[Vertical Stab & Rudder]
Building the vertical stabilizer and rudder.
Construction
The vertical stabilizer was the first part of the empennage to be completed. Because of it's size and relative lack of complexity, it was a good introduction to using the different profiles of stock and the gluing of larger gussets. The stock for the leading & trailing edges and main beam was planed to size, with dados cut on the table saw and rounding done with a router.
Similar to the wing rib jig, a jig was constructed in conjunction with the construction of the vert stab. The dimensions were drawn out on the MDF board, with blocks stapled around the outside perimeter. As pieces were cut, blocks were stapled on the inside to hold them snugly in place, but still allow them to be removed with relative ease. The gussets were dry fit before gluing and the lower main beam piece was cut to allow gussets to extend to the bottom, as per the original plans.
The beams were first edge glued together, then the gussets were glued and stapled on while in the jig. The assembly was then removed from the jig, while the other side was completed. The vert stab was weighed on a flat surface to cure.
Finishing
After the initial constructed vert stab was fully cured, the bottom was sanded flat and flush. The top curved part (with an outside radius of 6") was sanded flush and smooth, and the leading edge of the curved top was rounded to match a similar profile to the leading edge beam. All rough spots were touched up with sandpaper, and sharp edges broken to allow safe handling and prevent problems during covering.
The horizontal ribs were to be added last after the other joints had been glued and fully cured to prevent warping. The ribs are 3/16" X 1/2" strips. These were ripped and planed to size, then cut to fit the length and angles needed. They were glued and held in place with a single staple in each. The front of the strips were rounded to be flush with the leading edge of the stabilizer, as the leading edge does not fully engulf the strips, as per the plans.
The piece was sealed with spar urethane diluted with mineral spirits. The staples were pulled from the piece once glue set.
Rudder
The rudder was assembled with a similar jig made on the backside of the same MDF board as the vertical stabilizer. The gussets for the two acute angles in the rudder that are called for in the plans do not extend back enough to encompass the support 1" X 3/4" support beam. As the rudder horn and ribs depend on this support beam for stability and strength, an elongated gusset was needed that would cover both the outside corner and the junction between this supporting beam and the top/bottom. This gusset was made by sketching out the essential dimensions, then using a French curve to connect points. A template was made out of 1/8" MDF to trace the shape for the four gussets to be cut on the bandsaw.
The rudder was also sanded and sealed with diluted spar urethane, in addition to the removal of all staples.
