Cowl Skin - Part 2

This blog covers the installation of the cowl skin.

Preperation
Installation of the cowl skin required a decision on the type of riveting and it was decided that flush would offer the best appearance. The skin was dimpled using the existing dimpler die with a new riveting gun - GESIPA Flipper.

This was purchased as a replacement for the traditional hand riveter because it offered a mechanical ratchet, one handed operation making installation 4 mm rivets practical in small places. 

A trial was conducted using the Flipper with the dimple die and it was found to produced a high quality dimple. 

This was a result of the one hand operation allowing the other hand to center the die using the ratchet to lock the assembly. 

The first click tightens up just enough to lock the die while allowing final centering with the last click bottoming the die locking the assembly. A push forward on the handle unlocks the tool releasing the dimple die. 

The  only change was that the nails used with the die require changing about 20 pulls to maintain consistency. 

Highly recommend are the Australian agent ToolFix at Kings Park Blacktown. I managed to kit the new gun because of PRM [Please read manual]. They reassembled the gun checked it out at no charge - truly excellent.

Next the firewall and new tabs were dimpled using the same procedure. Finally the channel spreader was countersunk using a micro stop and 120 degree tool. The skin was fitted, fully clecoed, doubler's fitted, sealed and riveted onto the airframe. With all checks completed the clecos were removed one at a time and riveted using 3.2 x 8 mm countersunk pop rivets.

All faces dimpled ready to rivet

Skin fitted and dressing edges straight to accept covers

Note: cover is hand made and this is not required with the
factory panels which are CNC punched.

Silicon applied to weather proof cover.

Note: Spread silicon very thin to allow doubler to be flush after riveting
Too thick as shown

Packer was installed under channel
before final riveting

Skin and doublers riveted to airframe

Aluminium 0.020'' added to cover gaps created by the the profile adjustment