Fleet Yaw In Action (And AK-74 Goodness, Too)

Previously, we talked about the fleet yaw problem, and the challenges it presents to infantry rifle ammunition developers, and how those challenges have been met with improved projectile designs. However, what we haven’t seen is real-time video of fleet yaw in action. For that, we turn to Larry Vickers, and a recent video he published on the AK-74 rifle:

The whole video is well worth watching, but for those looking specifically to catch fleet yaw as it happens, go to the timestamps 0:26 and 1:06. Very evident is the bullet, which is fully stabilized by the in-spec Bulgarian barrel, yawing violently due to the turbulent forces acting upon it at the muzzle. This behavior continues for about the first 50m of the bullet’s travel, after which point the projectile settles down.

This is not to ignore, of course, the rest of the video, which contains some great high speed footage of the AK-74’s very violent operating cycle.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


  • Giolli Joker

    AK-74 shooting full-auto flawlessly with no dust cover but with no additional foreign material inserted in the bolt path: ok.
    AK-74 shooting full-auto flawlessly with no piston tube: holy cow!!!
    I think my face went from mildly interested to wide-eyed surprised…

    • Riot

      Seeing an AK with the piston exposed like that is weird.
      Really cool but still weird. Does show how the modification valmet made to the piston will help really well, I think.

  • Very high quality production on that video. I agree with joker, its surprising how well that gas system worked without a tube. It looked like it was not going to seat properly at first.

    • Cal S.

      There is one point where it clearly ends out of battery, *just* before the camera break where it comes back looking just fine.

      Editing shenanigans.

      • Giolli Joker

        I’m not that sure about it.
        You may be right, but it seems to be out of battery more than once, in every single shot indeed, then it finds its way.
        Miracles of a loose fit, probably.
        Still cool.
        Really no need for cutaways…

      • Grindstone50k

        Then there’s the part where it goes into battery a couple times in a row.

    • BrandonAKsALot

      The gas tube is not so much a gas tube as a piston guide. The piston gets the impulse it needs to cycle in the gas block. The tube also helps to keep gas and carbon away from the face.

  • Steve Truffer

    Something seems rather off with that AK. 45 degree block, sidefolder, and full giggle? The only country I’m aware of that carried the 45 block into sidefolder production was Romainia.

    • BrandonAKsALot

      It is a Romy and it appears to have had a sidefolder added.

    • Arsenal AK-smithed it into being, I am sure.

  • Tom

    I am wondering if the yaw is caused by the muzzle device. It would be interesting to repeat the test with the device removed. I know serious group shooters don’t want them on their rifles.

    • Heretical Politik

      Had the exact same thought.

    • The yaw would happen regardless of whether there was a muzzle device or not, but I also thought it might be possible that the brake was exacerbating the yaw.

      Which actually is not a bad thing. You want the bullet to strike the target at a more severe yaw angle, not a less severe one.

    • Changing or omitting the muzzle device would change the amount of yawing, but it would not eliminate it. It could be better or worse.

      Two supposedly “identical” (say, consecutive rifles off the line) rifles could be different, as could two “identical” (say, bullets from the same lot), based on infinitesimally small production differences.

  • Joshua

    Last time I checked bullets aren’t supposed to tumble until they strike their target…not during their flight to the target.

    • Giolli Joker

      One would expect arrows to fly straight as released as well, reality tells a different story…

      • Joshua

        Last time I checked arrows don’t flip end over end either. They may wobble a bit, but they do not do backflips.

        • Giolli Joker

          What I meant is that stabilization apparently is not as instantaneous as we might believe.

          • CommonSense23

            I think what he is getting at is that appears the bullet isn’t so much yawing as going end over end.

          • Joshua

            Exactly. I posted a .gif. Awaiting approval that shows the bullet doing backflips and over end.

            It’s clearly keyholing.

            Best part is everyone Saying that it’s normal.

          • heynorm

            Yes a gyroscopically stable bullet does this, it is not going end over end, it is wobbling off center the ogive and the spin will stabilize the projectile within 50m. It is less noticeable with most projectiles than that 7n6 round it is a very long rd. It is 53gr but .99″ long, which is as long as a 77gr smk .224 pill. Over stabilized bullets do not do this. Like most 1-7″ ARs.

          • Joshua

            Look at the .gif when it gets approved then get back to me.

            Bullets should not flip and over end. The .gif makes it very clear it is keyholing.

          • Check out 1:06; it’s very clearly fleet yaw.

          • iksnilol

            Not really, you clearly see the bullet wobbling/going back and forth. Not keyholing.

            Optical illusions and all.

          • According to the paper released in fleet yaw, this happens to all bullets, regardless of how well-stabilized they are.

          • Miles

            That is correct. There are slow motion films of artillery firing where this is more easily seen.
            What is being seen is the change between a bullet rotating while constrained by the bore of the barrel and it’s rotation around it’s center of mass once it’s in free flight and subject to centrifugal force.
            Since there’s no such thing as a perfect bullet, or perfect barrel, the bullet isn’t traveling down the bore of the barrel in perfect alignment with it’s center of mass.

          • It is not keyholing. 🙂

          • nadnerbus

            It’s hard to tell from such a short amount of time. But at the end the thing is almost vertical, and you can see the shock wave double in width because of it. If fleet yaw can be that wild and still bring the bullet back into stability after fifty yards, that is pretty impressive.

        • It isn’t tumbling end over end. That’s an optical illusion caused by the yaw.

    • Weaver

      Bullets don’t come out straight. It isn’t tumbling either. Bullet as we know bullets have a spin to them which stabilizes them but it doesn’t “fully” stabilize them. There is always going to be some sort of wobble as the bullet is flying.

    • Fleet yaw isn’t tumbling, exactly, it’s a yaw induced by the turbulent exit of gases from the muzzle. The bullet is still stabilized, and will settle down, but for the first 50m or so, it will be taking like that.

    • Here you go, a GIF of the fleet yaw precession:


      It is apparent that the projectile is not keyholing.

      • Giolli Joker

        I guess that the frames in the first gif show one of those not so unequivocally clear things that once your brain decides that it’s in one way, it’s very hard to see any other interpretation.
        The second gif is clearly, unequivocally yaw.

        • I agree that the first looks much more like end-over-end tumbling, but pay close attention to the meplat (tip) of the bullet, which stays highlighted due to light reflecting off it. It is nose-forward the whole time.

          • Giolli Joker

            Yep, apparently while getting out of the picture frame the bullet is trying its best to perform Pugachev’s cobra… it should be a Russian thing. 🙂

          • Hypermaneuverable Russian bullets can shoot down aircraft diving down at them… And they can supercruise. 😉

    • Gyro stabilization takes a finite (but incredibly short) time to damp out the wobble caused by a combination of factors (muzzle gasses pishing the bullet slightly asymmetrically, less than perfect balance, etc.)

      So, yes, bullets *do* “settle down” a short distance downrange, even when they have the appropriate twist rate, and they do not “tumble” again until velocity drops to the point that gyro stabilization no longer overcomes other effects (although that spinning top will try to stay pointy end forward all the way to the end.)

  • Jeff Smith

    There’s nothing better than mechanical porn. This video is mesmerizing.

  • iksnilol

    This gave me some ideas regarding an ultra-lightweight AK.

    • Giolli Joker

      As long as you wear gloves. 😉

      • iksnilol

        I don’t know, I hold the rifle in the corner between the receiver and magazine. So I think I could get away with removing the handguards completely. Should save some weight that.

  • Bob

    I’m pretty sure the key-holing is caused by a worn out barrel. I’m sure Arsenal only uses that gun for demos anyway.

  • MattCFII

    This fleet yaw like Nathaniel says, not tumbling, not necessarily a shot out barrel. 7N6 is a very long bullet for the weight that it is resulting in a low sectional density (for the same length in 5.56, it would be more in the 70 grain range instead of 52), making very prone to these early wobbles. All bullets do this to an extent, but 7N6 is especially prone to it with the steel core bringing down the density for the length. If you have a 74 that somebody suspects as being shot out be sure to actually shoot it over 50m to confirm.

    Snipers and other long range shooters talk about bullets “going to sleep” where accuracy actually improves because this wobble has stopped and that is normally after the first 100-200 yards.

    Re: no gas tube, Ultimak has had a similar video for years showing the gas tube is really not needed most of the time on an AK, it is really more a guide tube for the piston than to help with gas pressure, hence why most AKs run fine with vent holes in gas block where the tube attaches or in the muzzle end of the gas tube.

    • Yeah, I’ve seen some American parts kits builds where the piston doesn’t like to go home without the “gas tube” – I’ve always suspected their issue was a subtle misalignment.

      • Internet Browser

        My Arsenal wouldn’t be able to shoot without the gas tube due to its degree of gas block cant. It’s not an American parts kit thing, it’s an acceptable AK tolerances thing. Some AKs are straighter than others. As long as the rifles function normally, it’s not considered a big deal.

  • Mister Thomas

    Absolutely amazing video. Thank you for posting this here, I hadn’t seen it until just now.

  • Zebra Dun

    That was an amazing video!
    The bullets and projectiles of almost all rifles do this yaw some right down to the target yet make round holes.
    An arrow wiggles like a snake on fire just after being fired and then settles down after the feathers takes over.

    Has anyone ever found out if an AK will shoot while fully disassembled?

  • Zugunder

    Just when you thought you understand ballistics pretty well you see sh..t like that. Amazing.

  • Patrick M.

    Larry’s show has been providing some incredible footage lately

  • What the difference between keyholing and fleet yaw.

    • Hi John,

      Keyholing is where the projectile has been insufficiently gyroscopically stabilized (which could be due to an insufficiently tight twist rate or a shot out barrel), and therefore tumbles end-over-end in flight.

      Fleet yaw is caused by the effect that turbulence plays on a bullet as it is leaving the muzzle. All bullets suffer from it to a degree, because there is always pressure at the muzzle of a firearm. The result is that the bullet is stabilized, but being rocked by turbulence, causing yawing. The projectile naturally wants to fly point-forward due to the gyroscopic forces imparted on it, but the turbulent air around it causes it to rock, or precess, changing its angle of attack in the air, which follows a dampening circular cycle due to the projectiles rotation. This effect is most dramatic at ranges below 50m, after which point the gyroscopic forces on the projectile sufficiently overcome the initial turbulent fleet yaw effect to achieve more stable flight.

      At least that’s my understanding of it, John.

      • I wonder if a muzzle attachment would help reduce gas turbulance, like a muzzle brake.
        It would possibly explain the incease in muzzle velocity when using a brake.

        • I’m really not sure, as that subject is well beyond my expertise.

      • FarmerB

        Well, I thought the main cause was (also in a reply below):

        1. when in the barrel, the bullet rotates around the centre boreline of the barrel; and

        2. upon exiting and in free flight, it rotates around its center of mass of the bullet.

        Since barrels and bullets aren’t perfect, these two centre lines are not the same. Hence it’s ‘upset’ upon leaving the barrel (like tapping a spinning top).

        The bullet is still stable – just momentarily upset (and a muzzle brake will not fix it).

        • I believe that is also a factor, yes. Excellent comment.

    • Tassiebush

      Keyholing is loss of stability as rotation slows and fails to stabilize bullet while fleet yaw occurs from turbulence of being fired before the bullets stabilize.

      • And suddenly going from mechanical stabilization (bullet in bore, around mechanical centers) to free flight gyro stabilization (around CG centers) is *not* instantaneous.

        That gyro (the spinning bullet) has to “yank” the bullet into a CG centered stabilized flight.

  • Brassfetcher’s greatest strength is in the tests he performs, not his analyses, unfortunately. There are several things he says in the article you link that are misleading or not true. For example, he states that the 1/14 twist barrel of the original pre-602 AR-15s was a major factor in their terminal effect – actually, over normal distances fleet yaw would so totally override any instability of the projectile due to the twist rate that you’d see virtually no difference. He knows about fleet yaw, so why he doesn’t recognize this connection is something I can’t account for.

    He then implies that the short-barreled rifle is suffering substantially in terminal effect versus the rifle. This is a common assertion, but his own analysis sheds down on it. First, fleet yaw isn’t really that velocity dependent, it’s more dependent on the distance from the barrel that the projectile strikes the target. So who cares if the SBR has a shorter barrel, if it’s just as effective over short distances? Sure, an SBR is not the all-purpose device that some believe it to be, but it’s also not the squirt gun in terms of lethality that some think it is.

    • Darkpr0

      I agree that some of the assertions in the article are not perhaps as well-informed as they might be, but I firmly believe that the base evidence is good: the supersonic flow around the bullet and the study of a bullet’s yaw angle by range in particular. The rest of the article I could take or leave, but it certainly does give some food for thought.

      Taking the evidence alone, I more or less came to my own conclusions. As for the SBR, I certainly wouldn’t want to be hit by it. But I do believe there is sufficient evidence to say that at “some” range the wounding pattern of 5.56 will go from violent yaw yielding fragmentation to yawing while the projectile stays more or less together (albeit deformed, in all likelihood). I also believe there is sufficient evidence to tie the range at which that happens to parameters of the projectile as it leaves the barrel, some of which can be controlled (barrel length, powder charge, calibre, bullet weight and geometry in particular) and others of which can not. I personally believe that the most effective wounding method for 5.56 is fragmentation on an unarmored target (armor changes the problem completely for sure), and that’s where it shines. So, if I proceed under that assumption, the ‘ideal range’ for me to use 5.56 is whatever the fragmentation range extends out to. In most cases, I happen to want that range as far out as possible for flexibility and I don’t mind some extra length, so I go with a 20″ barrel. If the situation demands a shorter rifle, then that adds a new constraint to the equation and stuff goes out the window.

      The M4 is reputed to have a fragmentation range of 50m, though I haven’t crunched numbers or seen hard evidence to confirm that. If it’s true, it definitely does the job: compact, urban-warfare platform with outstanding performance up to typical ranges. It can extend past that range so long as the yawing effect produces sufficient terminal results (and I’d say it does, especially if the ‘shoot-to-wound’ theory is taken into account). A super-short like the Colt Commando is also something I wouldn’t want to get hit by, although I would suspect that it may not show fragmentation at all. If that does the job, though, then it does the job.

      Problems like this are why I’m such a proponent of bullpups, particularly among 5.56. To get (what I believe is) the best performance out of it, you want velocity where you can get it, and if you can’t sacrifice mobility then the bullpup design really starts making hay over an equivalent-length conventional layout.

      • I don’t have a problem with his assessment of yaw, but I am commenting on his analyses in general. John Irvin sometimes writes things that don’t seem to gel with the tests he’s done.

        Fragmentation is clearly the most violent and effective wounding methods for a standard FMJ round, and the 5.56mm is adapted well to exploit that mechanism. An SBR will definitely reduce the fragmentation range, but not as much as has often been claimed, and even if the projectile isn’t fragmenting it may still be highly effective thanks to remote wounding effects and a large, fast-expanding temporary cavity, both of which are caused by high velocity (>1,800 ft/s) projectiles.

        If we use 2,000 ft/s as a minimum fragmentation threshold, just as an example, we can see how much the M4 loses vs. the M16. Graphing M855 over these distances, the M4 retains 2,000 ft/s out to 290m, whereas the 20″ barreled M16 retains the same out to 345m, a difference of 55m at the very edge of the rifleman’s combat effectiveness.

        I address a lot of these myths in my article from my old blog, The New Caliber Mafia. Might give it a read:

        “Now, we can plug this figure into a ballistic calculator and see if our commenter is right. I am using the above velocity (2,611 ft/s), a ballistic coefficient for M855 of .151, a zero range of 25m, a maximum range of 500m, a range increment of 1m, and a minimum fragmentation velocity of 2,140 ft/s.** The result is that the bullet reaches minimum fragmentation velocity at 154 meters. If a threshold of 2,300 ft/s is used (which I’ve seen quoted a few times), then it reaches that velocity at 101 meters. Only if a threshold of 2,500 ft/s is used does the fragmentation range drop below 50 m. This is not the minimum threshold of fragmentation, but the upper bound minimum velocity at which the jacket may split along the cannelure.

        Keep in mind, an M4 that clocks velocities this low is considered unserviceable and should be removed from service and fitted for a new barrel. If a more reasonable velocity of 2,970 ft/s* is used, the M4 Carbine stays above the 2,140 ft/s until 260 m, and above 2,300 ft/s until 207 m. Even if a threshold of 2,500 ft/s is used, a muzzle velocity of 2,970 ft/s gives a fragmentation range for the M4 of 143 m.”

        • Darkpr0

          In fact, I have already read this article. Our numbers are even quite similar at the top: You quote a familiar frag pattern at 2900 ft/s, and the numbers I ran with come out to 2880 ft/s. The place where we take different paths on the minimum velocities to achieve that: I stick with 2880 and you move down to 2140. I can understand the reasoning, but I was attempting to identify the ranges where 5.56 outright excels. I would agree that fragmentation can take place beyond that range, but what resources I can find suggest that it will not happen “as often” (massive nebulous quotation marks here due to lack of a statistical study that I can find). I think there’s also a good argument to be made for making the cutoff at the 2523 ft/s mark because that’s where we start seeing catastrophic failure of the bullet’s structure on impact (based on the photobucket scan). I might throw some numbers at that when I find my calculator again.

          The problem comes in with ‘reliability’ of the fragmentation. One would expect the effect’s frequency to be related to the object it hits, and the bullet’s rotational energy at impact (assuming the system remains the same). You could probably assume a standard distribution among the rotational postion/velocity on impact, but judging how often you’ll hit bone versus squishy bits versus nothing is probably a lot more problematic. How those affect the bullet at varying impact circumstances is probably opening a can of irradiated, fire-breathing worms, and probably best left to someone with a much bigger ballistics gel collection than me.

          I think, on the whole, you and I agree on more than we disagree on, we’re just looking at different bits of the problem: what is acceptable performance versus what is optimal performance.

          • I’m glad you’ve read it.

            There’s a very big problem with using “minimum” velocities: Fragmentation doesn’t have a threshold, the extent to which a projectile fragments decreases gradually as velocity goes down. So the bottom has to be set somewhere. A bullet that merely splits into two pieces may still expend a lot of energy into the target, while producing two wound channels substantially improving the chance of incapacitation, so discounting this level of effectiveness is misguided.

            Further, the type of bullet, its jacket thickness, construction, and even manufacturing variances all help muddy these figures to the point where “easy” answers are impossible. Because of all this variation, saying “I will only use 20″ barrels because I want the extra fragmentation range” is not well-advised.

            You and I certainly agree on some of what we’ve discussed in the comments. I used to be much hotter on bullpups than I am now, because I liked the extra compactness. However, I think their disadvantages are hard-to-grasp, but numerous and highly relevant, while their advantages are easily quantified, but not nearly as relevant as often portrayed.

          • Darkpr0

            I’ll agree that stratifying the problem results in the loss of continuity for the end picture, but without a nice swath of statistical data to plough through, it’s the best I can do on limited man/calculatorpower. And I agree on bullet construction as well, it plays a huge role. I go with calculations based on military FMJ, but the reality is that I’m only barking up one tree in a forest so there’s definitely that to consider. And while I wouldn’t say I only use 20″ barrels, but they are my preferred form of 5.56 given that there is a terminal performance advantage, and the disadvantages of it generally do not cause me any undue grief. If I had a serious problem at 400m and all I had was a 14″ barrel, I’d still be lobbing lead downrange with the expectation that any impacts would cause a certain amount of distress for the target. It just wouldn’t be my ‘go-to’ if I had free choice of whatever I wanted.

            As for bullpups, I feel like they are in a state of stagnant flux, for all the sense that makes. The bullpup design as it is has some underlying assumptions… Fully mechanical actuation and ignition, traditional ammunition type and mag type… This imposes a lot of constraints on how it has to work and feel. I feel that if one of these obstacles was broken down (say… caseless ammunition, or electronic ignition) bullpups would very quickly pick up steam. As it is, though, they’re all still chasing the same problems of 40 years ago: ergonomics, reliability, and safety.

            And how-to-feel-like-an-AR-ism. 🙂

          • I’ve heard major objections to caseless and electronic ignition. Caseless in particular is not likely to mature until materials science is much, much more advanced.

          • Darkpr0

            Agreed. We’re not there yet, but making strides towards them. It’s nice to see the occasional outlier like the VEC-91 go for the gold, even if it doesn’t work.

  • Tassiebush

    It probably isn’t a problem if the bullets ultimately achieve stability, but I wonder if porting the barrel to bleed of gas would reduce this effect?

  • Nope. Watch the meplat.

  • Rodger Young

    seriously, get a copy of Hatcher’s Notebook, sober up one night and read it.

  • Grindstone50k

    Oh. My. God. That was so sexy.

    Ugh, if 5.45 surplus wasn’t banned, I’d by a 74 so fast right now.

    • You can still get both surplus 5.45 and unbanned civilian production at reasonable prices. Not popcorn cheap like it was fifteen years ago, but still cheap. Even Silver Bear is pretty cheap, if you watch for sales and duy by the case.

    • I just bought a couple cans of surplus for less than commercial ammo. It’s a shame that it’s not $.12/round like it used to be, but it’s far from “banned”.

  • Guido FL

    With soo many “experts” voicing their expert opinions I’m in awe.

  • fred flintstone

    Fleet yaw, learned a new term!

  • fred flintstone

    Having worked in high-speed film (Fastax) trust me, shooting this with high-speed video cameras was quite the task and was done beautifully. FWIW, when I ran the Fastax for the first (and last) time, when done shooting, opened up the 16mm camera and there was nothing but film turned to dust.

  • Doom

    Well, I think I just found out that I was gay for AK’s. I mean I knew I loved my SGL 21, but that was just exciting watching all those parts move. hnnngg!

  • scaatylobo

    HUH ?, Vickers is boring to be polite.
    This video was a waste of time.
    If this is your cuppa ,go for it.
    Sorry I wasted the time to see the end —- it was as ‘exciting’ as the start.

  • Brian M

    I didn’t know they posted porn on TFB.

    Wait, wasn’t there supposed to be more about the Fleet Yaw Problem?

  • disqus_NQ1fmfqOTw

    I use a YHM Phantom 556 Titanium suppressor on my 105 clone, AK74s and my 5.45×39 Remington Model Seven (not a factory rifle). I have never had any baffle strikes. Shooting paper with the various barrel lengths of a RPK74, AK74, Model Seven, 105 clone & an AKS74U, from 10 yards to 500 yards, I have never noticed anything but perfectly normal holes. I have an AK74 build which started as an original barrel parts kit from a rifle with much wear. I have put this rifle through paces in various classes, adding another 6K or so to its round count. It is no longer a 4 MOA rifle, but the holes it produces are still round.
    Could it be that Vickers is demonstrating the 74 operation from post-dealer samples (at least two different rifles are shown in the video) that have been run hard in training classes? That slow-mo bullet sure looks like it is tumbling to me. It reminds me of my first transferable, an AC556 I had to get rebarreled because it was tumbling bullets at 20 feet.

  • Lyle

    Why are we calling it fleet yaw? Where’s the fleet? Who’s fleet is it? How many, of what, make one of these fleets? Wouldn’t “bullet yaw” or simply “yaw” suffice?

  • Cattoo

    I kept expecting Money by Pink Floyd to start playing.

  • Johnny McNair

    All this is really irrelevant since the end result is a really good weapon. I’ve built four and they all are awesome. They are light and shoot well…they are all very accurate. The wood is excellent for a past war weapon.

  • T Sheehan

    The physics, in my minds eye, of the bullet settling down on its trajectory, seems based on 2 metaphors where both touch on the inefficiency and lost velocity caused by fleet yaw:
    1. The boat tail catching the expanding propellant gasses is equivalent to launching a football by a slap in the ass as opposed to applying both force and torsion from a balanced center point (i.e. A normal throw from the center & laces), imparting the wobble because all the pressure continues to hit it in the ass, “shoving” rather than “dragging” the round from the forward point of the round (I’ve never heard of this type of round existing, however).
    This gives rise to inefficiency number:
    2. The ass of the round bouncing back and forth between the walls of supersonic air resistance has GOT to be robbing it of energy during the yaw process before settling. Picture your dog wagging its tail, and put your hands on both sides, and slowly closing them together (as air pressure that has been displaced would do). That action is responsible for imparting stability, but imparts friction and abosrbs energy.
    So that leaves me with a question: if you remove fleet yaw, how much velocity could be regained just for distance/range purposes? I am leaving the terminal energy/lethal tumble argument out of that question.

  • buzzman1

    Well the bullet is traveling at close to 3000 fps so some fleet yawl is understandable.

  • Kivaari

    The yaw is not a good thing.