I modified the plenum in the tail of my IV-P to handle a 4-inch duct which I run thru a 12 volt, 4" blower to cool the condenser for my A/C.Since I drop out the A/C when I pressurize, I would like to cut off the 4 inch duct to reduce drag.Has anyone come across a 12 volt duct valve in their travels??Regards, billhogarty@direcway.com