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Old 11-15-2009, 09:55 PM   #1 (permalink)
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Lotus 7/Locost Aero Rebody

An extreme aeromod in progress: a low Cd and low frontal area body to fit over a Locost (scratchbuilt Lotus 7 lookalike). I'm shooting for 100 mpg, got the running gear up to speed and now it's aero time.

Here's what it looks like "stock"; Cd 0.7 roughly. As you can see, it's an all weather car--all the weather gets in the car with you--so I'm looking at a coupe or convertible.




What makes this project interesting is I have about a $2000 body budget. If I had unlimited funds, I'd do something like this Bristol 450 LeMans racer (shown in blue over a red Lotus Seven) of the early '50s (though not so steep on the back because I know better--I have my Hucho and Bristol didn't). But I don't, so I'm looking for as few compound curves as possible, in hopes the bulk of it can be made from sheet materials.



Anyway, I got a bit of a do-over, thanks to a recent burglary, and I'm starting with a clean slate. Suggestions will be appreciated. [EDIT: For example, can anybody tell me how to submit my jpgs as pix rather than thumbnails?]

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Last edited by JackMcCornack; 11-15-2009 at 09:57 PM.. Reason: Seeking tech advice for posting graphics
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Old 11-15-2009, 10:13 PM   #2 (permalink)
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Before we can offer advice: will you be driving it forward or backward? Just kidding.

But seriously: the location of the cockpit at the extreme rear is going to make this challenging. How much longer are you willing to make it?

One option you have is to go with a driver-only windscreen/canopy, with an optional 2-person version for the more sociable trips. Not often we get to cut down frontal area so dramatically.




---

To add full size images to your post after uploading, you get the URL of the full size image, then click the "add image" edit button () and post the URL to the image.

If you're not sure "how to get the URL" of the uploaded image, just ask and I'll post more detail.
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Old 11-15-2009, 10:55 PM   #3 (permalink)
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I was just looking at your page two days ago... so you lost all that work? sorry to hear that.
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Old 11-16-2009, 12:56 AM   #4 (permalink)
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Went on your site, that is waaaay cool!

Very much like what I'm trying to do with my 356TD, but a lot more work -- good on ya!

Sorry to hear of your lost work, hope you can get back on track.

For a body, how about something like a Lotus 11, but with fastback or kammback top?

http://www.historiclotusregister.co....otus11-515.jpg
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Old 11-16-2009, 07:10 AM   #5 (permalink)
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Have you considered using fiberglass over foam construction?
Not building a brick with layers, but single sheets bent to shape.
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Old 11-16-2009, 09:34 AM   #6 (permalink)
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How about the Morgan Lifecar - even made of wood and as you live in a wood and its green ?

http://www.waymotor.com/img/1640-Mor...oncept-Car.jpg

Your styling 3D images look like you are most of the way there already.
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Old 11-16-2009, 04:36 PM   #7 (permalink)
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Wrote MetroMPG:

> Before we can offer advice: will you be driving it forward or backward? Just kidding.

Both ways, actually, but backwards mostly when parking.

> But seriously: the location of the cockpit at the extreme rear is going to make this challenging.

Man, tell me about it! The highest point of the car is at 3/4 chord. It would indeed be easier to streamline it in reverse. You can see why my next clean-slate project is a Metro middy.

> How much longer are you willing to make it?

Gosh, I guess I'm willing to make it for another month or two. Longer if I have to.

I have no specific limit for length, but it needs to be a practical vehicle; I don't want the transom run over in grocery store parking lots. It's going to have to be a Kamm back, there's not enough room to make it pointy unless I'm willing to about double the overall length.

Here's a drawing a fellow contributor to LocostUSA.com sent me, it's kinda in the British tradition and I expect it would be an improvement. I doodled a kammback on it. I've some aesthetic limits, but mostly the goal is streamlined and cheap.

PS--please walk me through the jpg posting process. It might be good in the FAQs.

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Last edited by JackMcCornack; 11-17-2009 at 11:10 PM.. Reason: Trying to figure out how to post pix
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Old 11-16-2009, 08:20 PM   #8 (permalink)
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I could be wrong, but the front fenders look like your major source of drag. Could you just bring the fender around the front of the wheel? Then a bit of aero shaping, maybe embedding the headlights, and fill the empty space rearwards of the wheel with skinned foam, with a good aero shape?
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Old 11-16-2009, 08:48 PM   #9 (permalink)
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Whaddyamean, jamesqf, like the ones on my avatar?

Yeah, there's some low hanging aerodynamic fruit on that car, all right. Front fenders were the first thing to go. Since when it comes right down to it, the aerodynamic goal of everything forward of the thickest part of a car is to keep the airflow attached so the rear of the car can pull it back in again, I figure I can tuft test my way from front to back. Anyway, the pontoons between the rear and front fenders are 26 gauge metal roofing (light, cheap, painted already) the front fenders are molded fiberglass, the top part of the empty space rearward of the wheel is also molded fiberglass and the lower part is...cardboard right now, I hadn't made those patterns before the data burglary.

The front fenders look a bit blunt, and indeed they are, but I think adding length to the back of the car will have greater results than adding length to the front (so for any reasonable overall length, the lowest drag will be achieved with a fairly blunt nose), and the bulbous bit forward of the wheel is necessary to fit a headlight inside (centered at the legal 22" above the asphalt).

PS--somebody please tell me (in painstaking detail) how to post jpgs on this site. Everything I've posted to date has come out a thumbnail.
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Old 11-16-2009, 11:56 PM   #10 (permalink)
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JackMcCornack -

The thumbnail is the way it displays. I have a complicated cheat that will work with attachements, but it's ... complicated.

Another way to do it is to start an album in your User CP. Go here :

User CP -> Networking -> Pictures & Albums

Once you have uploaded and saved a picture, you can click on it. You will find a "BB Code" image url text that you can copy-paste into your post.

Soooooo, upload your pictures in the album, and copy-paste them as you please.

CarloSW2

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