exterior sunvisors
 

has there been any discussion or testing about the advantages to having sunvisor on big rigs, or flater windshield trucks, do you think there is an aerodynamic advantage, I have been working on one for my Kurbmaster thinking that I can gain something but wonder if they act more like a scoop then air deflector? Anyone have any ideas, would load a picture but have not been able to sort out how, they are all too big for some reason even after resizing.

Seriously?

dead serious
 

I got a mock up done but still can't figure out how to get the pictures have uploaded to photobucket but not sure how to get them here,

I suppose it might be possible to design one that improves the flow at what would be the windshield/roof junction like Dr. Paul Macready's patented leading edge device purportedly does, but I've never seen one like that. They appear to usually be quite aero awful, especially the "vented" ones.

by vented do you mean with a gap between the visor and the roof, I was thinking after seeing them like that on most trucks that I would have to do that as well to allow the air out so it would not blow off, If attached directly to the roof as in my mock up( wish I could figure out the pictures would save 1000 words) I was worried that I would be trapping air and even though it is a steep angle the air would run up the windshield and stop putting a lot of pressure on the visor acting like a scoop eliminating the possible advantages of the deflector

yes

http://http://i1066.photobucket.com/...ght579x362.jpgsee if this photo works, if it does this is my mock up was intending to leave a gap between the roof and he visor

http://http://i1066.photobucket.com/...ght579x362.jpghttp://http://i1066.photobucket.com/...ght579x362.jpgtry this

I can't seem to get the photo up will try again tomorow

You had "http" in there twice. Try this one:

http://i1066.photobucket.com/albums/...ght579x362.jpg


To embed it, you use the img tag inside square brackets: []. Then the URL for the image file, then /img in square brackets. The result is:

http://i1066.photobucket.com/albums/...ght579x362.jpg

-soD

now we are talking
 

isn't she a beautiful brick !!! I want to improve mpg and this is what I was thinking, I have fabricated a new bumper which consists of a alluminium tube rolled back, that will bolt onto the upper bolts of existing bumper. I started a pan last summer that will attach under the grill between the frame bent down and back directing air under the front suspension and engine pan. I am now thinking or some kind of front tire deflectors like shark teeth. A belly pan will be relatively easy, attaching to my lockers and lower step on both sides joined together with a central piece all made from light guage alluminium. I was thinking a panel about 5 to 8 inches on edge from inside the front wheel to outside the rear attached to the belly pan, something like transport trucks, the visor not sure it that will work planned on leaving a gap between roof and visor so air can escape, was thinking it would deflect some air??? and a small kamm back made in one piece that would come out, down roll down the sides as big as I can get, still being able to open the rear doors. I doubt I would be able to get more the 18 inches. I was wondering if I should be thinking dam instead of directing air under vehicle. I am limited as to how low as I use it as a stealth, back country camper and want it to be practical, I will likely be carrying my scooter on the back as well. Would love to hear what you think and if you have any suggestion or if I am going in the wrong directon. cheers FK

If you want to cool off the cab, get one of those reflectors for when it's parked. If you want better aero take the visor off. The visor will do nothing but create drag. If you want to post pictures use this http://ecomodder.com/forum/images/ed...nsertimage.gif

Sweet van! Seriously, making it look odd may work against any plans about stealth camping you may have. Close to stock may be your friend, IOW. And save more money that way.

If you're getting near 16 on the highway then it's doing quite well. What does it weigh and how have you outfitted the interior? (If it isn't prying).

A great choice for a camp van. You might look up

Cummins 4BT & Diesel Conversions Forums

for info on an engine that, with manual, would put you right on up there for mpg.

I did weigh it last year but I can't remember, van is in Canada and I am in NZ so can't check for you , it is not much heavier then a car, it is all alluminium, inside is done with 4mm panel and cedar for framing sterefoam insulation, not finished yet a work in progress but looking good, very livable, you are right I don't want to stand out too much and also right about changing over to manual and a deisel but not sure I want to invest that much into it. The aerodynamics are easy and cheap for me. I have access to slightly scratched alluminium and a few breaks along with some experience working it. cheers fk

I think the best thing to do with that for is to cover the top half of the back wheels and smooth the bottom of the truck.

Now just guessing for the visor leaving an inch gap between the visor and the front of the truck to let air out at speed. Also I would raise the visor up and make it a shallower angle so the visor could help direct air over the truck and help negate the drag created from air escaping between the wind shield and visor.

visor
 

The fiberglass fairing on the upper leading edge when applied to a bus,with a 140mm radius ( 5.91") reduced drag by 12%.
By placing the straight-sloped ramp visor in front of it will cause the flow to overshoot the roof,causing immediate flow separation and higher drag.
Texas Tech's Aero Lab has investigated this sort of thing and it's REAL BAD.

that is interesting, funny how sometimes logic does not make any sense. It already has a leading radius edge, I guess Grumman Olson put some thought into this, they have rounded all the edges. I might have to scrap the visor idea even though I like the look of them. So do you think all those transport trucks are doing themselves a big disservice by having those funky visors. I guess I will focus on smoothing the bottom, perhaps fender skirts. I have seen a kurbmasrter with a dam on the front but my logic was telling me to eliminate as much frontal area as possible and duct air under, smooth the underside, who has thoughts on that. Anyone with any ideas on channeling the air with a side deflector that runs from the inside of the front tire to outside the rear. cheers fk

visor
 

If I was still trucking and driving into a sunrise or sunset with one hand shielding my eyes while trying to row through a Road Ranger transmission I might want some kind of visor.
But it should be designed with physics in mind.
You can fool most of the people most of the time,but you can fool the troposphere none of the time.;)

I think I will try and build it in a wing shape, leaving from under the lights on the roof coming forward and down rolling in the same radius as the Texas tech study mentioned above and securing back under the radius held in shape by the end caps bracketed to the side and center pillars with round or wing shaped tubing

Proper design can make the visor virtually zero impact and may improve aero on some vehicles with a sharp windscreen/roof angle. I have read a lot of trucking papers that touch on this subject, quote below from one I just found, point is if you want to keep the visor and have good aero you will need to do more research.
"Cab Sun Visors
Sun visors can be specified in two designs and are added for driver comfort. One design extends out from just in front of the cab roof and, despite slight rounding of its edges, will increase the drag in nearly all circumstances.
The second design is more rounded and extends over the top of the cab windscreen. This design rounds the front roof edge and can improve the aerodynamics of cabs with sharp front roof edges."

I'd go for some heavy tint across the upper portion of the windshield. And some Drivewear prescription sunglasses. If that works (and it does, for me, in a latitude with far more heat & sun than Canada) in big trucks and small, then it ought to work on a bread truck in a cold climate.

Belly pans and boat-tail a la' Orbywan ought to be studied for effectiveness. I notice that FRITO-LAY is now using little vans like this with full rear wheel skirts.

Visors are kinda "ghetto" anyhow. Right up there with too many running lights. Pretty soon it starts to look like a jitney or the questionable ice cream truck belting out Pop Goes the Weasel with all the wrong connotations associated with such. TV culture being what it is (welcome to the America's) expect that this (below) is an image one never wants:

http://images.wikia.com/wikiality/im...ampedobear.jpg


In contrast here is a wireline truck (oilfield service company) owned by friend of my late father-in-law:

http://www.fescoinc.com/media/equipm...line_wl-21.jpg

Completely custom on the one hand, low key on the other. Has windows. Service access doors. External power ports. Etc. People obviously work from it, in other words. Mild color. Discrete logo. Respectable.

Fulfill their expectations (even with a modified boat-tail) with some low-key fake name (Eindhoven Associates, Don Mills, ON) or some such on the side. A name they can't pronounce therefore recall. After all, what is your business is your business. You are "consultants" or "field engineers" or whatever.

Aero work can be "blended" with a plausible appearance that allows for a bit of oddity. And this anonymity is a mighty thing. So change the wheels/tires to a "commercial" look as well. Lose the racing stripe. And a few antennas on the roof play it up farther (and which you may already need).



.