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  #1  
Old 09-18-2013, 01:10 PM
lpeeds lpeeds is offline
 
Join Date: Jan 2012
Location: Shelby, NC
Posts: 26
Default Noise when Skyview powered

I just powered up my Skyview for the first time and as soon as I turned on the Master, before turning on the Avionic or Autopilot there was a continuous loud noise coming from behind the baggage bulkhead. The noise sounds like a loud rattle or vibration. I'm sure I should have checked the Skyview before sealing the bulkhead and installing the fuel tank but I don't remember seeing anything stating the order of things at this point in the build. Basically the plane is built. Just the final checking remains.

Any ideas on what I'm looking for when I open up the back end again?

Paul Eeds
#120506
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  #2  
Old 09-18-2013, 01:21 PM
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txaviator txaviator is offline
 
Join Date: Jan 2005
Location: Arlington, TX (DFW)
Posts: 1,164
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Quote:
Originally Posted by lpeeds View Post
I just powered up my Skyview for the first time and as soon as I turned on the Master, before turning on the Avionic or Autopilot there was a continuous loud noise coming from behind the baggage bulkhead. The noise sounds like a loud rattle or vibration. I'm sure I should have checked the Skyview before sealing the bulkhead and installing the fuel tank but I don't remember seeing anything stating the order of things at this point in the build. Basically the plane is built. Just the final checking remains.

Any ideas on what I'm looking for when I open up the back end again?

Paul Eeds
#120506
Behind the baggage bulkhead? The only things powered back there are the ADAHRS, the trim servo (way in the back), and the roll servo. Very interesting. Could it be something up front and the sound is resonating to the back perhaps?
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  #3  
Old 09-18-2013, 01:40 PM
DFlyer DFlyer is offline
 
Join Date: Dec 2008
Location: Edmonds, WA
Posts: 131
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To troubleshoot, you might try pulling one circuit breaker at a time and see if you can isolate the source. If it is coming from the back of the plane, it is unlikely to be the SkyView. A broken SkyView fan blade might sound like that, but would be from the front of the plane.

-Robert
Dynon Avionics
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  #4  
Old 09-18-2013, 01:49 PM
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Tony_T Tony_T is offline
 
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Location: Lacey, WA
Posts: 1,365
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You do know that the fuel pump runs continuously when the master is turned on? It makes a very loud rattle especially if it is running dry.
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E-LSA RV-12 ULS

Last edited by Tony_T : 09-18-2013 at 05:10 PM. Reason: sp
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  #5  
Old 09-18-2013, 02:18 PM
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txaviator txaviator is offline
 
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Location: Arlington, TX (DFW)
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Quote:
Originally Posted by Tony_T View Post
You do know that the fuel pump runs continuously when the master is turned on? It makes a very load rattle especially if it is running dry.
I bet Tony has the winning solution here. A quick pull of the fuel pump fuse will confirm this. I'd bet Tony is right on the money, and the sound from the pump just seems as if it is coming from aft of the baggae bulkhead! Good call, Tony.
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RV-12 Built / Sold / Flying
Currently Flying: Cessna Skyhawk 172
Rebuilding a true barn find J-3 Cub
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  #6  
Old 09-18-2013, 02:41 PM
DHeal DHeal is offline
 
Join Date: Sep 2006
Location: Windsor, California
Posts: 924
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I suspect that most of us initially test the Fuel Pump circuit to ensure that it works and then we pull the FP fuse until we have fuel in the tank. Rumor has it that running a FP while dry is not good for the pump's inards (besides, it's very noisy).

Keep in mind that the FP circuit also supplies power to the two avionics cooling fans located on the forward shelf. I guess that if one were to test-run the avionics for a longtime with the avionics cover panel in place and high ambient temperatures, the absence of the two cooling fans might cause a heat problem for the avionics bay.

Another "noise in the back" could be the autopilot's roll servo ratcheting. As stated earlier, just start pulling fuses until the noise goes away!
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  #7  
Old 09-18-2013, 05:02 PM
lpeeds lpeeds is offline
 
Join Date: Jan 2012
Location: Shelby, NC
Posts: 26
Default Noise when master on

Thanks for all the suggestions. I just went out and checked and it is the fuel pump. I will go out in the morning and get a few gallons of 100LL and hopefully that will solve the problem. Thanks again.

Paul Eeds
#120506
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  #8  
Old 09-19-2013, 01:46 PM
664781 664781 is offline
 
Join Date: Jan 2005
Location: Powder Springs, Ga
Posts: 309
Default Fuse

Paul,
Pull your fuel pump fuse while you are doing all the check outs. The cooling fans won't run while the fuse is pulled so don't let that fool you. Ask me how I know?
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Powder Springs, Ga
RV6A "Kurt's Toy" - Flying
RV12 - Flying - Sold
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  #9  
Old 09-19-2013, 10:34 PM
lpeeds lpeeds is offline
 
Join Date: Jan 2012
Location: Shelby, NC
Posts: 26
Default Cooling fans

Just a note for information. I did pull the fuel pump fuse. My cooling fans were still running.

Paul Eeds
#120506
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  #10  
Old 09-19-2013, 11:18 PM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by lpeeds View Post
Just a note for information. I did pull the fuel pump fuse. My cooling fans were still running.

Paul Eeds
#120506
There are three different fans.
The two fans mounted to the panel deck are indeed powered by the fuel pump circuit and will stop when you pull the fuse (if everything is wired up as designed).
.
There is a third fan in the AV-5000o box that is powered by a different circuit.
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Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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