In Micromouse (https://en.wikipedia.org/wiki/Micromouse) - a competition where autonomous devices solve a mouse maze - the fastest competitors are all using fans to increase traction (and thus speed).
radicalbyte, you're absolutely right that the use of fans in Micromouse increases the traction, and therefore the speed at which the maze is solved. Suction allows for impressive performances.
However, a small caveat that might be worth considering is that while the suction indeed increases speed, it might be more accurate to say that it primarily improves acceleration instead of car speed: The issue often lies with achieving rapid acceleration rather than with maintaining high speed. Even systems with relatively low traction can reach high speeds given enough time and distance, but the ability to accelerate quickly is crucial in competitions like Micromouse.
Something weird about this is that humans very often ascribe the sensation of d^ns/dt^n, to feeling d^n-1s/dt^n-1.
So people will say that something which accelerates quickly is 'fast'. Or they will say, when they feel themselves initially being pressed back into their seat as a plane starts its takeoff roll, that they are experiencing 'acceleration' when what they are experiencing is actually jerk.
The thing is, you can't actually feel motion at a constant speed - so the only thing that tells you you are acquiring speed is your body's experience of acceleration - so when you feel yourself accelerating, you associate that with speed. Likewise, your body also can't really tell the difference between constant acceleration and just... being at a different angle, and maybe a bit heavier than normal. So it's when you experience changes in the apparent direction of 'down' and the overall 'weight' you're feeling that you think 'oh, we're accelerating'.
My favorite way to get a sense of what acceleration, jerk and snap feel like is to focus on what happens when you're in a car that's braking hard. You're decelerating at a relatively constant rate while the brakes are applied - it feels as if 'down' is pointing slightly forward, meaning you'd be sliding off the seat if it weren't for your seatbelt holding you back. When the car finally stops though, there's a very abrupt change in acceleration - a 'jerk'. 'Down' switches to pointing straight down again, very quickly. You're pulled back into your seat. That's jerk. And specifically the sudden onset of that swing in what direction 'down' is pointing, and then its rapid disappearance is snap. Your body feels like it's being 'jerked' around when the car stops precisely because that motion has high snap - you experience a sudden high amount of jerk, then the jerk ends.
Well, if you're on a 2D plain, it's pretty easy to tell. If the solid plain is stationary to your motion, then the air is fast. If the solid plain is moving, then it's a little tricker to figure out.
Hmmm, from a Newtonian perspective I would have argued (or at least my personal impression is) the only thing we actually perceive is force (i.e. acceleration). All the situations you described are just (higher-order) changes of acceleration and even if you give them a name: At the end of the day, the only thing that matters to our bodies is the force.
Sure, but my argument is that you only really take note of changes in the acceleration you experience. Yes, your internal sense of ‘which way am I accelerating’ is the sensor you’re using (also ‘which way and how hard are my limbs being pulled’ and ‘how much force am I feeling in my joints and on the parts of my body that are touching the objects around me’) - but when those all indicate a generally constant vector with a magnitude close to 10m/s^2 your body just intuits that that direction is ‘up’. If that vector is changing your body figures you must be moving because ‘up’ normally doesn’t move.
So it’s changes in acceleration that create movement sensations, not acceleration itself.
Interesting thought but I'm not entirely convinced yet: 10m/s² down (along your body axis) is not the same as 10m/s² in any other direction. I would assume the body is perfectly able to distinguish between those.
Sure, but once you have speed you can use aerodynamics to get grip (e.g., F1 cars). So this is really only relevant if you need acceleration from low speed.
An issue with aero features (other than not producing their effects at low speed) is their ability to stall. Ground effect was especially dangerous (back when high-ground-effect designs were allowed) because if it stalls during a high speed corner (say from driving over a bump, like a kerb maybe) you can instantaneously lose a huge amount of downforce, which is obviously quite dangerous.
Exactly, thus you can simply integrate over a longer time span.
But if you want to increase the acceleration you need traction, your tyres need to be glued to the asphalt. Since you don't have aerodynamic pressure at those speeds you need to suck the vehicle to the ground.
