truck topper modifications

[craveman85]

I've got an aluminum truck cap for my ranger. I've been contemplating cutting and reshaping it to a wedge shape. Any of you guys done this ? I think for a ranger aero cap the rear should be about 10.5" tall for the optimal angle. One hicup I'll have to deal with is the windows. Anyone know if truck cap windows are tempered? I'd probably need to cut 2 side windows and the rear gate. I suppose I could use lexan or other stuff but I'd like to do this on the cheap. If this venture doesn't work out I've got some lightweight foam rubber sheets that I could make a shell out of.

[freebeard]

A curved taper would be better than a wedge. Where do you plan to make the cuts?

Try scratching a window. Maybe it's already Lexan.

Would the 'lightweight foam rubber sheets' make a rigid surface?

[elhigh]

Any improvement is an improvement. Freebeard is right, a curved profile that more closely resembles the template would be best, but I think a straight wedge that dips below, then back above the template's profile would give the airflow a chance to reattach. I'm guessing here, Aerohead would be a much better reference than I.

I think any reduction you can make to your wake is a good thing, and if you leave a few percentage points on the table by being conservative, well, that's still better than not caring.

[craveman85]

I was going to cut it lengthwise below the radius of the upper corner then make about a 9 or 10° cut below it removing a triangle piece from each side. Then the top would slant down 10°. I know the rear end of the side walls would have to be tilted inwards more to meet up with the roof. However I thought further on the project and realized that if my roof stays the same length and I simply tilt it down then it won't extend to the back of the bed. It will become the long side of the triangle. I might scrap the idea and maybe use the frame to build something maybe using new aluminum sheet for a cover. The aluminum on the cap is that textured crap they use on trailer siding so it's not very smooth.

[BabyDiesel]

Do you have any pics, craveman85? Have you used the Aerodynamic Streamlining Template?

Aerodynamic Streamlining Template

From what I have read, your methods sound good. However, if you're going through the trouble of cutting a bed topper, might as well get it as close as possible the first time

[deejaaa]

lots of good things being made from rigid foam:
http://ecomodder.com/forum/showthrea...9-a-23152.html
http://ecomodder.com/forum/showthrea...per-20880.html
Foamie Teardrop Camper
Google Image Result for http://www.tnttt.com/images/2012/foamie158.jpg
foam with carbon fiber shell:
Hooked Up Films Adventure Camper Build | Hooked Up Films
Google Image Result for http://ecomodder.com/forum/member-a8ksh4-albums-camper-shell-continued-picture4526-img-20130101-161609.jpg
One-Off Construction Using Fiberglass Over Foam
Google Image Result for http://i00.i.aliimg.com/photo/v5/484038804/SB9021TLJ_Travel_Trailer_Camper_trailer_Closure_Tr ailer.jpg

[craveman85]

It's not really a rigid foam like insulation. 1" thick, gas and oil resistant, flexible, nearly no water absorption. I actually use it for boat flotation. I used a weight to submerge 100gr of it for 2 weeks then weighed it at 100.1gri don't have any pictures at the moment and I can't get the overlay thing to work on my phone. I don't have a computer.

[aerohead]

Originally Posted by craveman85

It's not really a rigid foam like insulation. 1" thick, gas and oil resistant, flexible, nearly no water absorption. I actually use it for boat flotation. I used a weight to submerge 100gr of it for 2 weeks then weighed it at 100.1gri don't have any pictures at the moment and I can't get the overlay thing to work on my phone. I don't have a computer.

If you can get an image of your truck and the template,you could use a copy machine to make enlargements giving the same height to both.
Then overlaying one atop another on a pane of glass,and with a light source below you can make comparisons and scaling of dimensions.
Etched (sand-blasted) glass or milky Plexiglass offers a nice light diffusion compared to clear glass.
I also have no computer and do everything low tech.

[freebeard]

That's old-school. You could tape them to a window on an over-cast day.

craveman85 -- I'm probably going to suggest cutting gores right on the upper corner, but I'm waiting to see pictures of the internal construction.

[craveman85]

I'll try to get some pics tomorrow. Way too many projects going on right now.