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Old 05-06-2008, 11:35 AM   #17 (permalink)
lunarhighway
Master EcoModder
 
Join Date: Feb 2008
Location: belgium
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vectra a - '95 Opel Vectra GLS
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weight is only an issue in the design stage of the car i think. if weight saveing is a design goal in a new car design saveing some grams on every part and keeping all mechanisms simple and therefore light might reduce the overall weight. on the other hand most single wipers that cover the same area as double ones use a more complex mechanism, so theres not that much weight saved. so unless you already ripped out the interior and all seats and drilled holes in all non load bearing structures etc...don't think about the weight of a single wiper.

aerodynamic drag is another thing and more important although still marginal in relation to other areas of the car.The way wiper blades park and the blades themselves is more important than their number. a good wiper design should park outside of the airflow into a recess, the base of the windshield is a high pressure area so it's not as critical as other parts of the car but a fairing in front of the wiper that deflects the air over it is usually a good thing. also recently flatblade wipers have appears also as aftermarket add ons. these have an overall lower profile than conventional blades so they'll generate less drag when in use. i have used them and i'm quite happy with how they look and perform, they have a spoiler like top that performs pretty well at high speed to keeps the wipers stuck to the windshield rather than start to flutter , although this probably doesn't directly serve as a drag reducer the overall setup probably has less drag than normal wipers.

some racecars (and cars trying to look like them) have single wipers that park in upright position. perhaps these wipe better, but i assume the single wiper is for simplicity. an upright position in the center of the windshield won't add that much drag, an interesing example is the opel eco speedster wich was a concept car that set a diesel speed/economy record and was desinged for very low drag.

so if you're wipers are very exposed to the airflow pulling of a single wiper will arguably reduce drag, but will compromise wiper performance although this might be compensated fro with a single bigger blade that roughly clears the same surface

imho, installing a deflector in front of the wipers (for some trucks this is available as an aftermarket feature although mostely for looks i think) that shields them from the airflow as well as looking for flatblade wipers is the best way to reduce drag without compromising safety or running into legal issues.

if you have a coupé like hatchback with airflow attached to the rear window that has a rear wiper, pulling that off might create a slightly cleaner wake. and if the airflow is attached you won't really need the wiper anyway.
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