Stargazer ACCESS: USAP Top Contributor Senior Member Joined 25 June 2009 Messages 15,517 Reaction score 9,300 21 September 2012 #1 From: AN ANALYTICAL INVESTIGATION OF THE EFFECT OF VARYING ROTOR TIP SPEED 10 REDUCE HELICOPTER ACOUSTIC DETECTION (August 1979) Attachments US Army notional helicopter 1.gif 72.1 KB · Views: 115 US Army notional helicopter 2.gif 71.5 KB · Views: 112
From: AN ANALYTICAL INVESTIGATION OF THE EFFECT OF VARYING ROTOR TIP SPEED 10 REDUCE HELICOPTER ACOUSTIC DETECTION (August 1979)