Aerocap for a Tacoma Pickup?

[aerohead]

Originally Posted by ccrider

i finished my first tank with the aero cap and i cant catch a break with the weather after the monsoon rain i drove through last weekend on my 200 mile trip i did a good amount of city stop and go driving and my tank average was 27.74 mpg. which is a little better than what i have been recording in my fuel log for the last few tanks but considering the extreme conditions i guess my results are good. now this weekend i made my 200 mile weekend trip, the temp was 10 degrees when i arrived and it was night driving, my scan gauge read 27.9 mpg at the end of the trip.

one of these days the weather will break and i think i will get the substantial increase in mpg that i would like to see

maybe in the warmer weather i will try a A B A test. the only thing is my truck is a base truck and does not have cruise control. so would i be wasting my time doing an A B A test?

cc,I just duplicated a 613-mile run I attempted last year which was frustrated by 330-miles of rain.
This time I had dry road the whole way and saw a difference of 36 mpg vs 31.8 for the wet conditions last year.
The stop and go will also severely cut into mpg.It can be 1/2 your HWY mpg!

[ccrider]

i just logged my second tank on my truck with the aero cap. the first 120 miles of the tank were in 10 degree weather at night that i was averaging 27.9 mpg and the rest of the tank was the return 200 mile trip that started with the first 60 or so miles using the lights and the air temp when i started was 20 degrees and it was about 30 degrees when i finished the trip. the tank average was 30.09 mpg. i think that if i got a full tank in with temps above 30 degrees i would get somewhere in the 32mpg range.

its funny but it turns out that my first tank that i logged is the same exact miles and fuel used without the aero cap but the weather was allot warmer. it seems to me that ever 10 degrees is about 1 mpg.

[mjboks]

Originally Posted by ChazInMT

Hey MJ, I finally got my cap built. Just last night as I was about to cover the thing with shrink wrap I had an epiphany. I wanted to just scrap my cap and build my new idea. My inspiration is all these low cd cars & SUVs we see that have a large rear surface area. So this is obviously not the enemy. On my cap, I wanted the back to be as low as possible, but I'm afraid it may be a mistake for 2 reasons. 1) Not really the most efficient aero design, 2) Not real practical at all.

So what I would build now would look more like this.


[...image deleted by cfg83 at request of OP...]

(Photoshop creation)

This design would taper the air down the top and sides. By angling up the tail gate hatch area, it allows a large door access and window. The hatch door could even be removed to haul tall stuff, or even make it like 2 doors for more free head room when removed.

A simple line drawing would be like this.


[...image deleted by cfg83 at request of OP...]

Just more food for thought, I think this would be easier to build than my cap and way more practical. Built using CCriders basic technique.

I'll post updates of my build later this a.m.

Now you're just teasing everyone here. I want to see results from your current cap before you scrap the idea. I think you're first cap is a great aero design. Although it doesn't lend itself to a great hatchback design which I'm going for. I'm one those that use my truck for hauling and will need access to the back. I also want it somewhat easily removable for when I have a lot of gear or something tall to haul. I'm also leaning towards the easier and more practical design for myself without sacrificing as much aero as I can. Ideally it would be a roller tonneau that would follow the curve back to the tailgate.

As for your new design, I like it and looks a lot like the newer hatch back vehicles coming out. It sort of reminds me of a Volvo C30 which I happen to see on the drive to work this morning.


For the sake of everyone following your progress, at least do and A-B-A test with the current cap before you scrap it.

btw, what software are you using to create your designs?

[ChazInMT]

I just open a word doc, and use MS Draw, believe it or not it is a very handy CAD program. I mostly use the Autoshape/Lines/"Polygon-S Sided Icon" and try to make as few points as possible getting a rough shape. The "magic" happens when you right click on the object you've roughed out and "Edit Points" is the option. When editing points you can move them anywhere, and if you right click a point, you can change its attributes, I like making a lot of corner points because it gives you these 2 little bug antennae you can manipulate to create whatever curve shape you want from the corner. Once you make a shape, you can "Format Autoshape" and hit Size tab to see how big it is out to 1/100th of an inch, on a 1" = 1' scale, that's a 1/8th of an inch resolution, that's close enough in my world. This is a good tool to make things to scale and correct proportions.

I have gotten the hang of it pretty well and can trace out a car in like 5 - 10 minutes to FlowSimulate. Then I take whatever drawing & photo thing I have and convert it to a .pdf, then Adobe lets me save it as a .jpeg. It took me about 30 minutes to create the cap line drawing above. I do have a talent, don't mean to brag, but I can think in 3D pretty well, so the above was done essentially free hand, I just manipulated the points til it looked right according to the image I have in my head.
I should probably take an hour or 2 in the next 2 weeks and organize my thoughts & techniques on using MS Draw into a guide for folks. As I say, it's about all you need for the stuff we do, and I think pretty much everyone has it.

Found this basic guide online: SDSU Training Guide for Drawing Toolbar

[ccrider]

i just completed another 200 mile trip with my aerocap. it was a sunny day with the temps in the 30's with some side wind and head wind depending on my direction the driving was during the day except for the last 30mins i had the lights on. i was going around 65mph and about 20 min the traffic had me going around 55mph. i drafting behind some rigs for about 20mins. when i arrived the scan gauge read 32.8 mpg.

i am just about done with my 3rd tank with the cap but the tank is not going to be as good as my 200 mile drive because of the city driving i did.

[MetroMPG]

Congrats on tying your previous best tank MPG!

[ccrider]

i just finished my 3rd tank with the cap and it came in slightly under my best tank at 29.31.

in a couple of weeks i will be in sunny warm Fla with my truck for a few weeks with not much to do so you might see a tuft test and a ABA test from me. i think metrompg would like to see those tests.

also i will be driving the truck to Fla which is a 1200 mile trip so i will get some straight highway tanks in. the only thing is i will be carrying around 600lbs (trucks sure are hard to get consistent mpg readings) in the bed.

[ccrider]

mjboks are we going to see a cap out of you? or is the mpg results from use guys who have done them making you think twice? if you don't do allot of highway driving the results maybe pretty small. i think that i am getting about a 10% increase (but only a ABA test will show) with my cap on highway driving.

[aerohead]

Originally Posted by ccrider

i just logged my second tank on my truck with the aero cap. the first 120 miles of the tank were in 10 degree weather at night that i was averaging 27.9 mpg and the rest of the tank was the return 200 mile trip that started with the first 60 or so miles using the lights and the air temp when i started was 20 degrees and it was about 30 degrees when i finished the trip. the tank average was 30.09 mpg. i think that if i got a full tank in with temps above 30 degrees i would get somewhere in the 32mpg range.

its funny but it turns out that my first tank that i logged is the same exact miles and fuel used without the aero cap but the weather was allot warmer. it seems to me that ever 10 degrees is about 1 mpg.

cc,your numbers seem very reasonable,and congrats for 30.09 in the cold temps.
This coming spring and summer,I've no doubt that you'll see 32.The Tacoma probably has a similar seasonal mpg variation as with the T-100.Keep us up-dated!

[mjboks]

Originally Posted by ccrider

mjboks are we going to see a cap out of you? or is the mpg results from use guys who have done them making you think twice? if you don't do allot of highway driving the results maybe pretty small. i think that i am getting about a 10% increase (but only a ABA test will show) with my cap on highway driving.

Yeah, I'm still planning on building one but it's not really high on the to-do list right now. I have it 90% designed in my head. I really want to go with a hatch back style so I can access to the back. I also want it somewhat easily removable for different configurations. Actually if Bondo made one for the tacoma, I'd buy it (hint hint if you following this bondo).

However, this time of the year (winter), I'm not doing a lot of highway traveling with the truck, mostly a short commute to my day job. If we don't need the truck for highway traveling, I'll take the wife's Civic.

Hopefully this early spring will allow time to build my aerocap.