Why Do Backwards Wings Exist? 

Fun fact: The X-29 didn't just have 3 redundant flight computers, they were also each programmed by a different team so they would have different software bugs. The idea is, at any given moment, at least 2 of the 3 computers would agree on how to adjust the control surfaces, and the disagreeing computer would be voted-down until the next set of attitude measurements came in from the sensors. This is standard practice in military avionics nowadays.

RU-vid: Why backwards wings? Me at 3:53am: I must find out immediately

Most importantly: They look really cool..

this video made me realize how much i liked planes as a pre-teen...something i had forgotten about as an adult. so thanks for that!

I love how like 10% of how a wing works was explained in the 4th grade, and then you never hear about it again until youtube comes out.

Me looking at title and thumbnail: “So the planes can go backwards, duh”

Ace Combat Devs: **watches video** Also Ace Combat Devs: _I'm gonna pretend I didn't see that_

I used to think some of Starscream's alt modes that had reverse wings were just nonsense sci-fi designs but now thinking about it a sentient plane that could control every flight surface like a limb actually makes sense

The X-29 no matter how short lived, was a beautiful aircraft.

Germany at the time must’ve used the research_all command in console

I guess it's about time to fire up kerbal space program again.

Came here to learn about backwards wings. Instead learned how to make better forwards wings on KSP.

Cause it looks cool? Duh!

Me: Also me: I don't need sleep, I need answers!

you say "aerodynamic instability", I hear "Involuntary hypermobility"

*Engineers at Boeing* "Ummm...because it looks cool?" NASA ".......WE'LL TAKE A THOUSAND!"

7:34 no one gonna talk about how it looked like that airliner just went vertical?

*Real Engineering:* Uploads plane video *Wendover Productions would like to know your location*

4:05 when you think ww2 german engineering could't possibly impress you more than it already has, in comes the Variable-sweep wing.

The X-29 was noteworthy in the way that was designed from an existing airframe to minimize costs. The fuselage is basically an F-5 Freedom Fighter with the engine from a F-18 Hornet.

More like: 100% control sensitivity

Its not aerodynamic instability, its supermanuverability!

The superior wing design in Kerbal Space Program

I have flown several gliders that had mildly swept forward wings. That was done for a very practical reason, as those gliders were all 2 seat trainers, and the rear seat was at the CG position of the lift of the wings. That made the weight of the person in that seat, non-contributory to the trim of the glider (only affected the total weight), and the front pilot was the only one that affected the weight and balance.

Actually the engineers got drunk, put the wings backwards then decided to go with it.

I can imagine that on the X29, agility was also improved, since as soon as you start rolling, the inherent instability causes the plane to want to keep rolling, rather than to want to stop.

It's a shame that the X-29 project was cancelled, it looks awesome.

Awesome video! I have piece of information Id like to add about the P-38. The hydraulics on the P-38 had enough advantage to be able to overcome any aerodynamic stiffening, so that was not the issue. The airflow separation that came from main wing by exceeding the max mach number caused the tails control surface to be caught in a "vacuum". With the hydraulic boosted controls the pilot would have been capable of full elevator deflection, but he lack of air flow over the control surface would make it too ineffective to change the pitch of the aircraft. The only time the P-38 could reach these speeds was when it entered a dive, so if this mach number was reached in the dive to cause the shock wave to form, then there would be almost nothing the pilot could do to regain control as he would be stuck in the dive, unable to pull up with the now useless elevator. From colder (higher) dives the speed of sound is slower, so most of the time get out of the high altitude dive would be that the higher temperatures at lower altitudes would raise the mach number enough to get them out of trans-sonic speeds and regain elevator authority. You can actually find experimental P-38 with an up curved tail boom to try and keep the elevator clear of the "vacuum area", but it proved to be too weak of a structure. The Germans, with there hydraulically advanced aircraft, would eventually figure this out and used this knowledge to be able to escape by diving, knowing the P-38 would not be able to follow them in the dive. Where as the Japanese Zeros did not have hydraulic assistance, so they too were unable to enter a high speed dive, but for the reason of aerodynamic stiffening, so the P-38 dominated the sky where the enemy fighters had no way out.

The F-14 Tomcat is a great example of both proponents in action. But even when fully extended, the wings have a slight sweep.

Could you make a video about bush planes and how they can stall at such low speed ? This would be awesome

Do you accept machine oil as a donation?

I personally find the X-29 to look kinda goofy, but the Su-47 is my all-time favourite fighter jet even if its exists more so in research papers and blueprints than it does the sky. Forward swept wings have always been so fascinating to me, thank you for clearly and concisely explaining how they work.

Why do backwards wings exist? Can't let em know your next move

No one, literally no one... RU-vid Algrorethim: *why are wings back wards?!?!?* Me at 1 AM: idk

As someone who is building planes in Kerbal Space Program, there where a few things to learn here that explain certain things. Good stuff!

So we have tried forward wings, backward wings, straight wings, double wings, triple wings... what left to try? Honey BBQ?

Already watched a video on this.... there's so many. EDIT: Your video has so much more information, I can't imagine how much research you do before a video. Nice job.

I'm quite ashamed of myself for watching the whole video without understanding anything....

Great video as usual. My only nitpick would be the screeching sfx for the text labels.

Am I the only one who thinks "Hitler's Miracle Machines" sounds way too fun and wholesome as a title for that documentary he plugged at the end? lol

I live in an RV, and the 'squeaking chalk' sound you use for illustrations in the video had me convinced my foundation was shifting or the wind was throwing the antenna outside for a spin. Hahaha. Much love, I've often wondered about this as an aviation-enthused child when I first saw the X-29 in a book. Thank you for answering a very old question of mine.

Thunderbird 2 is a classic example of this, pretty impressive given the huge fuselage and vehicles on board!

Maybe not the most ideal design on terms of functionality, but wow is it a sexy aircraft.

Can't stop watching these videos, so informative and well edited. Great content mate, keep it up!

the squeaking sound effects whenever a new line of text shows up is quite annoying. Could be much better with a different sound effect that doesn't hurt ears as much

There may already be a bunch of comments on this, but I have to mention that Bernouli's principle (the equation you displayed) is only applicable when the air is flowing along a streamline. Because the wing is in open air, the air is not forced to flow from the leading edge to the trailing edge of the wing. Testing shows the air over the top of the wing actually meets at a point a ways behind the trailing edge of the wing while the air below meets more or less at the trailing edge, thus not on a streamline. (air is also compressible and viscus but these are not as important at low speeds)

It greatly improves turn radius and pulls ridiculous G's!!

There are some forward swept aircraft in production. (I flew three of them: Ka2b, Ka7 and ASK-13.) Also, the HFB320 Hands Jet had forward sewpt wings, mainly to place the spar carry-through behind the cabin and pressure vessel. On a side note about canard wings: You don't want them to deliver lift essentially, because they suck at it. For efficient lift you want high aspect ratios and a good elliptical lift distribution. Canards can't deliver that and are usually highly stressed when contributing to the lift of the aircraft. But they can be designed inherently stable, as the Rutan-Designs and Derivatives show (VariEZ, LongEZ, SpeedCanard, Cozy, Velocity, Starship). Best efficiency is reached in classic configuration though, with a tailplane delivering as low force as possible. This is why practically all high performance gliders are of classic design with a small tailplane on a (more or less) long boom.

Been asking this question since playing Ace combat and get attracted by the SU 47

It's not that the bernoulli effect isn't real -- it's just not the primary source of lift that people were taught it was for many years. The primary source if lift is wings pushing air down like giant ceiling fan blades. If that weren't true, airplanes could not fly upside down, where not only do the wings have to provide enough lift to lift the weight of the plane but also enough to overcome the bernoulli effect that is actually pulling the plane down.

“One that broke ALL aircraft design convention,....... However, this aircraft was not the first of its kind.”

I remember the 1st time I saw this plane with backwards swept wings in the thumbnail. My grandparents bought me a subscription to this thing called "Wheels & Wings" where they sent you a binder and different sheets about different planes and automobiles, tanks, etc... This plane was one of the planes they covered.

huh, in KSP, I tend to reverse the wings on air craft that I want to make more agile. It's always been a hazardously delicate balance, but understanding why now is pretty cool!

"The Germans experimented with the idea in late stages of WWII" - Instant +50 to the credibility of the idea. Its amazing how many modern things are just WWII ideas reinvented / redesigned / refined.

Could you do a dissection of the F-15, and what has made it such a long lasting design?

first saw the x29 in Ace Combat 2 and I love the design!

The problem with the wingtips stalling first is the sabre dance. Tail heavy is unstable with or without a canard, nose heavy is stable. You can make convention swept wing planes tail heavy and they became unflyable without a computer system updating the control surfaces many times a second; it is why F-16s are fly by wire.

Why backwards wings: Because they look fuckin awesome

As someone who greatly enjoys the Sukhoi Su-47, I am very happy that he mentioned it.

The P-61 Blackwidow also a World War 2 design features a way to turn that’s on a lot of modern jets called spoilerons which at higher speeds allow it to turn. It also features ailerons to provide roll control at lower speeds.

Forward swept wings typically have highly non-elliptical lift distributions (cCl) resulting in much higher induced drag, not lower as your video suggests (6:48). The sectional Cl's at the wing tips are lower which typically produces better stall characteristics but with a normal taper ratio (

I mean the SU-47 IS unstable, BUT! It's also extremely maneuverable (which, in a air combat, could be useful vs. missiles when countermeasures are depleted).

Growing up on Long Island where Grumman was and this was built I actively followed its development. I was in HS from 84 - 88 and it was engineers from Grumman who spoke to us about working as aerospace engineers, which is the degree I achieved in 1992. Sadly by then the Cold War had ended and Grumman was completely imploding as a result. Still, during those years from 84 - 88 I followed everything I could about the X-29 and my mom's house still has the X-29 sticker on my old bedroom door. As the video accurately points out, the real take away's from the program turned out not to be the use of forward swept wings but the advancements in computer controlled/enhanced flight and advances in composite materials, both of which are major aspects of new military and larger commercial aviation.

Learned about this plane in Janes ATF Advanced Tactical Fighter. A truly wonderful game. The maneuverability of this plane was second only too my favourite the x-31. It had full 360° vector thrust abilities. God that game was good. I miss good flight sims.

Does this mean no real life X-02 or the ADF-01? *NOOOOOOOOOO*

I'll start working on my reverse-swept-wing fighter jet tomorrow.

Loved the vid. Do you think you'll ever do a video on delta wings? Those have always fascinated the hell out of me, particularly how they use vortex lift at low speeds to generate lift.

Reading the story of the plane pictured, it was built with reverse wings so as to make it as unstable as possible and then test out computers in the plane that could possibly overcome the innate instability. It was built for the testing of computer controls. The plane is at the USAF Museum in Dayton, Ohio, and is featured in some of their books about the planes in the museum. The man / men who actually flew the plane had to have a triple set of cajones, but it apparently did its job, because it is still in one piece and not amongst a pile of scrap aluminum.

Last year I snapped an image of a hummingbird tail up, with its beak in a flower. When I checked the images, I noticed that while the hummingbird was facing down, the leading edge of its wings were facing up. I had to look at it a few times to be sure. Apparently hummingbirds can rotate their wings 180 degrees, and this showed it well. Amazing.

I saw this jet fly over my house in the 80's surrounded by 4 other jets. I was about 5 or 6yo. My 4 brothers and I stopped playing and looked up. My oldest brother was jumping with excitement. This was on Long Island, NY.

Forward-swept wings exist because they grant +10 to Badassitude.

1:09 that break off is so nice

*Engineers:* If it works, it works

The big reason for swept forward planes was it gave G. I. Joe the Conquest to battle the SR-71 inspired Cobra Night Raven.

Yet again we see that Nazi Germany was mother to all modern inventions what the hell?

I saw the X29 in the air and space museum as a child. The forward swept wings captivated me and it’s been one of my favorite planes ever since.

The squeaking noise was driving me insane. Good Video!

The rusty hinge noise is VERY annoying! Amazing video otherwise

I've always been fascinated by backwards swept wings, and am very fond of all their implementations

I wonder if this design would be worth revisiting with modern technology. It's a very cool looking plane for sure.

I enjoy that he just casually throws in footage of a captured Zero in US markings. You know, because he can.

So my todler drawings of airplanes became Real Edit: Thank you for 420 Likes

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The real answer is: "because it looks more badass".

I play a game called TerraTech and before even knowing these planes existed, I made my own and now I'm surprised at how accurate the game was because controlling the plane was like trying to control melted butter. Another weird thing is I called my plane the X-Fighter.

It was largely retired because it's composite wing reinforcement was cracking. Graphene based materials might revive the idea in future planes. Although for fighter aircraft, especially stealthy fighter aircraft, the 'diamond shaped' wing of the YF-23 addresses many of the sought benefits, without many of the problems.

I'll admit. This is probably the hardest to understand RU-vid video I've watched, and there's nothing wrong with the presentation.

Clear explanations supported by top-knotch graphics and serious amounts of research.Spot on.Thanks dude!.

Next jet. Explain the boeing bird of prey. The jet which has no wings!

Now you're in my country and, may I say, well done! I'm definitely sending this out to all my students.

This was very engaging! I enjoyed every clip and explanation, and I learned a few new things. Thank you for working on this!

7:37 "we need to build an adequately strong and stiff wing" at the precise moment that the jetliner is using sheer engine power, not aerodynamic lift, to gain altitude.

I think maybe the term should be 'forward-swept wings'. Traditional wings are already swept backwards.

I'm the backwards plane, the backwards plane, I can fly backwards fast as you can!

oh well, even if forward-swept wings don't exist irl, I can always go back to Ace Combat for the FALKEN, Morgan, and Wyvern.

The Westland Lysander also had swept forward wings, and before WW2. This was done for very different reasons but it did give the aircraft more manouevrability than it might otherwise have had, enough to make this army observation aircraft suitable to be drafted in as a fighter.

Real engineering : Why Do Backwards Wings Exist? Me : In case the plane needs to fly backwards silly

SU 47 gang where ya'll at?

Can you do a video on the German submarine team type 212 it has a unique hydrogen engine and it's super stealthy

I was curious about this, the SU-47 is one of my favorite planes in Ace Combat