Sunday, September 16, 2012

The Eagle Is Growing A Lower Torso

Work began today putting the finishing touches on the F-1282 bottom skins which first needed to have a stiffener attached to each skin prior to assembly.  The F-1283-A&B stiffeners require shear clips riveted to each stiffener. While working with the shear clips, discovered a misprint in Van’s plans … the left and right F-1284 shear clips need to be flip flopped because as called for in the plans, the holes don’t come anywhere close to lining up. The drawing is correct in the way the parts are attached but the left and right callout is incorrect. No big deal … it was easy to figure out there was only one way to make the parts fit together as shown in the drawings. AN470AD4-4 solid rivets were substituted for the LP4-3 pop rivets called for in the plans.
                  Using the pneumatic squeezer to rivet the F-1284 shear clips to the F-1284 stiffeners with solid rivets.

Once the shear clips are riveted to the F-1284 stiffeners, both stiffeners are then Clecoed to the bottom skins, match drilled to the bottom skin’s J stiffener and then riveted in place.
                                      Riveting one of the F-1284 stiffeners to one of the tail cone’s bottom skins.

The biggest challenge proved to be what seemingly should have been the simplest step of the assembly process … sawhorses. Assembly begins with the left F-1282 bottom skin placed upside down across a pair of sawhorses. Next the three fuselage frames are Clecoed to the left skin then the right skin is Clecoed onto the assembly. Looking good so far. Next the two F-1281-L&R lower side skins are to be Clecoed to the bottom skins.

Huston we have a problem! The saw horses purchased by the DOG Aviation procurement department are the Stanley HDPE plastic, adjustable height variety. The problem is they are too wide for attaching the side skins because the side skins will extended below the level of the saw horses. Bummer!
                        Looking at the rear sawhorse, one can easily see the problem … the lower side skins
                       will follow the radius of the frames and end up lower than the level of the sawhorses.

The moment of disbelief quickly turned into one of frustration knowing before the cross country move last year, all sorts of lumber was thrown into a dumpster or given to neighbors.  Fortunately, Van’s supplies the builder with plenty of wood. I ended up scrounging around and found two small pieces of plywood that were used to seal the ends of a crate and used them to prop up the tail cone assembly from the inside. The wood was clamped onto the sawhorses and padded on the top to protect the skins.  I wish it were more secure but it will do.
                           Plywood clamped onto the saw horse to support the bottom skins from the inside.
                                                       Clecoing the left lower skin onto the left bottom skin.
                                                     The right lower skin Clecoed onto the right bottom skin.
               Bottom tail cone assembly ready for riveting … I see a long riveting session or two on the horizon.

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