The 2nd coming of the YF-19, Part 2

[Jedi Knight]

I wonder if a combination of forward canards and thrust-vectoring could manage a longer duration of negative alpha? Even so, I can't see much point in that angle of flight anyway.

[Chet]

I wonder if a combination of forward canards and thrust-vectoring could manage a longer duration of negative alpha? Even so, I can't see much point in that angle of flight anyway.

Canards? Those are ducks, right?

[drifand]

Always did wonder if FSW designs are LESS stealthy than 'normal' designs...

[Sumdumgai]

Mmmmm, duck...

On subject though, I'm glad that the canards fold on the 19 toy rather than stick out the sides.

edit: oh, they fold! Dang, I mixed it up with the VF-4. I was looking at the Design Works recently and the toy pics and mixed them up. Thanks for setting me right on that. I hate mixing htings up.

Edited October 23, 2006 by Sumdumgai

[David Hingtgen]

The whole duck/canard thing actually is the reason they're called that on planes. Long story, but basically both ducks and canard-equipped planes look like they're flying backwards. To the French at least it would seem. And remember--the very first plane had both canards and warpable wings.

I too have read FSW is extremely unstealthy, but never any comment/reason why. Could be a myth like instability.

PS--Sumdumgai--the Yamato YF-19 canards don't fold, they simply rotate 180. Due to their extreme dihedral, when they're rotated 180 they closely follow the fuselage contour. A VF-4 however actually "folds down" its canards (that's both canon and on the SHE). The YF-19 officially seems to have its canards both shrink and fold UP flat against the sides of the "spine". That or they magically disappear--hard to tell from the lineart alone.

[ComicKaze]

As far as the YF-19 goes, I think you're right about it being just for aesthetics.

But I did hear/read somewhere that FSW actually make the plane incredibly unstable. I can't confirm that in any way, shape, or form. It's just what I heard. *shrugs*

You have to remember that that is not a bad thing in terms of flying as you would assume by the negative connotations of the word.

INSTABILITY IS A GOOD THING!!! You want jet fighters to be dynamically unstable - that's how you get them to be highly manueverable because it will be natural for the plane to veer away from a straight flight path against aerodynamic forces.

All modern jet fighters since the 70s are designed to be naturally as unstable as possible and they are kept undercontrol with fly-by-wire technology - computers that control all the various flying surfaces compensating for the instability in real-time.

Edited October 23, 2006 by ComicKaze

[David Hingtgen]

And as I mentioned, FSW isn't unstable and has been used on passenger biz-jets. It just happens that the two most famous FSW planes are unstable so a lot of people (and books, magazines) think they all are.

Also, planes that are unstable are barely unstable. The F-16 was designed with an alternate wing location in case the FBW couldn't be made to work, to make it a traditional stable plane. Move the wings 8 inches back, and it's stable. Alternatively, put a really fat person in the cockpit. Only a few hundred pounds up front will make an F-16 stable.

[Graham]

I too have read FSW is extremely unstealthy, but never any comment/reason why.

In the case of the YF-19/VF-19, it doesn't really matter if the FSW design is inherently unstealthy though as they have an active stealth system.

Graham

[Dante74]

Any new magazines out? I'm dying to see some new pics. Even the boxart will do.

[Graham]

Mags come out between 23rd to 25th of each month.

Graham

[Shaggydog]

Saying 'instability is a good thing' is obviously an oversimplification. I'm assuming 'instability' means that when you tilt the aircraft, it tends to amplify the tilt (continue to tilt further) rather than correcting back towards the flat (stable) condition (in electronics we'd call this 'positive feedback'). If this is the case, then a small amount of instability would be nice, given that you can incorporate electronics that will provide 'negative feedback' to prevent utter disaster. A little instability would theoretically give the plane the ability to maneuver faster. But, if the instability were too great, it would become increasingly difficult to design electronics capable of compensating, and you'd have a deathtrap. I would assume that David is correct: practical unstable jets are just barely unstable.

I had always heard that FSW automatically increased instability past the tolerable level, but I'm willing to accept that this information is incorrect if people can provide some references on it.

Edited October 23, 2006 by Shaggydog

[David Hingtgen]

I think part the issue is people confusing instability with divergence. (divergence is another long story about FSW, but let's talk stability)

Shaggydog's comment about trends is correct--stable and instable is all about what'll happen if you do something--will it correct itself, or further deviate--so long as you can prevent things from getting out of hand, a little instability helps it "deviate from the course" faster. All airliners are stable--if they pitch/roll/yaw, and you let go of the wheel--they'll naturally return to straight and level flight.

Now, when talking about stability in a plane, 99% of the time we're talking about PITCH stability. (Roll stability is determined mainly by wing dihedral or anhedral--and I think people are sick about me talking about YF-19 anhedral) Pitch stability is most important, mainly because the lift of the wings is the biggest force acting on a plane, excedding any wind or gravity. And pitch is also very important in turns, even more so than roll. (because anyone who's flown a sim or game or real plane, knows that simply rolling won't make you turn much--you have to pull back and increase your pitch to actually get around) So pitch stability is the most important.

Now, pitch stability of a plane is determined by a simple relationship:

Center of lift vs Center of gravity. "Wing sweep angle/direction" is not in the formula.

Center of gravity should be obvious. Center of lift works basically the same, but the force is up instead of down---aircraft tend to produce maximum lift at around 25-30% of the chord length (distance from leading to trailing edge). Now, sweep angle will affect center of lift and center of gravity, but indirectly:

To be stable, center of lift must be behind center of gravity. If center of lift is forward of center of gravity, aircraft is unstable. (If you've ever heard about "tail heavy" planes being hard to handle but manueverable---that's related to instability---moving weight aft is effectively the same as moving lift forward)

Now, center of lift can be affected by FSW in two ways:

The sweep angle itself, and the location of the wings (which also affects center of gravity).

Look at the YF-19 or X-29 from above. See how the wings are mounted quite far back? That's actually mainly to make it more stable than it otherwise would be. (X-29 is unstable, but not insanely unstable---by design, it was carefully tweaked to have the exact amount of stability (or lack of) that the designers wanted) By having the wings mounted far back, the center of lift (since the wings make the lift) is moved back. The farther back the lift (and farther forward the center of gravity), the more stable the plane is.

However, moving the wings back also moves the center of gravity back, since they're fairly large parts of the plane. But wings always make more lift than their own weight (a lot more, usually) so the net effect is moving lift back.

Now, sweep angle also affects center of lift. Lift tends to be concentrated inboard, so the location of the root is more important than the tips for affecting center of lift. But, sweeping the wings back will bring the center of lift back, and sweeping them forward will bring it forward. Usually the sweep angle and wing location tend to "average" out the affects of each other---swept-back wings tend to be mounted forward, swept-forward wings tend to be mounted back.

So all that together? Basically, it just averaged itself out. BUT, there is one big factor that does tend to lead to FSW being easier to make unstable:

Engine weight. Engines are by far the heaviest thing in a plane, proportionately (and sometimes absolutely). And with few exceptions in FIGHTER planes, jet engines are in the rear. And having big heavy engines in the rear will bring the center of gravity back.

Now, most planes will be able to easily compensate--look at the F-14 and F-15. Very large engines in the back, yet still stable without having odd proportions. However, with FSW, since the wings are typically mounted a bit further aft, you're going to end up with more weight at the rear, and will generally be less stable. Note, LESS stable. Like how a 737 is less stable than a C-5. They're both very stable, but there is a difference.

Now, you'll note that the Su-47, X-29, and YF-19 all have their wings mounted far aft. The YF-19's is probably just to look cool, or copy the X-29. The X-29 and Su-47 do that to bring the center of lift back to counteract the canards. Otherwise they'd be *very* unstable. Canards actually will have a bigger effect than almost anything else to instability, far more than FSW IMHO. Moving the wings back pretty much counteracts all stability affects of a FSW. But moving the wings back can't alone counteract the combination of FSW AND canards. (canards generally move lift forwards)

So all together, I'm basically saying: it's not so much the SWEEP of the wing, it's the POSITION. You can easily make a plane that is very unstable, with swept-back wings. Just move the wings forward--that's how they made the F-16. Forward swept wings will move the center of lift forward a bit, but not enough to completely change a plane from stable to instable. If you took the canards off an X-29 or Su-47, they may very well be stable (or close to it) with their current wing position. If you moved the wings even further back, that could also make them stable. The X-29 and Su-47 were designed to be about as unstable as could be controlled, and a big part of that was the COMBINATION of FSW and canards. And I think the canards are an even bigger factor than the FSW in their instability.

I'll try to update this later with some images, but I have to go get supper now.

Basically--wing sweep, wing position, and canards will affect pitch stability the most. (since center of gravity is harder to change, and almost all jets have the engines in the rear--there's not much to mess with, the overall configuration is fairly set).

But, if you COMBINE the least stable options all together, then you will almost certainly get an unstable plane. The X-29 and Su-47 are examples of "every possible way to reduce stability combined". But FSW alone certainly isn't enough. It's just the most visible. Everyone notices the FSW, few people notice the canards. X-29, YF-19, and Su-47 all have canards, and are unstable. (we presume the YF-19 is). The HB-320? FSW, but no canards--and stable. The Ju-287--FSW, no canards-and stable.

[JELEINEN]

Graham: can we assume that this will come with its own stand adapter pieces like the 0 did?

[David Hingtgen]

I think we already saw a stand adapter clipped onto the "codpiece" in the first set of "painted plastic" photos.

[JELEINEN]

I think we already saw a stand adapter clipped onto the "codpiece" in the first set of "painted plastic" photos.

Ah, I don't recall having seen that pic (and I've been following these threads all along). Answers my question though, so thanks.

[Briareos]

I think that picture came from the thread on Macrossnexus.com. The discussion jumped over there when the site got hacked.

Newbb posted this on Sept 6th:

<quote>

I hope these haven't been posted yet but its new to me.

http://www.moeyo.com/2006/09/post_1110.html

http://www.moeyo.com/2006/08/post_1001.html

</quote>

Concerning that stand attachment. I wonder how stable that attachment is. After all it's attached to the cod piece that swings down on top of the landing gear.

Other concerns of mine.

The trap door on the legs that allow the arms to hide in fighter mode tends to be slightly open in alot of the photos. I hope they fix this.

The forward swept wings have small tabs that seem to the main body in fighter mode.. But how do they stay up in gerwalk mode?

Drew

Edited October 24, 2006 by Briareos

[Nani?!]

well whatever we see, we'll see in a couple days~

I also hope they finally let the cat out of the bag with the 21!

[David Hingtgen]

Actually the pic I reposted is from post 1, page 1, of this thread.

[recon]

issit me or the red looks abit pinkish, would have prefer them to be a darker red.

The additional gimmick looks like foldable intake covers from the looks of the pics posted.

Cheers

Edited October 24, 2006 by recon

[Nani?!]

issit me or the red looks abit pinkish, would have prefer them to be a darker red.

Cheers

If anything I think it has something to do with the lighting of the picture...

Edited October 24, 2006 by Nani?!

[jenius]

Where are the new pics??? That's it, this thing is Vaporware. Yamato just loves to drag out the YF-19 to get people psyched and then doesn't actually build the toy. It's the 1/72 Fast Pack version all over again.

Nah, I'm not really serious.

[Knight26]

I doubt that the intake covers fold in. That impingment on the intake, see the lumps up in the inner corner, would prevent such a thing.

[Nani?!]

I doubt that the intake covers fold in. That impingment on the intake, see the lumps up in the inner corner, would prevent such a thing.

yup. foldable intake covers would be a pain anyway to fold back to closed position. I rather them concentrate on taking out the unsightly gaps and tampo printing all markings including the macross kite.

[promethuem5]

I wouldnt get too worried about the red yet anyways... red is notorious for not coming out quite right in digital photos.... I'm psyched with every pic I see.

[Graham]

Guys,

Attached are the latest YF-19 pics from the new December issues of Hobby Japan & Dengeki Hobby magazines

Click on thumbnail to enlarge

Click on thumbnail to enlarge

More of the features are revealed, which are:

1) Removable head cover and visor, as shown in the anime when the YF-19 is undergoing maintenance.

2) Removable gunpod magazine as shown in the anime. Some MWers already guessed this feature.

3) Display stand can attached to Battroid mode as well as fighter mode.

4) Anime accurate two-piece opening canopy,

Graham

[myk]

Thanks for the pictures Graham.

This is looking to be the best $200 I ever throw away..

Edited October 26, 2006 by myk

[DARKWIND]

This just makes me even happier about pre ordering it! ! !

But just a couple questions, how will sturdy the hip joints be?

Also, what is the deal with the elbow joints?

It looks like a killer design with very good details.

All I have to do now is sit back and wait for to ship to the house. . .

Edited October 26, 2006 by DARKWIND

[Graham]

Hip joints are very sturdy. Twin left & right solid metal bars, so no worries.

Also, just to preempt any concerns, the rotating canards are not made of ABS, but of POM or some other type of tough plastic and are much sturdier than they look.

The special elbow joint is to allow the correct positioning of the arms in fighter mode.

Graham

[isamu_dyson]

can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait can't wait

it's incredible ....

[eugimon]

oooh, thanks for the new pics! I really dig the head detail... and yet, I have fear that the "cap" will fall off easily a'la the initial 1/48 nose cone....

[DARKWIND]

Thanks for the info again I'm sold IMO another Yamato Home Run!!!!

[UN Spacy]

How many are you going to get Graham?

[Graham]

Probably just 3. As much as I'd like more, my finances are not up to it at the moment with my present crappily paying job.

Graham

[UN Spacy]

The special elbow joint is to allow the correct positioning of the arms in fighter mode.

Graham

Is that also going to be made out of a tough plastic?

That joint looks a bit fragile.

[jenius]

so you're saying it's not vaporware

Oooh I like it a lot... although I do find some of the gimmicks pretty... gimmicky but I'd much rather have it that way then sitting there thinking "couldn't they have just added x?"