jriddle@thealpenanews.com News Photo by Julie Riddle TOP: Its twin set of 375-pound rotor blades drooping like an old ceiling fan, a massive CH-47 Chinook Army National Guard transport helicopter hulks on a snowy runway in Alpena on Thursday as Capt. Charles Auer explains how the Winter Strike training held this week at the Alpena Combat Readiness Training Center prepares military personnel for overseas missions. ALPENA — Helicopters have had a busy week at the Alpena Combat Readiness Center. Two Army National Guard battalions out of Illinois and U.S. Marine Corps squadrons from North Carolina converged at the CRTC this week to practice helicopter maneuvers as part of Winter Strike, a joint military exercise.