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Static dischargers

S

striker

Member
For the past several weeks ( which does parallel our cool/dry weather ) I have noticed some radio interference on the Garmin 430.We start our flight and everything is fine- about 10 minutes later we start the static and after an hour we can barely hear the tower. I called Garmin and they said I needed to install some static dischargers on the trailing edges of the control services. Just curious if anyone else has had this issue and if so what you did about it. Thanks for any help.

Pete Joslin
RV-6A, 105.5 hours
IO-360 ECI Titan
 
I have the static discharger wicks on my -6, but they were installed because I used to have Loran (100khz). Precipitation static normally doesn't interfere with VHF.
 
Maybe related to the static whips but how about bonding the trailing edge surfaces. Does anyone do that. Just curious.

Thanks,
 
At the SportAir avionics/electrical workshop a few weeks ago, Dick Koehler said the problem is caused by the charge buildup in the control surfaces, and the interference is caused by a discharge to the wings... like an "arc" .. lightning bolt.

He said, as I recall, the solution is to ground the control surfaces to the wing, although I didn't at all follow how that would be accomplished (a wire?), not did I understand how they're not already grounded.
 
Usually the control surface "bonding" process is done on plastic airplanes. Normally the control surfaces on a metal airplane are "bonded" sufficiently through the attach bolts.
 
Alternator ground?

As I had terrible noise problems because my Alternator did not have a good ground to the engine block (painted the bracket) could this be your issue?

Frank
 
Static wicks

The problem with static is not related to the frequency of the radio necessarily, the noise is most likely coming though the audio system. The pops you hear are little lightning bolts jumping between surfaces of your aircraft and/or from the aircraft to the surrounding air. The bonding between control surfaces and the rest of the airframe is not efficient due to the fact that they are attached though hinges, or bearings all of which have grease/oil to prevent wear. You can bond the control surfaces to the airframe by using the shield of coax cable and ring terminals. I would also suggest installing a few static wicks on the trailing edge of the wings, HS and VS. The function of the static wick is to dissipate the charge gradually and not let it build up to the point that it would produce a "pop" when it discharges. Typically, you'll see more of a problem on dry weather, and with faster airplanes as the air friction on the airframe creates a difference in potential.

I hope this helps.
 
Another source of "noise"

Totally unrelated to static discharge, but I got a laugh the other day and thought I'd pass it on. While doing our taxi testing, I had our local CFI take the 9A down the runway to see if he found any problems. He reported that it did very well, except it had a bad buzz in his headset. I asked when it occured and he said about the time he lifted the nosewheel. I thought about it for a moment, went through the interface of the Dynon and pushed the audio stall warning test. "That's it!" I guess some noises are okay afterall.

BTW, installed static wicks during final assembly. They don't weigh much, can't hurt anything, may actually help and look SO professional!

Bob Kelly
 
Static wicks will definitely cut down on radio noise by dissipating charge. There are two sources of radio noise due to static charge - discharge to atmosphere, and discharge between airframe parts (such as control surfaces to wing/HS/VS). Discharge to atmosphere is accomplished via static discharge wicks, discharge between parts can be taken care of with grounding straps (any metallic connection between control surface and frame). Caution - do NOT use graphite powder in your hinge joints - it will solve your static discharge problem, but will set you up for all kinds of galvanic corrosion heartburn down the road. Any small wire connection will do without causing galvanic corrosion.
 
Static wicks

From my GA maintenance days, ;)
I recall that all of the metal aircraft that were certified for IFR and weren't high wing Cessna's, had bonding straps from the major airframe to the control surfaces.
Many times they had worn out due to repetitive motion. Sometimes the manufacturer did not even list a part number for their replacement.

I would make up replacements from electrical terminals and a braided metal strap aka "solder wick" If you use tinned copper terminals it is best to put on a little dab of the special conductive grease electricians use (found in most decent hardware stores), between the bare spot on the aluminum frame and the the terminal, as well as the bare spot on the control surface and the other terminal.

Some of the aircraft had aluminum terminals an aluminum braid. If you have a source for that please post it.
 
Also known as Malaax

Available form the aviation aisle in Home Depot...All my grounds feature a dab of this grease, especially between the alternator bracket and the engine block.

Frank
 
Digging up an old thread here, but just curious if anyone who has noticed static in their headsets had the problem resolved by adding bonding straps and static dischargers.

I'm having a problem with the radio being clear on takeoff, but over the length of a long flight noticing static getting worse and worse that by the end of the flight I can barely hear my passenger or the tower.

I've also noticed my compass being off a bit which suggests an electrical problem of some sort that is creating a magnetic field.

I just did a search on the topic to see if I could find my answer.

So who has solved their problem, and what did you do to solve it?
 
Oil on the Antenna?

7A_Driver said:
Digging up an old thread here, but just curious if anyone who has noticed static in their headsets had the problem resolved by adding bonding straps and static dischargers.

I'm having a problem with the radio being clear on takeoff, but over the length of a long flight noticing static getting worse and worse that by the end of the flight I can barely hear my passenger or the tower.

I've also noticed my compass being off a bit which suggests an electrical problem of some sort that is creating a magnetic field.

I just did a search on the topic to see if I could find my answer.

So who has solved their problem, and what did you do to solve it?
Click to expand...

I think my static problem is caused by oil on the antenna. If I transmit it goes away for a while, and it goes away if I clean the underbelly antenna.

Hans
 
Adding Static wicks on trailing edges

Does anyone have anymore thoughts on adding static wicks to the trailing edges of our VANS airplanes? GA and other certified aircraft have these added at the factory.
 
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