95 Dakota Extended Cab Aero-Topper

[freebeard]

4th gen Camaro/Firebird is like unto the GM EV-1. I was thinking of the actual glass but the contour is a little hard to see, so here's a louvered overlay.


http://www.andysautosport.com/window..._firebird.html

[jviolet10]

Hey everyone,

A quick thank you to FreeBeard, AeroHead, and NeilBlanchard for your input.

Aerohead, regarding the ring-vortex you brought up. Would this be a worthwhile option for an additional accessory "box" with the shape mentioned that could mount to the tailgate? I could fold the tailgate down and attach the box that during long trip. Yet be able to store in the bed when in town (because I'm certain juveniles won't be able to resist tampering with it). Did you ever have problems with people messing with your builds?



Anyways, a quick update on my progress. I finally finished out my senior design project and get to move forward with my life lol. Attached below are two pics of a little progress I made last night on the cab. The hardware cloth seems like it will mold perfectly to my desired shape. There was a minor design change too, I needed more height at the tail to make it practical for my fatbike to go in and out of with the top on.

I'm still debating how to finish out the top lid.. I can't decide if I want to make my own tonno cover to roll down it or an actual hard lid.

The fiberglass and resin arrived and my application plans are to apply 2 layers, use a little bondo as needed to fill the divots, then finish it with 2 or 3 final layers.

Again, thanks for reading and any and all input is appreciated!

[freebeard]

The thing about the Morelli ring vortex is it is 360° with special attention to the wake coming off the back tires. It actually has turbines in the wheels that pressurize slots at the ring. The pickup bed tailgate hinge line falls about the middle of the ring.

[a]erohead has built pneumatically inflated tailgate add-ons. Check his albums.

http://www.boatdesign.net/forums/materials/pet-g-mylar-film-46223.html

I would do 2 or 3 layers of fiberglass, hit it with 80-grit sandpaper, and then do the last coat or two using Mylar. I always though you puddle it and squeegee it out, but the linked article suggests a toothed applicator.

There is some discussion of trapped air bubbles. I'd try pricking the Mylar to let the air out in that case.

[aerohead]

This is the inflatable boat tail which Freebeard mentioned.
It's basically a wooden box which encloses a 12-VDC blower fan which breathes through to a tailored bean-bag envelope,stapled to the perimeter of the box and attached to the tailgate.
It did require a stabilizing spar affixed to the bottom to prevent oscillation.A simple electrical umbilical cord ran under the truck and simply spring-clamped onto the battery terminals during testing.
It's very light and with the 1/2-tonneau and the cargo box in the bed,it gave 5+ mpg at constant highway speed.

The Naughehyde envelope created a square-to-rounded corner transition which kills attached longitudinal vortices and allows for the ring-vortex.

[freebeard]

It did require a stabilizing spar affixed to the bottom to prevent oscillation.

If the box has a lid that hinges at the bottom, that would substitute for the spar.

[jviolet10]

Well guys, I made it to colorado Thanks again to everyone for the help and advice!

Summary: I suck at fiberglassing lol. I got 2 coats when building the truck but that was all I had time to do. The hinged lid works flawlessly so I was able to load everything into the truck with the topper in place.

Fuel Log:
I traveled a total of 1478 miles.
Starting elevation was 500 ft and final elevation is 5600 ft.
Estimated weight including furniture, 3 bicycles, and an extra passenger is roughly 800lbs.
Average speed from Ohio through Missouri was 70-75mph.
Average speed through Kansas and Colorado was 80-82mph.
From Dayton, OH to Columbia, MA I had to fight an awful storm that caused tons of flooding.
Since the sender unit was out and my credit card required pre-paying, I wasn't able to get all the individual numbers.


The final fuel consumption was 71gallons resulting in nearly 21mpg average in an automatic truck. As a bonus, even though my aero topper was hinged and I dealt with rain for almost 10hrs straight. ALL of my stuff stayed perfectly dry! I couldn't be happier with the end results. Thanks again to everyone for the input!

I'll upload photos within the hour anyone interested.

[BamZipPow]

I'd love to see yer finished cap!

[jviolet10]

Here it is with the 1st layer of the fiberglass cloth but no resin yet.


My Firestone tire Destination A/Ts... I wanted a little extra traction for the dirt roads out here.


And here is it at the apartment complex in downtown Denver. Don't hesitate to enjoy a glace at the beautiful bikes in the back


Will upload pictures of it open in the upcoming days

[stovie]

So jviolet, your getting over 25mpg with aero top and electric fan?? Or is there more you've done so far??

[jviolet10]

Originally Posted by stovie

So jviolet, your getting over 25mpg with aero top and electric fan?? Or is there more you've done so far??

Yea, just those 2 main mods. Thats pretty much it besides a good tuneup on the engine.

It should also be noted that the fuel efficiency is naturally better in Colorado than other places since the air in Denver is only about 75% as dense as sea level. At my friends house in Alamosa, I was getting almost 30mpg in a 2010 highlander because the roads were perfectly flat holding a constant 65mph at 8k ft. elevation (approximately 65% air density)