revtothelimit - motorbike forum

You're reaching the limits of my knowledge here, and that's based on a chat 40 years ago with an ex-aircraft designer I was working with.

Mr. Dazzle wrote: Tue Sep 05, 2023 9:11 am It's more about the frontal area though - literally what you'd think: bigger worse than smaller

Actually, I wouldn't

I'd think maximum cross sectional area

Notice how these cars all tend to have gently sloping rears though. As loads of people know the way teh air leaves the car is critical to drag, probably more than the front end.

He said, for typical vehicles, the teardrop should be (IIRC) 3.5:1 length ...

So they these Kammback style rear ends. It's really obvious on Teslas.

... but that the front could be blunted and about 15% could be chopped off without too much adverse effect.

From the link

The ideal shape to minimize drag is a "teardrop," a smooth airfoil-like shape, but it is not practical for road vehicles because of size constraints. However, researchers, including Kamm, found that abruptly cutting off the tail resulted in a minimal increase in drag.

Kamm's design is based on the tail being truncated at the point where the cross section area is 50% of the car's maximum cross-section

So that's different.

There is no one solution and obviously you need to fit a boot in etc as well. Electric cars give you way more options though because packaging all the drive parts in is way easier. You also dont need to supply thousands of litres of air to the engine every minute and get rid of 700°C exhaust gases etc.

You just end up with general trends in shape, which is why so many EVs look similar. Convergent evolution.

Mr. Dazzle wrote: Tue Sep 05, 2023 9:54 am There is no one solution and obviously you need to fit a boot in etc as well. Electric cars give you way more options though because packaging all the drive parts in is way easier.

You just end up with general trends in shape, which is why so many EVs look similar. Convergent evolution.

I remember posting on TRC or VD that electric power provided a great opportunity to rethink bike design/layout away from the traditional bicycle + engine format.

But rider conservative attitudes won't allow it

Horse wrote: Tue Sep 05, 2023 9:58 am I remember posting on TRC or VD that electric power provided a great opportunity to rethink bike design/layout away from the traditional bicycle + engine format.

But rider conservative attitudes won't allow it

While I was at the RockStore recently, no less than SEVEN HD LiveWire electric bikes pulled in. One arrived solo, then a while later the other 6 showed up together. One of the 6 had a small bar mounted screen, which partially broke off when the pillock riding it fell over when he stopped. It hit the exhaust of a mates Triumph Sprint, but didn't lave a mark.
It then took to combined efforts of ALL SIX to figure out how to pop the fastener back in the screen to reattach it. Not all at the same time, they worked in shifts of 4 for a total 30 minutes.
The bloke who arrived solo was with us on Vultures Row at the top of the steps. His only comment was "Having watched that farce, I wish I left mine at home today"
It looked like a hipster convention. During the reattachment performance there was always one filming the comedy with a cell phone... so they now have 30minute of video of them being unable to comprehend how to loosen & then tighten a fastener.

Would the outcome have been different with a petrol engined bike?

Mr. Dazzle wrote: Tue Sep 05, 2023 6:02 pm Would the outcome have been different with a petrol engined bike?

Probably... No one riding a proper bike fell over in the parking lot.

I'm pretty sure in any group of 6 people riding together, you'd have at least three or four who had a basic understanding of how to loosen & then tighten a nut/bolt

ZRX61 wrote: Tue Sep 05, 2023 8:36 pm

Mr. Dazzle wrote: Tue Sep 05, 2023 6:02 pm Would the outcome have been different with a petrol engined bike?

Probably... No one riding a proper bike fell over in the parking lot.

I'm pretty sure in any group of 6 people riding together, you'd have at least three or four who had a basic understanding of how to loosen & then tighten a nut/bolt

Can I interest you in some beans?



These days you'll be lucky if 1 in 6 understand that coffee comes from them....

US Energy Sec went on a 4 State tour to promote EV's.. in EV's.. Had difficulty finding charging spots & in one case had a staffer in a gas car occupy a charging spot until she showed up to use it... That stunt caused someone wanting to charge their EV to call the cops... which lead to the cops stating that it's not illegal to use a EV charging/parking spot to park your gas powered car.

I commented on our new 'country park' yesterday. Wandering in I noticed a big green box with 'Danger of Death' stickers etc. Wondered why they needed an electricity sub-station for a park. Had a look at the park web site today. 60 parking spaces, 10 of which are charging points. That's the way to do it.

ChrisW wrote: Tue Sep 05, 2023 7:34 am

Mr. Dazzle wrote: Tue Sep 05, 2023 7:15 am

That’s the first BMW I’ve liked the look of for ages. I’ll hold off until I’ve seen the front, though. Just in case.

Just seen this. It’s a Saab 99 that’s been polished.

Mr. Dazzle wrote: Tue Sep 05, 2023 6:47 amThe purification claims are just straight up weird.

And were banned by the ASA:

The Advertising Standards Authority (ASA) found that while the car does filter incoming air, it still releases pollutants from tyre and brake wear, with road tyres being a huge source of toxic particle pollution. Hyundai considered it had corroborated its claims, making clear it did not intend to suggest the vehicle left no particulates in the air, but the ASA ruled the ad was misleading and should not be used again.

https://www.theguardian.com/environment ... ing-claims

Mr. Dazzle wrote: Tue Sep 05, 2023 7:15 am

Looks like it was designed in the '70's & they added Clown Shoe wheels.

Edit: First & third Gen Corolla...

0-62mph in...

https://hackaday.com/2023/09/14/student ... ld-record/

...and they've delayed the 'no more new petrol cars' rule.

Never saw that coming. Much.

Count Steer wrote: Wed Sep 20, 2023 4:50 pm ...and they've delayed the 'no more new petrol cars' rule.

Never saw that coming. Much.

Haven't Germany already done the same?

If they hadnt they would have been unelectable. Mind you, they still may be.

Count Steer wrote: Wed Sep 20, 2023 4:50 pm ...and they've delayed the 'no more new petrol cars' rule.

Never saw that coming. Much.

Not only that but they've added in a "other countries need to do more stuff" bonus.

Its almost like they're trying (desperately) to appeal to a certain demographic

Potter wrote: Thu Sep 21, 2023 6:50 am It’s the only practical solution.
I don’t know if many of you get out of Europe much but it’s laughable to think that the UK would have any impact on the planet even if ICE cars were banned today.

It's a pretty mixed message from UK Gov though

The 20-whenever-it-ends-up-being ban on the sale of pure ICE vehicles gets all the press, but the government also have not changed their plans on EV quotas from manufacturers. SO they're saying "you can keep selling ICE cars until 2035" but they're also saying "X% of the cars you make MUST be EVs". Said percentage steadily rises, IIRC it's something 80% by 2030. So yeah, you can buy an ICE car but the manufacturer's aren't allowed to build any.

Feels a bit like Hobson's choice at the moment Or if you're feeling cynical, a vote winning announcement of no substance.

I’m pretty sure it will get kicked down further down the road in the next few years.

The elephant in the room that no one seems to be mentioning is that are there enough minerals to mine to fill the need for the batteries? Not sure how many cars are on the road worldwide but it’s got to be well over a billion.

I would bet that if there’s a study to examine the amount of rare earth metals available (let alone those available in politically stable countries) then it would probably not be enough to replace the current cars on the road with EVs. Let alone do the same again in 7 years when the batteries wear out.

Yes we will move to zero emission tech for cars, but batteries aren’t the answer.

The answer of course, is find something other than lithium. People are kinda working on it Ditto on rare earth magnets, you don't have to use rare earth magnets, they're just the low hanging fruit and hence what you see the most now.

Also assuming you only use brand new lithium. Unlike petrol lithium can be recycled.

It's another one of those "if it's obvious to a layperson how obvious do you think it is to the industry?" things. They just don't talk about it much cause press offices like to talk about what they've got to sell right now.

https://www.apcuk.co.uk/future-lithium- ... r-concern/

APC by the way is a legit government organisation, not a dodgy advocate website! They work on all parts of vehicle propulsion, including ICE.