Tuft Testing on Insight Hatch Glass (2006 Honda Insight, 1st gen.)
 

OK. FINALLY got time to do the Insight hatch testing. Set up my camera with wideangle lens to see the entire glass. Set up three rows by 4 columes of wool tuft. The bottom line is that there is slight turbulence but no detachment. I will post the video soon as someone tells me how to do that. Question, the video is from my Canon 5DMkII and the smallest frame was 640x450 pixels, so do I need to resize this somehow? (I'm a still photographer!)

Someone in the know please tell me how to get this video onto the site please.

Thanks,
Jim E.

The easiest way is probably to upload it to youtube.com. From there all you have to do is paste the link to the youtube video and the forum software will embed the video in your post.

First I have to get it off the flash card and into my computer:confused:

It is in .MOV format which is apparently a Canon format. I have Canon s/w which should get me over that hump.

Once I get it into my computer, what format should I use for U-Tube postings?

uploading it to YouTube and they will convert it.
.mov is the default file type for movies on a mac :)

I'll bet the flow is pretty smooth. On mine with some rain-x on the glass the drops never stayed there for any amount of time. Even in a downpour the glass looked dry as long as you were moving over 25 MPH or so.

regards
Mech

You're right. It is pretty smooth. Just looking at the video from my camera, and harkening back to the explanation that Metro had given with his boat tail video, I think the flow would be classified as very slightly turbulent, but not detached in any sense. Later, I'm going to raise the hatch a couple of inches and see if the flow improves, but for now I'd settle for getting the first video uploaded.:confused:

I'm computer challenged so I'm having my problems with getting the video onto youtube. Last night I realized that I had the radio playing in the background, which the camera of course recorded with the video data. I haven't found a way to edit out the sound. I suspect I'd get myself into trouble uploading copyright material to youtube, so I'm reshooting the data this morning. I also need to sort out my camera format settings.My Canon 5D MKII records in .MOV vs. .mov, an apple format. I'm not sure they are the same, but I'll try to upload it anyway. Wish me luck.

File names (and file name extensions) are not case-sensitive. Upper case or lower case = same result. If you have a file "haha.txt" and try to save "HAHA.TXT" it won't let you do it, because you already have a file by that name.

If you like, email me the .MOV file and I'll post it on EcoModder's YouTube channel. darin@ecomodder.com

Don't worry about copyright in that case. Your intention is not to reproduce the music- it's just on by coincidence, undoubtedly with lots of background noise. There will be no problem uploading your video.

You should be able to directly upload the .mov file. YouTube will take whatever you've got and convert it into its own format. After it's done uploading it will give you a link to the video.

To record better quality video I'll give you some instructions. This is based on my Rebel T1i but it should be the same.

-Put your camera in video mode
-Press Menu
-Use the left-right arrows to go to the movie tab (it should be a red video camera icon on the top left of the screen)
-Using the up-down arrows, scroll down to Movie rec. size. Yours should say 640x480.
-Press "SET" (between the arrow keys). This will bring up several resolutions. -Set it to the highest available. My T1i goes to 1080p which is standard HD quality like on your TV.
-Press "SET" again to save your changes
-You should be ready to take high res. video now! :)

Not necessary to re-shoot. See above comment.

Also, you can remove the audio from a clip after it's uploaded to YouTube, if you're still concerned.

I'll give that a try. Fingers crossed;)

I'll bet the file is (way?) too big for email -- you could try Dropbox?

Uploading to YouTube is easy, though.

Well, it's up on youtube. Neil was right, neither ISP that I use would forward the attached video via email. One service simply said as much, the other just choked and stopped without explanation.

Go to youtube.com and search for "Insight Rear Hatch Tuft Testing," or use this link directly:

http://youtu.be/1s807EGEpWc

I don't have immediate confirmation, but hope this all works out:thumbup:

http://www.youtube.com/watch?v=1s8O7EGEpWc

Excellent - thanks for doing that work, Jim!

Very nice. Does the fluttering indicate significant turbulence?

OK. It seems to be up and working.

My take is this:
1. The middle row and the bottom row tufts all indicate attached flow, but slightly turbulent.
2. The top row tufts are more turbulent and I think that this is caused by the the airstream "tripping" slightly on the rather large open seam between the hatch and the roof.
3. Honda pushed the very limit with the hatch angle. They probably figured and optimum compromise between aerodynamics, length, and rear visibility.

Just as a guess, one might raise the hatch lid a couple of inches and achieve better aero. In a couple of weeks I'll probably give that a try. All comments very welcome:thumbup:

The front windshield wipers and door mirrors would also be contributing to the turbulence seen. (Assuming they are in place!)

or they will do it for you if they feel there is copywrite infringement.

It seems to me that the turbulence is very slight. Probably about as good as anywhere else on the car. The tufts are six inches long, so it is kinda inderstandable that they might flutter a bit on the ends.

I have removed the front wiper and the right side mirror, so I'd just guess that we'd see some asymmetry if your explanation were the case.

One other thing I want to do is put tufts somewhere where I know the flow to be extremely good, like middle of the hood, and see how those look. It just might be that tufts need to be shorter, like 4 inches.

I was amazed that the turbulence did not get worse further back on the hatch. I had been conditioned to think that flow deteriorated as one got closer to the rear edge.

All very interesting. Seems Honda got it pretty much right.

Looks good! I just ordered my GoPro Motorsports so I'll be able to get some vids later on.
Planning on a boat tail?

What were the wind conditions during the test? (crosswind?)

Isn't there a "lip" at the end of the hatch? Wouldn't raising the hatch change the angle of the lip and possibly cancel-out benefits by adding downforce and turbulence at the trailing edge?

Look completely calm from the leaves on the trees.:)

Yes, there is a small lip, but near as I can tell, it is at same angle as hatch. I don't "think" it would impact testing. It is largely a trim item. Honda may have added it to protect the rear edge of the glass. Just guessing as to purpose. Thanks for the comment.

I have one of those that I use in my racing Miata. Problem I had with it in the current test was that the lens does not have a wide enough field of view. I though hard about using it, since the files would have been much smaller. The GoPro is very small, so I intend to use for some outside applications, sorta like Darin's "webcam on a stick."

I agree. It definitely doesn't hint at separation, which would have the tufts swirling, and ultimately flowing "backwards" up the glass at times.

You can see what tufts in very clean flow look like in this video I did. Jump ahead to about the 2:40 mark - particularly note the tufts that are furthest forward and on the top row:

www.youtube.com/watch?v=Lo3EEHDoUgc

It does if the shape isn't optimal ;)

Seems that way.

yep, that is about what I expected. The front can be very smooth, before any edges or misshapen parts get in the way. The front fender skirts have a very impressive result.

But, the question is, how do we translate something like fender skirts into an estimate of lowered Cd. Guess, less wind tunnels, we only have A-B-A MPG testing and rolldown testing, both rather imperfect for small changes.

To be honest, I'm less interested in trying to calculate actual Cd than I am in finding differences in coast-down times or MPG readings.

tufts
 

I'm late to the party ( happens quite often).Just watched the video (an amazing tool!).
The flow looks okay.A bit nervous,but no reverse circulation,so the appraisal that Honda got it right on the ragged edge is confirmed.
On my last trip I tufted the hood blister near the windshield.Those behaved as if they were painted on.They didn't move at all except when encountering gusts or bow,stern waves off big trucks.
The top of the trailer was a bit nervous as was expected,as there was a significant gap remaining.
The lower sides which I could see from the mirrors were VERY nervous,although no recirculation visible.They remain the 'dirtiest' location until completed.
It will be interesting to see the 'raised-hatch' results,and if some of the quaking diminishes.
Nice work HONDA!
Nice tuft-testing Jim,and thanks to Darin and all which made all this happen.
I may lean on all of you as I attempt this same sort of thing.I've got a 7-meg camera with a short video capability.And friends have volunteered to do the chase car driving and videography when the time comes.Again,thanks Mucho!

I second the thanks to Darin. We have a wonderful site, largely through his hard work!

When you start making videos with that 7-meg camera, set the resolution as low as your can, and keep the segments to an absolute minimum length. Otherwise it takes forever to get it uploaded to youtube. Powerful tool, but needs some discipline;)

.


Thinking this through a bit more, I think I misled you on this statement. Reason my upload was so slow is that I use an air card to connect and it only runs at 100kb/s or so. Sorry :o

Nah - I haven't done any hard work in years! :D

If anyone deserves praise for making EcoModder wonderful, it's the members in general.

If you haven't seen it before ... you can also see it in the wind tunnel video bellow ... if you haven't already seen it before ... even if there is only a short piece of the video showing it.

http://www.youtube.com/watch?v=8MX8qN-2EpU

Not much for the back window, but there is an interesting moment at 2:05 for the driver's rear view mirror. Seems to be a giant turbulent zone that explodes around and behind it. I know the mist does not tell a lot and that it can be manipulated in video. What does the video suggest to you?

Wow - that's instructive!

Phil's right when he said Honda took the rear hatch curvature to the ragged edge - the boundary layer looks like it practically triples in thickness between the top of the hatch and the tail end - without separation rearing its ugly head.

It is an amazing video. I'm sure I'll spend hours watching it.

What does the thickening of the smoke trail mean in practical terms. Obviously pressure is being lost, but since it stays attached, do we interpret this as a negative for this car length? For boat tails, should we try to raise the hatch a couple of degrees, by some means?

I wouldn't go to the trouble of trying to raise the hatch, but in terms of making a boat tail, I would not continue increasing the curvature much beyond the last "angle" at the end of the hatch.

camera viewpoint
 

It would have been beneficial had the camera shot from roof level rather than the beltline.
All in all,its a glimpse into a controlled access environment.Thanks for the look!

I wish my Japanese weren't so rusty but I am sure they said several times the Cd is 0.25.

Agreed ... But I have not found other wind tunnel videos yet... although I have no doubt hours of such video exist from every angle ... until someone finds other videos ... all we can do is more cost effective things like the Tuft testing, and cost down testing.

welcome.

Suggests the same thing to me ... which is what I would expect , given the shape of the side mirror ... but it is what people expect ... to have side mirrors ... and alternatives to keep the same functionality without the aerodynamic hit of the current design , would cost significantly more ... for a side mirror the current OEM design is not bad , and it is only a small % of the total vehicle frontal area.