November 21, 2021 – The process of identifying the correct (or best) location for each of the components that will be installed on the firewall (on the engine side) has been a good learning experience. As with every other project, it has forced me to step back and carefully think through the process, look at multiple options, and test each before making a cut or drilling a hole. In this case, the lack of specific installation procedures by Rans for this particular model of the Rotax engine (912is) has required that I dig much deeper into every aspect of the build to ensure that I thoroughly understand each sub-project before I begin. Although this can be frustrating when I want to simply complete a task and move on, the learning experience has been very good and I believe this was part of God’s calling for me to step into such a complex project in the first place.
So, with those steps in mind, I invested a significant amount of time yesterday to work through the process of laying out the different components as follows: Rotax 912is Fuse Box – The fusebox is relatively large (Width: 9″, Height: 5.5″, Depth: 4.5″). As I dig through the web for data and/or pictures I’ve seen the fusebox installed in several different locations including the top center of the firewall, installed across the top of the engine mount, which sits above the engine and is mounted via fabricated mounts on both top bars of the engine mount. The third option is to install in a vertical orientation on the side of the engine mount. Below are a few pictures that show these different options:
After trying out different locations, I ultimately decided to install the Fuse Box in the top-center position of the FW. It seems to be the best approach.
Oil Container Location – Once the decision had been made on the location of the Fuse Box, the locations on the other large items became obvious. The Oil Container can only be installed on the side of the engine mount. This was a simple process once I figured out how to make sure the container would sit level on the mount when in flight. As the pictures below show, I positioned the mount against a wall in the garage and then fabricated the lower mount bracket to ensure the container would sit vertically when the aircraft is in flight.
The Battery Box – of Rivnuts for the smaller (lighter-weight) items and nut plates for the heavier ones (battery box and fuse box). And naturally, I realized that I’m missing the stainless steel rivets for the nut plates, which led to an activity to make sure that I need stainless steel rivets when attaching parts to the stainless steel FW. I found a site that clearly describes which materials can be joined together. Here is the link: https://www.essentracomponents.com/en-gb/news/product-resources/rivets-which-material-is-best-for-you.