Defroster is a must for me
On my first -7, I used one computer cooling fan.
Allthough this is usable, I used four fans on my second -7 (2+2) installed on each side of the inlet for cabin heat.
For fans, I used the expensive type so the bearings would have better quality.
Here's a closeup of one of the dual fans installation:
And here's the air outlet:
BTW: all hoses where secured with clamps after the install.
The defroster are wired to a separate switch.
I only need it on the ground, because once airborne, the canopy clears quickly.
I have not installed any "air-spread" outlet, because I didn't want to restrict the airflow.
Th right seat is pilot seat so I've installed the outlet in front of the pilotseat.
The top of the windshield is painted flat black so noone sees the hole anyway, at least not on a TW.
The defroster works great for me, and I'm VERY I installed it! I'm using it on every startup from Fall until Spring.
The best reason I can think of for installing a defroster system, is that it would be a VERY difficult job to install it after the plane is done.
In fact, I can't imagine how it'd be possible...