Wednesday, May 28, 2008

Lubricated by their own squeak

Germany during WWII was a remarkable hotbed of engineering. Almost all of their innovation during this time was, of course, in weapons; and most of this innovation was not as readily transferable to peacetime applications as other nations' wartime advances (like Great Britain's work in computers and radar, for example; or the US's work in atomic fission).

But many of their innovations were decades ahead of their time. Look at the Tiger tank, for example -- and how dissimilar it was from other tanks of the day, and how remarkably similar it is to tanks like the Abrams, still online today. Look at the Me262 fighter, and compare it to other planes of the day, and even to jets that came later (like early Sabres and MiGs). Even in small arms development, the Germans led the way with the first legitimate assault rifle.

But one of the more interesting advancements by the Germans wasn't so much a result of their technical ability as it was pure serendipity, and their inability to produce a sealed bearing that would survive the harsh environment of a tank tread. I've only ever found one reference to this anecdote, so it might well be spurious; but it has the ring of truth to it.

Apparently, the Germans had an issue with squeaky bearings in the Panzer tank tread. This wasn't a big problem, since the sound of the squeak was usually accompanied by the sound of the tank's massive diesel engine; but the Germans were concerned about bearing wear. When they looked into this, they found that they'd stumbled upon a bearing that didn't need lubrication -- the squeak was just the right frequency to cause physical separation between the two surfaces for a substantial amount of time, and when the two surfaces weren't in contact, coefficient of friction and wear both went to zero.

But again, like many of the German innovations of WWII, I'm not aware of any applications of this phenomenon in more constructive endeavors. If any readers know of any other uses of this acoustic lubrication, let me know.


ed said...

The Tiger tank wasn't really especially innovative or advanced, as implied here. It was conventional for German tanks of the time, just bigger.

The later Panther tank was somewhat innovative, in that it had better ballistic arrangement of its armour, but that emulated the earlier Soviet T34.

Interesting about the acoustic lubrication, though.

Anonymous said...

The self-lubricating squeaky baring is mentioned on Wikipedia, without a source. Where did this story come from?

Anonymous said...

I don't get it. Nothing is free... No matter how you look at it, the weight of the tank is still supported through the contact points of the bearing...even though the dwell time that the contact points are actually contacting each other is reduced. So what does that mean? It means that when the ARE contacting for those shorter time intervals, it is with a much higher force. So doesn't the higher force more or less negatively offset the apparent advantage of reduced contact time?

mickybob said...

Perhaps some of the energy that would otherwise have worn the bearings is dissipated as sound?

Anonymous said...

I agree, the bearings must be supporting the weight of the tank at some point. Also if there are bearings experiencing moments of less load due to vibration, then I think in those same moments other bearings are experiencing increased load! In any case, let me share my own vibration experience: I use vibration all the time as a furniture mover. You encounter old office cabinets, in tight spaces, butted up against walls, and they're sunk into carpet. Most times you cannot simply just drag the cabinet out because there's too much friction due to being sunk into carpet. Shaking the cabinet (vibration) as you pull and shimmy it (left and right) works like a charm. In those shaking moments, some corners of the cabinet are 'lighter' on the carpet than others, and combined with you pulling, eventually you're able to get the cabinet sliding on the carpet because it's now out of that sunken carpet patch.

Anonymous said...

Adding a second vibration experience, just for fun! Vibration is also a tool in martial arts, especially when you're grappling. For example, someone bear hugs you from behind, shaking violently may help introduce an opportunity for you to break free from the hold. Also if you have someone in a joint lock, some vibration can help make it more painful or difficult for them to break free. For example, you have someone in a standing armbar and you're trying to direct them to the ground. If they're resisting, you could start shaking their arm and it becomes confusing for their body, and they become much more submissive. However there are counters too all of this too!