Thank you

[freebeard]

Originally Posted by Vmann455

"Optimal design" doesn't mean anything short of reshaping an entire car isn't worth doing.

Doesn't mean reshaping an entire car isn't worth doing. I still think a fiberglass Volkhart-Saggita body would have sold well in the 1970s.

On this forum the most we see is pickup truck aerocaps. Were I a Bitcoin millionaire you be seeing [right now] an Arcimoto FUV with a folded stainless steel boat tailed body.



Shiny. It's really an lo-poly version of the ME-262, but I'd be criticized for drinking the Template Kool-aid.

[JulianEdgar]

Originally Posted by freebeard

I was thinking you were saying the best shape is no shape and the best angle is no angle, but now I can't explain the gap between a mock-up and a template.

If you can't explain the gap between blindly following a template, and developing an optimal shape through test and development, then I can't help you. I would have thought the difference was obvious and profound.

[JulianEdgar]

Originally Posted by Isaac Zachary

The phrase: "there comes a point of diminishing returns." comes to mind. The question I'd have is how much would I benefit from the work involved. To get everything "optimal" in my mind requires not only redesigning the rear window and trunk area, but also making my own windshield and hood. At what point does optimal become OCD?

I really don't know why you take a simple example and then extend it to something quite different, as if that were being discussed all along. We are discussing the use of the template as purporting to suggest an optimal boat-tail shape. I don't know where that suddenly turns into reshaping the entire car.

If all it takes is a "little testing" "simple testing" that makes sense. However, in my mind it sounds like a lot of work. I'd be tempted to see if I get good mileage with the first mockup and then leave it on permanately if it does.

I've tried testing fuel/air ratios and degrees of advancement. And even though with those it's just a small twist of an ajustment screw or a distributor it's still a lot of work.

Now building not just a 3 dimentional mock up but several of them sounds a bit harder than just twisting a screw, at least for me. Or maybe I just don't understand the concept of "simple testing of mockups."

However, I'm still interested in trying a boat tail at some point as it seems to be the best way of getting better fuel mileage. So thank you, I'll keep these points in mind.

Turning air/fuel ratios and ignition timing is a good parallel. How would you react if someone said that for best power, you must have 12.5:1 AFR, for best economy, 15.7:1? I hope that you would say, "On what car and engine?" Because, as you are probably aware, suggesting that such rules of thumb should be universally applied is also rubbish. You can find these optimal values only through testing.

Re testing. It's the same with any car modifications - engine management, sound systems, suspension, cylinder head work, engine intake systems, aerodynamics. You can follow some rules of thumb - that may or may not work - and accept whatever results. Or you can do some testing and development and 90 per cent of the time get much better results.

Why? Because it's easier to just go with something predesigned. And if it produces possitive results, it stays on the car. If it doesn't it gets taken off.

But you make it sound like the level of effort isn't much different either way, template or mock-ups.

[shrug] Is fitting whatever springs Fred says will work best (because he has a completely different car but they work on his car) better than making some measurements of the existing springs and then developing new ones from that starting point? Pretty obviously, no.

It's not a radical idea - actually making a car modification through measurement and development, rather than guesswork.

Sounds like he can't be happy with someone trying something that's not optimal, even if it ends up giving them a small benefit.

I've done aero modifications that either worked or didn't (ie made drag better or worse) through a 3 degree change in the angle of a spoiler. That's stuff you'll never know through blindly following someone's guesswork.

That's what makes it hard to follow his posts, for me anyhow. It's kind of like one guy saying he's going to lean out his carburetor and another ridiculing him for not installing fuel injection and tuning each cylinder's AFR.

It's nothing like that at all. A much better parallel is ridiculing someone for following the AFRs and ignition timing given to him as being optimal by someone who didn't even know what engine he is using. That's how stupid The Template is as a guide to aero car modification.

[Isaac Zachary]

Originally Posted by JulianEdgar

I really don't know why you take a simple example and then extend it to something quite different, as if that were being discussed all along. We are discussing the use of the template as purporting to suggest an optimal boat-tail shape. I don't know where that suddenly turns into reshaping the entire car.

I suppose because I was thinking more along the lines of boat-tail since I've been under the impression there's more to gain from boat tailing than front end-mods. And with a boat tail there's the angle on the top, angle on the bottom and angle on the two sides. Not to mention the question as to where to start the boat-tail in the first place, from off the trunk or start up at the top of the car above the rear window. How do you make a mock-up that's easily and acurately changed for testing.

Plus you keep mentioning the work "optimal" here. If following a one-size-fits-all rule-of-thumb or template has zero value, then following a one-size-fits all design and just moving it up or down a few inches to see where it's optimal doesn't sound like it would improve much either. It sounds, to me anyhow, like taking a template shaped car and then slighly lowering or raising the front and/or rear to see what gives you an optimal angle after a little testing and calling it good.

Originally Posted by JulianEdgar

Turning air/fuel ratios and ignition timing is a good parallel. How would you react if someone said that for best power, you must have 12.5:1 AFR, for best economy, 15.7:1? I hope that you would say, "On what car and engine?" Because, as you are probably aware, suggesting that such rules of thumb should be universally applied is also rubbish. You can find these optimal values only through testing.

Re testing. It's the same with any car modifications - engine management, sound systems, suspension, cylinder head work, engine intake systems, aerodynamics. You can follow some rules of thumb - that may or may not work - and accept whatever results. Or you can do some testing and development and 90 per cent of the time get much better results.

Maybe it was just coincidence, but I found that starting with the rule-of-thumb (or just a guess from my intuition) made the biggest difference (end result 24mpg to 30mpg). Trying to fine-tune from there didn't seem to help very much (30mpg to 30mpg)

Not only that, but with my testing I really felt that I was at the end of my measuring techniques. Throttle stops, coast downs, and other such rudimentary testing are nearlly impossible to get consistent results from. Do the test 10 or 20 times and then average the results... But it also gets kind of weird having neighbor folks watch you go up and down the same street day after day doing testing.

If I ever did an engine again I'd want access to a dynanometer. But would it be worth the $700 for just one testing session?

Originally Posted by JulianEdgar

[shrug] Is fitting whatever springs Fred says will work best (because he has a completely different car but they work on his car) better than making some measurements of the existing springs and then developing new ones from that starting point? Pretty obviously, no.

It's not a radical idea - actually making a car modification through measurement and development, rather than guesswork.

I've done aero modifications that either worked or didn't (ie made drag better or worse) through a 3 degree change in the angle of a spoiler. That's stuff you'll never know through blindly following someone's guesswork.

I would like to say to most everyone else's credit is that rarely do you find people on here who don't do any testing at all. What I mean is doing a mod and then seeing if you get better fuel mileage or not and then deciding to leave it on or not is still a form of testing. Sure, such a person may not get "an optimal" design, but if he or she gets better fuel mileage I think we can all be proud of him or her, can't we? Maybe in a few months or years they'll try out a slightly different version of the same thing and compare which of the two helped the most.

Originally Posted by JulianEdgar

It's nothing like that at all. A much better parallel is ridiculing someone for following the AFRs and ignition timing given to him as being optimal by someone who didn't even know what engine he is using. That's how stupid The Template is as a guide to aero car modification.

It's not the idea, it's the wording. As Freebeard mentioned, it seems you say one thing and then another. Not that you do, but this is what I was trying to get at earlier. What does the average Joe reading your posts understand from them?

This is what an average Joe will think, at least on the posts I've read (or tried to read):

1. Hey! I found a template that looks like a very aerodynamic shape on this site called Ecomodder. Cool!
2. A guy named Julian hates the template... So much hate, it sounds like he has no faith in aerodynamic shapes.
3. But wait a minute Julian says make a mockup and try it. But what's the difference between making a mockup based off of the template, and just making a mockup based off of my own guess and trying it? (Did he say try one mock up or two...??)
4. But wait again. Julian is now directing his disdain towards an individual. So maybe he's here for personal reasons...
5. Trying to read through the mudslinging...
6. More mudslinging...
7. Is this an ecomodding forum or a political debate?
8. Hey! Another topic on VW diesels! Maybe I'll move out of the aerodynamic forums for a while...

I'm not saying you said anything of this sort. But that's what the average Joe will understand from it all. Stick to your facts, be nice, don't direct thing personally towards others. Show a possitive before a negative

For an example, "I see you like this template here. A car shaped like the template both front and rear and everything in between may be more aeordynamic than your average car. But you're not going to be able to make your car exactly like it. My recomendation is, if you want mods that make your particular car much more aerodynamic than justfollowing that template then try this! I think you'll be much more pleased with the results!"

IF you learn to talk properlly you can learn to talk in a languange more average Joe's will understand.

Take me for an example. I'm finally understanding what you mean. But only after how many posts and threads? Forced ideas always become interpreted as something they don't mean. Persuasion gets more people to understand you.

[Piotrsko]

Hello, I must be going
I cannot stay
I came to say
I must be going
I'm glad I came
But just the same
I must be-- going


I'll stay a week or two
I'll stay the summer through
But I am telling you
I must be -- going. Groucho Marx, animal crackers

[freebeard]

If you can't explain the gap between blindly following a template, and developing an optimal shape through test and development, then I can't help you.

But you can dodge the question. I can't explain your conceptual leap from no-template to mock-up.

We're back to using 'rule of thumb' instead of 'first approximation'? I don't have any more success than you do.

Think of it as more a guideline than a rule of the sea (Prts f th Crbbn). The spirit, if not the letter of the 'guideline' is that to get a smooth flow off the tail you need a clean stagnation.

[redpoint5]

Can we change the thread title to "Thanks for nothing"?

[jjackstone]

I haven't posted in a long time mainly due to the battle between Aerohead and JulianEdgar. Pretty much even quit looking at the aerodynamics section for the same reason. I didn't read all of this thread because it got boring after a couple pages and worse after that. Just a couple things I'd like to say and the I'll bow out again.

Mr. Edgar was writing about posting facts in there somewhere. I suggest that the facts should be posted with all references and the references qualifications if not already being done.

The other thing is, instead of arguing back and forth over who is correct, find someone to sponsor a contest between the two men and get each one of them an identical vehicle to modify. Then find a neutral party to test which vehicle has the lowest drag and is still roadable. The one with the lowest drag wins. End of battle. Elvis is leaving the building.

JJ

[freebeard]

Elvis was in Follow That Dream, the most anarchist movie of 1962.

I support the notion, but to broaden the appeal to everyone, I suggest the identical vehicles be VW Beetles. In fact I would donate my 1958 Canadian body on 1971 floorpan. It's just taking up space in the carport anyway. Denton, TX, is closer than Australia.

[JulianEdgar]

Originally Posted by Isaac Zachary

IF you learn to talk properlly you can learn to talk in a languange more average Joe's will understand.

I thought the propositions I am putting have been repeatedly made clear? If not, I'll try again:

1. Using any predetermined shape (including The Template) to guide the aerodynamic shape of extensions to cars, to guide the heights of spoilers, to assess the 'aerodynamic purity' of shapes, to determine where there will be attached and separated flow (etc) is just rubbish.

2. But don't believe me - don't believe a word that I say. Go and do you own research, make your own aero measurements, read the aero textbooks for yourself. Then the amount of misinformation being promulgated here will immediately become obvious.

3. People here have been misled for a very long time by one person. His odd theories have become adopted here as fact, despite them not being supported by any technical reference. That person refuses to change his mind, irrespective of the evidence that is produced, and so normal discussion with him is impossible. If he says night = day, he appears to believe that is the case.

4. In all my years of writing about car modification, I have never seen a group of people so mired in information that is so divorced from what credible technical references and industry professional engineers actually say. Normally, when there is such BS being spouted, the group self-corrects over time, but here the BS just gets accepted as fact and repeated. Those who try to correct it usually give up after a short time and move on.