Mirror designs, if we can't use cameras yet.

[67-ls1]

Grim, the California mirror law states you must have a center and a left mirror. It does not state the left mirror must be exterior.

[Madact]

Local laws where I am do allow a passenger car to have only an interior main mirror, but there are also design standards for newer vehicles which are referenced by road-worthiness tests (in other states this info is available on the net, in my state it isn't explicitly stated though), and current design standards require exterior mirrors on both sides

Not wanting to get the boys in blue too narky, and actually finding the side mirrors quite useful in any case, I'm looking to create an aerodynamic set of mirror housings (one of my one-day-when-I-don't-have-a-million-other-things-to-do projects that keep piling up ) using some blue styrofoam scrap and spare fiberglass/epoxy.

So, I recently grabbed a pair of these, which are right on the design standard minimum height and only about 2cm wider than the minimum height:

F1 Design Carbon Style Racing Sport Side Mirror X 1 Pair Left AND Right | eBay

I'm thinking of something a bit like this - apparently they've patented the rear box cavity "on a rear-view mirror" in much the way other companies patent rounded corners "on a mobile device" (sigh) but I'm sure playing around with stuff in my shed will be fine

[Smokeduv]

Originally Posted by Madact

Local laws where I am do allow a passenger car to have only an interior main mirror, but there are also design standards for newer vehicles which are referenced by road-worthiness tests (in other states this info is available on the net, in my state it isn't explicitly stated though), and current design standards require exterior mirrors on both sides

Not wanting to get the boys in blue too narky, and actually finding the side mirrors quite useful in any case, I'm looking to create an aerodynamic set of mirror housings (one of my one-day-when-I-don't-have-a-million-other-things-to-do projects that keep piling up ) using some blue styrofoam scrap and spare fiberglass/epoxy.

So, I recently grabbed a pair of these, which are right on the design standard minimum height and only about 2cm wider than the minimum height:

F1 Design Carbon Style Racing Sport Side Mirror X 1 Pair Left AND Right | eBay

I'm thinking of something a bit like this - apparently they've patented the rear box cavity "on a rear-view mirror" in much the way other companies patent rounded corners "on a mobile device" (sigh) but I'm sure playing around with stuff in my shed will be fine

The last ones are like the ones I want to make. Too bad that the design doesn't allow for a camera to fit inside with all the cabling all the way to the cabin

[Madact]

Originally Posted by Smokeduv

The last ones are like the ones I want to make. Too bad that the design doesn't allow for a camera to fit inside with all the cabling all the way to the cabin

Actually, you'll notice that the 'stalk' is an airfoil section - plenty of room in there for cable runs. And with a rectangular mirror, you could round off the outside end to allow for a camera mount.

There's a neat trick to making hollow things with fiberglass / carbon fibre: if you make the form out of styrofoam and use epoxy resin for the fiberglass, you can lay up the fiberglass right over the styrofoam, and then when the resin is set, a very small amount of acetone will melt the styrofoam away. You can't use standard polyester 'fiberglass' resin though, it'll melt the styrofoam too early

Regarding styrofoam, if you want to go this route, use the 'extruded' stuff, which is made by dow, comes in pink and blue, is fairly affordable, and should be readily available from building material supply places and refrigeration specialists (or possibly skips at building sites - ask nicely ). Don't use the white 'expanded' polystyrene, it's made of little balls which are a nightmare to work with. Extruded polystyrene cuts neatly with a sharp knife (a break-off utility knife at full extension works great) or a hot wire, and sands fairly easily (use a vacuum to avoid static-clingy dust everywhere).

[Smokeduv]

Originally Posted by Madact

Actually, you'll notice that the 'stalk' is an airfoil section - plenty of room in there for cable runs. And with a rectangular mirror, you could round off the outside end to allow for a camera mount.

There's a neat trick to making hollow things with fiberglass / carbon fibre: if you make the form out of styrofoam and use epoxy resin for the fiberglass, you can lay up the fiberglass right over the styrofoam, and then when the resin is set, a very small amount of acetone will melt the styrofoam away. You can't use standard polyester 'fiberglass' resin though, it'll melt the styrofoam too early

Regarding styrofoam, if you want to go this route, use the 'extruded' stuff, which is made by dow, comes in pink and blue, is fairly affordable, and should be readily available from building material supply places and refrigeration specialists (or possibly skips at building sites - ask nicely ). Don't use the white 'expanded' polystyrene, it's made of little balls which are a nightmare to work with. Extruded polystyrene cuts neatly with a sharp knife (a break-off utility knife at full extension works great) or a hot wire, and sands fairly easily (use a vacuum to avoid static-clingy dust everywhere).

That's almost what I did, although I wasn't sure it was going t work, so thanks for clarification. I used some blue stuff and cutted it (don't think is the same thing, but I'll try int anyway) and this week I'm going for the fiberglass route and I didn't knew of the different resins. I have a 3M one which I think is the epoxy type. Hope it doesn't melt it...

This is the stuff right now. Still needs sanding because now it looks like it's been done by a 5-year old kid

[Madact]

Good start by the looks of it - what will melt it and what won't depends a lot on the kind of plastic it is, definitely test on offcuts / scrap first! Bear in mind that resins & epoxy may also release chemicals while curing, so be sure to test it on offcuts with mixed resin first. It's quite possible to have a resin that doesn't appear to dissolve the foam at first, but will gradually eat away a thin layer, so test on a scrap overnight. Of course, if you intend to remove the foam, and the resin sets before eating it you may get away with it You'll also want to check whether the foam in question does dissolve in the solvent you intend to use - polystyrene melts like nobodies business with acetone, but depending on the plastic YMMV... that stuff looks like you could dig it out after the fact easily enough though.

For reference, epoxy resins generally have mix ratios between 1:1 and 5:1, while polyester resins only use a very small amount of hardener, generally in the range of 20:1 through 100:1. I've used West System epoxy and generic solvent-free "marine" epoxy with good results on styrofoam, but some epoxies do contain solvents that can attack plastics. Marine grade epoxies should generally be OK, as the volatile solvents which attack plastics would also leave the cured epoxy slightly porous, which would make it unsuitable for marine use.

[SvdM]

So, would this be a bad idea for side-mirror drag reduction?

Viewed from the front, the stalk / rectangular catchment area has about 1/2 the m² area of the mirror. In plan view, the 'triangular exhaust' area has just more than 1/2 of that again in m². It's close to Template C in plan.

Those with access to 3D printers could easily make this. It might need some beefing up in the area where the two connect etc.

[freebeard]

Photobucket said 'Sorry...moved or deleted', but when I logged in even that went away; so—no piccie.

aerohead reported similar problems with Photobucket. MetroMPG suggests using your ecomodder account albums, or an attachment.

[SvdM]

Yes, I had that problem, but then it went away and worked. I assume I can see the image (it loaded) in the above post, because it's in my cache?

Anyhow, image attached here too now.

My premise was that most mirrors nowadays have substantial stalks for rigidity and I guess, looks too. But I always wondered what would happen if the width of the stalk would stay the same or even more aero, but act as a channel.

[cowmeat]

Bullet Mirror Fender for Retro Car Mazda Toyota Datsun Mitsubihi ect LH RH New | eBay

I'm considering trying to retrofit something like these on Turtle. They seem to fit the profile of sticking out far enough to detach the airflow. What do you guys think?

I'd want to make the installation reversible so I could re-mount the oem mirrors when I go to sell it, but these seem like they would cut a lot of the mirror drag.