Fabricating the Rear Tie Down

There are three tie down points on the aircraft, one on the tail and one on each wing. Here we will install the large nut plate for the rear tie down bolt. It is located next to the aft most bulkhead so the load is distributed to the fuselage structure.

Obtain a ¼-20 eye bolt and a couple of nuts for the rear tie down.  Weld a nut to a 2” X 2” thin steel sheet as shown below.

Tail Tie Down Location

.  Place it just forward of the rear bulkhead and mark the hole location on the center line as shown below.  Drill a 5/16" hole through the fuselage bottom.

 

Position Tail Tie Down Nut Plate

De-core the foam in the area of the hole and mix up a batch of thick micro.  Wax the threaded portion of the eye bolt with mold release.  Fill the hole with the thick micro and work it into the de-cored area.  Apply thick micro under the metal plate.  Install the eye bolt up through the hole and into the metal plate.  Hang a weight from the eye bolt, about 10 pounds and let the micro cure.  Apply a 4 layer fiberglass laminate over the metal plate extending at least 1.5 inches onto the fuselage bottom and up the rear bulkhead.  Let cure.