Good lord, you're right. I tought it's some compression artifact at first. I had other plans, but now I'll try SpinLaunching some Kerbals this weekend.You can't see it in the gif, but you CAN see it in the Youtube video, that sucker be TUMBLING
Dude it is the Everlasting Gobstopper of engineering comedy. I was discussing it with my cousin pretty much all night last night and it became clear that Spinlaunch has made no provisions for the hypothetical counterbalance that uhhh they're totally going to want to let go of once their "11,200 kg" payload isn't being constrained in a 45 meter arc at 450 RPM. 11,200 kg experiencing 10,000g has the effective weight of an Aframax crude tanker. In order to, you know, not put a bearing load equivalent to an Aframax crude tanker on your driveshaft you would ideally let your counterbalance go the same time as your payload but unfortunately they appear to have planned a control room there. Which is probably okay because frankly? Flinging eleven metric tons into the ground at Mach 7 is not ballistically dissimilar to Tunguska. So I guess you could imagine a structure capable of carrying an unbalanced load equivalent to an oil tanker through 90 degrees at 450rpm but that's the sort of phrase you don't usually see this side of the event horizon. The best part is you've got a discus with an effective weight that makes the top ten on this list but you think it's a javelin, and once it "breaks the seal" your three-Goodyear-blimps-worth of hard vacuum is going to eagerly slurp down the incandescent star you are making right at its mouth so if nothing else, at least the electromechanical apocalypse you've instigated will happen in a 6000k environment.
I'm in biotech so I have a lot of experience with centrifuges of various types, though almost all small. If you unbalance a centrifuge that weighs, say, 50 kg, by a few grams and you run it at 2,000 g, you get some serious wobble. You let it run for more than a few seconds and the machines all set themselves down, because you'll fuck the bearing quickly. You get to 100,000 g and then you're talking about balancing to the hundredth of a gram. Obviously it's all relative, and here I'm sure they've designed to the known forces and expected changes in angular momentum, but I just don't see how you don't break the rotor arm here. Maybe a sliding counterweight on the opposite arm that can be brought to the center immediately upon release? You could change the moment of inertia pretty quickly that way.
My mother used to point out the patched hole in the ceiling at one of her labs where a grad student loaded up an ultracentrifuge without a counterweight. I guess it was easier to do in the '60s. LOL they have done no such fucking thing. What cross-section shall we pick for the arm? How 'bout 2m? 10,000g x 11,200 kg x 9.81 = 1.09e12 n /2 = 500GPa. Know of anything with a tensile strength of 500GPa? 4130 chrome moly is at 0.435 GPa so normie shit is straight out. Kevlar 49 yarn is at 0.235 GPa (with 3% elongation - that's 14cm on this rig). Carbon nanotubes? 270-950 GPa! Hey we have a solution! Except they don't exist for lengths longer than a stack of dimes and we haven't exactly broached the subject of our release mechanism yet. If a cursory examination of the Newtonian mechanics at hand invokes unobtanium, we can safely argue that absolutely no analysis such as this has been shown to investors or shareholders. Somebody on the company either has a rich daddy or serious kompramat over Airbus Ventures, Kleiner Perkins or both. "Effective weight equal to an ocean liner" plus "brought to the center immediately" is a delightfully humorous concept. Conservation of angular momentum dictates that to take the counterweight force to zero by pulling it towards the center, velocity must go to infinity which, I mean, given everything else going on, why not? So now your gear motor must do more than sling a pair of ocean liners around at 450 RPM, it must also be capable of accelerating to light speed instantaneously. Or I dunno I guess you could do that and then hit your magnetic brakes in a futile attempt to absorb that energy. So what took you an hour to pump in, you now need to pump half of it back out as close to instantaneously as possible. Which I'm not going to do the math on but I'll bet it's in the neighborhood of having your facility struck by lightning.You get to 100,000 g and then you're talking about balancing to the hundredth of a gram. Obviously it's all relative, and here I'm sure they've designed to the known forces and expected changes in angular momentum, but I just don't see how you don't break the rotor arm here.
Maybe a sliding counterweight on the opposite arm that can be brought to the center immediately upon release?
Uh, yeah. These days every UC is programmed to go to low speed to sense the balancing before it ramps up. From what I understand there were many lab incidents that led to those engineering changes. Even if no one gets hurt, you're still out $80k when you have to buy a new machine, because user error voids the warranty.My mother used to point out the patched hole in the ceiling at one of her labs where a grad student loaded up an ultracentrifuge without a counterweight. I guess it was easier to do in the '60s.
Yeah every piece of lab equipment I've ever seen has been safe as houses... with the exception of the janky shit bought out of China that will totally kill you given half a chance. My wife's college had some industrial herb grinders that would absolutely dispose of a body by accident.
You know, sometimes one comes face to face with one's shortcomings, and this might be that moment for me. When faced with a factset that doesn't add up, my reaction is almost always, "Well if I can see that this is bullshit in 2 minutes of calculations, then clearly I'm missing something." Techbros notwithstanding, my reaction is rarely. "Oh, easy, they're lying for money." I can be very credulous even at times when everything says to be the opposite.LOL they have done no such fucking thing.
If I hadn't had my very own "lolnope" moment with Theranos I might feel the same. But I mean https://en.wikipedia.org/wiki/ADE_651 That right there? is a dowsing rod bought by Seal Team 6.
Ah, a rookie mistake: you counterbalance your payload with a second payload, release 180 degrees later. And people thought a theorist can't engineer good. I'm mildly disappointed they aren't hiring anyone to develop inertia dampeners or cetacean tractor beams.Spinlaunch has made no provisions for the hypothetical counterbalance