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Old 01-29-2021, 01:24 PM   #11 (permalink)
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fully attached flow

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Originally Posted by AeroMcAeroFace View Post
I am very familiar with Sunswift eVe, I read that paper a while ago. They don't start with a template and make no mention of a template in the paper. Just in case anyone is mislead by the original post.

Fully attached flow, I completely agree with, that is the goal, getting there is rarely if ever done using a "template" in any form.
That's the whole point! All the really low-drag vehicles have the subtle, continuous, unadulterated aft-body contours which guarantee flow attachment and pressure recovery. They're all 'STREAMLINED.'
Any contour which distinguishes itself as 'streamlined' qualifies as a 'template' by default.
Sunswift's aft-body contour itself is a 'template.' It's not rocket science.
Any university team could simply 'copy' Sunswift and experience identical aerodynamic performance. Easy! No measurements. No testing. Guaranteed results.
That's what 'templates' do.

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Old 01-29-2021, 01:58 PM   #12 (permalink)
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I need to know every keystroke, including whether a right-click, or left-click, before I can even get to the ' How to: Post pictures on EcoModder so they never die'
For that we'd need to know your operating system.

First step, be willing to try.

Then learn to recognized a properly formed tag: [U*L="x"]x[/URL].

You can just type it out by hand and never have to click a button.

Who populated your albums in 2008?
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Old 01-29-2021, 02:22 PM   #13 (permalink)
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populated

I'm not sure what 'populated' refers to.
PhotoBucket was purchased by seven venture capitalists. They seized all accounts, and have held them for ransom.
I can't access any of MY materials unless I pay the ransom.
I spent $ 770 just in scans to get them into PhotoBucket.
All conditions of the original hosting arrangements were ex post facto erased.
( I've purchased your home mortgage as a derivative, and even though you thought you had 30-years to pay it off, I'm now demanding immediate payment in full ) sort of warm, fuzzy feeling to it.
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Old 01-29-2021, 03:16 PM   #14 (permalink)
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expanded data

I've added material from Julian Edgar's book, at the bottom of the original post on page-1
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Old 01-29-2021, 03:17 PM   #15 (permalink)
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Off by one minute.

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What is meant by populating database? - Quora
https://www.quora.com/What-is-meant-...tabase?share=1
As others already wrote, to populate a database means to add data to it. The background of the term is in the foundation of database theory.
I was referring to ecomodder.com/forum/member-aerohead-albums-book+illustrations.html and ecomodder.com/forum/member-aerohead-albums-aircraft+-+watercraft+-+spacecraft.html

Sorry for ripping the scab off the Photobucket story.
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Old 01-30-2021, 07:17 AM   #16 (permalink)
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Quote:
Originally Posted by aerohead View Post
That's the whole point!

Sunswift's aft-body contour itself is a 'template.' It's not rocket science.
Any university team could simply 'copy' Sunswift and experience identical aerodynamic performance. Easy! No measurements. No testing. Guaranteed results.
That's what 'templates' do.
So every car fits a "template" because every car is a template, so what is the point of having a template. To get low drag you need a template you keep saying, and then keep claiming that everything is a template.

"5) The fact is, that for half-bodies, the 'template' is the lowest drag form ever measured. If you take exception to that, I recommend that you take it up with those who measured it."

Maybe it is the lowest drag half-body, what is the relevance of that? It is easily possible to go lower drag by using a non-half body.
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Old 01-30-2021, 11:05 AM   #17 (permalink)
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Originally Posted by aerohead View Post
5) The fact is, that for half-bodies, the 'template' is the lowest drag form ever measured. If you take exception to that, I recommend that you take it up with those who measured it.
This is an odd statement to make. Scibor-Rylski developed a streamlined body with a contoured underside in the City University of London wind tunnel in the 1970s that came in at cD = 0.07 in ground proximity. It looks very different from the "template." Why shouldn't we all build to that form as a "first approximation"?

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10) Only until one has put an 800-hour project behind them, do they realize the benefit of a 'template', as a 'first approximation'.
I disagree. Testing should be the first attack, to find out what is actually going on. I could have spents hours building up the rear glass on my Prius to conform to the "template." It would have been a complete waste of time, since a simple tuft test showed it already had attached flow. So, why not use the 3rd generation Prius profile as a template?
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Old 02-03-2021, 12:39 PM   #18 (permalink)
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what is the point

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Originally Posted by AeroMcAeroFace View Post
So every car fits a "template" because every car is a template, so what is the point of having a template. To get low drag you need a template you keep saying, and then keep claiming that everything is a template.

"5) The fact is, that for half-bodies, the 'template' is the lowest drag form ever measured. If you take exception to that, I recommend that you take it up with those who measured it."

Maybe it is the lowest drag half-body, what is the relevance of that? It is easily possible to go lower drag by using a non-half body.
--------------------------------------------------------------------------------------
So, let's back up a few paces:
1) road vehicle aerodynamics is about pressure recovery.
2) 'streamline' profiles are all about pressure recovery.
3) wings and half-bodies are all Hucho qualified as candidates to really low drag.
-------------------------------------------------------------------------------------
4) In the context of EcoModder.com, I've yet to see a production automobile derived from a wing section that we might 'mod.'
5) 'Wing'-derived competition vehicles are already as large as the largest production vehicles manufactured in recent history, while being just large enough to accommodate one or two occupants.
6) ' Enlarging' these types of bodies, to accommodate a family of four or five introduces 'size' challenges which may not be capable of overcoming.
7) Some of them don't even provide for forwards or rearwards outward vision. This is especially true of some that Hucho presented in his 2nd-Edition.
The VW Drop-Shape is already 'full-length.' Only wheel integration could lower its drag.
-------------------------------------------------------------------------------------
8) All production automobiles, which already accommodate four or five occupants, do qualify as a mutilated, severely-truncated, half-bodies, in the context of Paul Jaray's body-morphing, from semi-circular section, to a more rectangular section, respecting tumblehome and minimum edge radii as a mission-critical prerequisite for flow attachment without vorticity. Most CUVs are 'Kamm-esgue' although Renault Vesta-II and Boxfish are the only few actual 'Kamm-backs', in the strictest sense of the term.
-------------------------------------------------------------------------------------
This is the context of a 'template.'
9) If a particular vehicle 'starts out' streamlined ( in the aft-body ), then Hucho, or any other aerodynamicist or aeronautical engineer involved in drag reduction, emphasizes 'elongation' of the truncated body, and along its non-truncated, extrapolated profile.
--------------------------------------------------------------------------------------
10) No straight-roofed, or straight-sided vehicle can be a 'template.' They are incapable of pressure recovery, by default.
11) Most passenger automobiles already embody camber in elevation and plan-view.
12) The rear camber IS the beginning of 'boat-tailing,' by definition.
13) Really low drag vehicles begin this camber at the driver's shoulders, tapering the rest of the aft-body continuously, while maintaining only the 'moderate' pressure rise, which protects the TBL from separation.
14) The Renault Vesta-II, EV1, Bionic Boxfish, and VW XL1 all have this, and their Cds are virtually identical. All three are AST 'template' vehicles, although you'll have to interview the designers to find out why they chose the shape they chose.
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Old 02-03-2021, 12:49 PM   #19 (permalink)
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Cd 0.07

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Originally Posted by Vman455 View Post
This is an odd statement to make. Scibor-Rylski developed a streamlined body with a contoured underside in the City University of London wind tunnel in the 1970s that came in at cD = 0.07 in ground proximity. It looks very different from the "template." Why shouldn't we all build to that form as a "first approximation"?



I disagree. Testing should be the first attack, to find out what is actually going on. I could have spents hours building up the rear glass on my Prius to conform to the "template." It would have been a complete waste of time, since a simple tuft test showed it already had attached flow. So, why not use the 3rd generation Prius profile as a template?
1) It would be great if we could see this form.
2) Morelli's shape bottomed out around Cd 0.05. As a more carlike body, it came in at Cd 0.161 without wheels. Adding wheels pushed it to Cd 0.35. Then ,after 'integrating' the wheels into the body, they ended up with Cd 0.201.
3) Rolf Buchheim et al.'s VW Flow Body Long-tail was Cd 0.091 without wheels. Cd 0.14 with.
4) 'Baby-template' came in at Cd 0.1209, implying that there's something to be said about Goro Tamai's wheel integration at M.I.T..
5) 2013 CUER came in at Cd 0.11 in the Airbus wind tunnel.
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Old 02-03-2021, 01:02 PM   #20 (permalink)
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Prius

yes, it's unfortunate that it took as long as it did before the other profiles got published. Same for Insight-I.
Relying on 'experts' for profiles is certainly a limiting factor for amateurs.
Ultimately, you would have arrived at the same Cd, in a long-tail configuration, however with more material and weight.

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