Fuselage Firewall - Part 2

Flying Legend has informed me that from Jan 2015 all Tucano's will have a 0.015'' stainless steel firewall fitted, so the real purpose of this blog is to document the work for the approval requirement's and to show you how much fun you miss out on.

Wheel Well
The wheel well was fabricated from 0.5 mm stainless steel sheet to allow it to match the strength of the aluminium but it proved to be a bit of overkill as 0.015'' will do the job. The new profile was folded from 316 annealed stainless steel to just fit inside the existing wheel well cover. This was done to allow all the pre-drilled holes to be added to the new cover with the highest level of accuracy.

Once the fit was checked it was clecoed into position and a new back fabricated from 0.015'' stainless steel grade 304. The 316 annealed stainless was easier to work with but that was not available. The rear cover was matched drilled from the new well cover and clecoed into position with the final job to pop rivet all the panels using 1/8'' stainless steel rivets x 6.4 mm long.

Firewall
The easiest way to cover the existing panels was to duplicate the existing aluminium panel in 0.015''stainless steel. The issue was that the material sourced was not large enough so it was decided to manufacture the lower corners as separate pieces. The profiles were traced onto the blank sheet and cut using a combination of a nibbler and snips. The edges were then dressed using a 300 mm disc sander to final profile.

The upper panel had the original holes for pop rivets added and these were duplicated at the bottom edge using a strip cut from the firewall containing the original pop rivet holes, when complete they were clecoed to the firewall. 

The lower panels were cut next with an additional 20 mm added to slide under the upper sheet and secured to the new row of rivet holes.

The final task was to fold angles to cover the junction with the well and fires wall. Once completed a bead of high temperature silicon was added to cover up a couple of small holes and another dab added at the corners of the wheel well.

Trial Assembly 

Repairs
Stainless steel is razor sharp when cut so the various blood trails were moped up and fresh strips added to cover the various body wounds. The builder then sterilized himself with a couple of high alcohol beers - very cold beers.