VF-1 Fighter Mode Aerodynamics

[SchizophrenicMC]

David, I'd assume less. They're smaller than jet turbines and they're OT.

Steve, the F-16 can't fly if what you're saying is true. Nor can the F-22, F-35, or really any fighter plane since 1980-something. The computer controls the plane's control surfaces, making very minute changes to react to the slightest movements off-level. The adjustments are minute, so unless you were on the plane, looking at them, the paddles wouldn't appear to move. Also, Macross animated on a 1980s budget. That's just not possible to do that at that time. That said, the VF-1 is explicitly stated by all sources (Yes, even Robotech) to have both 2D thrust vectoring and Fly-By-Light controls.

Fly-by-wire and Fly-by-light are used a lot lately, not only because the systems weigh less, but because they can provide changes to control surface area by the tiniest iota, according to computer commands, meaning the flight data actually goes to good use, keeping an unflyable plane in the air.

Besides, the VF-1 likely has most of its weight towards the back, meaning it can be more easily thrust-stabilized, if I'm not mistaken.

[Mr March]

Since the issue of weight distribution has come up, it's probably worth mentioning the VF-1 Valkyrie is also described in the official literature as a Control-Configurable Vehicle (describes those aerospace craft specifically designed such that the distribution of the vehicle mass provides maximum maneuverability).

[ChronoReverse]

This was probably already brought up but here's the F-117

http://upload.wikimedia.org/wikipedia/comm..._NIGHT_HAWK.svg

It doesn't have tailplanes either. It's not stable in any axis but still flies (if somewhat wobbly).

[SchizophrenicMC]

This was probably already brought up but here's the F-117

http://upload.wikimedia.org/wikipedia/comm..._NIGHT_HAWK.svg

It doesn't have tailplanes either. It's not stable in any axis but still flies (if somewhat wobbly).

It's nearly delta-winged, though. It uses elevons. Though it's unstable on all axes, you can't use it as a comparison for a plane with no horizontal stabilizers.

It would be like saying a Rafale, Typhoon, or Mirage is inherently unstable, simply due to lack of tailplanes.

[ChronoReverse]

Perhaps with the Mirage (which is a true delta unlike the F-117), but both the Typhoon and Rafale has canards which serve the same purpose so they do not count.

The F-117 is quite far from a delta though, however its instability stems from more than just the lack of tailplane of course.

[SchizophrenicMC]

Perhaps with the Mirage (which is a true delta unlike the F-117), but both the Typhoon and Rafale has canards which serve the same purpose so they do not count.

The F-117 is quite far from a delta though, however its instability stems from more than just the lack of tailplane of course.

The Canards are DESTABILIZING surfaces. IE, they're there to force the plane from level, not keep it there. They work by forcing the nose of the plane up or down, rather than pushing the tail up or down.

However, to make up for the comparison, how about the F-106 or Avro Vulcan? Neither of them had problems

Anyway, the F-117 is far closer to delta than most planes the military uses. Really, its wings are a lot closer to the F-14's at high sweep, given, but they also resemble, perhaps even more closely, the VF-1's at high sweep.

And the F-117 still flies, even despite its lack of tailplanes, boxy fuselage, and general other problems with the design.

As a note, the F-117 has similarly-angled vertical stabilizers to the VF-1

[ChronoReverse]

Eh? I thought canards simply provided pitch control. They're movable for that purpose aren't they? Even if they're being used to increase maneuverability, they can still be configured for stable flight if need be (unless they're like the tiny little ones on the YF-19).

In any case, a true delta doesn't need tailplanes (although many do have them) to control pitch. Even if you insist the F-117 is close to delta, it's still a swept-wing design. Of course, I recall another discussion in this forum where it was asserted that F-22's wings were delta (it could be argued as a modified delta but it's far from even "usual" modified deltas). Just remember why a delta wing is a called a delta wing (hint if it's a quadrilateral, it's not really a delta).

Edited September 13, 2009 by ChronoReverse

[Steve68]

Steve, the F-16 can't fly if what you're saying is true. Nor can the F-22, F-35, or really any fighter plane since 1980-something. The computer controls the plane's control surfaces, making very minute changes to react to the slightest movements off-level. The adjustments are minute, so unless you were on the plane, looking at them, the paddles wouldn't appear to move. Also, Macross animated on a 1980s budget. That's just not possible to do that at that time. That said, the VF-1 is explicitly stated by all sources (Yes, even Robotech) to have both 2D thrust vectoring and Fly-By-Light controls.

Fly-by-wire and Fly-by-light are used a lot lately, not only because the systems weigh less, but because they can provide changes to control surface area by the tiniest iota, according to computer commands, meaning the flight data actually goes to good use, keeping an unflyable plane in the air.

Besides, the VF-1 likely has most of its weight towards the back, meaning it can be more easily thrust-stabilized, if I'm not mistaken.

I'm not sure if this was directed at me, but what I'm saying is true. The center of lift of the wing is NOT at the center of gravity. That's a fact. Because of this the aircraft needs to have something to counter act the pitching moment that is created by the difference between the two points. This is why non flying wing aircraft have horizontal stabilizers. The stabilizer in level flight provides a downward force on the tail of the aircraft. Without the the tail the plane would pitch down and be unable to fly. The amount of travel that an aerosurface moves on modern fighters is directly proportional to the aircraft speed. You should watch some video of the planes taking off or landing. You will see surface movement that you could measure in feet! At higher speeds the aerosurfaces movement is less dramatic. Another point to remember is that tail surfaces by their shear size provide a lot of lift (remember all modern fighters have full flying stabs) so a little bit of movement provides a lot of force as the speed increases. Thrust vectoring is different. You need a lot of movement to get the same amount of pitch force. Don't believe me. Watch this video at about the 3 minute mark you can see how much nozzle deflection is required to get the nose to pitch up.

http://www.youtube.com/watch?v=HDDmRC_bsmE...feature=related

Steve

[eugimon]

Steve68, watch the video that anime52k8 posted, the VF-1 thrust vectoring has a range of movement far greater than what the F-22 shows in the video you posted.

[David Hingtgen]

Canards do whatever the designer wants them to do. They can be primarily for pitch stability, pitch control, pitch de-stabilizing, or merely an "influence on airflow over the wing". Or any combination of the above.

Most of the Eurocanards tend to rely on them heavily for influencing the wing airflow, especially at high-alpha. It's their "little secret" for high-alpha performance---use the canards to control the wing, not to control the plane.

[Steve68]

Steve68, watch the video that anime52k8 posted, the VF-1 thrust vectoring has a range of movement far greater than what the F-22 shows in the video you posted.

Watch the video I posted. The F-22 nozzle movement is not far off what is shown in the PS1 DYRL video. Also note that the horizontal stabilizers in the video I posted are moving in addition to the nozzle. So the plane would be pitching less if the stabilizers had not moved. What that means is that for a fighter to use thrust vectoring alone to achieve large pitch changes is going to require the nozzles move huge amounts. If the nozzles deflected that much then the plane is going to slow down very quickly as you are trading straight line thrust for a vertical component. It's a pretty simple trig problem to figure out that your thrust would go down by 30% if the nozzle pitched to 45 degrees. At 60 degrees the horizontal component of thrust would be 50%. I think the lesson to be learned is that thrust vectoring works well with horizontal stabilizers to 'augment' pitch control, but as the sole means of pitch control it is a poor choice.

[eugimon]

Watch the video I posted. The F-22 nozzle movement is not far off what is shown in the PS1 DYRL video. Also note that the horizontal stabilizers in the video I posted are moving in addition to the nozzle. So the plane would be pitching less if the stabilizers had not moved. What that means is that for a fighter to use thrust vectoring alone to achieve large pitch changes is going to require the nozzles move huge amounts. If the nozzles deflected that much then the plane is going to slow down very quickly as you are trading straight line thrust for a vertical component. It's a pretty simple trig problem to figure out that your thrust would go down by 30% if the nozzle pitched to 45 degrees. At 60 degrees the horizontal component of thrust would be 50%. I think the lesson to be learned is that thrust vectoring works well with horizontal stabilizers to 'augment' pitch control, but as the sole means of pitch control it is a poor choice.

There's a difference of 10-20% there on the downward alone... that's a huge difference. And there are real world examples of aircraft that fly with high maneuverability sans horizontal stabilizers. Just because the F-22 doesn't utilize that solution is hardly an indication that the feat cannot be done, especially when there's proof that it is possible.

[ATMacross]

The VF-1 could probably fly. Someone has made an RC model (light depron foamie) and it flies. Not to say that it means that the VF-1 will fly, but the silouhette is a viable design. But given the right controls and thrust, you can make a flat plate fly. The concept is a variation of a V-Tail. The canted ventral fins add lateral stability, but the V-Tail albeit split V acts both as a conventional rudder and the elevator. Real planes demonstrate the V-Tail like the Bonanza, a gen av plane that doesn't have thurst vectoring since it's a single prop in the front. FBW - just means computerized flight controls. So instead of conventional control cables and rods connecting the flight stick and rudder to the control surfaces, there's a computer between the control surface and the flight stick. Let the flight computer do all the calculations and movements necessary to keep the plane stable and do exactly what the pilot wants. Less workload and lets the pilot do more meaningful tasks like selecting targets and weapons, vs keeping the plane upright and flying. The F-117 is another example of a V-Tail aircraft.

Now, can the VF-1 fly past Mach 1? That, I doubt b/c the tail fins are not moving planes, but only control surfaces. I think Chuck Yeager in the Bell X1 has demonstrated that you need a fully moving tail surface in order to have control beyond mach 1. The shock wave that the tail leading edge makes would make the small control surface useless. Or was that because the shockwave of the main wing, that made the control surface of the tail useless? I can't remember.

[David Hingtgen]

You people are all "over-estimating" canted fins.

VF-1 doesn't have a V-tail. It merely has canted v.stabs. They're rudders, nothing more. And they may work like an F-18's where they have a "fully inwards deflection to make a slight pitch-up effect", but they are not for pitch control--no more than an F-18's.

Think about it---are you even going to have much effect in pitch when you're only 20 degrees or so away from vertical?

[anime52k8]

You people are all "over-estimating" canted fins.

VF-1 doesn't have a V-tail. It merely has canted v.stabs. They're rudders, nothing more. And they may work like an F-18's where they have a "fully inwards deflection to make a slight pitch-up effect", but they are not for pitch control--no more than an F-18's.

Think about it---are you even going to have much effect in pitch when you're only 20 degrees or so away from vertical?

what he said. Now if were talking about the YF-21/VF-22, yes you have the rudders also acting as elevators, but not on the VF-1 or just about any other valk for that matter.

most of the planes pitch control would be through TV and control surfaces on the wing. there is one component that I think we're forgetting though; vernier thrusters.

now I've never seen any numbers on how strong the verniers actually are, and of course they'd me much less effective in an atmosphere than in space. but I could still see them working along with TV and the conventional control surfaces to maneuver the plane.

[eugimon]

what he said. Now if were talking about the YF-21/VF-22, yes you have the rudders also acting as elevators, but not on the VF-1 or just about any other valk for that matter.

most of the planes pitch control would be through TV and control surfaces on the wing. there is one component that I think we're forgetting though; vernier thrusters.

now I've never seen any numbers on how strong the verniers actually are, and of course they'd me much less effective in an atmosphere than in space. but I could still see them working along with TV and the conventional control surfaces to maneuver the plane.

the ones on the VF-0 were strong enough to push it around in water... so I'd imagine they'd work decently well in atmosphere.

[ChronoReverse]

The verniers are strong enough to provide hovering capabilities in fact IIRC. But it was already clear that even VF-1 had so much excess thrust that it would fly even if it was a brick. It's just more interesting to figure whether it would fly with our knowledge of flight mechanics (This discussion still seems be focused on whether the VF-1 could be a stable design which ultimately doesn't matter even if it were). It has to be qualified as "with our technology" since there's almost certainly some sort of OT mechanics as well (for instance, in the Macross Plus OVA, Isamu mentions that the YF-19 has the new Active Aerodynamic Control System.

Edited September 14, 2009 by ChronoReverse

[akt_m]

they could probably build a plane that looks like a VF-1 that has near VF-25 performance, but why would they want to? for all the effort they'd have to go through they'd be better off just designing a new plane from the ground up.

(as an aside, in the VF-X video game they had an upgraded VF-1X, and it had a T-W ratio of 3.14)

If the writers wanted they could make in the plot a VF-0 with a superior performance than the VF-25. By the way what are the numbers for the GhostX9??

[SchizophrenicMC]

Note that the question is about the plane's aerodynamics, not its verniers.

And, we've established non-vernerian flight is possible.

I think the real question is "How the hell can the VF-17 fly in an atmosphere?"

It doesn't even have 2D thrust vectoring.

[ChronoReverse]

Heh, it _was_ supposed to be primarily space based. I suppose since it was inspired by the F-117, we could say that it flew really wobbly in an atmosphere?

[Mr March]

When you think about it, every variable fighter with engine nozzles for feet should have some degree of thrust vectoring in all dimensions, regardless of whether they are designated 2D or 3D. Lateral ankle movement is a must for the Macross Battroids, so it follows that engine thrust from nozzles that double as feet should have the same freedom of movement in fighter mode as they do in Battroid, the VF-17 Nightmare included.

[hobbes221]

Good point March, but as some of the later model VFs have feet/nozzles that retract a little (VF-25 is a good example) in fighter mode the ankle system may simply be locked out until the feet are deployed for whatever reason. Not saying you're wrong and I'm right or anything just a counterpoint. But if they are free, how much range of movement do you think we are looking at?

[Zentrandude]

guess someone could model the vf-1 in x-plane 9 using the plane maker and see if our current understanding of flight aerodynamics would support the design. any takers?

[David Hingtgen]

I like the locked-out theory. There's a really good explanation for them not moving all around in fighter mode. Because they don't have room--think about it---nearly every valk has the feet slide out, THEN open up and transform into feet. Even on the toys, you don't have lateral movement of the feet in fighter mode--have to slide them out first (with excessive force in the case of many a Yamato). Thus, 2D-only vectoring for most valks in fighter mode, due to the ankles being "shoved up inside the nacelles" in fighter mode.

YF-21 is the only valk with 3D vectoring, as it's the only valk where the nozzles aren't the feet.

[SchizophrenicMC]

And all of this (save March) reinforces the value of my question.

The VF-17 and 171 don't have anything but yaw vectoring. How the hell do they perform the same kind of tweaking any FBW plane does in an atmosphere?

[anime52k8]

And all of this (save March) reinforces the value of my question.

The VF-17 and 171 don't have anything but yaw vectoring. How the hell do they perform the same kind of tweaking any FBW plane does in an atmosphere?

probebly using the control surfaces on the wing

Even though the VF-17/171 are based of the F-117, their actual layout is much closer to a delta winged aircraft ala the Delta dart or the delta dagger. Pitch and role control would be from the flaps on the wings.

Interesting thing to note, the vertical "tails" don't appear to have any way of actually moving. I think the reason the legs end up on there sides is that TV is the primary mode of yaw control, and the vertical fins are only there to serve as ballistic shields in battroid mode and to provide lateral stability.

also on the subject of recessed feet, I think that even if they're retracted, they'd still have some range of movement, maybe only a few degrees but enough to be used for fine adjustments.

[azrael]

Interesting thing to note, the vertical "tails" don't appear to have any way of actually moving. I think the reason the legs end up on there sides is that TV is the primary mode of yaw control, and the vertical fins are only there to serve as ballistic shields in battroid mode and to provide lateral stability.

IIRC, the VF-17 has horizontal thrust-vectoring and the VF-171 inherits this feature.

[hobbes221]

Here's a shot of a -171 using it in action

Edited September 17, 2009 by hobbes221

[anime52k8]

IIRC, the VF-17 has horizontal thrust-vectoring and the VF-171 inherits this feature.

That's my point. The VF-17 has horizontal TV which effects yaw. Since the tail fins don't appear to move, in an atmosphere TV is most likely the primary way of controlling yaw.

[SchizophrenicMC]

Well, see, my issue with that theory, Mike, is that the sweep of the control surfaces is really deep. I'm no expert (Not even an amateur, admittedly), but it would seem they'd be pretty insufficient at that angle for a lot of aerial maneuvers.

Let's ask the engineering student. Dex? What's your take?

[ChronoReverse]

Well, even if we finally admit that they wouldn't be able to fly easily with our technology, there's no reason to believe that there wasn't some sort of OT helping the aerodynamics. I've mentioned how the YF-19 was explicitly expressed to have the "new active aerodynamic control system" by Isamu for instance.

[IAD]

I don't see why the VF-1 can't be considered a flying wing, plain and simple... I've been building autonomous UAVs for the last couple years, and I've been using plank-type flying wings the whole time... (See attached.) Unswept wings, with elevons along the back. With the correct airfoils and CG, they have neutral pitch stability, and are a lot of fun to fly in manual mode. (In autonomous/FBW mode, they're completely stable, of course... You just stand there while the flight plan executes, watching a laptop for system messages/faults. "Don't take your eyes off that monitor!")

I've also flown more conventional swept flying wings, which work well, too... Basically, these configurations bracket the range of sweep the VF-1 exhibits. By extension, the VF-1 doesn't need thrust-vector, verniers, or even FBW in order to be controllable/flyable, as long as the CG stays within the required range during wing actuation. (FBW becomes necessary if you move the CG back, to optimize combat maneuverability... Same for thrust-vector; not needed, but it makes it fight better.)

~Luke

[SchizophrenicMC]

Well, even if we finally admit that they wouldn't be able to fly easily with our technology, there's no reason to believe that there wasn't some sort of OT helping the aerodynamics. I've mentioned how the YF-19 was explicitly expressed to have the "new active aerodynamic control system" by Isamu for instance.

They can fly easily with our technology. A good way to look at it is the X-36, which had no vertical stabilizer. It still flew, and straight, though it had no large yaw-based control surface. The flight dynamics, then, work similarly with the VF-1.

I think Isamu was talking about a much more precise version of FBL to go along with the forward-swept VG wing on the YF-19. Perhaps, it even shifted weight within the valk to change the CG actively, increasing combat maneuverability, while retaining stability in normal flight.

I don't see why the VF-1 can't be considered a flying wing, plain and simple... I've been building autonomous UAVs for the last couple years, and I've been using plank-type flying wings the whole time... (See attached.) Unswept wings, with elevons along the back. With the correct airfoils and CG, they have neutral pitch stability, and are a lot of fun to fly in manual mode. (In autonomous/FBW mode, they're completely stable, of course... You just stand there while the flight plan executes, watching a laptop for system messages/faults. "Don't take your eyes off that monitor!")

I've also flown more conventional swept flying wings, which work well, too... Basically, these configurations bracket the range of sweep the VF-1 exhibits. By extension, the VF-1 doesn't need thrust-vector, verniers, or even FBW in order to be controllable/flyable, as long as the CG stays within the required range during wing actuation. (FBW becomes necessary if you move the CG back, to optimize combat maneuverability... Same for thrust-vector; not needed, but it makes it fight better.)

~Luke

Though, another problem I notice is at high sweep, the VF-1's wings are too far over the wing for the ailerons to move down, due to the engine nacelles. This would severely limit its ability to control itself at high sweep, sans thrust vectoring. Given, you'd be unlikely to see it at speeds low enough to warrant full range of motion.

[ChronoReverse]

They can fly easily with our technology. A good way to look at it is the X-36, which had no vertical stabilizer. It still flew, and straight, though it had no large yaw-based control surface. The flight dynamics, then, work similarly with the VF-1.

It's like you argue for the sake of arguing. Since you were discussing about how the VF-17 could handle well in the atmosphere (fly well) beyond the TV I simply mentioned that it's possible there were more aerodynamics being taken advantage of that we aren't aware of. Did I even say "the VF-17 can't fly" or "It must be using OT to fly"?

With that said, the X-36 does flies unstable (which doesn't mean it can't fly straight and steady; something that could be said of the VF-1 and is probably even a design goal) and features a type of aileron design the VF-1 doesn't have.

Though, another problem I notice is at high sweep, the VF-1's wings are too far over the wing for the ailerons to move down, due to the engine nacelles. This would severely limit its ability to control itself at high sweep, sans thrust vectoring. Given, you'd be unlikely to see it at speeds low enough to warrant full range of motion.

Do we see the VF-1 do large maneuvers at high speeds without verniers? Supersonic maneuvering using control surfaces doesn't allow for the sort of movements the VF's can make if they were designed for subsonic flight and it's possible that they switch to pure thrust to deal with super high speeds. Note how the YF-19 folds up its wings completely when in high speed configuration.

Edited September 18, 2009 by ChronoReverse

[IAD]

I thought the inboard panels were Fowler flaps anyway? (Like an F-14.) They wouldn't be used for pitch control. In any case, with the wings fully swept (high speed config.) my assumption would be that more than enough control could be derived from the surfaces out near the tip, due to higher airspeed. Plus, with the wings in full sweep, the pitch moment arm would be longer, allowing a smaller surface to provide adequate control.

Do I have to build a lineart-accurate 1/12 scale RC VF-1 to demonstrate?

~Luke