It sounds ludicrous right? Being able to travel faster than the wind using only the wind sounds like an incredibly crazy idea as for it to work there has to be some kind of other external force acting on it for that to work. Indeed the idea perplexed me for quite a while, in a much similar way as the airplane on a treadmill problem did, but once you get your head around the idea of apparent wind it starts to get a bit easier. Of course nothing beats a good example and it just so happens that there’s been a cracker of one to cross my decks recently.
The video above shows an intriguing vehicle called Sailrocket 2, a sail boat that has a rather intriguing design that allows it to travel at almost 3 times the current speed of the wind its in. The simplest way to explain this is that, as the design kind of suggests, it’s not travelling directly down the wind. It’s in fact travelling across the wind which causes it to experience another apparent wind due to the direction its travelling in which allows it to gain speed. Although this sounds a bit perpetual-motiony things like the hull resistance, efficiency of the sail and how close the boat can sail to the apparent wind it generates. Done right however you can get up to 6 times the speed of the prevailing winds which can be pretty damn fast as Sailrocket 2 demonstrates.
But what if I told you that, through some engineering trickery, similar things can happen travelling directly down the wind?
That my friends is a vehicle that is capable of just such a feat. The concept had been making waves for quite some time as whilst the idea of going faster than the wind whilst travelling across it is well known and proven doing the same thing travelling with the wind was seen as impossible. 2 years ago however a team headed by Rick Cavallaro built one of them and proceeded to set records with it not long after. It works by actually being two cars in one with its first mode of operation being directly driven by the wind and the second using the wind as a power source to drive the wheels directly (at least that’s my understanding anyway). This is what allows it to travel faster than the wind that’s driving it and makes for a pretty neat piece of engineering.
It’s this kind of non-intuitive science and engineering that really gets me going. I spent hours trying to understand all the principles behind this when I first heard of them and even now I’m still not 100% on them. That’s part of the fun though as the more I read about it the more I understand and the more interesting projects based on those ideas I uncover. It’s a rather deep rabbit hole to fall into however and I wouldn’t recommend it unless you’re as fascinated with science as I am.