Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
Fuel Pump Noise Filter Installation
- Thread starter JohnF
- Start date
Detail...
It appears the filter can be installed by removing the fuel pump inspection cover without removing the fuel tank, but I haven't installed it yet. No doubt, it would be easier to do it when the fuel tank is out for the annual or other reason (more room to work).
Tony
It appears the filter can be installed by removing the fuel pump inspection cover without removing the fuel tank, but I haven't installed it yet. No doubt, it would be easier to do it when the fuel tank is out for the annual or other reason (more room to work).
Tony
DakotaHawk
Well Known Member
Here's a photo of how I mounted my cap. It's (+) goes to battery positive, (-) goes to battery ground. The capacitor does a great job of removing alternator whine and strobe light noise. Probably fuel pump noise as well - I simply don't hear any electrical noise in my headset.
dick seiders
Well Known Member
John and Tony, how is the pump "noise" manifesting itself? Is it impacting the radio transmission, or other avionics issues?
Thanks for feedback.
Dick Seiders
Thanks for feedback.
Dick Seiders
yankee-flyer
Well Known Member
Install from above
I installed my filter from above (it's not necessary to remove the fuel tank) while everything was opened up for the FAA inspection. It wasn't too much of a problem. I can't say whether or not it helped since I hadn't run the engine before it was installed, but I don't get any noise that I associate with the pump. It was expensive, though. I AM looking forward to pulling the Dynon download wires out of the tunnel to see if that helps.
I installed my filter from above (it's not necessary to remove the fuel tank) while everything was opened up for the FAA inspection. It wasn't too much of a problem. I can't say whether or not it helped since I hadn't run the engine before it was installed, but I don't get any noise that I associate with the pump. It was expensive, though. I AM looking forward to pulling the Dynon download wires out of the tunnel to see if that helps.
Walt
Well Known Member
Capacitors
Just a comment from an electrical standpoint, filter capacitors should be placed as close as possible to the noise source with the leads kept as short as possible.
The battery is already a great "capacitor" itself, so placing another capacitor across it's terminals would likely have negligable or no effect at all on noise generated by the pump, alternator or any other device.
Also, caps don't really do well in heat so the FWF location shown is not ideal.
Just a comment from an electrical standpoint, filter capacitors should be placed as close as possible to the noise source with the leads kept as short as possible.
The battery is already a great "capacitor" itself, so placing another capacitor across it's terminals would likely have negligable or no effect at all on noise generated by the pump, alternator or any other device.
Also, caps don't really do well in heat so the FWF location shown is not ideal.
Last edited:
DakotaHawk
Well Known Member
Heat and Location
(First of all, I apologize for posting a pic of an RV-7 installation in an RV-12 thread. RV-12s have to be built per the manual!)
Walt,
You make good points about the FWF heat, and putting the cap as close (electrically) as possible to the noise source.
As for the FWF heat, I can't argue about the temperature - I don't know how hot that area of the engine compartment is getting - but the cap has been flown in OAT up to about 100F, altitudes up to 17,750', and looks as good as new.
As for the electrical noise, when I installed the cap, I simply wanted to provide a "sink" for any stray noise in the system. The wiring runs are all relatively short - maybe 10' of wire max from the battery/alternator to each of the loads, so the cap is (electrically) very close to each of the noisy loads. Since I don't experience any noise, I haven't felt the need to relocate the cap.
FWIW - noisy loads are going to be the Strobe power supply, the Alternator, the Fuel Pump, Trim Servos and Autopilot Servos, and Magneto P-Leads.
(First of all, I apologize for posting a pic of an RV-7 installation in an RV-12 thread. RV-12s have to be built per the manual!)
Walt,
You make good points about the FWF heat, and putting the cap as close (electrically) as possible to the noise source.
As for the FWF heat, I can't argue about the temperature - I don't know how hot that area of the engine compartment is getting - but the cap has been flown in OAT up to about 100F, altitudes up to 17,750', and looks as good as new.
As for the electrical noise, when I installed the cap, I simply wanted to provide a "sink" for any stray noise in the system. The wiring runs are all relatively short - maybe 10' of wire max from the battery/alternator to each of the loads, so the cap is (electrically) very close to each of the noisy loads. Since I don't experience any noise, I haven't felt the need to relocate the cap.
FWIW - noisy loads are going to be the Strobe power supply, the Alternator, the Fuel Pump, Trim Servos and Autopilot Servos, and Magneto P-Leads.
Dick, in my plane I hear the fuel pump ticking noise in the headsets when I plug a music source (iPod) into the music jack. I can not detect the fuel pump noise in any of the avionics or intercom functions or when there is no music source plugged in. I'm not crazy about music when I fly, but the music jack is there so I would like to use it occasionally.
Tony
dick seiders
Well Known Member
Thanks Tony,and John. I have heard no noise as yet so will put the cap. install on the back burner for maybe.
Dick Seiders
Dick Seiders
