Impact of vertical tail on stealth

[helmutkohl]

While browsing the General Dynamics ATF thread..

I was wondering about the impact of the vertical tail design on stealth/radar signature

I've heard rumors that a giant single tail was not good
canted tails (at an angle similar to the fueselage) is generally better.

any thoughts?

also some other designs

via YF 23 site
canted inwards.. I havent seen this really being used

on the wing rather than fueselage (also via YF23)

winglets (this one is angled down rather than up.. if you can consider this a winglet)

or no vertical tail which may have the least signature like on the x-36..but this one has canards

 

[overscan (PaulMM)]

Here's a quick survey to add to what you already posted. Source : Jay Miller, FA-22 Raptor, Aerofax. I don't think any other design has tried so many vertical tail positions. The WW2 bomber one looks especially desperate.

 

[Trident]

Somebody at GD rummaged round the old Consolidated windtunnel model parts bin and dug out a B-32 tail fin!

More on topic, I think to answer this question you really need to define "stealth" more precisely. Especially the aspect angles where your mission requires RCS reduction and by how much. If, as ATF eventually did, very strong and simultaneously all-aspect stealth is specified, a single tail fin is probably no longer going to cut it, for fairly obvious specular reflection reasons. This was not the case from the very start of the programme though, initially the requirement was more limited in scope to primarily head-on RCS reduction. It seems likely that the single-tail GD designs would date mainly from that earlier phase of the project.

 

[apparition13]

It seems likely that the single-tail GD designs would date mainly from that earlier phase of the project.

The single tail was their ATF submission. They wanted to go with two canted tails, but couldn't get the aerodynamic performance straightened out and had to fall back to one, which left them short on stealth compared to Northrop and Lockheed. Hence the third place finish.

 

[siegecrossbow]

Even canted slabs negatively impact stealth from the side profile. The problem could be compounded if you approach the aircraft from above since the horizontal and vertical slabs join together at an acute angle, contributing to higher radar returns.

This is why sixth gen fighters that achieve true all-aspect stealth will require the removal of either the vertical or horizontal slabs.

 

[elmayerle]

You can have all-aspect LO and a single vertical tail, TSSAM (AGM-137A/BGM-137B) managed it nicely, though it was an all-moving tail. BGM-137B was the real challenge on vertical tail design, the vertical surface had to unfold and deploy through the plume from one of the boosters and not lose its LO nature; that took considerable R&D and testing.

 

[rooster]

Were not the tails on the sr71 made of plastic that radar passed through?

 

[Sferrin]

Somebody at GD rummaged round the old Consolidated windtunnel model parts bin and dug out a B-32 tail fin!

And slapped TWO of them on the YF-22. Almost for that reason alone I was like, "please God, don't pick the F-22".

 

[djfawcett]

Were not the tails on the sr71 made of plastic that radar passed through?

They were not composite. I am pretty sure they were titanium. A group of investors had us look into the operations of a company they were funding. In the companies hangar was a vertical of the SR. There were going to make a conference table from it. A fork lift was required to move it. I use to laugh how heavy it was. The leading edge was removed, so part of the structure could be seen, and it was definitely metallic.

 

[Whisperstream]

On the Blackbirds, each vertical tail consisted if a stub fin fixed to the nacelle and a movable rudder. The stub fin was constructed of titanium alloy, and housed the rudder servomechanism and pivot post. Rudders were identical and interchangeable, and came in two versions: metal and "plastic" (silicone-asbestos composite). The metal rudders were constructed with a central box section and attached leading and trailing edge assemblies, all skinned with titanium sheet. The plastic rudders incorporated basic frame members of titanium alloy and subordinate members (ribs, spars, and external surface panels) made of reinforced bonded silicone-asbestos materials. The plastic rudders weighed about 500 pounds, slightly more than the metal ones.

 

[Richard N]

Vertical tails are on airplanes because they are absolutely necessary. The three basic flight controls are pitch, roll, and yaw. Fail to have adequate control over any one of any of those and your flight will be unpleasant and short. I've seen a number of pieces of art that seem to find the elimination of vertical tails esthetically pleasing, but I dare any of those artists to remove the vertical tail from a conventional airplane and get in and attempt to fly it. The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

Accepting that vertical tails are a necessary evil on most conventional aircraft, there has to have been work done to make verticals from materials that absorb or deflect radar waves, possibly with electronic manipulation.

 

[rooster]

Vertical tails are on airplanes because they are absolutely necessary. The three basic flight controls are pitch, roll, and yaw. Fail to have adequate control over any one of any of those and your flight will be unpleasant and short. I've seen a number of pieces of art that seem to find the elimination of vertical tails esthetically pleasing, but I dare any of those artists to remove the vertical tail from a conventional airplane and get in and attempt to fly it. The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

Accepting that vertical tails are a necessary evil on most conventional aircraft, there has to have been work done to make verticals from materials that absorb or deflect radar waves, possibly with electronic manipulation.

Tailless Aircraft Flies Under the Radar

Earlier this year, the Air Force Research Laboratory put out a little noticed article about Northrop Grumman’s Supersonic Tailless Air Vehicle (STAV), a concept that could someday lead to a supersonic aircraft. Unlike the DARPA-funded "Switchblade" flying wing project, this research, sponsored...

www.wired.com

 

[VTOLicious]

Vertical tails are on airplanes because they are absolutely necessary. The three basic flight controls are pitch, roll, and yaw. Fail to have adequate control over any one of any of those and your flight will be unpleasant and short. I've seen a number of pieces of art that seem to find the elimination of vertical tails esthetically pleasing, but I dare any of those artists to remove the vertical tail from a conventional airplane and get in and attempt to fly it. The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

Accepting that vertical tails are a necessary evil on most conventional aircraft, there has to have been work done to make verticals from materials that absorb or deflect radar waves, possibly with electronic manipulation.

Best proof of feasibility of a tailless fighter design is the X-36 (Tailless Fighter Agility Research Aircraft). And that was almost 25 year ago!

"...The X-36 project team examined the aircraft's agility at low speed/high angles of attack and at high speed/low angles of attack. The X-36's speed envelope reached up to 206 knots (234 miles per hour); the aircraft was very stable and maneuverable and handled very well at both ends of the speed envelope..."

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-065-DFRC.html

 

[red admiral]

Best proof of feasibility of a tailless fighter design is the X-36 (Tailless Fighter Agility Research Aircraft). And that was almost 25 year ago!

But supersonic aircraft yaw stability is generally driven from the high speed case. i.e. max speed drives fin size. X-36 didn't do this.

 

[VTOLicious]

Best proof of feasibility of a tailless fighter design is the X-36 (Tailless Fighter Agility Research Aircraft). And that was almost 25 year ago!

But supersonic aircraft yaw stability is generally driven from the high speed case. i.e. max speed drives fin size. X-36 didn't do this.

Tailless fighter designs have been studied extensively over the last 25 years. I would assume supersonic designs as well.

 

[red admiral]

Tailless fighter designs have been studied extensively over the last 25 years. I would assume supersonic designs as well.

Quite. There's quite a few unclassified projects on this.

Flying a tailless aircraft supersonically looks quite feasible, but then you still need to add a bunch of other things to turn this into a "fighter"

 

[helmutkohl]

Vertical tails are on airplanes because they are absolutely necessary. The three basic flight controls are pitch, roll, and yaw. Fail to have adequate control over any one of any of those and your flight will be unpleasant and short. I've seen a number of pieces of art that seem to find the elimination of vertical tails esthetically pleasing, but I dare any of those artists to remove the vertical tail from a conventional airplane and get in and attempt to fly it. The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

Accepting that vertical tails are a necessary evil on most conventional aircraft, there has to have been work done to make verticals from materials that absorb or deflect radar waves, possibly with electronic manipulation.

Best proof of feasibility of a tailless fighter design is the X-36 (Tailless Fighter Agility Research Aircraft). And that was almost 25 year ago!

"...The X-36 project team examined the aircraft's agility at low speed/high angles of attack and at high speed/low angles of attack. The X-36's speed envelope reached up to 206 knots (234 miles per hour); the aircraft was very stable and maneuverable and handled very well at both ends of the speed envelope..."

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-065-DFRC.html

Im wondering how feasible a scaled up and manned X-36 would be

 

[VTOLicious]

Tailless fighter designs have been studied extensively over the last 25 years. I would assume supersonic designs as well.

Quite. There's quite a few unclassified projects on this.

Flying a tailless aircraft supersonically looks quite feasible, but then you still need to add a bunch of other things to turn this into a "fighter"

Indeed, Boeing MRF for instance: https://www.secretprojects.co.uk/threads/boeing-mrf-24x-tailless-fighter.528/
However, this thread is about vertical tails anyway

 

[rooster]

Tailless fighter designs have been studied extensively over the last 25 years. I would assume supersonic designs as well.

Quite. There's quite a few unclassified projects on this.

Flying a tailless aircraft supersonically looks quite feasible, but then you still need to add a bunch of other things to turn this into a "fighter"

How much twisting and turning do you think happens in an era of "look and shoot" missiles?

Remember the saying from the ATF days: First look. First shot. First kill.

With even the largest flight control surfaces you're not going to out turn a missile.

 

[In_A_Dream]

How much twisting and turning do you think happens in an era of "look and shoot" missiles?

Remember the saying from the ATF days: First look. First shot. First kill.

With even the largest flight control surfaces you're not going to out turn a missile.

Or a swarm of up-close attack drones with much more accurate gunnery.

 

[publiusr]

Did any tails have a hinge? To allow an angle only in radar range? At the so-called flying ram page..an image of a cockpit atop a T-tail as an escape craft popped into my head...

 

[X-39]

I remember reading an article about the use of radar transparent materials in the SU-57 vertical stabs. Is this an effective tradeoff between somewhat mimicking the signature reduction of a pure tailless aircraft and agility? Are the manufacturing processes of other 5th Gens currently in production taking a similar approach?

 

[1635yankee]

Were not the tails on the sr71 made of plastic that radar passed through?

No. The technology of plastics didn't, and likely still don't, permit their use in something with the thermal and aerodynamic loads the SR-71 vertical tails were subject to.

And radar doesn't "pass through" plastic quite so cleanly as you may think; plastic has a different refractive index than air, so some radar energy is reflected. Graphite-reinforced plastics are full of long, thin conducting elements. They may be less effective reflectors than aluminum (or titanium), but they still reflect radar.

 

[edwest4]

I recommend the following book since it covers various experiments regarding RCS.

Amazon.com

 

[Cordy]

Feasible/drawbacks? - Three axis control of tailless aircraft using fluidic actuators - Aug 21

https://www.researchgate.net/publication/353535448_Three-axis_control_of_tailless_aircraft_using_fluidic_actuators_MAGMA_case_study

 

[TomcatViP]

We have also here a thread dedicated to Darpa research program on fluidic effectors:

https://www.secretprojects.co.uk/threads/darpa-control-of-revolutionary-aircraft-with-novel-effectors-crane.32882/

 

[Sferrin]

The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

The YF-22's were huge compared to the F-22A's. The F-22A won't win any awards in aesthetics in profile but at least it's an improvement on the YF-22A. And yes, we're all well aware that airplanes need tails.

 

[helmutkohl]

The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

The YF-22's were huge compared to the F-22A's. The F-22A won't win any awards in aesthetics in profile but at least it's an improvement on the YF-22A. And yes, we're all well aware that airplanes need tails.

Functionality aside... I guess I might be the only one that found the YF-22A to be aesthetically pleasing (but then again I also like the looks of the X-32). Looks a bit balanced, compared to the J-20 whose small tails makes the plane look longer than it really is.
but overall I've liked the look of V-tails like on the YF-23, McDD JAST proposal, and Su-75

 

[rooster]

The F-22 has huge verticals because it cannot maneuver fully without them, not to upset someone's idea of a pretty airplane.

The YF-22's were huge compared to the F-22A's. The F-22A won't win any awards in aesthetics in profile but at least it's an improvement on the YF-22A. And yes, we're all well aware that airplanes need tails.

I for one loved the yf22 over the f22.

 

[Manuducati]

Which one is the best looking between YF-22 and F-22? I raise my F-23 joker!

And talking about about tail less design:
Post in thread 'Northrop/McDonnell Douglas YF-23 and EMD F-23' https://www.secretprojects.co.uk/th...ll-douglas-yf-23-and-emd-f-23.1092/post-15388

If I remember correctly it was a... Boeing proposal for a yaw control demonstrator reusing a stored YF-23 (I think I read this in the same thread but can't pinpoint the information at the moment).