The Fastback bloc

[Fat Charlie]

If your method of correcting erroneous information is heavily loaded with rudeness, I'm okay with that.

This isn't the back room of an aeronautical engineering department at a college somewhere, it's a public forum about cars.

Edit: see post #33 for clarification

[California98Civic]

Originally Posted by Fat Charlie

If your method of correcting erroneous information is heavily loaded with rudeness, I'm okay with that.

This isn't the back room of an aeronautical engineering department at a college somewhere, it's a public forum about cars.

Sure. I get that. Heavy rudeness now and then is one thing. Obsessive focus on one person is another. No job I ever worked before education (retaurant kitchens, cab companies, nightclub staff, sales) would allow one employee to repeatedly take time to pick out every little error in one otherwise productive co-worker over and over for months with the purpose being to insist that every error means he's unfit for his job.

It's not so different in education, either. There is plenty of conflict and heavy rudeness. Harrasment is where the line gets drawn.

[Fat Charlie]

Taylor95 hit send just before I did, which messed up the continuity I was trying for. What I was saying is that I'm okay with JulianEdgar leaving us to it.

We're not a group of colleagues arguing about one point behind closed doors, we're a public forum that's interested in a pretty wide area- and while JulianEdgar has brought a lot of great stuff, there are way too many personal attacks. Having them all target one person just makes it look worse.

[California98Civic]

Originally Posted by Fat Charlie

Taylor95 hit send just before I did, which messed up the continuity I was trying for. What I was saying is that I'm okay with JulianEdgar leaving us to it.

We're not a group of colleagues arguing about one point behind closed doors, we're a public forum that's interested in a pretty wide area- and while JulianEdgar has brought a lot of great stuff, there are way too many personal attacks. Having them all target one person just makes it look worse.

Ah, I get it. Thanks for the clarification. And I think I could not agree more--including that he brings a lot of good stuff here, too.

[JulianEdgar]

Originally Posted by Taylor95

It's pretty unrealistic to call an idea rubbish and expect a positive response.

In such disagreements, most of us like to see the reasoning and science behind the different lines of thought. That's what I value, anyway.

1. I have covered how fastback shapes cause lift many times here before.

2. I suggested that 'Aerohead' (and of course anyone else who wants to see what really happens) measure aerodynamic pressures on some cars - easy to do. Best not to take my word for it, but to see for yourself.

3. When a discredited idea is trumpeted again and again by the same person, I'd call that idea rubbish.

[JulianEdgar]

Originally Posted by Fat Charlie

If your method of correcting erroneous information is heavily loaded with rudeness, I'm okay with that.

This isn't the back room of an aeronautical engineering department at a college somewhere, it's a public forum about cars.

Edit: see post #33 for clarification

Such gentle souls! Where I come from, we differentiate personal abuse (ie abuse of a person) with denigration of what that persons says, the ideas they espouse, etc.

I think about half - or perhaps a bit more - of what 'Aerohead' writes here is wrong, misleading or irrelevant. Since he is the most prolific poster - by far - on technical aspects of car aero, that is a concern to me, especially when most people uncritically accept the rubbish he (mostly) writes.

I do not like seeing amateur car modifiers being given incorrect information - as an amateur car modifier myself, I am only too well aware of how that can waste people's time and cost them money.

[JulianEdgar]

Originally Posted by California98Civic

Sure. I get that. Heavy rudeness now and then is one thing. Obsessive focus on one person is another. No job I ever worked before education (retaurant kitchens, cab companies, nightclub staff, sales) would allow one employee to repeatedly take time to pick out every little error in one otherwise productive co-worker over and over for months with the purpose being to insist that every error means he's unfit for his job.

It's not so different in education, either. There is plenty of conflict and heavy rudeness. Harrasment is where the line gets drawn.

This is not an employment space; nor is it an education space - your analogies are tenuous, to say the least. It's a public forum of car enthusiasts.

I have no power over anyone else here; however it appears that I am in a position to perhaps better recognize rubbish being disseminated under the guise of good advice.

'Aerohead' beats every other poster hands-down for giving advice that is wrong, misleading or irrelevant to the question being asked.

[JulianEdgar]

Originally Posted by Fat Charlie

Taylor95 hit send just before I did, which messed up the continuity I was trying for. What I was saying is that I'm okay with JulianEdgar leaving us to it.

We're not a group of colleagues arguing about one point behind closed doors, we're a public forum that's interested in a pretty wide area- and while JulianEdgar has brought a lot of great stuff, there are way too many personal attacks. Having them all target one person just makes it look worse.

I am not aware of having personally attacked anyone. Perhaps you confuse the idea of attacking what someone writes with attacking someone personally?

'Aerohead' very often writes material here that is wrong, misleading or irrelevant. That is a judgement on what he writes here, not a judgement on 'Aerohead' as a person. (eg I would never write that Aerohead is a fool, a simpleton, or an idiot - that would be a personal attack.)

[JulianEdgar]

Incidentally, for anyone who is actually interested in facts rather than supposition and erroneous theories, take the Porsche Taycan as an example of a modern fastback - and let's look at the topic of aero lift.

In profile:



CLr (coefficient of lift, rear) : 0.16

(That figure is from a presentation Dr Thomas Wolf of Porsche was kind enough to send me - rear spoiler not raised.)

Frontal area 2.33m^2.

Calculated rear lift at 100 km/h - 17kg

At 200 km/h - 70kg

At 260 km/h - 119kg (that's 262lb!)

No wonder they fitted an automatically deploying rear spoiler....

All fastback shapes with attached flow develop lots of low pressure over the upper curves. That can only be offset by:

1) rear spoiler (usually only a partial offset of lift), and/or
2) very effective underfloor aero (can completely cancel lift)

But as I keep saying, there's absolutely no need to guess or use only factory coefficients. Just measure the actual, real, aerodynamic panel pressures on your car on the road.

My Insight's measured pressures (my car runs very effective undertrays) - Pa at 80 km/h:



Note the low pressures all the way across those upper curves. It's just what happens with attached flow and these shapes.

So the next time that 'Aerohead' states his completely wrong notion about fastback shapes having no lift, can we actually ask for some evidence - real evidence - and not just pretend the emperor has clothes... and that we should all be politely agreeing with claptrap?

[freebeard]

We appreciate your insight.

Yesterday you posted four separate times in 17 (I know!) minutes. Instead of editing. We have another poster with that same habit. You have more in common than you realize.