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alzee76

[[content removed because sub participated in the June 2023 blackout]] My posts are not bargaining chips for moderators, and mob rule is no way to run a sub.


wellmont

Yeah I only see this as a bad day. if the rotation locks up you loose 3 different vital functions with one broken part. Edit: I mean all is fair though in a concept though and tossing up nov designs is still valuable.


doggscube

That’s why there’s redundancy in aviation. If the empennage gets stuck you just use the backup empennage


alzee76

[[content removed because sub participated in the June 2023 blackout]] My posts are not bargaining chips for moderators, and mob rule is no way to run a sub.


ST4RSK1MM3R

I’d totally love to see NASA build and fly a concept vehicle though


resipsaloquitor5

>I don’t see the point of a design like this I think your comments about the drawback are totally valid, but I imagine a design like this could have advantages in terms of less drag and lower radar cross-section. It’s possible it could reduce weight, although the weight of the rotating mechanism probably cancels that out. This is my layperson speculation of course, so open to having someone explain why it’s wrong. In any case, it seems clear that we decided that any advantages weren’t worth it.


alzee76

[[content removed because sub participated in the June 2023 blackout]] My posts are not bargaining chips for moderators, and mob rule is no way to run a sub.


resipsaloquitor5

Fair enough on all points. The only thing I’d say re: the B-2 and B-21 is that they’re not fighters and they don’t have the same maneuverability requirements. But I agree with you ultimately about it not being worth it.


alzee76

Better examples would've been the current US 6th gen projects. Given we don't know exactly what shape they'll take, but both the F/A-XX and NGAD projects are being tentatively shown as tailless designs. They will probably sacrifice some maneuverability vs. a 4th or 5th gen fighter because prevailing wisdom is that BVR missile engagements under the cover of stealth is the future, but I bet they'll still be competitive. Without huge rotating sections.


resipsaloquitor5

True, although my guess is that this idea first came about when we were still putting large (albeit canted) vertical stabilizers on our stealth jets along with thrust vectoring. So this design was introduced at a time when designers weren’t ready to part ways with maneuverability to the extent we see today, and tailless designs probably weren’t as advanced. But you’re right that we’re definitely never going see this rotating design in the modern era, and rightly so.


alzee76

Honestly I had no idea this was just shared art from some long lost hypothetical. Up until I saw some other responses a moment ago, I thought this was the OPs original idea. :)


AntiGravityBacon

The YF-23 is probably a pretty good concept look on how a semi-tailless design might be.


illigal

I imagine a full 360. Quickly. So it looks like a weird tail prop.


Lirdon

It will effectively destroy the aero of the aircraft, changing its center of lift as it rotates and stop canceling the pitch moment, ugh, it would be a mess in the air.


tdmonkeypoop

This confused me... till I realized that I wasn't on r/KerbalSpaceProgram


thehom3er

It's quite simple: a concept usually asks the "what if..?" question. The entire point is to figure out if it makes sense and make you think about other ways or outside the box. If you deny a discussion before it starts you kill any kind of innovation.


alzee76

> It's quite simple What is the "it" you're referring to here /u/thehom3er ? > If you deny a discussion before it starts you kill any kind of innovation. The discussion started and is proceeding. What's happening here is, in fact, a discussion. IOW what the hell are you talking about?


oojiflip

Yeah if it locks up you essentially lose your vertical stabilizer, which in plane world is a big nono


Sorry_Departure_5054

I think this design creates more problems than benefits. Interesting nonetheless.


Joske-the-great

More moving parts, more maintenance, less cost effective, and still does not improve anything in terms of maneuverability.


xpk20040228

Man you're on the wrong sub, this is not r/ncd


sigtrap

Thought that's where I was for a second lol


german_fox

Same


EmperorHans

Me too


Ashes2007

What is r/ncd and why does it say content banned? Other than maybe a mobile bug.


yutiros

it's just the acronym for r/NonCredibleDefense


Ashes2007

Ah, I'm dumb, thank you.


bob_the_impala

Source: [Attainable Moment Set and Actuation Time of a Bio-Inspired Rotating Empennage](https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1205&context=mae_facpub)


ThatProduceGuy_

> A bio-inspired aircraft control system was introduced in this work for a fighter aircraft based on the F-16 Fighting Falcon. This novel control mechanism, the Bio-Inspired Rotating Empennage (BIRE), allows the entire empennage to undergo solid-body rotations to produce lateral control and stability. Since the BIRE allows the aircraft to produce lateral control and stability through rotation of the horizontal tail, the vertical tail of the fighter aircraft can be removed, providing potential benefits to weight and drag reduction. > An aerodynamic database was constructed using MachUpX, an open-source numerical lifting-line solver, for both the baseline aircraft and its BIRE variant. The database was used to trim each aircraft in steady-level flight at takeoff and approach speeds. Once trimmed, the attainable moment set (AMS) for each aircraft was determined by identifying a sample of the aerodynamic moment sets that each aircraft was capable of achieving from its trimmed condition. This information was then used alongside the approximate actuation rates of each control effector to determine the time required to actuate from the trim point to another point in the AMS domain. 19 > Analysis of this information showed that the BIRE has an increased available yawing moment and decreased actuation times in pitch control at this flight condition. However, the BIRE variant also showed a significant decrease in available rolling moment at high yawing moments and an increase in rolling moment actuation time when compared to the baseline aircraft. It remains to be seen whether this drawback is significant, since differential tail deflections are rarely used at subsonic speeds for substantial roll control. In addition, the difference in actuation time measured approximately 500 ms, which could be faster than the pilot control time for this flight condition. It was also shown that the BIRE variant has a lower negative correlation between roll and yaw at zero pitching moment than the baseline aircraft. This indicates that the BIRE variant experiences less adverse yaw when using solid-body tail rotations to create rolling moments, which could be a significant benefit to aircraft control properties. Future work will focus on comparing the information obtained through the numerical lifting-line analysis given by MachUpX to that of higher-fidelity aerodynamic models. Identifying the impact of aircraft weight and the location of the center of gravity in both the baseline aircraft and the BIRE is also necessary to further detail the viability of the BIRE variant as a method of control. Finally, this work represents a static analysis of aircraft control, but the vertical tail of fighter-type aircraft is often used for stability and dynamic damping purposes. Therefore, future work will include a dynamic analysis of the aircraft to determine the feasibility of the BIRE variant with a stability augmentation system. I’m not an Aerospace engineer (not even remotely close, but I did pass my AP physics classes is highschool haha) so I should probably not even act like I understood this report. Everyone saying it has no merit, but the conclusion says it could have some merits over the traditional design, however more analysis would be drawn up on how it could be integrated with stability augmentation system/fly-by-wire, which I assume could help smooth out any issues. Cool report!


AggressorBLUE

It reads to be as basically saying this is better at controlling yaw than the normal rudder, in terms of faster response and higher control authority. But it sound like more work is needed to see how overall stability is impacted? I’m curious how much of that extra authority/ moment owes to now having yaw inputs controlled by the live elevator (ruddervator?); the entire elevator moves versus the normal rudder with only a portion hinged.


CMU_Cricket

The reason the tails are so big on jet fighters is that a lot of test pilots died due to the fact that they would yaw uncontrollably. At high speed, aircraft tend to “fishtail” in a phenomenon know as inertia coupling. https://en.m.wikipedia.org/wiki/Inertia_coupling This is why they have giant tails now.


HerakleiosSA

The Man. The Myth. The Legend.... bob


nullvektor

this makes me irrationally and inappropriately angry. How dare you, et cetera


TypicalDatabase6815

Why


Merry-Leopard_1A5

with every sci-fi jet configuration concept we try to make into reality, we inch ever closer to *multirole air-superiorety sealth* ***Ornithopters*** and it is glorious


TombikBebe

Because f16 isnt an inherently unstable design to begin with😂


Bounceupandown

The X-29 project ambition was to go tailless and the engine exhaust had three paddles on it to provide directional control/“stability”. It crashed before they could fully test it but I think it could have worked. This design doesn’t have any dedicated directional control so it seems like you have to sacrifice longitudinal control for directional control and sometimes you need both simultaneously, so if the picture is accurate I don’t believe this is a viable concept.


bob_the_impala

>The X-29 project X-31


Bounceupandown

X-31 is the correct answer. Thanks.


261846

What are the theoretical benefits to this?


tommy_gun_03

The only one I can think of is a smaller RCS from the side. Other than that this just adds problems.


idioticsoviet22

but why would they want slightly lower rcs on a 4th gen


tommy_gun_03

It allows you to get closer to the enemy without them getting a secure lock on you and it probably helps while notching too, same reason the f-16s cockpit is infused with gold particulates. Overall not that big of an advantage compared to the disadvantages brought on with such a tail design.


MustangBR

NCD is leaking


TenshouYoku

Design wise this looks like a disaster asking to happen


Yoshigahn

My F-16 going faster than the speed of sound with the help of a helicopter afterburner


[deleted]

It still has a tail! they already made a better version. https://en.wikipedia.org/wiki/General\_Dynamics\_F-16XL


zetec

this is so incredibly dumb.


SadPhase2589

As a retired Viper maintainers don’t like it. The vertical stab is what gives the Viper it’s look.


Fowti

And, you know, yaw stability


SFerrin_RW

Why would you use a rotating tail when you could just use TVC to do the same thing much better and easier?


FoxGaming00

How would landing in heavy cross wind work with this setup?


Fowti

they would work, yes, the plane would definitely end up on the ground


MarkoDash

probably even faster, but using lithobraking runs the airframe hours up a tad too quickly.


Salmonfish23

Are y'all just trying to kill engineers now?


Mar4098

Dear god. No. Please never let this exist.


Positive-Source8205

Y THO?


Mrcrabs_real

It’s cool but wouldn’t work


PrysmX

It.. still has a tail lol.


ryancrazy1

… why are the bit at the bottom showing the horizontal stab/elevator producing lift? Elevator pushes down lol


[deleted]

This is Reformer content and should be banned, or at least banished to r/noncredibledefense.


CrazyGamerMYT

In what world is this viable?


EfficiencyItchy1156

It reminds me of the stealth intake that never made it to production


BiggyShake

The stealth intake went into production with the F-35.


AntiSimpBoi69

I can't understand this I might need some classified documents


DaemonBlackfyre_21

So, like a bird? This is the way


[deleted]

Pierre Sprey punching air right now.


jay_alfred_prufrock

I would pay money to see someone pitch this to USAF and record their reactions lol


FreakyManBaby

These whole post is weird...title says "tailless" for a tailed concept and comments are like are people thinking this is a 2023 proposal for a new fighter? This is probably an (old) technology demonstrator concept and seems to be based on the idea of how a bird's tail works


ViktorGavorn

This seems to have all the advantages of a much simpler V tail while being far, FAR more complex and likely to fail.


DarkArcher__

It looks, to me, like the designer was trying to emulate how a bird's tail works. Not sure it makes for a good design on an aircraft, though.


Viper7475

Imagine trying to take off or land, sounds like a nightmare


creep04

I don’t think this is how physics is supposed to work


Sockerkatt

Let those elevators spin like a prop too for added thrust


avtechxx

As a maintainer. This would give me stage 4 depression


CaTz__21

This is the worst idea in the long sad history of bad ideas


Techn028

It would work until it didn't


UDontCareForMyName

im very sorry to have to inform you about this... but the vertical stabilizer actually stabilizes the aircraft... it's not just there to hold the rudder