On Tuesday, June 9, 2015 at 9:56:55 AM UTC-4, wrote:

I've found this that I can order here, whcih seems to be the same:
http://www.advantagesgs.com/3M-8482-...-15-x-10-yards

You're right. Scotchcal is a much better choice, especially because it needs no adhesive to adhere. When the color fades, peel it off and replace it.. No penalty for experimentation.

I was poking around using the search terms 'daylight conspicuity' and found some research on motorcycle conspicuity. (Motorcycle has roughly the same silhouette as a glider fuselage flying straight at you.) Some results show that orange works because of contrast with the background (apt for the French Alps), whereas yellow works by brightness/luminosity (shows less contrast with background). The orange areas need to be large to be effective (entire orange jacket opposed to orange tape on fenders). This suggests that glider markings need to be large. I wonder if two orange wingtips would be a lot more effective than a single orange nosecone. I wonder if orange Scotchcal on the entire leading edge of the wing would be more visible (and whether the edge of the film would increase drag... like bugs).

There was some research in the UK that applying 'mirror film' to ailerons such that they work like 'signal mirrors' in direct sunlight make a glider on short final more visible to aircraft that were flying faster and behind it on final. Seems like the 'signal mirror' effect would work in other scenarios if the mirror film were applied to the rudder. The intermittant glints of reflected sun would be conspicuious and not annoying. The drawback is that the mirror film uses adhesive.

The scenario of two gliders 180 opposed and converging under a cloud street or landing/taking_off on opposing runways might be best addressed by a forward facing white LED strobe such as http://www.vehiclesafetysupply.com/p...ite-p-412.html (assuming Experimental Airworthiness). The low light levels near cloud base makes a strobe more effective as does a narrow forward focus. Only one glider needs a strobe.

Retroreflective tape might somewhat increase conspicuity in lower light like under a cloud street, but the thickness and the adhesive are drawbacks.

To increase glider conspicuity to overtaking aircraft one might easily affix one of the newer streamline self-contained strobing LED lithium battery bicycle lights tail to the top of a T-tail. No wiring needed.
http://www.bikeradar.com/us/gear/art...cycling-32289/ Similar mass and mounting technique to a Go Pro.

Then there is the scenario where you see another glider, but you're not sure that he see you (say opposing flight on a ridge). Flashing an extra bright forward facing strobe a few times might have some value. Ideally, the opposing pilot flashes his strobe to acknowledge.

I'm hoping to get feedback on these ideas before I impliment any of them.

I'd like to see universal installation of Powerflarm, but until then...