DIY Hillbilly Truck Bed Cover (Tonneau) for 2019/20 Ford Ranger.

[DIYAndy]

You want to believe the opposite,...fine....I generated solid data...

I believe you, (I was just pulling your chain), since you are an engineer from a company that has been making vehicles for over 100 years.

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[jsphlynch]

Air flow is not intuitive and you cannot see its flow

This.

There's a Mythbusters episode where they used clay to create a dimpled effect all over the surface of a car, essentially turning it into a big golf ball. Intuition tells you that such a rough surface would impede airflow, thereby increasing resistance and decrease gas mileage. But intuition is wrong, and the dimples actually improved fuel efficiency by helping air flow around around the car.

Incidentally, Mythbusters also tested various bed modifications, and did some tests using a pickup model in flowing water to visualize the fluid mechanics (their budget obviously increased over the course of the show, but apparently not enough to get to use Lockheed's wind tunnel). They concluded that the cushion of air created in the bed was necessary to optimize airflow, and this was backed up by their MPG experiments with an actual truck. Kinda cool to hear that they were essentially doing a poor-man's replication of a Ford experiment, and that they got the same results.

 

[jsphlynch]

DIY Hillbilly Truck Bed Cover (Tonneau) for 2019/20 Ford Ranger.

Due to the high cost of commercial Tonneau (In Ohio, we call them truck bed covers - no french spoken here) and a bet from the local bar room Ford Ranger owners, I decided to do a DIY design and build my own Ford Ranger truck bed cover for ~ 1/5 the cost and about less than a day's work (6 hours)!...

Cool project.

When I was buying my truck, I passed over another one in part because it had a factory-installed hard cover. I thought I had no use for one, and it was kind of an expensive extra.

On the second day of owning my truck, I was driving around with my wife riding shotgun and the three kids in the back, and my wife starts talking about how nice of a setup it is, as everyone fits so comfortably and reaching back to pass things back to the kids is so easy, and there's so much room in the bed for cargo...wouldn't it be nice to take the truck instead of our SUV on our planned ~4000-mile road trip next summer? Only drawback is that things are so exposed in the bed, so we need to have some sort of cover...

So anyway, I'm now in the design phase of a DIY hard cover. The overall design is somewhat different than yours, but I might have gotten some inspiration from some of the elements of yours. I can't find any indication that you've filed any patents on any of it, so I think I clear from a legal standpoint...

 

[DIYAndy]

I can't find any indication that you've filed any patents on any of it, so I think I clear from a legal standpoint...

Hillbillies don't file or get patents they just do it to get the job done

 

[jsphlynch]

Hillbillys don't file or get patents they just do it to get the job done

Whew!

 

[DIYAndy]

Just in case you missed this but my cover design also serves for many alternative uses ...

So far, my DIY hillbilly truck bed cover (Tonneau) has five other alternative uses ...
1. Drone launch pad.
2. Saw horse work platform/table when panels are removed from the vehicle truck bed.
3. Emergency firewood source, in an unlikely event, my Ford Ranger breaks down in Timbuktu.
4. A makeshift picnic table for the whole family.
5. Mobile bar top.

Your family could have a free picnic table for your family vacation

 

[jsphlynch]

Just in case you missed this but my cover design also serves for many alternative uses ...

So far, my DIY hillbilly truck bed cover (Tonneau) has five other alternative uses ...
1. Drone launch pad.
2. Saw horse work platform/table when panels are removed from the vehicle truck bed.
3. Emergency firewood source, in an unlikely event, my Ford Ranger breaks down in Timbuktu.
4. A makeshift picnic table for the whole family.
5. Mobile bar top.

Your family could have a free picnic table for your family vacation

I'm thinking with a mobile bar top, ours will be the most popular campsite in the whole campground!

 

[DIYAndy]

Each run showed a increase of Aero HP

Forgot to ask " how much in gas MPG reduction (%) would I expect with a truck bed cover (Tonneau) ?"

 

[P. A. Schilke]

Forgot to ask " how much in gas MPG reduction (%) would I expect with a truck bed cover (Tonneau) ?"

Hi Andy,

I do not know was I did not correlate aero hp increase to reduction in fuel economy and do not remember the specific values since it was back in the mid 80s when we ran hit the Lockheed Wind Tunnel... Our goal at that time was increased speed for the Racetrucks... I was actually in the Lockheed tunnel twice...once with the Saleen Racetrucks and once with our mule offroad Class 8 racetruck. Both time was a quest for increased speed. This is where we learned that tailgate down or removed is also an increase in aero hp. The Sports Club of America had a sponsor proposal that wanted to have the racetrucks run a tailgate net. Steve Saleen, his crew chief and I discussed and without tipping our hat on the aero findings, I voiced the Ford Manufacturers opinion that the tailgate showcased the Ford oval on camera and did not support running a flippin' net!...Reps from the other manufacturers agreed and the whole idea was dropped...

Okay another back story

We finished up the Lockheed work on the desert racetruck. Armed with this information extracted from the windtunnel data, we held a Tech forum at the next offroad race and prior to the Baja 1000. The teams had the choice of incorporating what we found, much could be done with a roll of racers tape and other proprietary details on the undercarriage. Our Class 8 Rough Rider team Enduro, with Dave Ashley/Dan Smith reported that they experienced helmet lift to the point that they had to hold the helmet with one hand crossing a dry lake...something they had never experienced before and was verification that we had increased their top speed by some 15mph or more. Something on the order of a top speed of 140mph... Worth the $20,000?...When We win it is worth every penny!

Best,
Phil Schilke
Ranger Vehicle Engineering

 

[DIYAndy]

The Internet/Google says "a 10% gain in MPG" and a Ford engineer (retired) says an "unknown" reduction in MPG when you have a truck bed cover (Tonneau) installed on a Ford Ranger or on any truck bed vehicle? This is like a "Mexican Standoff" and the only way to resolve it is very simple - this summer, while on vacation with many tanks of gas, I will check my MPG, on my Ford Ranger, with my truck bed cover on/installed and off/removed to see if there is any noticeable or negligible differences in MPG.
(It only takes 3 minutes to completely install or remove my DIY Hillbilly truck bed cover)

On another note my next project - DIY Hillbilly Truck Bed Slider.
This ridiculously, over priced truck bed accessory which, I believe, can be easily made for about 1/10 the cost - stay tuned for further updates.

 

[Floyd]

You inspire me!
I found a discarded flip type cover from a fullsized truck with damage along one hinge face and no mounting hardware,
I plan to disassemble it and resize it to fit my Ranger, then devise a pair of clamps and a striker for the latch.
I'll post here if I find the ambition to do it!

Update...
Spent 6 dollars and probably about 6 hours to convert the bed cover.
Got it done today, looks and works great.
Thank you, DIYAndy for the inspiration.
Pictures tomorrow if I find the time.

 

[Floyd]

Well , here's the pictures of the box cover.
It was badly damaged, especially on the first hinge from the back.
The hardware was either destroyed or missing.
It was off an SOB fullsized truck (Chevy?)
I had to cut it 8" narrower and mke my own attachment points.
I will be installing a funnoodle or waterpipe insulation to seal the front edge of the box.
The entire cover is removable with only two hand nuts on the front panel after unhooking the rear straps and folding the cover.
not too bad for six bucks!

 

[DIYAndy]

not too bad for six bucks!

You are going to put the third party accessory vendors out of business!
Nice DIY job

 

[Floyd]

Hi Andy,

Actually a tonneau cover increases drag. I spent 10 hours in the Lockheed wind tunnel on several occasions trying to improve Race Truck aerodynamics and the tonneau was top on my list of things to try. Results was a significant increase to the tune of about 10% in aero drag for a tonneau cover. Ditto for tail gate removal... Best increase was a 6" strip across the box at the tailgate. Doing the smoke test you could see why this worked when other items did not work....Air flow is not intuitive and you cannot see its flow. For the cab the air rolls and spirals in such a fashion that this 6" strip alters the spiraling. It was amazing that the Ford Aerodynamist with me could envision such things working...
So I wish to debunk this theory that tonneau covers on pickup trucks decrease aero drag, Tonneau covers increase drag...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

Thanks for the experience,
I do think it varies from truck to truck, or when towing the effect may be different.
On my former Ranger, we did an unscientific experiment.
With no cover, I placed a paper cup inside the box next to the tailgate, at around 60MPH the cup would suddenly slam into the front of the box from the air coming over the cab and dropping into the box right about the tailgate and causing a low pressure area behind the cab.
When I raised my sunroof (about3") the cup would stay calmly at the tailgate all the way to the truck's rev limiter.
I don't know if there is more or less turbulence with the box cover installed and the sun roof down,but I do know that the sunroof pushed the air beyond the box when it was up. That would then seem to mean a zero effect good or bad for the box cover in those particular conditions.
I just installed a box cover for an upcoming trip which also includes a travel trailer so I was curious about the effect.
I doubt that the difference will be significant enough to be easily measurable, especially since the box will be full of boxes and gear either way.
As you say, it is not all it seems, My 1976 Econoline had a drag coefficient of .33 whereas the average bicyclist is about a 1.0.
I have also found that bicycles in an open trailer produce notably better fuel economy for the tow vehicle than bicycles on the roof without a trailer.
Most all of this is anecdotal and the purpose of a box cover is to secure cargo and keep it safe,dry, and out of sight

 

[P. A. Schilke]

Thanks for the experience,
I do think it varies from truck to truck, or when towing the effect may be different.
On my former Ranger, we did an unscientific experiment.
With no cover, I placed a paper cup inside the box next to the tailgate, at around 60MPH the cup would suddenly slam into the front of the box from the air coming over the cab and dropping into the box right about the tailgate.
When I raised my sunroof (about3") the cup would stay calmly at the tailgate all the way to the truck's rev limiter.
I don't know if there is more or less turbulence with the box cover installed and the sun roof down,but I do know that the sunroof pushed the air beyond the box when it was up. That would then seem to mean a zero effect good or bad for the box cover in those particular conditions.
I just installed a box cover for an upcoming trip which also includes a travel trailer so I was curious about the effect.
I doubt that the difference will be significant enough to be easily measurable, especially since the box will be full of boxes and gear either way.

Hi Floyd,

Yes, the effect is likely as we used to say "like picking fly shit out of the pepper". It takes very accurate equipment to measure the change in aero horsepower. That is why Andy attempting to do this on the street is likely to deliver very mixed results as there are so many variables on the road that cannot be accounted for in such a non scientific manor. What we found was a 6" wide strip at the back resulted in a decrease in aero horsepower but the drag of the air rolling off the cab onto the tonneau cover increased aero horsepower required to maintain 90mph. What the testing told us was to keep the tailgate up (Big Ford Oval on the tailgate for the TV cameras) and allow the box to fill with a cushion of air as opposed to drop the tailgate or use a net etc. The sanctioning body would not allow the 6" strip as they suspected some sort of trickery from Ford (read directed at ME!) Your sunroof deflector certainly redirected the air over the tailgate.

A bit of a backstory that I may have mentioned in another thread...CRS here! We did get around the sanctioning body with a composite pick up box used on the electric Ranger. When they found out our pick up boxes were composite (saved about 150lbs) they were absolutely furious. I got called to their trailer. I calmly reminded them of the rule in their rule box that any Manufacturer part could be used if it has a manufacturer production part number, of which the composite box had a valid part number. Shut them down almost instantly...thus we were able to run composite pickup boxes with their reluctant blessing. Protests by the other manufacturers were dismissed.... I love beating the sanctioning at their own game!

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

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