The basic idea:
The airwiper would consist of a wiper arm, the approximate length of a conventional wiper but a little wider, perforated with columns of small holes to allow air to escape. The perforations would be aligned so that as the wiper moved, a small bow wave of air would always be on it’s
leading edge.
This escaping air would cause the arm to hover just above the glass without any significant noise (think of an air hockey table), or direct contact.
In case of no air pressure, the wiper would function conventionally, albeit not as effectively as a purpose built friction wiper.
Washer function would not be altered using this system, and if anything, could be enhanced.
Other uses:
-Hot air, heated in the same way the cabin air is, could be used to help keep the windshield free of ice in the winter time.
-Steam could be injected into the air stream to remove road grime, bugs etc.
-Cabin exhaust air, in the middle of summer, could be used to cool the windshield slightly, rather than go to waste.
-A glycol mixture could be pumped through the wipers when the car alarm is sounded. This would simulate smoke (without any residue or health risk) and attract attention.
Air from where?:
Air could come from a variety of sources. On turbocharged cars, it could be taken after being pressurized by the intake impeller. This would be akin to bleed air, on a jet engine.
With, or without a turbocharger, the best source of air pressure would be a small pump that delivers a constant pressure stream in proportion to wiper speed.
This is easy, and hardly uses any power at all. I use a CPAP (look it up) machine to help me inhale when I’m sleeping, and it delivers an air stream perfect for this application and draws only an amp of power.
Heat could come from obvious sources like an exhaust intercooler, or an electric heating element.