Aerocap for a Tacoma Pickup?

[ccrider]

i did not think of making it topless. i guess i could do the torneau idea if the top gets annoying. i would have to leave the supports in the middle to stop it from collapsing so i could carry tall things but they would have to fit in between the supports.

i am thinking that i could take off the piece of plywood above the tailgate so it would give me about 7 more inches above the tailgate to get stuff into the bed. i am going to attack the whole cap with 4 brackets to the metal at the top of the bed. so if i need to take it off i will crawl in the bed with a battery drill and take off the 8 screws that will be holding it on and then stand up with the cap over my head. (sound good on paper HUH).

[Big Dave]

A fixed bed cover will get annoying. Mine has.

But maybe fixed is OK for a "Mark I" version thatcan be refined later.

[MetroMPG]

FYI, just found a video of someone tuft testing a cap very similar to yours in construction, except 8 degrees decline.

Posted it in a new thread: http://ecomodder.com/forum/showthrea...per-11522.html

[ccrider]

dont know if i learned anything from the video but it sure did make me dizzy. is that a 8 degree angle? the height of my cap at the tailgate is going to be 9" tall. that looks to be about the same if i had to guess. mine will have a bit of a round to it and i am going to try and get the gap between the cab tighter. his cap seems to be a little taller than his cab at the front of the cap. mine is actually about 1/2" shorter. which i hope would be better.

[MetroMPG]

I kind of felt a bit sick at the end too! Camera work could have been steadier.

He says it's an 8 degree angle in the video details.

I think going shorter by 1/2 inch is a good call.

[Sean T.]

I didn't read the whole thread, so sorry if this was already mentioned... but you could use plywood on the top and hinge it near the cab, so it has a top, but it's openable.

Or you could have an opening where the cover is small enough to take off and put in the truck bed when you need extra height.

[ccrider]

if i made a hinge on the front i would have the suports still in the the way of sldiding something big in. i dont think the sides would be sturdy enough to remove the suports. maybe i could remove the back 2 suports and have it hinge like the drawings that mjboks did. i guess it might work out to have the top to hinge up in the middle of the cap so it can flip all the way up and lay on the front half of the cap. this way when i am driving it will be secured down on the top an not sticking up in the wind.

[ccrider]

i was looking at a new pruis yesterday and i noticed at the rear roof of the car there is a little kick up in the body shape. is this to create a high pressure area right at the rear of the vehicle to stop separation? should i put this same kick at the rear of my cap?

[MetroMPG]

A rear spoiler at the end of the Prius could have been put there for several reasons, and unless we can talk to the aerodynamicist, we'll never know for sure which (or which combination of these) applies:

• as a styling element (ie. aerodynamically useless or even detrimental)
• to reduce rear lift
• to reduce drag by changing the "effective" rear slope
• to reduce drag by forcing cleaner separation where airflow might otherwise "wrap" around a surface

I would just carry on with what you're doing and not worry about a spoiler. The angle you're working with is fine, and that's the most important issue.

FYI, in your previous post you said you weren't sure if you learned anything from the Ranger tuft testing video. The key thing there was we saw the tufts streaming aft on both the sides and top surfaces of his aero cap, which indicates attached flow. It confirms that his angles weren't too extreme and that he should see an efficiency improvement from his work.

[mjboks]

btw - great build here:
http://ecomodder.com/forum/showthrea...ead-11611.html

I've taking a closer look a the "ideal" aerocap for my tacoma and found there is a slight decline at the end of the double cab (its not just in the picture). So the top of the streamlined template is back just above the middle of the rear door. With the template moved forward it reduces the tailgate height a bit. I previous calculated about 8-9 inches and now it's around 5 inches. Although is it better to error on the side of caution and make it higher?



I will also have to deal with the gap from the top of the aerocap to the cab. It appears if I go straight up from the bed I'll have a 6 inch gap that would create a bit of turbulence. Either build it flush or have some type of filler.