Zulu's Build Thread (Honda CR-Z)

[CigaR007]

Here is the detached kamm tail. Weight is just shy of 40 lbs, (hitch tow bar alone is about 12 lbs). I foresee a weight around 47-50 lbs when all is said and done. Definitely a weight penalty but it might improve the weight distribution of the car, which is 55-45 stock.

[jimchitas]

nice job dont worry 50lbs isnt really a lot weight and yea its helping with weight distrubution but mostly you will decrease drag coefficient so its pretty fair penalty

[aerohead]

Is there a plan to fabricate Plex or Lexan covers to cover the void behind the taillamps?
This area is critical with a fastback body. It needs the tumblehome and curvature to mitigate formation of vortices, blending the 'sides' into the 'roof.'
If you can't do it, you might as well foam the whole area in, on both sides, and put a trailer light kit on the back of the tail.
According to Jeff Powel and associates in England, you could be introducing, something on the order of a 33% drag liability.

[CigaR007]

Originally Posted by aerohead

Is there a plan to fabricate Plex or Lexan covers to cover the void behind the taillamps?
This area is critical with a fastback body. It needs the tumblehome and curvature to mitigate formation of vortices, blending the 'sides' into the 'roof.'
If you can't do it, you might as well foam the whole area in, on both sides, and put a trailer light kit on the back of the tail.
According to Jeff Powel and associates in England, you could be introducing, something on the order of a 33% drag liability.

Lexan covers is an option, just not sure how to work with it, in order to achieve the desired shape (heat gun ?).

Filling with foam is also a possible scenario.

Been also considering vortex generators just before the taillights, as to force the air to "hug" and re-attach onto the upper kamm tail side wall. A tuft test might shed some light.

[aerohead]

Originally Posted by CigaR007

Lexan covers is an option, just not sure how to work with it, in order to achieve the desired shape (heat gun ?).

Filling with foam is also a possible scenario.

Been also considering vortex generators just before the taillights, as to force the air to "hug" and re-attach onto the upper kamm tail side wall. A tuft test might shed some light.

On an episode of 'Rick's Restorations' he reproduced the original Carl's Jr.' fast food illuminated outdoor sign for the founder.
The 'body' was rendered in AUTO CAD, medium density fiberboard tooling was constructed, over which heated Lexan was vacuum-formed to create the complicated 3D shape.
To properly do clear covers would require the same degree of fabrication sophistication.
If it weren't a 3-D bend involved, you could fake it with a 1600-Watt heat gun and a crude wooden form.
I don't know about VGs. What you're looking for is the graduated deceleration and pressure recovery that the complex shape would provide, not just 'attachment.'

[freebeard]

Instead of the compound curve you could have 2 or 3 flat clear base plates; progressively smaller. The templates so to speak of the desired shape.

[jimchitas]

foam with fiberglass ??

[aerohead]

Originally Posted by freebeard

Instead of the compound curve you could have 2 or 3 flat clear base plates; progressively smaller. The templates so to speak of the desired shape.

There once was a time when people could purchase the commercial solvents used to weld Acrylic to itself, creating an exquisite, invisible joint. Then came the EPA.
They sure make it hard to get cancer and birth anomalies these days!

[CigaR007]

What would be the ideal thickness for the lexan, in this application ? I don't know how lexan fares in extreme cold though.

[Piotrsko]

Mek in the original formulation mixed with some acetone and added shavings or kerf from cutting the acrylic works wonderfully and USED to be cheap.

Went looking for MEK at the orange store the other day and all they had was synthetic. Guess I'm screwed when my 5gallon can goes empty.

The colder it gets the more brittle it becomes. @-20f you can break 1/4" with a good snap bend. You also don't want it above 160f where it becomes soft like artists clay.