I read an article in Auto Trim and Design dated August 2001 and they quoted Jack Williams of Ford Aero Systems Engineering who said they have seen drag resistance reduced by 8 to 10% on F150 short bed.

a good web site to lookat is truckgadgets.com they sell a lot of different types of covers wholesale.

 

Would there not be a huge difference between a long bed and a short bed seeing as on a short bed the wind has less tiem to get over the tailgate? I may be talking out of my butt, but just wanted to throw this out there.

 

With no bed cover leave your tailgate up.... try this... have a trustworthy friend (who by no means is in your will and cant be manipulated into something) drive your truck now u sit in the box against the cab have him speed up to get the wind going... now slide yourself back till you feel the wind and where it starts on my old 2000 the wind did not start to hit or move air in the box till right before the tailgate almost on the top lip on it.... the new fords are desined to run with the tailgates up because of there rounded cab and body design push the air around the truck, i installed a soft touno cover helped a bit... also with all these drivers atr lights now that get under our rear bumpers... why risk em hittin your tailgate.. and the point of the u shaped tailgates....good one seen a few of em around also those SUV's with the rear tire on the back hatch... makes a nice windowless look when they back into something LOL

 

I noticed that this University study started with a baseline assumption of a .43 CD on the Ford truck with NO SIDE VIEW MIRRORS. That's .04 lower than the .47 CD estimate I found in a US Government funded study about how future mpg improvements may be designed into various vehicle classes. I believe the .47 CD is more realistic for stock pickups since most comply with state laws demanding outside mirrors to pass as legally roadworthy. Video cameras with inside displays are the only legal way to avoid their wind drag cost. Sometime in our lifetimes, that kind of system will be common. One trick variant combines 3 camera views to display a super wide angle composite rear view on the screen. I hope their 17 year patent won't expire before it becomes a commonly installed system. Innovators deserve rewards for their contributions.

Lifting pickups with suspension lifts is an aerodynamic disaster. Some of these truck owners do the equivelant to shooting their calf muscle with a 22 and then wonder why they limp. Funny. It's common to see tall lifts alone cause 3 or more mpg losses at highway speeds. Most understand this trade off and do it with their eyes wide open. But some think lifts don't affect mpg. Lowering pickups lowers effective frontal area so picking up 2 mpg at highway speeds is possible there. Adding a front air dam can increase mpg by up to 1 mpg more while it lowers under-vehicle air pressure which improves air flow through the radiator/intercooler/AC condenser and increases tire loading pressure at high speeds. This secondary pressure effect adds slightly to high speed rolling resistance (a negative) but it improves road adhesion (a positive) from the induced extra down pressure.

I have in my old saved auto magazine article collection a test of 4 cylinder mini pickup trucks in which the only thing they changed during the test was adding clean-fitting cab-height toppers. No high lift rear end models, and these all had a minimal gap between the cab's contours and aligned topper surfaces. They all seemed to get about 2 mpg better with the toppers even though some of them added quite a bit of weight. Increased rolling resistance from the extra weight was trivial compared to their lower wind resistance at highway speeds. I expect heavy toppers might lower mpg by some trivial amount while driving in stop and go traffic averaging 30 mph and less. But that's speculative.

Ok, I recently saw, advertised on the I-net, a really trick power-lift hard-top bed cover. It had a cleverly configured sliding scissors lift mechanism powered by a hydraulic pump, much like some auto convertible tops from years gone by. Flip a switch inside the cab and the top lifts or goes down. They had this top configured to lock over the tailgate to prevent content theft when down, a nice design touch. But it was only offered as a level bed cover to which a camper tent option could be attached. I think this clever lift mechanism should be combined with a slick CD tapered top featuring a top-surface window.

About 15 years ago I built a hard shell tapered topper to lower wind resistance. Our design had a huge rear piece of Plexiglas so you could see out the center rear view mirror. We attached the front to the rear top of the cab with a 4 feet long aluminum "piano hinge." Our wedge shaped topper experiment really improved our coast down testing results. MPG at road speed went way up. But our design induced a lot of extra noise into the cab from the flexing topper attachment. As if that weren't bad enough, loading when alone took more strength than most women drivers could gracefully exert. It was tough for one person alone to pivot up on the front hinge, then support the rear with one hand while dropping down and locking in place one of the two rear side support arms we made to secure it in the up position. Yes it was beautiful. Yes living with it was ugly, especially with a heavy frozen snow and sleet load. Talk about HEAVY! I had just about as much of that beautiful design as I could stand. (stop laughing, would you have predicted these problems?) Most of the time I tried to just open the tailgate to avoid the hassle of lifting and locking it open to load, then reversing the process before being ready to drive away. On balance, it turned out to be one of my vehicle "improvements" which acomplished its design goal wonderfully but could only be considered to be an overall improvement if you were willing to overlook how miserable living with it was.

Now I see an opportunity to combine this clever power lift scissors design with an aerodynamically ideal hard tapered top which would retain the best benefits of both designs while avoiding the problems my old design caused. I believe this approach can produce a convenient-to-use lowered F Series truck with a CD below .30!!! Frankly, if Ford doesn't build a prototype using this design approach, I think they will be dropping the ball terribly. That's the way a big percentage of pickups should be configured from the factory. I'll try to find the link to that power lift topper maker's I-net site and post it here. If someone else has that link, please post it here.

IT'S ABOUT TIME we have clean low CD trucks available instead of bad aerodynamic jokes.
John

 

>I installed my cover too early to tell if it made any
>difference in mileage. The link below is interesting
>though... even if they did use a Dodge as the test truck.
>
>http://mars.acnet.wnec.edu/~ehaffner/did.htm
>
>
>Matt
>



yes this is a really good study.

However, I feel that it is a bit flawed, I believe that the weight of the cap, tonneau and air net should have been taken into account and compared against the tailgate.

my .02

P.S. I believe in my home state of S.D. it is illegal to drive with the tail gate down, and I'm pretty sure there are others as well.

 

[updated:LAST EDITED ON 23-Dec-02 AT 05:31 AM (EST)]Go to ~
http://www.streamlining.com/
Then follow the links and study the photos and explanations.
Gary Wheeler, the inventor, is a very clever fellow.

Then take all the blank spaces out of this address ~
http : // www. top up camper. com/
This is the lift mechanism I referenced in my long post above.
It would be a wonderful marriage with a topper shape that minimizes wind drag while maximizing enclosed interior volume and minimizing rear window size. That will take a longer post to explain again. It's based on published 30+ years old GM wind tunnel test information.

Later, I'll explain how to build a much better topper than any I've found currently offered after many hours of looking at topper and bed cover manufacturers and vendor sites.

John

 

Those interested in minimizing your vehicle's wind drag should also visit
http://www.airtab.com/
These are another source for Wheeler Vortex Generators, but aimed toward the OTR (Over The Road) truck market.

If you had a chance to visit someone well informed about highway transit technology from 50 years in the future, I think they'd consider this technology application standard equipment and the lack of it to be an indication that someone was making an obvious (to those in the future) mistake.

Just my opinion.
I have no affiliation with any of these linked vendors.