lml@lancaironline.net Mailing List Archive

<x-html> <HTML>John, You wrote: <<A good workshop overall....however, there was one major oversight. When we closed the horizontal stabilizer and elevators, we did not drill the required 1/4" vent holes in the ribs.>> Did you take pictures as you went along for your log?  I remember that the holes were already drilled in mine and I added a few more.  I have pictures and I can make them available to Marv for posting. Take out page 2-9 (I think that's the number) that represents the view of the H-stab and elevators showing the ribs as a reference: Each elevator has only 2 chambers.  The inboard chamber on the trim tabbed elevator is vented thru the tab actuator push rod hole.  If you used the 1/4" rod thru a holes drilled into the elevator horns and into the hinges for alignment during skin close out, the hole in the horn rib should take care of the outboard chambers since the outboard rib does not completely closeout the trailing edge.  I can't tell from my pictures, but I think there were holes in the elevator mid span ribs.  After the elevators are finished (rudders clearances cut) the inboard trailing edge of the rib can be drilled.  The trim tab won't need a hole since it is foam filled.  One must be careful with hole placement so that rain (in flight or on the ground) cannot fill the chambers. There are eight (8) chambers in the H-stab.  In mine, the ribs and forward spars all had holes drilled in them and the aft center chamber had a hole drilled in the bottom skin as the final vent.  If you have no holes in the ribs and spars, the center chambers could be vented, thru holes in the bottom, to the tailcone.  I have not seen the H-stab fairings yet, but maybe the mid-board chambers could be vented into the fairings?  Otherwise, thru the main aft spar.   The outboard chambers could be vented thru holes at the ouboard end of the main spar. maybe one high on the spar and on low to ensure drainage... Even the 320's had these holes since an early builder had separations from the pressure differential. Scott Krueger N92EX Legacy #2 </HTML> </x-html>