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Old 11-12-2020, 07:46 PM   #51 (permalink)
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Quote:
Originally Posted by freebeard View Post
Here's the money shot:
Great Caesar's ghost that's complex.

Certainly not his first venture into fabrication and modification.

The KISS-Method is a rear spoiler expressed as a Bonneville-style rear deck extension and maybe toss in some side panels plus bottom diffuser action in stages as time permits.

1. Do not scare off the female of the species.

2. Do not invite bullies such as cops to pull you over or juvenile vandalism.

3. Make it easy to attach and detach.

4. Go back to chasing women and drinking beer.


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Old 11-12-2020, 08:55 PM   #52 (permalink)
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Weren't you around then?

I thought the solution was minimal to providing an opening trunk. Agreed the build quality left a lot on the table. And in the ditch.

Compare the tube frame alone with the flying buttresses of the GTI W-12 650. Then substitute JulianEdgar's extruded aluminum in the center section.

Teardrop external hinges are an OEM part from the 1930s. Not sure I'd recommend #4 to someone under 21.
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Old 11-12-2020, 09:26 PM   #53 (permalink)
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Quote:
Originally Posted by freebeard View Post
Not sure I'd recommend #4 to someone under 21.
I thought 18 or 19 was the drinking age up in Canada.

Anyway, it's supposed to be fun, letting a project get out of hand, drain your bank account and turn you into a social hermit isn't healthy, pandemic aside.
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Old 11-12-2020, 09:45 PM   #54 (permalink)
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Game was rigged from the start, I live in a dump and going out and drinking can end with you dead. Our town is most famous for a brutal murder case, lmao. I just hang with my close friends every now and then.

Anyways, sorry that I’m bad with terminology. I have a knack for getting it wrong. I’m asking how beneficial it is to have side panels on a rear deck extension. I feel that if I’m going to make a deck extension like that, it’s not much harder to add two side plates, making it a boxed cavity. It doesn’t seem like it’s that much more effort.

That mechanism is a sweet design! I think I may copy that in the future, but with a sheet of Lexan so I can see.

Police pulling me over is the main concern. As I said before, they pretty much take it into their own hands, and love to give tickets.
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Old 11-13-2020, 01:10 AM   #55 (permalink)
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If your thinking about filling the inverted U with Lexan that would be a base plate (an extreme spoiler). A Kamm-back with a 2nd Lexan rear window would be a truncated boat tail.

The Nissan pickup shows that box cavities don't have to be deep. And how taillights are problematical. Here's something snagged from Coventry University:

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Old 11-13-2020, 01:40 AM   #56 (permalink)
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Don't forget it can be really easy to test any modifications you want. Julian Edgar has a good summary of testing methods on his youtube channel and a few threads here on ecomodder.

https://www.youtube.com/channel/UCK9...uiCjxcQ/videos

https://ecomodder.com/forum/showthre...uff-38359.html

And

https://ecomodder.com/forum/search.p...9&pp=25&page=2

I have tried the pressure testing, wool tuft, and the throttle stop testing. All are easy to do. The key to the throttle stop though is the road. It has to be relatively flat (I think a slight up/downhill is ok as long as it is a consistent slope) and no curves.

Good luck. Like most forums we like pictures!
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Old 11-13-2020, 06:24 AM   #57 (permalink)
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Originally, I was going to tuft-rest some Masito model cars in front of an electric fan, but my engineer friend explained the complexity of scaling airspeed with size ratio and it’s a whole mess. Those methods seem better. I guess I’m just skeptical about a box cavity functioning that well. Without a tapered reduction in size (like the box cavity on that white van sent earlier) are you not just trailing out the airflow some more in the same direction? The box cavity on the Nissan pickup and the van in #55 seems like the sides wouldn’t do much. To me, I’d think air would rush off the side edges before it gets to the sidewalls of the cavity.

I think I’m just used to streamliner dynamics. Looks like things get different with a wide shape.
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Old 11-13-2020, 09:42 AM   #58 (permalink)
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Quote:
Originally Posted by JacobLeSann View Post
The box cavity on the Nissan pickup and the van in #55 seems like the sides wouldn’t do much. To me, I’d think air would rush off the side edges before it gets to the sidewalls of the cavity.
If you click on some of the links provided including a link to a semi-truck patent with stepped box cavity you will start to understand this as not so much about attached air flow or even reattached air flow but of tempering re-pressurization after a moving body passes through the air. Call it "filling the hole" if you will.

Quote:
Originally Posted by kach22i View Post
A little more info, some argue that it's about refilling the Aerotemplate- Part-C (or against).

https://ecomodder.com/forum/showthre...nit-33989.html
Several recent treads on this have explained it better than I can despite the personality disputes that colored them.

Do your cardboard and masking/duct tape mock-up, bet you will want those box cavity sides for structural stability.

I would do the bottom of the box cavity only after full belly pan and actually call it a rear diffuser at that point of the game.

If anyone finds a good CFD gif showing how a box cavity works it may do more for intuitive understanding than reading 30 pages of arguments.

I'll see what I can find, but now that you know what Google search terms to use you can feed yourself information to the point of overload.

EDIT: An LED brake light strip all along the ends would look cool and maybe keep people from walking into it in a parking lot.

Stupid people knocked off the mirrors on my S-10 by walking into them.
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You cannot sell aerodynamics in a can............

Last edited by kach22i; 11-13-2020 at 09:55 AM..
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Old 11-13-2020, 09:50 AM   #59 (permalink)
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Going back to the abstract for a moment, one of the first comments in this thread was about negative air pressures at the bow/hood creating thrust.

I found this for you, natures design.

Hydrodynamic performance of suction feeding is virtually unaffected by variation in the shape of the posterior region of the pharynx in fish
https://royalsocietypublishing.org/d...98/rsos.181249

Quote:
Our study, therefore, exceptionally shows that a streamlined biological shape subjected to fluid flows is not always the result of selection for hydrodynamic improvement.
I sort of get the feeling that if the suction is enough at the front/bow the sides and rear do not matter as much.

The body shape is being pulled into the fluid in front of it and not pushed through the fluid.

Again, this is a total aside and little to do with practical application of modifying a car for bad northern climate.
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Old 11-13-2020, 10:14 AM   #60 (permalink)
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I would like to see a rear 3/4 view of your car where the work would be concentrated, similar to the below concept sketch.

I took the original image from this link:
https://www.caranddriver.com/reviews...ivic-si-coupe/

I curved the lower support flanges, but they could be angled to the bumper or even come straight down for a true box shape or at lest an up side down "U".

If you surrender your truck access things will be a lot easier to affix.

Length must be based on side elevation with template overlay, do this and see how long it has to be. It may come out half as long as I've shown if you are lucky.

EDIT:

Material such as Polycarbonate or Acrylic might be out of your budget and or accessibility. Therefore coroplast or aluminum laminate sign board material ,scrap metal, thin plywood and other materials may be considered.

If the red plastic on the trunk lid is only a reflector and not an actual light then reflective tape on your spoiler may do.

And if as mused, an LED strip wired to the left brake light may substitute.

In my experience, the nicer you make it, and the stronger looking you make it the less likely some idiot will come along and try to damage it. If it looks frail someone may come along unable to resist temptation and test their strength on your property. Who would do such a thing? An idiot, the world is full of them.

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You cannot sell aerodynamics in a can............

Last edited by kach22i; 11-13-2020 at 10:49 AM..
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