Greetings all,
Dumb question, is heater, windshield heater working on the 407 or what i am doing not right to get rid of icing, frost?
As far as I understand: The Bell is not certified for flight in frosty conditions or icing.
Source: www.maunaloahelicopters.edu
BHT-407-FM-1 - ROTORCRAFT FLIGHT MANUAL - MODEL 407 (maunaloahelicopters.edu)
1-3. TYPES OF OPERATION
1-3-A. PASSENGERS
Basic configured helicopter is approved for
seven place seating and is certified for land
operation under day or night VFR nonicing
conditions
that is what i thought, was just not sure how much the windshield defog was strong for 
You would have thought that the rotors’ down-wash wouldn’t let water or ice settle on the windows long enough to freeze!
The strongest downwash is under the helicopter.
Another thought: According to your train of thought, the airstream should not freeze an airplane window in flight. But it happens anyway.
This is because of one of the basic concepts of fluid dynamics called the “no slip condition,” which generally holds true with sufficiently viscous fluids and models air and water well enough in most situations we experience to be assumed largely applicable. This is also why dust collects on computer fans and ceiling fans even when they are continuously turning for long periods of time. No-slip condition - Wikipedia
Basically, the velocity profile of our model fluid can’t have discontinuities and must have a zero relative velocity to a solid boundary, so it looks something like this (though this is generally at a microscopic scale relative to what we can normally perceive) [from What is a slip condition in fluid dynamics? - Quora]:
So, the air molecules and any water molecules mixed in there right above the surface of the skin or window of the aircraft are basically stationary relative to the surface.
There’s actually plenty of time, like when you see the drops of rain streaming across the windshield they can leave behind a thin layer of ice if it’s cold enough below freezing, which can then accrete into a noticeable amount of clear ice.
Check out this excerpt from this FAA training document[ ac 00-6a chap 10-12.pdf (faa.gov)]:
So, remember to try to avoid 1) visible moisture when 2) in temperatures near or below freezing…