Could RUSSIA USE this NOW? - Why Berkut and X-29 are a dead end. 

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I like this video. Compared to others on you tube that depend more on the flashy videos and graphics, this actually explaimed the aerodynamics quite well.

Great video, you forgot the main advantage of forward sweep though. Its 23% cooler than conventional sweep

Always wondered why Berkut and X 29 didn't result in more forward swept designs...now I know.. thanks for the explanation Gus and a medal for best use of a Ruler on RU-vid!

The Berkut and X-29 will always be fighters in our hearts... in Ace Combat.

Getting used to the high standard of your videos. The "simplified aerotronics" explanations are always to the point and give the listener a clear idea of why the technology has been accepted or rejected, together with what advantages it gives the operator. All that with a light-hearted approach. So basically in this one, reversing the wing sweep also means you need to reverse the tail position to canard-like (front tail effectively) due to inversion of force geometry (aero and structural) as if transposing all the lift producing surfaces of the aircraft (Ax=trans(x)trans(A)). Fantastic work. Can't wait for the next one. Grazie mille ))

This is probably the best video-form explanation that I've ever seen of aeroelastic divergence and how to fix it using anisotropy in a composite layup. Nicely done!

I think the solution is a diamond shaped wing with canards which normally blend into the wing, only separating during rotation/maneuvering.

Fantastic video reassuring to know you don't shy away from the technical stuff. When we need more technical stuff we will let you know.Just to let you know we need more technical stuff

A most informative video on a fascinating but ultimately dead end design concept. Went into great detail and depth without overwhelming me. And that demonstration of wing twist and composite reinforcement was an excellent practical visual aid. Superb work as always.

Thank you for showing a picture of the Let - L13 “blanik” glider at 0:45 ❤. My first solo was in that machine.. 😊

I was in the US quite near when one of the X29's crashed . I was glued to the TV news, but they did say very much .

Thanks going to you! I enjoyed this very much! :) Since 23 years or so I started to study aerodynamics by my own, with the "naïve" idea to, one day, be able to construct my own light aircraft... As that day never comes for any sort of reasons, I did spend that time working on several models for flight simulators, enjoying specially the 3D construction and the aerodynamic settings. I was surprised, hearing you, that still there is a child hungry of knowledge in me, trying to understand aerodynamics more and more. So again, thank you, this is a very nice video... Good luck!

I liked this first time, it is very informative and very well explained. Thank you. Great video.

A very nice video explaining why this kind of wing configuration didn`t go anywhere. The experimental part with the ruler was very simple and very useful. You promised a step up in production quality and there it is. Thank you for your effort. And as I said before, this is the kind of videos which make these channel outstanding compared to so many others.

im obsessed with the x29 and the idea of forward swept wings

Deep dives and steep climbs, thanks! Also congrats to Otis on the voice. 👍

Two kinds of people are afraid of flutter: Those who don't understand it... ...and those who _do_ understand it.

A number of fighter aircraft are neutrally stable (as in at optimal cruising airspeed, no downforce is needed in the horizontal stabilizers). This is true even in some models with no fly by wire. Even though this puts the drag at the center of gravity, the geometry of that drag can still offer some stability. A rearward sweep in the wing imbues some stability simply because if either side starts to slip out of axis of flight, the sweep on the side slipping forwards becomes more head-on to the air flow, while the other side becomes more swept away from the airflow. So side-slip tends to auto-correct. (nice YF-4E cameo there :) if you like that one, check out the F-4(FVS) idea too)

Excellent information explained in manner that is easy to digest even for those of us who are not aerospace engineers.

There seems to be an assumption that a forward swept wing forces the CG to be aft of the CP, and also requires the airplane to have canards and FBW. Seems to me if you want a stable relationship between the CG and CP you just move the whole wing farther aft, the same way the wing is moved forward when it has long rearward sweep (see B52). The JU-287 had a conventional tail rather than canards. Seems to me that If the CG is aft of the CP it is intentional because relaxed stability is desired. BTW, the Piaggio Avanti shown is not a good example because its straight wing was placed aft so that the spar would not interfere with the height of the passenger cabin, and that did necessitate a forward lift surface for balance.

Praises for how his diction is becoming more and more intelligible. It has developed so much I am now appreciating the accent. Keep it up.

Amazing. It would be awesome to see you speculate somewhat on what the su 47s further development in its original time might have been.

The X-29 is one of my favorite planes. It's just so beautiful, and the advancements they made on this project were really cool.

Loved this video, discussion, and “lab” examples. Such a unique channel, deserving of so many more subs.

I guess smaller wing structures for military aircraft could also mean less internal space for fuel tanks, which is a non-aerodynamic drawback for forward swept wings. But darn it, they just look so cool.

Thank you again for a very interesting, stimulating and well explained video :)

I always found the AGM-129A stealth cruise missile fascinating with its forward swept wings.

Now I can't stop wondering if Ace Combat's X-02S Strike Wyvern with its variable wings could be a solution.

The explanation was spot on! Sharing It right now to my friends

This was a really great video. Thanks for confirming many of my understandings of the subject. I tried to find more reasoning but this was the video that gave much clarity.

What a great video. Thank you!

Great video as always, super interesting. Keep them coming.

Been a subscriber for a long time, since you only had a couple of hundred subs. Quality like this is hard to get. keep it up!

7:39 Hey I have that middle one! Lots of sticky tabs on it.

Love your work. Loved planes all my life. Learning from you is fantastic. Thank you :)

That's it! My next cranked kite design is now a reverse cranked kite! 😂

Brilliant, I knew the why, but only in an elementary way. After the visual aid, the muddy waters are now clear, like I said brilliant. Thank you for the vid and cheers.

Thanks for the lecture. Grazie.

Dang I love your work!

Canard Phantom? Definitely need a video on that!!!

Fantastic video, thanks for putting it together! 👍

Nice explanation Is good listening from an expert

Super interesting with so much detailed information that one actually understand why !

What an explanation. Thank you !

There are going to be trade-offs in every design. Gaining performance in one area means sacrificing performance in another. Forward swept wings can be significantly smaller than straight and backward swept wings in order to achieve the same lift. This has many implications. And as you pointed out, all things being equal, their stall characteristics and performance at high angles of attack are superior to those of backward swept wings. These are certainly desirable features in fighter planes. And keep in mind, less forward sweep can negate the need for canards. In fact, there’s a Russian trainer jet that features forward swept wings with rear stabilizers only. Lastly, you mentioned thrust-vectoring. Any jet’s performance will improve with thrust vectoring, including a jet with forward swept wings.

Thanks for this! Always wanted more info on the idea then it's super unstable... Which Ace combat has a super plane with foraward swapt to diamond switch wings and I came up with what I call Dove wings that are horizonal wings with the forward swept aft end and canards+ tail... So it sweeps up to horizonal and no father then that.

Loved this 👏🏻👏🏻👏🏻

there's a really good video of a missile showing flutter until the wing rips off.

Great job!

The X-29's stall characteristics might be provided in significant part by the canards, rather than the forward wing-sweep.

About the yaw instability: In normal backward swept wings, if the plane's nose begins to point right, the right wing will present less area to the airstream while the left wing presents more, counteracting the yaw. With forward swept wings the right wing would present more area than the left wing, making the situation worse.

Great video! Make more of this kind!!!

I had an encyclopaedia when I was young which had some great sections on aerodynamics, which I always felt drawn to. The 1984 prototype was pictured, as were diagrams of all the wing configurations and brief descriptions of their strengths and weaknesses, which to this day I mostly remember. I’m Pleased to say that I knew half of what you explained in this video… So Thank you for the other half! Aerospace is absolutely fascinating and rewarding, even just as a hobby.

I like the technology videos better than the fighter political choice(-ish) videos. Very nice!

*forward-swept-wing fighter jets, all the hyphens are needed (compound adjective).

I saw a video where the FCS of a Su-35 failed so the pilot turned it off and then " flew " the plane back to the factory. I imagine if the same would have happened in a Su-47, he would be ded or would have had to eject which is also quite the same.

Wing flex under load increases the wing tip angle of attack.

Ahh, my favourate part of the video is that X-29 has a centre of pressure behind the centre of gravity but still horribly unstable. Many channels mistakenly claimed stability is always because of the position of centres, but as usual, you nailed it Sir. Thank you for those detailed and in-depth explanation!

Great information sir 😃

Overall, as good an explanation as I've heard on the forward swept wing for a fighter... But, I suspect practically all of the problems that are described in the second half of the video can be engineered so shouldn't be major problems. The basic advantage of a forward swept wing is its instability which should mean if extremely highly responsive acrobatics is desired, it's a big contributor to achieving that objective no matter all the other ways that extreme maneuverability can be achieved including thrust vectoring and additional control surfaces like canards. The big disadvantage as described is the backward stresses on the wing which could destroy the wing as more angular stresses are placed on the wing, and related instability. But these two issues can be addressed today as described forst by use of composites with extraordinary strength and the implementation of fly by wire to translate all aerodynamic factors into the pilot's desired action. For the above reasons, I suspect that the actual main reason not to implement forward swept wings is simply that acrobatic agility is no longer a primary objective... That other features are more desirable including increasing payload, improved efficiency in normal flight, minimizing maintenance and increasing lifespan. All these other desirable features are opposite an aircraft built to perform under high stress and acrobatically.

I wonder....what would a _reverse sweep flying wing_ be like in terms of flight characteristics? I'm thinking of a fairly large aircraft that would have no separate wings and no tail, and which would maneuver entirely using 3D TVC. The flying wing configuration provides maximum lift and gets rid of the trouble areas found with traditional wing/fuselage/tail configurations. With a flying wing, you don't have joints between wing and fuselage which are weak areas susceptible to, you know, ripping the wings off? With TVC, you immediately remove problems caused by control surfaces in relation to airflow. In fact, this would also solve the stealth issue with forward sweep because you just have a big forward swept wing and TVC with no slop anywhere. The negative stability could likely be reined in and harnessed by modern FBW FCS systems, so it could wind up being quite stealthy.

Having them sweped forward does have a few advantages. One is that the air dont slip of the wing... or at least does it to a lesset degree, reducing the need for winglets. For supersonic airliners that would be very preferensal. There is a few other advanatages. Of cause the increased weight is of consern. But there is a way around it. Have only the last 1/3 sweped forward and make the inner 2/3 softer than the outer 1/3. This will make the wing bed closer to the root making the aircraft fly closer to neutral.

I'd suggest a reason if I may. Even the most sophisticated military flight control systems are built on reacting to pilot intent. In order to establish that, there's a timeframe, and the longer you can make that, with declarative as against imperative control, the more useful unstable aircraft become

A video about submarines would be amazing , love your work and afforts keep it up ,wish u all good luck

3 min into the video, and I am thinking about the AFTI F-111 all the time. -- AFTI F-111 combined with X-29, and it seems like a dream for a university project...

I'm looking for a forward sweeping broom effective on trans hedgehogs 😆 Excellent video: so clearly explained. Thx

A good potential followup would be what makes the "diamond" variety of delta configurations (where the leading edge is backswept but the trailing edge is forward swept) so good, considering that just about every 5th generation aircraft (except possibly the SU-57) is using some variety of the design to an extent.

Channel reaches even higher quality by each video ! Awesome ! But can you make a video about the "forgotten" *rhomboidal wings* ? (annular and "closed wing" are also filling the term)

Un altro ottimo video. Complimenti😎

The Su-47 might be the coolest plane ever built. Very good video, thank you very much!

Su-47 helped with the testing of composite materials.

Very interesting subject, thank you! I would love to hear your take on the super low aspect ratio wings like Vought V-173 and the like.

Those are fine but they are not the craziest forward swept ideas I've seen about aircraft's. Take a look at ace combat X02 Wyvern... or ADFX01 Morgan... and there is also compressor stall champion ASF-X Shinden 2... I don't know who had the idea to put the air intake up there behind the cockpit.

1:44 Far better than I did in my Aero exams!😂

The fastest I ever flew a Blanik (0:44) was maybe 65MPH (105KPH). The only drag was that I was the heaviest pilot in the club.

The first time I saw swept back wings on a plane was in X men the animated series. The X jet they use

Great video. Thanks.

Nice to mention your professor 👍🏻

so you said a 3 surfaces configuration isn't great for stealth, but what about for example the fictional ADF-01 Falken from the video game series "Ace Combat" that probably uses it's inverted V-Tail (the tail points inward instead of outward) as the rear, downforce-generating surface? as for the yaw instability, couln't it be stabilised by thrust differential? also, we used different means to give classic wings designs the properties of forward swept wings designs, but couldn't we do the same for the forward swept wings? i am sure some countries would love a plane with reduced drag to save on fuel efficiency too

Dear Millennium 7, as always I appreciate your work, however I think you made a mistake in your video. You claimed that because FSW design have three sets of control surfaces it's definitely not great for stealth. Well, I definitely disagree. As far as I'm concerned, forward swept wing design is well known for having very good if not excellent stealth characteristics, at least in the frontal sphere, because radar beam impacting the leading wing edge is reflected toward the fuselage, quite effectively dispersing it, especially if you combine this feature with radar absorbent material on the aforementioned fuselage. If you add to this internal weapon bays and a s-duct, you have significantly reduced radar cross section, again in the frontal sphere at least. It's also worth to mention, that what we know today as Su-47 is an aircraft based on Su-27 fuselage, which by itself is not stealthy at all and initially Su-47 supposed to be much stealthier design called C-22 or S-22 (not to be mistaken with Su-22!). You can find some articles and some pictures of S-22 on the internet for further research if you want to, and I dare you that you'll admit that S-22 seemed to be much stealthier design than what it eventually became (Su-47).

The US did some investigation of the forward swept wing, think it was in the 1970's.

Oh, that 80's clip needs some Sabrina Salerno!, Boys!

But the Su-47 just looks so cool! My sweet baby, too good for this world...

I have dreamed about building a forward swept sweeping-wing aircraft. That would be cool. That would almost most certain give me a nobel of structural calculus, (if there was one..) ;D

Thank you. I enjoyed your explanation. I still wonder how this design would work with a ski jump.

11:88 is LERX, leading edge root extension

Question: Why not place the FSW more forward towards to re-balance the aircraft? Or would that move the tips too far outside of the transsonic / supersonic cone thus increasing supersonic drag too much?

When are You going to do a deep dive episode of the F-15 & it's variants?

Из последних попыток - учебно тренировочный СР-10. Он врят ли найдет большую поддержку в Министерстве обороны, так как там по-прежнему отдают предпочтение двух-двигательным самолетам, но сама машина получилась очень перспективной.

0:14 .... excellent suspense

I would think the pilot's neck would get very tired looking backwards all of the time.

I think the 747 had a wing flutter problem in testing at about Mach .80, I think they fixed it by adding tungsten to the wing tips.

The only channel in RU-vid that mentions fluttering! I am not sure if 6:30 is an allegory composites or a subliminal ad.

0:34 So sorry to make this comment, but the airflow becomes an “incompressible fluid” not a “compressible fluid” at transonic speeds. Slower, it is a compressible “fluid.” Faster, it “shocks” to incompressible. Other than that little detail, WELL DONE! Love your channel! FYI, I’m a commercially licensed pilot in the US, and high AoA in computer simulations, IRL model aircraft, and even STOL airplanes is my specialty. (Edit: I may have misunderstood the phrasing at 0:34. Check out my response to Mosca).

Next topic: importance of wing profile. Or alternatively, stand off nuclear missiles.

I gotta say, even Real engineering did not explain everything this well

Bravo another complex issue explained with clarity and balance. You conclusion of "yes but to what advantage?" is the balance upon which design inspiration and engineering effort sits. Wish you could do the same to the tiresome concept of "circular airports". P.s. I ignored the temptation to talk about the problems of 'self excitation' 🤔😆

Before you start the video, I was saying to myself, I don't like Forward swept wings because it move CL forward, and usually want to move it aft. One design I work on but gave up on because high speed stall was putting forward swept wings in rear and large canards in front. It was also very unstable but fast, low drag, high lift. Great takeoffs, lousy landings.

nice i love the su-47 so this was very fun :)