On Dec 8, 2009, at 12:15 PM, William Beaty wrote:
Dust impact? Glow discharge? Dust contaminates the N2O2 plasma?
Bright yellow glow from helicopter rotors
http://www.michaelyon-online.com/the-kopp-etchells-effect.htm
(from http://sprott.physics.wisc.edu/pickover/pc/realitycarnival.html)
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]"
"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]"
10. ^ Warren (Andy) Thomas; Shek C. Hong;, Chin-Jye (Mike) Yu, Edwin
L. Rosenzweig (2009-05-27). "Enhanced Erosion Protection for Rotor
Blades: Paper presented at the American Helicopter Society 65th
Annual Forum, Grapevine, Texas, May 27 – 29, 2009." (pdf). American
Helicopter Society. Retrieved 2009-09-02. "A secondary concern with
the erosion of metal abrasion strips pertains to the visible
signature that occurs when microscopic metallic pieces are eroded
away. In the erosion process, they often oxidize, giving off a
visible spark and causing a corona effect in sandy environments."
http://www.vtol.org/f65_bestPapers/productSupport.pdf
11. (pdf) Office of Naval Research Broad Agency Announcement(BAA):
Advanced Helicopter Rotor Blade Erosion Protection, United States
Department of the Navy, Office of Naval Research, p. 3, BAA 08-011,
retrieved 2009-09-02, "Although both Ni and Ti are hard metals, their
hardness values are significantly lower than that of sand, which is
primarily made up of quartz. This hardness differential results in
the excessive erosion/degradation of rotor blades in desert
environments. An equally important problem with Ti protection is that
a visible corona or halo is generated around the rotor blades at
night from the sand impacting the Ti leading edge and causing Ti to
spark andoxidize."
http://www.onr.navy.mil/Search.aspx?q=02%20OR%20baa%20OR%20docs%20OR%
20BAA%2008-011_ONRBAA%2008-011
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
