vectorsolid

This is a fun build we did with a relatively inexpensive wing. Are the better easier ways to do this? Probably. Are there better wings? Sure there are.

This is what we had. and this is how we made it with what we had. We wanted to get a bit of downforce on the back of the car for a track day event, and the stock hatch simply didn't provide enough mounting surface for the base of the wing.

Whole thing started out with the wings base mount being about 2-3" to long for the little piece of sheet metal on the back of the Rex hatch. So we made a wider lip back there and brought the roof line down and made the window smaller.

Made some HELLA STOUT mounts out of 1/4" aluminum angle. This wing is SOLID on the car.

Pics tell the story.

Here's what we started with:





New lip and wider sheetmetal for wing mount.


We made these heavy duty brackets for the wing mounts out of aluminum angle:


added the lip for where the lexan window will ride.






test to see if the lexan will be a good fit.

vectorsolid

Decided we didn't want the window to go all the way up, so we added some sheetmetal to the front of the hatch to make the window opening about half it's original size. Still perfect, un-obstructed visibility out the back.







Smoothed and test fit:


first mockup of the rear window (3/16 lexan) and the revised sheetmetal.

vtecing

Cool!

vectorsolid

Sheetmetal spot welded into place and the welds now being ground down.


You can see the nice lips we made for the lexan window.




Hatch back on to verify and check the body lines before we mount the lexan.

vectorsolid

close up of the wing mounts.


Welds and grinding were good enough that we didn't do any body filler. Just painted it quick with the old spray bomb. and started to mount the rear window. Needed drilled and countersunk.



Used Pactra RC paint for polycarbonate and painted the black edge around the lexan to cover the frame and give it that finished look.


Few things look worse than screws that are improperly countersunk or buckled lexan. take your time, and keep it smooth. This came out about perfect. Looks like glass. No distortions.

vectorsolid

Finalizing and getting it mounted for the last time.

vectorsolid

Just realized we didn't get any pics of the completed project. We'll get those shot.

We're happy with the way it turned out, and the wing is HELLA sturdy. Feels real good when you really try and wrestle it around. It's firm. And we've since had the car on the track, and it doesn't vibrate, or hum or flutter. Just sits where we put it.

This wasn't the original hatch for the car, was a spare hatch we had, so he has 2 hatches for the car. Normal hatch, and the track day hatch.

HCivExoo

pretty nice stuff i like it

exgr

So this is a modified stock CRX hatch? Excellent work as usual!! How about a few more photos of the finished hatch mounted... from various angels, and from distance? I'm interested to see what different looks it gives the CRX with the reduced window size.

The Destroyer

Looks awesome.

vectorsolid

Thanks guys. Can't get any outdoor shots, it's cold out. pardon the shop mess, it's been a long winter already.

I did do some measuring. Top of CRX roof, about 47", top of 2nd element on the wing 48" So it's about level with the roofline from the side.

There is "zero" loss of visibility from either the driver or passenger seat.

exgr

Looks really good! As far as weight is concerned though, wouldn't it have been lighter to have the sheet metal upper half to be entirely lexan? How thick is the sheet metal used in the upper half?

vectorsolid

I don't think so, with bracing because lexan is flimsy, it would have been a wash. To go with just a lexan window would have made it floppy, with a size of roughly 42"x32", so we'd have needed to add some kind of support. And that support would have ended up in the drivers line of sight (like you see on NASCAR windshields). and we'd have had to go thicker, likely 1/4" to get the same relative rigidity.

The dimensions below are "rough", but close.

Upper piece was 20 gauge sheet metal, .0375" thick 15"x41"
lower piece the wing is on, we went thicker to give the wing more support, 18 gauge .050", 7x41"
lexan is .187", 17.5"x43"

Stock rear glass was .136" thick, weighed 17.96#

sq foot of .187 polycarbonate, 1.15#
sq foot of .035 mild steel, 1.46#
sq foot of .050 mild steel, 2.09#
sq foot of .136 glass, 1.822# (also the structurally stiffest, by a LONG way)

Sheet metal thickness gauges for steel are based on a weight of 41.82 pounds per square foot per inch of thickness. Polycarbonate, 6.192
window glass 13.41

upper piece, 4.2708 sq feet = 6.40#
lower piece, 1.99 sq feet = 3.98#
polycarbonate, 5.22 sq feet = 6.04#
if we'd have gone to 1/4" lexan would have been 8.08#

total weight of the parts used, 16.42# With the lips to hold in the poly, I think it weighs exactly what it did in the first place (the factory glass at 17.96#), so it's only heavier by the exact weight of the wing assembly. I'd say that's a win.

exgr

Haha, that's the most technical post about the lexan window setup I have ever seen!! You guys rock!

I suppose another option was to build the horizontal bar in the middle to support the lexan, but go with lexan on the upper half still? According to your weight chart we can still achieve a weight saving of couple of pounds over mild steel sheets. :-) I do like how your current setup changes the look and bit it new life.

In your .sig 1993 hatch...1/4 mile 8.77@168.2... wow, any links to that setup?

Driven

not a fan, but do appreciate the quality of work.

mcolangelo2006

I realize it's out of the scope of what you're doing, but I'd really like to see a study of drag vs downforce for these wings.

VTECIntegra9

Pretty wicked nice work...

But where are the defrosters!?

DSMAddicted

^^^ this.

SHG_EasyE

Wow thats a great little project. Fit and finish is awesome. Top that off with a nice wing at some point down the road and I couldnt imagine how id do it any differently. I would consider adding some extra support underneath but only depending on how much pressure the wing exerts on its sheet metal base.

vectorsolid

That 18 gauge under the wing, we laid it over the existing CRX sheetmetal in that area. so it's 2 layers. Plus the lip of the sheetmetal is bent at 90 degree angle and then shrunk into a convex curve. And then another piece bent into a 90 degree angle with a curve in it was welded to front of it for the windowframe. and with the oversize aluminum brackets, you can hang off the wing. It's very strong. you could tow the car from that mount.

With the possible exception of Chuck Norris involvement, that wing isn't going anywhere.

Andy Hollis

Good stuff. Looking to do a new wing setup and lightweight deck for my Rex also. This gives some ideas. Thx.

0Deatschwerks

I'd thought of trying something like this with one of the molded plastic windows to try removing some of the air that gets brought in through the windows, but I'd be worried about increasing lift.





I'm not a aerodynamicist though, and this idea was incorporated before wind-tunnel testing was really prevalent.

powerneedy

To me exiting at the bottom would have been more beneficial with the parachute effect.