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  #1  
Old 01-15-2017, 04:34 AM
Janekom's Avatar
Janekom Janekom is offline
 
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Location: South Africa
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Default Glare Shield fans problem

I am busy test flying a new RV14 and it has 19 hours on it now, all flown in fairly hot summer conditions. It has two fans on the glare shield to draw hot air out of the instrument "bay". The two fans are covered with two metal auto style speaker grills.

Yesterday I have noticed two round areas on the canopy, above the fans where the plexi seems to be damaged. It appears slightly foggy and feels rough to the touch. I am worried about the integrity of the whole bubble canopy down the line?

Any comments?
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  #2  
Old 01-15-2017, 09:10 PM
salto salto is offline
 
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Location: Wee Waa Australia
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Hmmmm.. That doesn't sound healthy even if it is only aesthetic.
We operate in high temps here in Australia also.
Defogging is needed but not to the detriment of the plexi.
Question would be do the avionics need cooling or is the design just a way of finding a convenient heat source for defogging? Do the avionics supply enough heat prior to taxiing to be effective?
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  #3  
Old 01-15-2017, 10:14 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Have you been using the fans for a purpose other defogging the windscreen (as in removing visible moisture that condenses on the inside... that was the designed purpose of the fans)?
Such as trying to cool the avionics when the cockpit is very hot?

The temp which Acrylic begins to slightly soften is about 100 C. (212 F)

If the canopy has begun to change its composition above the fan vents then I would guess that something has been done that has causing air of a temp somewhere on this range to be blown on the canopy by the fans.
I wouldn't think heat from just the avionics would be enough.
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  #4  
Old 01-16-2017, 02:02 AM
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Janekom Janekom is offline
 
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Hi Scott,
Talked to the builder now. He confirmed that the plans state like you say. To be used for defogging or to get heat out.

The builder has wired them permanently on. Oops. It seems then that it is not a good option. I will disconnect them before the next flight and I will also try to take pictures and post it here in order for all of us to learn. I think might be possible to polish out what I see and feel there.

I am also thinking that one should have a reflector directing some of the air away. I have an STL file for my 3D printer that I intend to us on the RV10 that I am busy with. It will have a switch

By the way - I find it hard to land as I want to keep on flying it
20.3 hours as of this morning.
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Jan Hanekom
South Africa
Approved Person nr 325
http://www.rvbits.com
RV10 - ZU-XOX - (Flying)
RV7A - ZU-JRV - (Flying)
RV10 - ZU-JVR - (Written off)
RV7 - ZU-LOL - (Flying)
RV10 - ZU-RVI - (Flying)
RV7A - ZU-MER (Bought back)
RV7A - ZU-JAD (Sold Flying)
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  #5  
Old 01-19-2017, 09:51 PM
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Janekom Janekom is offline
 
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Location: South Africa
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Default No more spots

Problem solved. Yesterday after flying the 14 again I first took some polish and tried to get rid of the spots. Nothing. Then I tried thinners and off they went. So it has been a bit of clear coat overspray and nothing to do with heat.

This happened when the builder applied some clear coat on the inside of the canopy frame and the clear coat went through the holes onto the canopy.

My apologies for maybe having some of you worrying. We get old too fast and clever too slow.
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Jan Hanekom
South Africa
Approved Person nr 325
http://www.rvbits.com
RV10 - ZU-XOX - (Flying)
RV7A - ZU-JRV - (Flying)
RV10 - ZU-JVR - (Written off)
RV7 - ZU-LOL - (Flying)
RV10 - ZU-RVI - (Flying)
RV7A - ZU-MER (Bought back)
RV7A - ZU-JAD (Sold Flying)
Dues paid for 2020 WITH A SMILE
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