Video: on-road tuft testing Ford Ranger aeroshell / aerotopper / aerocap

[bondo]

Thanks for the compliment. You were blazing new trails in light truck aerodynamics back in the day at Texas Tech, long before I had a clue. Back then all I was worried about is where the next party was.

Thanks for all your years of hard work in vehicle aerodynamics and then the sharing of the massive data base you have put on line for everyone to have as a great reference here on ecomodder.

Bondo

[aerohead]

Originally Posted by Jethro

It's tempting to try something like this on the Ram.

It's gotta be real annoying not being able to see out the back of the truck though. How bad would it be to remove the tailgate? With as 'high' as my truck is, it'd give me a pretty good view that way!

Currently if I am gently cruising at about 60 I can get 17 out of her out on the highway.

Of course, I bought my 200SX, so the truck is now a foul weather / off road toy.

I cut away for the third brake light,a rear window,and incorporated a flush side window for safety when lane changing and backing out of parallel parking spaces.
The chopped away areas did not remarkably effect mpg.
The claims for attached-vortices appear to have great merit.

[drees]

I would think that a lot of the turbulence seen down the side is caused by the driver's side mirror.

[aerohead]

Originally Posted by drees

I would think that a lot of the turbulence seen down the side is caused by the driver's side mirror.

They're much better than in past generations of vehicles.By streamlining the mirror housing and moving them out away from the side has done a lot to reduce interference drag.
We're hoping that the automakers can successfully petition the DOT for the ability to replace the mirror altogether,replacing with synthetic vision from cameras and displays.
We wait.

[drees]

Originally Posted by aerohead

They're much better than in past generations of vehicles.By streamlining the mirror housing and moving them out away from the side has done a lot to reduce interference drag.

Right, but I'm talking about the Ford Ranger in the video. Definitely far from streamlined. I don't know of any pickups with streamlined mirrors since most are oversized to improve visibility, especially when towing loads.

[suchy21]

Originally Posted by drees

Right, but I'm talking about the Ford Ranger in the video. Definitely far from streamlined.

Yep, the 1993 Ranger's mirrors are flat-faced. Some lead in and extended trailing edge could help, but I would prefer to stick a few PS3 cams and a netbook in there.

[aerohead]

Originally Posted by drees

Right, but I'm talking about the Ford Ranger in the video. Definitely far from streamlined. I don't know of any pickups with streamlined mirrors since most are oversized to improve visibility, especially when towing loads.

drees,I went back and re-watched the video.While the Ranger's mirrors don't "look" streamlined,they actually are,given their frontal area.
If you could get a look at Hucho's book you would find two separate reports addressing the streamlining of bluff bodies,Figure 4.99 and Fig.11.26.
Hucho uses the expression "saturation",where,once a certain degree of rounding of a leading edge is accomplished,the drag minimum is achieved,and no additional streamlining will affect a lower drag.
They're not "swoopy" but aerodynamically,they are very correct.

[bondo]

In May of 2007, a friend of mine and I made a video of the first Aerolid with tufts of yarn on it. Here is a snapshot of the yarn tufts showing attached air on the sufraces of the Aerolid. I somehow lost the video but at least had kept this snapshot.

The air is attached on the top and sides. At the rear corners it starts to separate. What is really wild is how the air splits on the rear edge of the lid, dead center, and the yarn on the left points left and the yarn on the right points right. I always wondered why this happened.

At the wind tunnel at Allen Park the aero guys spent alot of time with the smoke at the back lip of the Aerolid. They told me the air was separating cleanly off of the roof and that two large counter-rotating vortices, with the one on the left side spinning counter-clockwise and the one on the right side spinning clockwise, created as the air blends off of the sides of the bed into the low pressure air at the rear of the truck, was causing the yarn (or smoke) to go right or left along the rear lip from dead center.

Flow visualization with yarn is easy and fun and can tell us alot about what air does over a surface as most of you know.

Bondo

[aerohead]

Originally Posted by bondo

In May of 2007, a friend of mine and I made a video of the first Aerolid with tufts of yarn on it. Here is a snapshot of the yarn tufts showing attached air on the sufraces of the Aerolid. I somehow lost the video but at least had kept this snapshot.

The air is attached on the top and sides. At the rear corners it starts to separate. What is really wild is how the air splits on the rear edge of the lid, dead center, and the yarn on the left points left and the yarn on the right points right. I always wondered why this happened.

At the wind tunnel at Allen Park the aero guys spent alot of time with the smoke at the back lip of the Aerolid. They told me the air was separating cleanly off of the roof and that two large counter-rotating vortices, with the one on the left side spinning counter-clockwise and the one on the right side spinning clockwise, created as the air blends off of the sides of the bed into the low pressure air at the rear of the truck, was causing the yarn (or smoke) to go right or left along the rear lip from dead center.

Flow visualization with yarn is easy and fun and can tell us alot about what air does over a surface as most of you know.

Bondo

Looks good to me! Kamm couldn't do better.

[phord]

You can improve visibility with plexiglass aerocap (I had seen a newer f150 with one and immediately thought that the driver was surfing the Ecomodder)