these are both anti ice systems not de-ice. You wet both the props and windshield to prevent ice forming
Now that’s interesting. I refer to RAF Pilots Notes for Dakota 2nd edition A.P.244D date June 1946.
Page 18 under OTHER CONTROLS, talks about Propeller
anti-icers and Propeller
de-icing pumps.
However, paragraph 34 talks about Windscreen
de-icers
The windscreens were not “wetted” as in precautionary measure to prevent ice from forming.
According to the RAF Dakota Pilots Notes publication two independent systems are provided. Sliding Panel de-icers and main windscreen de-icers. Note the words
de-icers.
The design required the de-icers to remove ice from the windscreen and sliding window after it occurred.