Static Wicks?

[Wayne Gillispie]

It is not that I don't think they serve a good purpose. I wanted to keep the cost, weight and build time down. I had to rent old 172's and build a family hauler on a limited budget. If one has the time, money and desire, go for it. I don't have an ifr ticket and I fly in a very humid area of the country. If I get the ifr ticket and have an occurence like Bill, then I will probably install them. I don't think speed has as much to do with it as does the atmosphere...heck I shock myself all the time walking across carpet in the winter and I am only moving 2 or 3 kts. Keep building guys and lets do some trips together.

[Mouser]

I chose to install them on mine, largely because there was significant anecdotal evidence in the forums that people in similar-performance aircraft had had issues with interference which were alleviated when wicks were added.

The particular parts I choose will allow the wicks to be removable, leaving very little visible or aerodynamic change to the airframe, so I will be able to test performance with and without the wicks. The total weight of additional components I'm adding to the build I would estimate at around 0.5 pounds, so the weight argument is essentially moot. There is a bit of additional labor getting the added nutplates and stiffeners fabricated and installed, but it really hasn't been significant at all thus far. The wingtips will probably be the most difficult part, and I'm coming up on that bit soon; everything else has been trivial from an effort standpoint. I definitely spent more time looking through the arguments for and against wicks and planning my install than I did actually performing the modifications as I built. As for cost, other than the wicks themselves I'm probably looking at about $10 in additional hardware. The wicks I'm using are pricey at ~$42 each, for a total cost of $504. There are cheaper alternatives out there; I went with these because they supported the easy-removal option that I wanted.

Here's what I've done thus far: http://www.mouser.org/projects/rv-10/staticwicks.html

There is a link near the top of that page to Dayton-Granger's recommended installation positions for wicks in the RV-10.

My advice to you is to weigh the risk for yourself, and ignore the blowhards. If you choose to install them, it can be done easily, cheaply, and quickly. If you don't, and you don't fly a lot of IFR, the evidence seems to suggest that your risk of a problem is quite low.

[n981ms]

Is there something more to these wicks than some wire and attachment hardware. $500 seems like a lot.


As a data point.
I did not build our 10 but it does not have wicks and I am not aware of any problem after about 150 hours.

[Mouser]

Well, $500 is for 12 of them as recommended for this airframe by the manufacturer. $42 a piece is still pretty steep, but then again these are TSO'd hardware.

The physics behind a static discharge device basically require that the conductive point(s) at the tip be as sharp as possible in order to maximize the rate of release of charge from the conductor to the surrounding atmosphere. While this can be done with non-zero efficiency with a standard wire, modern static wicks for small aircraft employ a bundle of ultra-fine metal fibers or conductive glass fibers at the tip in order to maximize efficiency.

The wicks will discharge your charged airfrarme at some rate that is proportional to the charge on the skin and to the wick efficacy. If the rate of discharge from the wicks is less than the rate of charge accumulation, then you'll build up a static charge on the airframe and possibly have issues with your electronics. The only ways to increase the rate of discharge are to add more wicks, move the wicks to areas of higher charge concentration, or use more effective wicks.

I choose to buy reasonably high-tech wicks with ultra-fine conductive fibers on the tips in order to maximize my odds of having sufficient discharge capacity. In the grand scheme of things, $500 is only a quarter of a percent of the cost of the aircraft. If adding wicks gives me some extra safety margin against my all-electronic control panel going wonky on me, that seems like it is worth an extra 0.25% to me. Your mileage will almost certainly vary.

[Bill.Peyton]

Mouser,
I agree with you 100%. I purchased my wicks from here http://search.skygeek.com/?vwcatalog...s=esd1&x=0&y=0 These are TSO'd wicks for $13 for the Piper/Cessna style wick. I have been using these on my current aircraft and they have held up for 10+ years.
Bill