On Tue, 8 Dec 2009, Horace Heffner wrote: > Titanium dust oxidizing. > > http://en.wikipedia.org/wiki/Helicopter_rotor > "When operating in sandy environments, sand hitting the moving rotor > blades erodes their surface. This can damage the rotors; the erosion > also presents serious and costly maintenance problems.[9]"
I'd have to track down the article and see if it's speculation. Or in other words, if we use a sandblaster on titanium, do we get the glow? Perhaps. Maybe the eyewitness report was wrong about the glow extinquishing when the copter ramp hit ground. > "The abrasion strips on helicopter rotor blades are made of titanium, > which is very hard, but less hard than sand; so when a helicopter is > flown near to the ground in desert environments abrasion occurs, and > at night there is a visible corona or halo around the rotor blades, > caused by the sand hitting the titanium and causing it to spark and > oxidize.[10] [11]" Sounds like they're assuming the light is from oxidation... without doing anything to verify the speculation. Here's one possibility. If you create a plasma in air, it's very dim and purple, but if you inject NaCl dust, it becomes yellow and very bright. Perhaps the light is from high voltage air glow with various kinds of dust injecting other ions which produce more light. The telling experiment would be whether titanium gives light when sandblasted, even if electrically connected to earth. (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 206-762-3818 unusual phenomena, tesla coils, weird sci
