Reducing Windscreen Wiper Cd

[CRGProducts]

Many designs park the windscreen wipers below the trailing edge of the hood or in a cowl recess in an effort to reduce the coefficient of drag.

If economics/body design be compromised and regulate the use of fully exposed wiper arm/blade assemblies, what could be some considerations to reduce Cd, wind noise, high speed flutter.

Have any auto manufacturers investigated an alternative to the wiper arm/flexible blade thats been with us for ages.
Compressed air?

Regards,

Robert Stanley

 

[mloew]

Robert,

Valeo has developed what they call the Flat Blade wiper system (

http://www.valeo.com/gb/activities/wiper_systems/fb.asp).

They claim the following benefits:[ul][li]High speed performance: > 200 km/h.[/li][li]Reduced aerodynamic noise.[/li][li]Reduced reversal noise.[/li][li]Reduced weight.[/li][li]Improved resistance in cold weather conditions.[/li][li]Little obstruction of the driver's field of vision.[/li][/ul].
Try searching through the resources listed in the FAQ: Who are the suppliers for X? (faq108-630) for other suppliers and information.

Also, for future reference this probably should have been posted in Automotive Engineering other topics Forum (forum108).



Best regards,

Matthew Ian Loew
"Luck is the residue of design."
Branch Rickey

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Peter7307]

Robert,

Several manufacturers have run tests on using compressed air as an alternative to the standard wiper design.
Some used a separate compressor and others a bleed from a turbocharger.

The results were an improvement in drag as would be expected but some distortion of the image perceived by the driver through the "curtain" of compressed air as it was pumped from the base of the screen to the roof line.

As far as I know some patents were filed but not carried through.

One alternative is to use a fixed blade and a plastic film running across the windscreen in the manner of some camera mounted F1 shown on television.

Interesting thread.

Cheers, Pete.