Partial Bed Cover- '98 Frontier

[aerohead]

Originally Posted by Bow

Thanks Chaz...

I think I need to figure out a Cab extension/wing next... that should be quick and easy... (famous last words... )

John Gilkison threw one together for the T-100.
It was a C-shaped plywood base laying flat across the front bed bulkhead,extending 18-inches back along the top of the rails.
The two sides were plywood skinned with hardboard and routed to accept Plexiglass window on passenger side,angled at 7-degrees and tilted in to approximate the tumblehome of the cab roof.
The top was just a simple plywood shelf which extended from below the 3rd brakelight straight back 18-inches.If you laid a straight-edge off the back of the cab roof,down to the top rear edge of the "shelf" that angle was around 12-degrees.Wood gussets provided rigidity.Drywall screws held the whole thing together.House paint kept it alive for years.
No attempt was made to provide a curved skin or any complex shape at all.
Not real pretty but the air was okay with it.
Fuel records indicate that it performed as Texas Tech had reported.

[Bow]

Originally Posted by mjboks

Nice work on the 2/3 tonneau cover. A 2/3 cover is not much better than a full tonneau.

Nope, but it was cheap to make and try out, which is a big plus for me.

The carry box is probably not helping the FE that much since the weight of it is probably offsetting any aero gain.

My cargo box in the bed might weight 40-50 pounds empty. I carry very little in it. It is mainly there because having a single cab doesn't give me anywhere to carry stuff out of the weather.

Originally Posted by aerohead

John Gilkison threw one together for the T-100.
It was a C-shaped plywood base laying flat across the front bed bulkhead,extending 18-inches back along the top of the rails.
The two sides were plywood skinned with hardboard and routed to accept Plexiglass window on passenger side,angled at 7-degrees and tilted in to approximate the tumblehome of the cab roof.
The top was just a simple plywood shelf which extended from below the 3rd brakelight straight back 18-inches.If you laid a straight-edge off the back of the cab roof,down to the top rear edge of the "shelf" that angle was around 12-degrees.Wood gussets provided rigidity.Drywall screws held the whole thing together.House paint kept it alive for years.
No attempt was made to provide a curved skin or any complex shape at all.
Not real pretty but the air was okay with it.
Fuel records indicate that it performed as Texas Tech had reported.

Thanks Phil, I'll have to see if I can locate any photos of that.

Straight back off the Cab roof, under the 3rd brake light would be very easy for me, the small structure I mount my antennas on is already located there!

[ChazInMT]

Here's a spoiler & half tonneau Flow Illustrator. The flow off the back does seem smoother.

Nissan Frontier with Partial Tonneau and Kamm Back on Cab

[MetroMPG]

Nice work, Bow.

Added to the project library. EcoModder Project Library - EcoModder.com

[alohaspirit]

what if the spoiler wasnt straight but curved?


would that help the flow more if it was at the correct angle?

[Bow]

I guess not all "Flukes" are bad...

I averaged 29.24 MPG on the way home... at one point, I had 30.2 on the ScanGauage, until the last 5 miles of my 42 mile trip that was pure stop and go on the freeway (I hate Houston)...

On another note, usually (for the past 9 years I've been driving this truck anyway), I usually travel about 75 miles to go from a Full tank to 3/4 tank level... Today, I was at 89 miles and on the 3/4 mark when I hit the driveway...

I think my $35 investment will be paid off in no time...

Not bad for a 268,000 mile truck on the original clutch...

[Christ]

Not bad at all. In fact, it's downright good!

[Bow]

Thanks..

I'm so stoked, I just had to post this pic I snapped on the way home...

I have not seen the average this high since I got my SG a month ago... and I doubt it ever has been this high...

[Bow]

Well, I guess I am into Phase II of the project...

After reading several things on this forum, Mr. Knox's many posts, and seeing Chaz's Flow Dynamics model of how much better the shelf makes the partial bed cover work, I decided to cook up a "Shelf" to mount under my 3rd brake light, as discussed earlier in this thread by Mr Knox.

Understanding that the angle to shoot for off the roofs 12 degrees, I decided to do a little Math (with the help of an on line calculator) to see how far out my "Shelf" would have to go to get 12 degrees off the roof line...

I found this site: RIGHT TRIANGLE CALCULATOR and plugged in my "knowns" to find out how far back my shelf need to come off the roof:

I know the my mount point for this shelf is 2.25" below my roof line.
I know the angle needs to be 12 degrees.

Shelf distance from the cab: 10.5"

So I found a lonely chunk of 6061 T-6 aluminum in the scrap bin at work.. about 0.075" thick.... Perfect

I cut it to the width of my cab at the roof: 48" and made the piece 10.5" wide (as per the on-line Calculator), and cut it to fit around my antenna mounts.

I just mounted it to my Antenna mount rail and it is quite stiff..

I guess we will find out if it helps tomorrow...

I guess the side pieces of the inverted "C" shape will take a bit more planing...

I'll try to get a photo tomorrow in the daylight.

[Christ]

Sniff is better than Smelly. Just sayin'.

Pics? (Can you take pics of how sniff something is?)