Report: Improving the Aero Characteristics of a Dodge Ram Pickup Truck

[aerohead]

Originally Posted by MetroMPG

Hi Geoff - Could be. The report states that the 1/18th die cast model was used in the water tank, but...



(Quoting Geoff again...)



I'm not clear on how the scale balance is set up. Can you explain it?

I'm guessing there's an actual scale to measure lift (which the student wasn't measuring for this test). For measuring drag force, is there a pivot on the rod holding the model (at the "floor" of the test area), and drag force is measured on the other side of the pivot point?

As it turns out, I tracked down the author and he got back to me yesterday. I'll ask, and If he gives permission to distribute the report, I'll make a digital copy (photos).

The "rod" could be a "sting." Texas Tech uses one from the tail of a military jet.The sting contains piezio (sp?) transducers which measure strain in six axis and their output can be interfaced with computer to measure real-time loads (ie. lift,drag,torsion).

[tasdrouille]

ptg0: Please define frontal area so we can all learn something.

Ok now that you've googled it you can go back and edit your previous posts...but I'll save the best part for posterity.

You know, the "large bubble of air" that exists in the rear of the vehicle that "aerodynamicists" claim to use as a design feature exists because of the 10 sq. ft of additional frontal area
created by having a tailgate in place.

Your site is interesting too. I particularly liked this passage:

Ranging from aeronautics to advanced hybrid power trains for ground effects vehicles, if you have a problem, we will find a unique solution.

Man I wish I had a ground effect vehicule

[ECONORAM]

I have been slowly working on this almost since I bought my truck. I dug up several websites about pickup truck aerodynamics and improvements. Here are a few:
A Truck That Drinks Less Than a Car? | Popular Science
http://gcep.stanford.edu/pdfs/ChEHeX...0_11_trans.pdf
Improving Aerodynamics to Boost Fuel Economy
RoadandTrack.com -- Tech Tidbits - Tech Tidbits — September 2004 (9/2004)

I also took a close look at a RAM SRT10 about 2 years ago. Some of the interesting things are the front air dam/bumper cover/splitter, the full tonneau cover w/integrated spoiler (said to improve airflow), lowered 2 inches to cut aero drag, and I noticed the air conditioner condensor and the radiator are inline, not side by side like other RAMs. There is about a six inch space on the driver's side of the radiator that is covered with a piece of black plastic, to cut drag through the grille.
I looked at my wife's 08 Avenger and discovered it has a full belly panel under the engine bay. I have been working toward several of these mods since I got back from Iraq. I will see if I can add the pix to my gallery or garage...
My truck will get over 23 mpg on the highway at 65mph now. I am aiming for 30...

[edit] I also need to ask if there is a how to for measuring Cd via coast down?

[Nigel]

Measure the drag coefficient of your car

[aerohead]

Originally Posted by ECONORAM

I have been slowly working on this almost since I bought my truck. I dug up several websites about pickup truck aerodynamics and improvements. Here are a few:
A Truck That Drinks Less Than a Car? | Popular Science
http://gcep.stanford.edu/pdfs/ChEHeX...0_11_trans.pdf
Improving Aerodynamics to Boost Fuel Economy
RoadandTrack.com -- Tech Tidbits - Tech Tidbits — September 2004 (9/2004)

I also took a close look at a RAM SRT10 about 2 years ago. Some of the interesting things are the front air dam/bumper cover/splitter, the full tonneau cover w/integrated spoiler (said to improve airflow), lowered 2 inches to cut aero drag, and I noticed the air conditioner condensor and the radiator are inline, not side by side like other RAMs. There is about a six inch space on the driver's side of the radiator that is covered with a piece of black plastic, to cut drag through the grille.
I looked at my wife's 08 Avenger and discovered it has a full belly panel under the engine bay. I have been working toward several of these mods since I got back from Iraq. I will see if I can add the pix to my gallery or garage...
My truck will get over 23 mpg on the highway at 65mph now. I am aiming for 30...

[edit] I also need to ask if there is a how to for measuring Cd via coast down?

I'll let others help you with the coastdown stuff but wanted to share another back door to Cd.
For 55 mph and 70 mph,a 10% drag reduction will net you a 5% and 6% mpg increase respectively.
So if you'd done a mod,and after comparing mpg to your baseline you showed a 5% improvement at a steady 55-mph,then you would have reduced your Cd by 10%.
This is a very easy way to determine your numbers.If you have the OBD-II Scan-Gauge or other instantaneous mpg display technology,you can get your results without having to burn a bunch of fuel.

[ECONORAM]

Here are a couple pix of my work so far:
I included the gap filler between the cab and bed, my belly panels covering the gaps between the frame rails and the body, and my front end splitter with another picture of the mounts to the bumper.
Guess I will have to break down and buy a ScanGauge or the software from Auterra so I can monitor this thing better...

[MetroMPG]

That air dam - is it an OEM piece?

(EDIT: removed my earlier comments about the air dam. Need coffee.)

Highly recommend you get the ScanGauge. It'll pay for itself in fuel savings, and you'll use it more regularly than a laptop based gauge.

[bondo]

Did you Know

It is quite remarkable how close the two students Cd numbers are to the real world. Their water tunnel and sensors worked quite well.

I have to admit, this is where I first got the idea for the Aerolid. These two young men deserve all the credit for showing what a large reduction in Cd can be achieved through pickup truck body aerodynamic optimization.

Bondo

[MetroMPG]

bondo: thanks for posting that link to the archived study the students did.

[bondo]

I would have posted the link the study sooner but I just found out where I had saved it yesterday.

Bondo