Drag Coefficient, and other parameters wanted |
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Drag Coefficient, and other parameters wanted |
astronomerdave |
Nov 6 2009, 01:21 PM
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#1
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Member Group: Members Posts: 69 Joined: 26-January 09 From: Los Angeles, CA Member No.: 9,979 Region Association: Southern California |
Does anyone know where I can find this information (for '72 914/4) ? . . .
Thanks, --Dave |
jd74914 |
Oct 7 2010, 03:05 PM
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#2
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Its alive Group: Members Posts: 4,782 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
Why don't you take a picture, print it on graph paper, count the squares, and then figure out the apsect ratio of the squares? I'm not sure how else you would calculate something like that without building a full CAD model and taking a crosssection.
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Richard Casto |
Oct 8 2010, 06:04 AM
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#3
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Blue Sky Motorsports, LLC Group: Members Posts: 1,465 Joined: 2-August 05 From: Durham, NC Member No.: 4,523 Region Association: South East States |
Why don't you take a picture, print it on graph paper, count the squares, and then figure out the apsect ratio of the squares? I'm not sure how else you would calculate something like that without building a full CAD model and taking a crosssection. I know very little about Cd CdA values, but I agree that you could do this via digital photo. Use a quality lens (to avoid distortions), get back a bit and zoom in to flatten the perspective, include a reference measurement (such as a yard stick, etc.) in front of the car. Take the photo and overlay a digital grid over the image that matches up to your reference measurement and count squares. The more granular the grid, the more accurate your results. If you want to go crazy, count pixels! I think there are computer programs that will measure the area of an irregular shape in an image file. I think Adobe even has one. There might be cheaper or free software that does that. If you want to do it manually, I can see getting a few large poster boards, marking them out with a grid, put them on the back of your garage, use a laser pointer attached to something to keep it perpendicular to the car and then trace the outline of the car. You would need a helper to trace the "shadow" you create with the laser pointer as you move it around the outline of the car on the poster boards. When done, count squares. If you park the car between to parallel walls, with the car perfectly perpendicular to the walls, you should be able to make this work. You could create a jig that holds the pointer perpendicular to a wall and then just slide the jig around on the wall as you trace the outline. |
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