Date: 23 Apr 97 02:58:14 From: Seth Dillon <firstname.lastname@example.org> Organization: All USENET -- http://www.Supernews.com References: 1
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McElravy wrote: > > On the last discussion of "stupid DC-9 tricks" (we were picking on Air > Canada I believe) someone asked what the hole in the base of the fin was > for. The question was never answered and I forgot on it until I had > occasion to fly on a few (NW) over Easter. As I was sitting in the gate > area I noticed the hole and remembered the discussion. The hole at the base of the vert, stab on a DC-9 is a ram air inlet for cooling air for the a/c pack heat exchangers. There is also a pair of fans. If i remember correctly the right pack fan draws air from the inside of the area aft of the p-dome and the left pack draws air in from outside. When ram air pressure is sufficient to overcome fan pressure in the plenum then a flapper door opens allowing this air to flow. The APU inlet is in the bottom of the area aft of the p-dome. I can not for the life of me remember where the rudder travel limiter gets its airspeed input on the DC-9. -Seth To replay remove the ".nospam" from my address.