Pickup Cab Wing Angle - Measure from Where?

[ChazInMT]

Keep in mind, the air affected by your mod extends up several feet above and around, so unless your leaf blower was originally used on the set of the movie "Twister", it really won't tell you much.

I think the reason your tufts point forward is due to your lack of a smooth transition, your flat wing creates this by default. I think it helps control the air in a good way for you. Short of building a complete cap, this seems to be the best you can achieve.

[kach22i]

Originally Posted by ChazInMT

.....unless your leaf blower was originally used on the set of the movie "Twister", it really won't tell you much.

Yea, could be right.

I think you would need another large fan behind the truck for drawing air in.

[Bruce]

I tested different wing angles today. I built adjustable braces and found a hill that is .9 miles long. My procedure was to put it in neutral at a mile marker at the top of the hill while traveling 55 mph, and then see how much speed I gained by the bottom. To make a long story short, at the low and high end of my adjustments I could reach 60.9 mph, but I found a sweet spot right around 10 degrees that would take me to 62.8 mph. I made about 20 runs in order to be sure my results were repeatable.

In my final run I removed the wing entirely and hit 65 mph.

Back to the drawing board.

[ChazInMT]

Originally Posted by Bruce

In my final run I removed the wing entirely and hit 65 mph.

Well I think it's fantastic that you got out there and really put it to the test, unlike so many who just hem and haw and never try to discover the real results with a legit test.

Ten stars for you!

[kach22i]

Originally Posted by Bruce

In my final run I removed the wing entirely and hit 65 mph.

Just my two cents, perhaps you are befitting from some down-force which has yet to be measured.

I'd rather have down-force than any kind of lift in a pick-up truck.

Next ice storm, just see which vehicles are in the ditch on the side of the road.

In SE Michigan they will be pick-up trucks (suffering from tail lift) and a few surviving Geo Trackers which are short wheelbase and perhaps of the 2WD variety.

[Bruce]

Originally Posted by ChazInMT

Well I think it's fantastic that you got out there and really put it to the test, unlike so many who just hem and haw and never try to discover the real results with a legit test.

Ten stars for you!

Thanks. I'm trying to figure out where to go next. I wish I could see that study that tested pickup truck bed drag. I wonder how they built their wing and arrived at their conclusions?

kach22i - I'm purely interested in increasing mpg. I'll leave my truck at home when the weather gets bad - or throw some weight in the bed. I wouldn't want to drive fast enough in an ice storm for my spoiler to create down force. But, yes, traction is horrible in a rwd pickup with an empty bed.

[Plush1992]

I'd hate to dig up an old thread but Id like to know why this didnt work? From my standpoint theres no reason this shouldn't of worked. Is the space forward of the half-tonneau cover creating a negative pressure under the kamm back and thus making it act like a wing providing downforce or is it just turbulent drag? How could the design be fixed?

I may be able to get a hold of a Ranger and would of loved to do this to it

In advance, great job Bruce and great thread!

[gumby79]

Was the gap at the gate causing problems?

[Plush1992]

Originally Posted by gumby79

Was the gap at the gate causing problems?

Very possibly. I wonder if he did this, if it would change anything? The Salt Flat Gm Cyclone had a half tonneau but it extended down to the bed as-well.

[kach22i]

Originally Posted by Bruce

I tested different wing angles today. I built adjustable braces and found a hill that is .9 miles long. My procedure was to put it in neutral at a mile marker at the top of the hill while traveling 55 mph, and then see how much speed I gained by the bottom. To make a long story short, at the low and high end of my adjustments I could reach 60.9 mph, but I found a sweet spot right around 10 degrees that would take me to 62.8 mph. I made about 20 runs in order to be sure my results were repeatable.

In my final run I removed the wing entirely and hit 65 mph.

Back to the drawing board.

UPDATE 2020


Was this project perhaps scrubbed prematurely because of dependence on on coast-down testing?

Would have Throttle Stop Testing or another means be a better indicator of success or failure?