How the McMurtry Electric Fan Car Clocked a 7.9-Second Quarter-Mile | Hacker News Reader

How the McMurtry Electric Fan Car Clocked a 7.9-Second Quarter-Mile

thedrive.com

106 pointsclouddrover83 comments

The downforce fan technique was also done by Formula 1 in the late 70s before being banned the year after. https://en.wikipedia.org/wiki/Brabham_BT46#Brabham_BT46B_%E2...

It was actually banned almost immediately after convincingly winning its inaugural race, at the hands of the legendary Niki Lauda.

I wonder why it still remains banned. Surely once all cars can get the same fans it should be allowed?

Costs cap most likely.

We could build a car which no human being could survive a 100 mile race in today. The human is the limiting factor so we have to limit the technology to what humans (even elite sportsmen) can deal with.

There are all kinds of restrictions added to race cars of almost any series, some for commercial reasons (promoting the original vehicle in rallying and touring cars for example), some for financial (generally to keep the price of entry reasonable) and sometimes for safety.

Relevant XKCD: https://what-if.xkcd.com/116/

Not at all related, but I watched the various motorcycle jumps of the Caesars Palace fountains the other day.

Watching Travis Pastrana jump the fountains on a fairly heavy Indian flat track bike, with modern ramps designed with computer input, and planning rather than seat-of-the-pants go-for-it-ness made it okay, but hardly death-defying. I see guys jump motorcycles furthers on the dunes in Southern California. When EK did it, it was terrifying.

Just like F1 was, once upon a time. Now F1 is scary because speeds are up against human reaction. It's inevitable the cars either have to slow down, or the driver needs to be on controls not in the car, making this ground-based drones.

F1 racing bans a lot of tech. For example, anti-lock brakes and AWD are banned in F1.

Just because all cars can get it easily doesn't mean F1 want it. Most often the quoted reason is to have a better spectator sport and to make it safer. I really doubt those reasons because you can still have a difficult and tight race while having all the modern safety features. For example why don't F1 cars have entire car air bags (ie air bags that envelop the entire car that deploy when the car goes airborne in a crash/rollover)? if it's too "heavy" just make a rule that all F1 cars need to have air bags so the playing field is even.

F1 cars should have self driving collision avoidance that can activate faster than human response times as well. that would be way safer for everyone involved.

Why not go all the way and just have RC F1 cars that are remotely driven like FPV drones? Then the cars can do truly insane stuff without any danger to the driver. But I feel it wouldn't be F1 anymore if this happens.

FPV1 would be a different sport. The element of danger is part of why so many are drawn to it.

I wonder whether an airbag enveloping the whole car would have been advantageous in the case of Romain Grosjean’s crash in Bahrain in 2020.

He might have bounced off the guard rail or be stuck in it just the same with extra material surrounding him and catching fire.

There have been also at least two cases I remember of race cars becoming airborne after touching wheels and being able to continue the race. This usually happens when the field is packed after (re)starts. Deploying airbags in such cases would probably entail a chain reaction that might resemble corn being popped.

I would watch F1 popcorn edition!

I thought F1 was used by manufacturers as a way to justify tremendous R&D, is that the case still? was it ever?

The problem is a lot of the R&D is focused on a very esoteric end itself. Sure, some of that technology ends up back at the parent companies and makes its way to consumer tech, but most of it just solves the problems of the moment to win races. They do push the envelope for material sciences more than anything else, but a lot of the engine design and other such things are wildly inapplicable to consumer tech and never will be. They can build million dollar engines out of rare and exotic materials that will never be consumer facing because they need 12 of them or whatever.

So, fun racing/physics lessons learned here: the reason fan cars and (in general) primarily ground effect cars are banned are because of unpredictability leading to unsafe situations. In a car that uses underbody suction to create downforce, any loss of a seal suddenly reduces grip that could leave cars unable to steer, brake, etc and cause much more severe accidents than a car with over-body downforce that still has that benefit of downforce even in an accident to slow down as much as possible before impact.

This is mostly a bad argument. F1 rules cause all kinds of similar problems due to their arbitrary rules. It's very easy for the aerodynamic rules to result in unpredictability.

The last 10 years many of the F1 cars due to the rules had catastrophic loss of downforce if they got too near other cars. The drivers had to work around this by not following too closely. F1 rules changes recently have tried to reduce these kinds of issues.

But even this last season was somewhat ruined by one team figuring out to work within the current rules and not have the porpoising problems that wrecked the other teams cars because they'd lose their downforce. That made the racing less exciting. And the whole problem never had to exist if it wasn't for the rules.

> The last 10 years many of the F1 cars due to the rules had catastrophic loss of downforce if they got too near other cars.

But I don’t remember catastrophic loss of downforce as bad as this: https://youtu.be/e21ZjwZGjiQ

> catastrophic loss of downforce if they got too near other cars. The drivers had to work around this by not following too closely

While the downforce loss was significant, it was predictable and could be easily avoided. The equivalent for ground effect, e.g. hitting a bump or curb mid-corner and lifting the skirt just far enough for the pressure seal to fail and your downforce to go from 100% to near 0% in an instant, is far more likely to lead to a catastrophic accident.

Anthony that causes the car to behave in a way the driver isn't expecting (collision avoidance) would probably lead to less safety rather than more. Besides, even Tesla autopilot can be fooled and certainly isn't designed for cars driving inches apart.

The air bags have been covered in other comments but similarly would probably reduce safety, not increase it. The cars are very much designed for safety, and to absorb impacts, which is why they are so much heavier than previous generations.

As far as anti-lock brakes and collision avoidance goes, most racing leagues tend to avoid tech that automates driver actions. The argument is that it makes it less sporting if the computers are doing the driving. Of course, those policies can be at odds with driver safety at times.

It would suck up rocks, dust, and debris from the track and spit it out to the driver behind. There are interviews with drivers complaining about it from the very start.

I think main goal is to avoid big deadly accidents. Drivers dying is not good out look for a sport from marketing standpoint. As such lot of thought is put in making the races slower and removing failure points that can lead uncontrollable 300km/h rockets. Like fan failing at end of straight and car becoming uncontrollable then crashing to concrete barrier. Very nasty for driver and possibly the audience and people next to track.

They need to slow the cars down to be safe. Recently, there’s a push to make the cars cheaper.

Tradition vs too much complexity balance. Adding too much smarts will make it the driver uses less and less skill. Adding fans would just make the car more likely to break down and screw up dynamics.

F1 stopped chasing the frontier of what's possible engineering wise back in the 80s. Cars were already potent enough then to exceed human capacity, even the very best drivers. F1 rule makers shifted to stuff they saw as the intersection of good racing and useful R&D for automakers.

In fact there's almost no racing events that have a true open class engineering wise anymore. It's just too dangerous. Look up what happened during the Group B Rally era for examples of how it can go wrong and blow back.

The BT46B being banned after a single race is a bit of an urban legend. It was not banned and was perfectly legal to run for the remainder of the year.

The background to why Gordon Murray (designer) decided to go with the fan design was the flat-12 engine used by Brabham didn't allow venturi tunnels along the side of the car (flat-12s being too wide) so he had to find another way to respond to the then-new ground-effect others were exploiting.

A neat legal trick was discovered: a fan could be installed on the car as long as its primary purpose was to cool the motor. Primary purpose in this case meant, and GM got a lawyer's opinion on this, at least 51% of the volume of air went to cool the engine. Brabham was very clear this fan sucked the car to the ground but also proved to the governing body that most of the air went to cooling, so it was deemed legal for the rest of the year but the loophole was to be closed for the following year. Stories by Andretti about the BT46 throwing stones and being dangerous to other drivers was complete rubbish made up by Colin Chapman to get the car banned as he saw Brabham would walk away with the championship. In effect the tips of the fans never moved particularly fast (ballpark 50mph along the edges) so it was never dangerous to other drivers.

The actual story as to why it was withdrawn is Bernie Ecclestone, then owner of the Brabham team was also the head of the Formula One Constructors Association and the other manufacturers threatened to leave the association if he didn't withdraw the car. Seeing the bigger picture of securing TV and advertising rights to F1, Bernie withdrew the car after a single race.

It was done earlier by Jim Hall with the Chaparrals.

"Although it was quickly banned, the 2J “vacuum cleaner” concept was copied eight years later by Brabham Formula 1 designer Gordon Murray who figured out a way to circumvent the rules." - Wikipedia

https://en.wikipedia.org/wiki/Jim_Hall_(racing_driver)

Figuring out a way to circumvent the rules was the reason for the F1 car being fascinating, and successful. It being a competition involving building the fastest car confirming to the prescribed Formula.

OG Can-Am was different - there were fewer rules, so things were limited by drivability. (Someday I hope to add a Can-Am car to my collection but I am also limited by driveability)

I would love to be limited by drivability rather than by economics from getting my hand on a Can-Am car. Good for you!

if you go for stuff that wasn't winning/famous at the time, the costs come way down. although since everything was bespoke, replacement parts are often complicated.

i have a '60s lotus 23, which was built for Le Mans, and it was very low six figures. but an engine rebuild is $30k...

Are track days the only viable place to find/meet these people who can help maintain such cars, or there are other ways. I couldn't hold back the question, but feel free to ignore

For stuff like that, best to go to the vintage and historic races and events. I explicitly looked for cars that were eligible for the Monterey historics (I have two currently.) It helps to find people who specialize in the vehicle you have, as well.

Trackdays skew towards much more modern cars. Although I met the shop that takes care of my stuff at one (they did Spec Miata rental, and now I race that too)

I think the hill climb record at Goodwood this summer was even more impressive. That thing looks like it is glued to the track. Check out a few other cars doing the climb and you will see a noticeable difference. https://www.youtube.com/watch?v=5JYp9eGC3Cc

For everyone who wants to see it in action, check out the video of the Goodwood hillclimb where the McMurty set the record. Ideally the full video with the runner ups, otherwise you would think the video is running at 1.5x speed.

Never has a car elicited such emotion from the crowd, it is amazing to see

CarWow too has a good video about it https://www.youtube.com/watch?v=TptzkkbC1vE

The Gordon Murray T.50 hypercar also has a downforce fan. https://gordonmurrayautomotive.com/cars/t50s

Kind of, it doesn't use a skirt or suck the car towards the ground. It uses a fan to guide the air allowing for steeper diffuser angles than would normally work. So you get an indirect downforce improvement.

In the end you get an effect that is 1 or 2 orders of magnitude smaller than sucking the car to the ground with a skirt.

This fan downforce enabled EV race car with slicks on it can do a 0-60 in 1.4 seconds.

I thinks this puts to rest the Musk claim of a 1.1 sec 0-60 Tesla Roadster if there still any people still hanging on to that fantasy.

They are claiming 1.9s? Where did you see 1.1?

https://www.tesla.com/roadster

Not the OP.

You're right, it was always 1.9. They're still talking out of their backsides though. If the Rimac supercars can't do it without a fan to suck the car to the ground, Tesla sure can't.

Without a fan you just can't get the traction you'd need. There's no tyre on the planet which could grip that hard.

Additional detail - I suspect with a one foot rollout, on a VHT surface, on a hot day, in ideal conditions, they might be able to get down to a 1.95/1.93 sort of area. But on actual normal road surface, from stationary, with the tyres it comes with? Not a chance. I'd be astonished if they got to a 2.05. 1.90? Not a hope.

Source - knowing far too much about tyre/road interaction.

Model S Plaid has been clocked at < 2s by 3rd parties so I don't think 1.9 flat is that farfetched for the roadster.

You're not wrong, but not entirely right either.

They've not done it on a road surface from standing start. I know a reasonable amount about the tests that have been done to make those numbers, and Tesla require a foot rollout on VHT to get a 1.99/1.98 time. That's not the same as from standing on tarmac or concrete.

Rough rule of thumb is that starting from stopped on tarmac costs you about 25-.3s depending on conditions.

He made the claim on twitter: https://twitter.com/elonmusk/status/1395474465794838528 ("Yes, with the SpaceX rocket thruster option package" is a reply to someone asking if 1.1 seconds is true).

That doesn't sound sarcastic at all. /s

I can see how Musk’s comment does sound sarcastic, but I think the Space X package isn’t generally being considered as a joke: https://www.motor1.com/news/508914/tesla-roadster-spacex-spe...

Whelp, no need for traction then :)

The human is starting to look like the weakest link.

For such a closed track (known route to the centimeter, guaranteed no obstacles, etc) - a Self-Driving version of this could do it a good deal faster.

AI plays better chess but no one watches them in tournaments.

>The human is starting to look like the weakest link.

Human is a weakest link since 80s. That's the entire reason Group B has been cancelled and F-1 regulated into oblivion.

It took WRC all of two years to be faster than Group B. Turned out focusing on suspension and handling improved performance more than pure performance. That being said, Group B was just awesome and crazy. And not just because of the cars or the drivers, spectators were just as crazy, as were officials with their utter disregard for safety.

Yeah I'd like to see that one day on regular tracks, a true mechanical and AI engineering arms race. Though I think it would be too expensive

There is no point without a human, what's the difference between that and a bullet/missile?

You could still have human operators. Competitive drone racing is pretty neat.

Meh.

There was a driverless series in development https://en.wikipedia.org/wiki/Roborace

Unfortunatly it looks like it might have floundered

You would think that to be true, but I don't know that any serious attempts (of which several have been made, see RoboRace et al) have yet bested a human driver.

When I read “electric fan car” I thought the fans would be producing forward thrust to accelerate the car, not downforce. This raises the question—would it be more effective to accelerate the car this way (probably less efficient, even with huge aircraft style electric ducted fans) vs. putting the force through the wheels (limited by traction)?

well it sucks to the ground AND blows that air out the back, though the thrust is negligible. The answer to your question though is no. It is much more efficient to push against the ground with the tire. In fact this sucking method is more efficient than a wing or other aerodynamic down-force devices. You might see the wing they have no go away at some point, as it was added to improve balance. Maybe they will figure out how to adjust that with the skirt or something.

I could go into the physics, but in short, no. Two hard contact patches just grab way more than a propeller can on air.

In water it'd work, but then you've made a boat and the wheels are irrelevant.

Boats have always been capable of faster acceleration in theory. Problem Child, for example, did 0 to above 250mph in about 3.5s.

Given the car is lightweight while the fan generates such strong downforce, would it lift off if it was to actually flip over?

no, you can get a lot more downforce with a skirt sealed against the road (nearly) than you would get in open air just trying to thrust upward.

No, it’s worth watching this video: https://m.youtube.com/watch?v=TptzkkbC1vE.

> a stupefying 1.4-second 0-60 run in less-than-ideal conditions.

I don't know why they call the following less than ideal:

> the manufacturer hired a jet truck to dry the back straight at the famed F1 circuit. There, and after doing a burnout to warm up the tires

Perhaps they could have waited for a strong tail wind?!

[EDIT: apparently it could be warmer and the road drier still]

Anyway, seems they have a good shot at taking over the 0-62 mph in 1.461 sec record set by these guys

https://techstory.in/students-of-university-of-stuttgart-mak...

A road-legal version is apparently on the way

https://www.autoblog.com/2022/07/01/mcmurtry-sperling-fan-ca...

The track still wasnt dry, you can see the moisture

They did this in winter in England. Even if the track was dry, it was still far from the ideal surface temperature for something like this.

The conditions certainly weren't aweful, but they were not ideal (or less-than-ideal).

Weren’t awful? That’s like saying a 99/100 exam score isn’t awful, but it’s not ideal either.

There was no tire spin and that was so close to ideal conditions that I imagine the most they could shave off is a few hundredths of a second. Even if they couldn’t, it’s mind boggling how fast this car is.

There was no tire spin because the computers don't allow it. If you provide more grip the car provides more power.

So many things were far from optimal for that run. Low air temperature, high humidity, low track temperature, low traction track surface, low temperature tires (even with the spin, that only affects the surface and dissipates very quickly).

The track was wet and it's common practice to warm up tires before racing or drag racings.

This number on a street legal (or technically soon to be street legal) car is insane. That 1.4 includes rollout compare that to a Tesla Plaid which does it in 2.3 seconds (the 1.99 seconds is only possible if you exclude rollout).

The McMurtry Spéirling broke the Goodwood hill climb record this year.

https://youtu.be/5JYp9eGC3Cc

That video is great, and less than a minute. For anyone watching, be sure to catch the reactions of those standing at the starting line.

That hill climb looks like a sped up Benny Hill video...

"Prepared surface" is a whole thing in drag racing. I remember reading how Dodge got their Hellcat under 10 seconds, and it involved not only special tires, but also a specific gunk that is apparently common to spread on the tarmac, said to be sticky even to walk on it.

Normal things in drag racing I guess, but no way they'd allow that in Silverstone.

The video was a joy to watch. Everyone on camera was having fun and allowing themselves to be fully excited and enthusiastic.

> It weighs less than one ton and boasts two electric motors that produce up to 1,000 hp. According to Chief Engineer Kevin Ukoko-Rongione, that's more than one horsepower per kilo

Good thing it was pointed out by the Chief Engineer. I wonder how he worked it out but I guess we can trust him... /s

What's the record for the quarter-mile using a high school track? That I would pay to see.

Here's a honda civic hatch doing a 6.9 second 1/4 mile.

https://youtu.be/vKFr82qnN0c?t=262

If we consider goals of future cars to emit less co2, microplastics, brake dust and safer, how does modern racing advance these goals? In my jaded view, rich guys are going faster and nothing trickling down to economy cars.

Current generation F1 engines for example, are limited to just 1.6L (97 cubic inch) displacement, and teams are not allowed to refuel during the race. This forces engineers to design more efficient engines (less fuel equals less weight). Last season's cars were reported to achieve over 50% thermal efficiency (compared to ~20% for a regular road-going car) and close to 1000hp.

Whether this technology actually trickles down to production vehicles is debatable. But traditionally racing has been the incentive for major advances to be made in efficiency, aerodynamics, drivetrain components, tyres etc.

Worth noting that seventy years ago we had 1.5L V16 F1 engines producing 600HP

https://en.wikipedia.org/wiki/British_Racing_Motors_V16

They weren't the most reliable things though....

I mean, in the 1980s turbo era F1 engines were putting out way more than that--try around 1000 hp/l!

That was done with absurd levels of boost, fuel that bore little to no chemical resemblance to gasoline, and engines with a life expectancy (in qualifying trim) measured in single-digit laps.

The advances in modern engines' efficiency and reliability are staggering.

https://en.wikipedia.org/wiki/BMW_M12

Think of racing as entertainment, what does tennis do for the world? And I think tennis is great

Reply on news.ycombinator.com