I want to build a 100-mpg car (and I want it to look vintage)

[freebeard]

Are you serious?! Apart from grille blockers and wheel covers, basically every aero modification that I have seen people do here has been based on religiously following the template!

aerohead's Baby Template aside, or maybe Old Mechanic's User Removed's tadpole, I'm having trouble of thinking of an example.


https://ecomodder.com/forum/showthre...ole-26239.html

I'd say the most common modifications would be grille blocks, air dams and boat tailing.

[JulianEdgar]

Originally Posted by Fat Charlie

Why shouldn't I take your word for it? You've got the brains and do the work, and your work looks really good.

But I can read. I see your "OMG, the horror, the Insight doesn't meet the template!" I also see "Look at how I improved the Insight." ... by bringing it closer to the template.

Pick one reality. Put your Insight mods against the template. But if you insist on "putting no more into it than I see done here", then post a good profile pic of your Insight so we can. If you won't even do that, leave. Go away. We'll call Darin in to delete all your spammy looking book links.

I'd rather they not be spam, though. Because you do really good work. You improved the first gen Insight, but you're pissed off that other people have also put time into aero work. Can't we all just get along? You're doing great work, why the need to trash other work? Ecomodder is a place to share so that everyone doesn't have to reinvent the wheel. A lot of good work has been done already, and a lot of it has been shared here. You've been adding to that.

Really, though- look at your Insight pic that didn't meet the template, and look at your personal Insight with your own spoiler. It looks like you wanted the Insight to meet the template.

Happy to talk about the Insight, even though it's a typical red herring to the argument.

1. The Insight has a sharper downwards rear angle than The Template, and so according to Aerohead, it should have separated flow across the hatch.

2. Of course it doesn't - The Template cannot be used to predict separated / attached flow.

3. According to Aerohead, rear spoilers 'reach up' to separated flow. Of course, that applies only in very old cars with separated flow on the back, not a modern shaped car like the Insight.

4. So, according to Aerohead's theories, the spoiler on the back of the Insight cannot work - its rear edge is no higher than the standard rear lip.

5. But of course, it does work - it's operating in attached flow. (Just as with the recent, properly measured, data on the Prius and its trialled rear lip*.) It works by changing attached flow direction, not creating flow attachment.

6. If I'd followed the theories of Aerohead and The Template, the spoiler would look nothing like it does. A spoiler made to his theory of reaching up would also have increased drag with its larger wake.

You improved the first gen Insight, but you're pissed off that other people have also put time into aero work. Can't we all just get along? You're doing great work, why the need to trash other work?

You're quite wrong. I am - in your words - 'trashing' incorrect theories and misleading advice.

Would you rather people were continually led astray?

* testing that of course Aerohead immediately denigrated.

[JulianEdgar]

Originally Posted by freebeard

I'd say the most common modifications would be grille blocks, air dams and boat tailing.

And The Template is always recommended here as guide to the angle of those boat tail extensions...

When I first saw that, I was quite bemused. If only it was all that easy.

[freebeard]

When I first lurked here, the accepted wisdom was that a 14° angle was all that was required. Pickup aerocaps and such.

Then aerocaps showed up that mimic the GM EV-1 roofline.

[sgtlethargic]

Originally Posted by JulianEdgar

Well, clearly I am not much concerned with following your advice in that regard, am I? You're never going to make friends on a forum pointing out how much people have been sucked in by rubbish, or as another poster here puts it, "BS".

I believe there is nothing inherently wrong with the AST. I think the problem is with your misinterpretation/misrepresentation of the AST.

Speaking of following advice: I have no interest in looking at your critique of the AST or things Aerohead wrote (even if Aerohead didn't handle it ~properly) because of your approach. I welcome the critique of the AST and anything else.

Now, that's enough of that bull**** on this thread. Good day.

I must chide Freebeard for bringing it into this thread.

[freebeard]

I might be culpable but I don't see it proven. I made a veiled reference at Permalink #56

The big tension nowadays is the grounded half-Zeppelin and modern [electric] sedans and CUVs. The Metro is neither. Better to start with a Porsche 356. Or an old SAAB.

Tried to steer back ontopic at Permalink #70

There are two users in the Aerodynamics subforum that advocate for The Template and for a less specific, more modern approach. It was a veiled reference, not wanting to drag the thread down — thanks for asking.

JulianEdgar was already posting in the thread and behaving himself. But at Permalink #71:

Unless I did it incorrectly, the BOcruiser is pretty close.

That's where it went off the rails.

I welcome the critique of the AST and anything else.

Everyone looks at the side view, nobody looks at (and conforms to) the front view.

'Nuf said abou dat?



You pointed to this in the windshield thread. Any idea what it was modeled on? We had a talented poster here, someone else will have to help with his name. He posted this:

[sgtlethargic]

Originally Posted by freebeard

That's where it went off the rails.

Too funny.

[sgtlethargic]

I was looking at the Bluebird land speed racecar thinking, "How could that be made streetable?" Then I saw that toy, which looks retro-futuristic. I would draw what I have in mind using Solidworks, if I had internet access at home. Another big influence is the 1938 Phantom Corsair. I'll edit this to post pictures. There's also a Russian artist, "600v," that draws some cool car stuff. I may have posted some of these here, years ago.

It looks like he was bitten by the AST bug!

[JulianEdgar]

Originally Posted by freebeard

When I first lurked here, the accepted wisdom was that a 14° angle was all that was required. Pickup aerocaps and such.

Then aerocaps showed up that mimic the GM EV-1 roofline.

There are almost no numerical rules of thumb in car aerodynamics. As soon as someone - anyone - starts to quote numbers in aero rules of thumb, you can be pretty skeptical.

As for The Template, it's just one of the low drag aero shapes (shapes, note: not cars) that have developed over the years. No more, no less.

But as I said, this group has been led down a rabbit hole wrt to The Template, and you can see how it has caused all sorts of misapprehensions to (1) develop and (2) then solidify.

To be honest, I think the huge underlying issue - that I am afraid you, Freebeard are a strong part of - is that speculation has become largely the culture of the group. To be blunt, posters just guessing.

That's why, I think, The Template has been grasped by people. Rather than just working by complete guesswork, here was (apparently) a form that could be followed to get best results.

But like any snake oil, it's all too good to be true.

If you are building a car from scratch, pick a template - it matter 4/5ths of stuff-all* which one you pick.



But if you are modifying a car in any way, as soon as someone starts talking about a template, or any other numerical rule of thumb, run a mile. Car aero is simply much too complex to apply that sort of simplistic analysis.

(*Except if you're also interested in minimizing lift. Then it matters!)

[JulianEdgar]

Originally Posted by sgtlethargic

I believe there is nothing inherently wrong with the AST. I think the problem is with your misinterpretation/misrepresentation of the AST.

Speaking of following advice: I have no interest in looking at your critique of the AST or things Aerohead wrote (even if Aerohead didn't handle it ~properly) because of your approach.

I welcome the critique of the AST and anything else.

Now, that's enough of that bull**** on this thread. Good day.

I must chide Freebeard for bringing it into this thread.

Glad we sorted that out!