your tips! I originally tried to do a bungee launch but couldn’t get it to work so hand launching was Plan B. I guess feet measurement would be more accurate and quicker(wouldn’t need to suffer as much through summer heat and barraging mosquitoes).

[@ninehunnerdriver]

Thanks new to RC and KF's now I know thank you

[@_BL4CKB1RD_]

Glad to help. This hobby is very fun and cool, hope you the best.

[@ArnasSigmaMale]

quite interesting video, great job

[@AerialWaviator]

Great experiment, with an entertaining presentation. Really like how you designed the fuselage using foldable facets that mated triangular tail boom. Simple, but very effective design. Environmental conditions likely the biggest variable (ie: wind, turbulence) While inconclusive, your two data sets have many similarities. Plotting the data on a graph (two colours) could help show that data is evenly distributed. Being similar can be a very valid result. Nothing wrong with this. Would have like to have seen similar data on the higher aspect ratio wing (assuming it has the same wing area).

[@_BL4CKB1RD_]

I appreciate the feedback. The high aspect ratio wing doesn’t have the same wing area, I just made it so i can fly it as an actual glider. If I do another experiment, I will keep graphing in mind.

[@scottriddell7893]

Nice video. Don't forget to add weight for the KF airfoil so that you are testing at the same flying weight. 👍

[@ethanbarnes3973]

Damn man thanks! Amazing video!

[@yaimem]

underrated channel. im gonna build the tileo plane u built. do u have a build video?

[@_BL4CKB1RD_]

Oh nice, but umm I don’t plan on doing a build video. I like to showcase an extended build montage which shows most of the build process. I’d recommend some basic knowledge with working with foam board, and it uses the same build techniques as flitetest kits do. Maybe I could write some instructions, but most of it takes some intuition. I’m glad you found my plane design worthy enough to build. Edit: also, I found that one drawback to the Tielo is that it requires a heavy nose weight in the front, you could modify the design to have an extended nose in order to need less nose weight.

[@yaimem]

@@_BL4CKB1RD_ alright! Thats perfect i have built a few flitetest planes before so im familiar with those building techniques. I’ll modify the nose just like you suggested. Im always on the lookout for neat pdf plans and your plane is just that. Neat, elegant and also extremely simple to build. Thank you for this video man, subbed🙂

[@_BL4CKB1RD_]

That’s great to hear. One thing I forgot to mention is that on the Google Drawings “Tielo Printable” file, make a copy. Then, drag any part into the checkered area (which is sized for a 11x8.5in printer paper). The design is meant to be printed to allow slightly more faster and accurate cutting of the parts, but if you would prefer, I could also list the dimensions and angles of each piece. If printed on paper, I’d recommend using pins to poke holes where corners are or hold the papers in place, you can also use them to trace straight lines. For the curves on the nose pieces, I poked a lot of holes following the path of the curve and used my trusty dusty pencil to connect the dots. I appreciate you asking. Let me know how it goes!

[@ililit-z5s]

Please make more videos

[@夏沫清风]

Great video with potential

[@VikashSingh-th9ez]

Nice & simple 👍

[@_BL4CKB1RD_]

Thanks!

[@basemandog]

Great job! Was very informative. Would you mind sharing your dimensions for the high aspect ratio wing?

[@_BL4CKB1RD_]

As of now, I have put the dimensions in the “Tielo Full” Google drawings file linked in the description. It can be found under the reference images section to the right. It is just a screenshot of the dimensions from the Onshape CAD file. Let me know if any part is unclear or if you would need any more help. Thanks for your time.

[@willwill5595]

Volume is much to low

[@sidariell6762]

Im the 101 sub! And does the foamboard have paper cuz mine dont

[@_BL4CKB1RD_]

Yes, it has paper. This is foamboard from my local Dollar Tree. Are you using depron foam?

[@sidariell6762]

@@_BL4CKB1RD_ no my country's foam board doesn't have paper but it's still foam board though

[@raypeery6317]

Why are you wearing a mask?

[@_BL4CKB1RD_]

Cause identity reasons

[@IndraKurniawan-vk2qb]

I like this editing style, hmmm, Need better mic tho

[@_BL4CKB1RD_]

Yep, just my phone mic

[@ralphjohnson4041]

Can’t cope with anyone talking to me through a mask.

[@_BL4CKB1RD_]

That’s fine.

[@thetwogardens6048]

Why you wearing a nappy on your Face. ?????????

[@tommypaget2294]

Won’t there be a lot of laminar flow separation just behind the drop, causing excessive drag?

[@Sandokans]

Please ware the mask, it's very dangerous..

[@planker]

MASK!!! BAD!!!

[@_BL4CKB1RD_]

I respect your opinion. I don’t have anything else to hide my face tho.

[@grim4this]

nobody wearing a mask should be listened too.

[@_BL4CKB1RD_]

Then don’t. If you don’t like this content, don’t watch it. Simple, now go work on your grammar.

[@grim4this]

@@_BL4CKB1RD_ kzbin.info/www/bejne/kKu5q5x4YsqSm8k

[@_BL4CKB1RD_]

Hey, you are wearing a mask too. Your anonymous online identity acts like a mask where you can rattle on mean things to people. Like you stated, no one should listen to you. Have a nice day!

[@danielcockerspaniel]

Everything in this video is wrong

[@_BL4CKB1RD_]

Elaborate?

[@yaimem]

okay cocker spaniel

[@PritneyBears]

Nice video. Would have been cool to compare these airfoils to a straight flat plate. To eliminate the variability from the tosses, maybe drop them from some consistent height instead of tossing them.

[@NeilGaede1]

Why are you wearing a mask?