Defrost fan - Page 3

Ron RV8 · #21 12-29-2014, 08:43 PM

Mine is a used 3" fan from our first computer. If it fails we have another from our second computer. Didn't even think about buying one new...

No idea of cfm but with only avionics as a heat source it clears the windscreen very quickly. I can just feel the moving air as it hits my face.

It doesn't take much if you put it on as soon as you get in. The aircraft is an -8 so a side by side would probably take two fans to clear the entire windscreen...

I did paint the "grill" flat black so it wouldn't reflect in the windscreen...

Canadian_JOY · #22 12-30-2014, 03:03 PM

Our GTX330 is recommended to have cooling air supplied (not absolutely necessary but in high-density traffic areas where the XPDR is getting lots of interrogations, the life of the box will be extended by keeping temps cooler with some pressure airflow through the box).

I was only able to find an avionics cooling fan with 3 outputs. Hmmm... 3 outputs, only one avionics box connected... that leaves two outlets unused. Seems like they might be able to provide some flow up to the windshield. Since I'm running the fan all the time anyways, plumbing the spare outputs to the defrost vents just seems natural, and it will help get rid of some warm air from under the glare shield.

BSwayze · #23 06-29-2015, 02:39 AM

I'm curious... how are some of you guys with tip-up canopies mounting your fans? I bought a pair of 3" computer fans to mount underneath the glare shield, but I'm running into problems. They will run into the top flange on the panel when the canopy is lowered. They can only be mounted so far forward under the glare shield before running into the canopy braces.

Does anyone have some ideas to share? Better yet... any pictures? It looks like I'll either have to get much smaller fans, or mount them on top of the glare shield (I really don't want to do that, if I can help it).

BillL · #24 06-29-2015, 06:09 AM

Quote:

Originally Posted by BSwayze

I'm curious... how are some of you guys with tip-up canopies mounting your fans? I bought a pair of 3" computer fans to mount underneath the glare shield, but I'm running into problems. They will run into the top flange on the panel when the canopy is lowered. They can only be mounted so far forward under the glare shield before running into the canopy braces.

Does anyone have some ideas to share? Better yet... any pictures? It looks like I'll either have to get much smaller fans, or mount them on top of the glare shield (I really don't want to do that, if I can help it).

I found the same issue on my tipper. I purchased squirrel cage blower style and plan to use some scat hose with slots. The plan is to pull from the heater box. It is not installed, so that could change.

I have seen the smaller fans installed neatly in the glare shield, don't know the size, or have a reference, sorry. I have extra axials

Taildrgr · #25 06-29-2015, 06:45 AM

Bruce,
A 3 inch fan is probably too big. Here's a pic of my 60mm fan. It overlaps the brace a bit, but it doesn't need to be perfect to move the air. It has to be back far enough so it doesn't hit the panel when the canopy is closed.

Note that I cracked the housing when I tightened the screws, but it still works fine. I already have a new one to replace it when it fails. They only cost $5 on ebay.

219PB · #26 06-29-2015, 10:10 AM

The fans are controlled via a panel on/off switch.

GalinHdz,

Where did you source the switches, cluster and labeling?

Looks great!

ArVeeNiner · #27 06-29-2015, 11:54 AM

Any recommendations for solving the foggy windscreen problem for an already flying slider? Installing a fan after the fact sounds very painful! I'm thinking that rigging one of those computer fans with a cigarette lighter adapter and then setting it atop the panel for a few minutes might work. Thoughts?

BillL · #28 06-29-2015, 01:25 PM

Quote:

Originally Posted by ArVeeNiner

Any recommendations for solving the foggy windscreen problem for an already flying slider? Installing a fan after the fact sounds very painful! I'm thinking that rigging one of those computer fans with a cigarette lighter adapter and then setting it atop the panel for a few minutes might work. Thoughts?

Have you ever had a foggy windscreen? Inquiring minds and all that . . .

chazking · #29 06-29-2015, 01:37 PM

I don't tend to have foggy windshields here in Florida but I find the defog fans useful for moving air from behind the panel and reducing temps for the avionics. (I think this was suggested in another thread).

I have a Troll Avionics fan electrically plumbed behind the panel. But I have not routed the scat lines to the avionics. I'm concerned that it would just move the hot air behind the panel to the avoinics; hot air blowing on the avonics does not seem like a useful cooling approach.

Taildrgr · #30 06-29-2015, 01:57 PM

The canopy of my -4 would fog up in the winter every time I got in the plane.
Its a fairly small cockpit and after pulling the plane out of the hanger, I guess I was generating a lot of steam

Once I got the engine running, it would clear up fairly quickly, but I had to delay taxi by a few minutes till it cleared up.

I did not have a fan in the -4, but thought it was pretty easy to put one in my 7, so I did it. Just started flying so I have not used it yet. Will see how it does this winter.