Aero trunk lid project

[California98Civic]

I would love to help. I want to see these pics!

So, you don't need a URL for a pic... the URL request is probably just for vids that you first upload onto something like youtube. URL is just another way to say "link" in this context.

Go to the reply section below this screen and click "go advanced" button just under the box for your reply. On the "advanced" window there is a button, lower down, for "manage attachments." Click that and you will get a popup window that will allow you to browse for and then upload pics from your computer. You will probably need to reduce the size of your pics before posting them. That's east to do in MS PAint, which is on nearly every computer. I hope that helps (and maybe other who read the forum too).

[backyard engineer]

tried that now got to resize for the forum limits please bear with me its late here I'll try again tomorrow. but If you can look into my album there are some there.

[California98Civic]

Originally Posted by backyard engineer

tried that now got to resize for the forum limits please bear with me its late here I'll try again tomorrow. but If you can look into my album there are some there.

Sure. In the mean time, check this out when you get a chance. This morning I made a stop during my commute. When I came out a very light misting had started. It had coated lightly the windows and tufts with specs of water. They stuck in position from a 45-50mph peak speed in my final short leg. See pic. Separation down the spine beginning faintly in the third to last row, spanning four tufts in the second to last row, and a bubble of 6-8 tufts by the last row. My new trunk lid covers the bottom row.

[brucepick]

I wouldn't have guessed the separation would be more at the center. Here's to real-world testing, in spite of the fact that it's tougher than drawing lines on a screen or writing proposals!!

[PaleMelanesian]

Thanks for testing!

I've seen similar effects on my sedan. I watch the drying dew in the morning - the upper corners dry first, the lower center is sometimes still wet when I get to work. I think the sedan must have a slightly larger bubble than yours, but the description is a close match.

[California98Civic]

Originally Posted by brucepick

I wouldn't have guessed the separation would be more at the center. Here's to real-world testing, in spite of the fact that it's tougher than drawing lines on a screen or writing proposals!!

Next I'll tuft the trunk and build the vertical spine that Cd describes in post #2 above. Those two together will give me a sense of how the air is moving as it separates, I think. I should get a better guess at what the "wake" is like, no?

[PaleMelanesian]

Can you confirm that airflow is reattaches at the end of the oem trunk lid? I've always assumed it does but never checked.

[California98Civic]

Originally Posted by PaleMelanesian

Can you confirm that airflow is reattaches at the end of the oem trunk lid? I've always assumed it does but never checked.

Funny you should ask! Here it is. See the attached pic. I got treated to another SoCal morning misting. Here my newly applied tufts on the trunk lid were set in the misty surface at a max brief peak speed of 48mph. With 96 tufts, it looks like a recirculation bubble at its largest around 4 tufts and decreasing in size and effect out one tuft further in each direction. Does that translate to approx 4-12% drag area near the lid/window interface along the car's spine? It reattaches before the end of the OEM lid. That seems small to me, but it is what the raised lid is meant to eliminate or reduce. Next I'll tuft the current raised lid for comparison, then build a vertical piece to run down the pine, with tufts on it, to measure how the air is behaving above the car's immediate surface.

[wyatt]

Originally Posted by California98Civic

Separation down the spine beginning faintly in the third to last row, spanning four tufts in the second to last row, and a bubble of 6-8 tufts by the last row. My new trunk lid covers the bottom row.

Is there any reason you are not going to have it go higher on your window, or further back? Both are beneficial, as the top left graph shows. You should still have good rearward visibility if you had your shelf cover the bottom two rows, and you should see a benefit.

[brucepick]

The reattach of flow at the trunk edge is pretty nice (in post #18 photo). But I wonder if it still happens at 60-70 mph? If you get another nice morning, can you tuft test at higher speeds?