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Comment by nathannecro | Hacker News Reader

This is not actually the first time that this idea of using a fan to create downforce. It's been something that's been talked about and modeled for a long while and I think a few years ago, the McMurtury Speirling was released. That set the lap record at Laguna Seca among other achievements. The car is about a million dollars, and the fans are basically completely useless anywhere that's not a curated track (think stones, dust, wood, other FOD going through the fans).

The new roadster is obviously cool, but it looks like a practically useless vehicle for 99.9999% of the population. It's purely going to be a track princess -- with lots of extra weight for frankly pointless (but very cool) thrusters.

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There was a Fan Car in F1 decades ago. Was good until it was banned!

Yeah, it turns out that in very specific and controlled situations, using a fan to make downforce is great. It's also a very obvious thing to do in those situations and doesn't do much for you otherwise.

Imagine a normal car having to carry around the added weight of fans, COPVs, and the plumbing to make it work. And only being able to use those only if the track is clean and there are no other cars nearby.

This is like asking to imagine a Hoover vacuum to have those fans. It’s silly because it would never happen. This is not a normal car. Comparing it to a normal car makes no sense.

You actually raise interesting point. What if we could remove bunch of complicated suspension and replace with a simple fan?

What suspension would you recommend removing? Are you envisioning some ridiculous Flymo-style car? I can attest that a Flymo lawnmower collapses onto the floor when its weight increases (eg with wet grass).

They make those - they are called hovercrafts. They tend to have lots of maintenance issues.

The Chaparral 2j is one of the most inventive and cool looking cars I've seen.

Not f1, Can-Am but yeah, I'm really surprised this isn't a more common approach to modern track cars. Obviously banned in most motorsport but I'm surprised with all of the one-offs these days that it's not more common.

Because nobody wants to be on a road/racetrack with a car that will pelt the car behind it with stones it pulls from the tarmac

Yeah, lots of prior art for fan cars.

At race speeds (say over ~150 mph), you don't even need a fan or any active mechanism. Just passive venturi channels on the underside can generate so much down force they are strictly limited in F1 because they can easily enable cars to sustain extremely unsafe speeds.

There are some McLaren street cars that use passive venturi channels which from their shape alone, generate more down force at high speeds than the car's weight. In theory, the car could drive upside down (if there was a Daytona-sized race track shaped like a ~30 ft diameter pipe).

Even though average lap speeds in F1 can be around 150 MPH or faster at some tracks, corner speeds are generally much slower (in some cases approaching relatively pedestrian city speeds). The beauty of active suction is it allows for much higher corner speeds on the slow sections of the track where traditional wings and underbody elements produce relatively little downforce (being proportional to the square of the car’s speed).

An F1 car would need to move at over ~100 mph to sustain inverted driving (assuming you modified the ancillary systems appropriately—the road orientation isn’t the only limitation); a fan car can do it standing still.

> but it looks like a practically useless vehicle for 99.9999% of the population

Well it's effectively useless for 100% of the population. It's just that 99.9999% cannot afford an expensive, useless car. Some people can, though.

It has pretty good filtration [1], and redundant fans. Some rocks aren't a problem. But, you can't be driving through LA.

[1] https://youtu.be/xkXvL8YCtIE?t=721

You can’t drive it anywhere that manhole covers might exist, lest you destroy the car and/or turn the manhole cover into a deadly projectile.

Yes, those are found in LA.

I mean it’s a 250k car. Why is it supposed to be practical?

There are levels of impractical - this is so far beyond useless even compared to the most ostentatious luxury cars.

I know yall don’t like Tesla but not sure I have any bone to pick at what is impractical for a car that is $250k+. Seems like an impractical argument to have.

Amazing how funny this is.

I mean, everyone buys cars for different reasons, but in that range you're buying it for 3 reasons I can think of: to drive it fast, to look at it in your garage, or to boast about how much you paid. It's not ticking box 2 or 3. The non-flying model does seem to tick box 1, but the exclusive flying model seems to add nothing there (presuming it ever gets made how many billionaires are even going to survive using it?)

Again this argument is hilarious. No idea what the purpose is. All I said is how can you argue about the practicality of a car that is going to be 250k+.

Whatever floats your boat though.

It's not centrally about practicality, it's about appeal. If practicality isn't the appeal, what is? It's not looks, it's not speed & it's not a Veblen good (relative to other cars - a Tourbillon is 16 times the price of a Roadster).

Ok so we have deviated off topic. Got it.

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