Tag Archives: Ramps

Ramping Up Franz and Kinematics

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Simple machines are the basis of industry. Well, sorta.

A simple machine is a device used to change the direction or power of a force applied to something in the simplest manner possible. There are six devices classically categorized as simple machines: axles and wheels, levers, pulleys, screws, wedges, and inclined planes (obviously the best).

The reason I said they’re only sorta the basis for industry, though, is that the idea of simple machines is itself an oversimplification.

First off, take a look at wedges and screws. A screw is nothing more than an inclined plane wrapped around a cylinder. When you’re turning a screw, picture it inside the material—climbing up or down the ramp—as the screw turns. Wedges are just two ramps hooked up to one another, bottom to bottom, for use in transferring force perpendicularly.

Ramps make up half of the classical simple machines. Ramps rule, but we already knew that.

Then you come to wheels and axles and pulleys. A pulley is just a wheel and axle with a rope attached. It’s still super useful, of course.

At first glance, our final classical simple machine, the lever, is pretty distinct from the others. A guy named Franz Reuleaux, however, realized that, like the wheel and pulley, the lever is just a body rotating about a hinge. Reuleaux was also the one who figured out that the screw, wedge, and inclined plane were the same. Really smart cookie.

So all in all, you’ve really got two simple machines and four variants on the original list. And that’s the first issue with describing the classical simple machines as the basis of mechanical industry.

The second issue? There are a lot more than six simple machines. You’ve got four-bar linkages and cranks, for example. Our good buddy Franz identified hundreds of simple machines using his self-invented science of Kinematics, which we still use today. Way to go, Franz. Not bad for a guy born in 1829.

Nowadays, thanks to Franz and Kinematics, we actually consider joints the basis of mechanics, but that’s a story for another day.

The Incan Terraces

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The Inca are surely one of my favorite ancient cultures. Much of this is due to the unusual amount of research available on their building techniques and architecture. The pieces of their engineering I’ve been reading about lately are their terraces.

Terraces might be something of an opposite of ramps, but that just makes them more fascinating. Living among some of the steepest mountains in the world, the Incans had to improvise heavily when it came to all sorts of facets of their life. Their terraces did a lot more than provide flat areas for food production (though don’t get me wrong: that was just a little bit important); they also helped to control erosion and landslides.

In fact, much of Incan architecture was built to be earthquake resistant, and the terraces were no exception. They were so well built that, despite the Incan’s comparatively low technological level, their terraces survived from Pizarro’s conquest of their empire, totally forgotten, all the way up to the twentieth century, when they were rediscovered.

Do you think anything we build today would last that long without maintenance? Not likely. This workmanship stretched all the way through their construction, too.

The Incans by no means had a monopoly on agricultural terraces, of course. Terrace farming has arisen independently in dozens of cultures worldwide, with almost as many individual styles. It’s almost certainly the most efficient method of farming in the mountains.

The most famous are almost certainly the rice terraces of the Philippine Cordilleras: they’ve actually been declared a UNESCO heritage site. You’ve almost certainly seen images of them before. They’ve been farmed continuously for something like 2000 years, which is absolutely crazy. That’s not just architecture, it’s a way of life.

Switchbacks: Ramp Diversity

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There is one kind of ramp I absolutely love, except when I’m using it, in which case I absolutely hate it. That ramp is the switchback.

Anyone who’s done much mountain driving learns to hate switchbacks, even though they’re some of the most cost-effective engineering tricks we have in the mountains. (Much, much cheaper than tunnels, that’s for sure.) Truckers especially hate them. I’ve known some who will go hours out of their way to avoid them. I think gearheads are the only ones who enjoy them.

One of the craziest examples of the breed is the Stelvio Pass in Italy. It’s one of the highest roads in the Alps and has 75 switchbacks. Seventy-five! Not a road you want to drive fast on, or even drive on at all if you can help it. Apparently, it’s so dangerous during the winter and spring that they close it completely during those seasons.

Of course, being dangerous, gearheads flock to it. That British car show everyone likes, “Top Gear” (I don’t watch that show anymore after what they said about the F150), declared it the greatest driving road in the world. (Or at least in Europe. Have you seen the pictures of the crazy roads they have in the mountains in India?)

The Italian bicycle Grand Tour frequently goes through Stelvio Pass. (The Giro d’Italia, sister race to the Tour de France. I try to catch all three of the Grand Tours when I can.) Thousands and thousands of cyclists ride through Stelvio Pass every year.

It’s easier to find info on battles fought at the pass than it is to find anything beyond basic info on its construction or maintenance, but that’s pretty constant. Historians are obsessed with wars, despite the fact that construction and architecture affect us way more.

I’m working on persuading Maggie on this European vacation bit but, as carsick as she gets, I don’t think that Stelvio Pass will be on the itinerary.

Friction in the Ramp Department

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If you’ve ever gone over simple machines in school, chances are—depending on when you took the course—there wasn’t a lot of math involved in the explanation. And if there was, it was pretty basic. It probably involved an absolute minimum of variables: when talking about pulleys, for instance, the teacher almost certainly didn’t include factors like friction, tension, sway, or sweaty hands. (That last one is hard to calculate mathematically, but definitely matters a good bit.)

With ramps, friction is the biggest variable left out; it’s a real pain to calculate. Often, teachers will just do the math with an idealized, frictionless ramp. Makes it really easy for students to figure out but gets a little ridiculous if you try to think about actually trying to use the thing—pure slapstick, really, and slapstick is one kind of humor you don’t want in the workplace.

Now, I’m not a great teacher, but I like to think I do an okay job at it. I helped the kids out with their math in school (I still do help one of the boys with some of his math from work, not naming any names), and I spent years using slide rules before converting to a calculator. I know my math, and I know how to show people how to do it. (No way I could put in the kind of dedication a real teacher does, though.)

So when one of the young guys at work came to me for some help with some math, I was happy to help. The kid thought he’d figured out a way to improve efficiency when loading and unloading. Given how much trouble he is at work, I really hoped this meant he was starting to actually care about his job. Didn’t think anything would come of his ideas, but at least he was trying, right?

Well, come the day he was to test out the idea, it turns out I’d taught him with the idealized frictionless ramp model. That should have resulted in a mess on its own but, luckily for me, his big mistake had nothing to do with my assistance.

The dumb kid hadn’t read the instructions on the ramp he was using. Should have lost his job, but kept it for the same reason he got it. Sometimes it’s about who you know. At least he got transferred to his dad’s department, so I don’t have to deal with him anymore.

Ramps in Higher Gravity

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Ramps get more useful in higher gravity.

You’re probably wondering what kind of nonsense I’m going on about now, aren’t you? “McCoy,” you’re saying, “that diet your wife has you on has driven you straight around the bend, hasn’t it?”

Well, it hasn’t. At least not mostly. Hardly any, really.

Anyhow, ramps at different gravity levels: generally speaking, they’re much more useful at the higher ones. If you’re in zero g, just floating around, a ramp is going to be pretty pointless. As gravity gets higher, though, more and more solutions for bridging vertical distances (or, as I prefer to call it, going up and down) become infeasible.

Elevators, for instance, become useless really fast. Materials technology just isn’t able yet to create a material that can maintain the tensile strength necessary for lifts, elevators, etc. Same thing for pulleys and lifts. Building a high gravity ramp, though, doesn’t require expensive, crazy space materials—it requires dirt. Just dirt. Good old fashioned, boring dirt. Just start piling it up, and there you go.

As far as I know, there’s only one book where a ramp saves the day, and that’s Mission of Gravity, by Hal Clement. It takes place on this weird planet with enormous gravity that actually changes between the poles and the equator. It’s weird, but the math works out. Anyhow, these little centipede aliens who live there are hired to retrieve a human probe near one pole, where the gravity is highest, and they end up using a ramp to retrieve the probe’s computer at the end. My oldest son found it for me, back in the kids’ rocket-ship-loving days. Not much of a reader, but I liked that book well enough.

“McCoy,” you ask, “that’s all fine and dandy, but it doesn’t actually answer my question. Are you thinking about heavy gravity because the diet’s working and you’ve lost weight? Or have you been cheating on the diet and actually gaining weight?”

Well, let’s just say Maggie wasn’t happy when she found me taking apart our scale to try and gimmick it to read my weight lower than it is.