This weekend we started to organize everything needed to get the missing face sheet finished. Many things have to be done before we start with it, for example filling the core. The honeycomb core has to be filled with a glass bubbles-resin mixture where it is subjected to high localized loads. This prevents the core from failing and is, among other places, needed on the left side of the cabin where the pilot will walk on top of the shell to get into the airplane. Though the glass bubbles reduce much of the weight of the mixture, it is still much heavier than an air filled honeycomb core. Thus, the places to fill should be considered very thoroughly.
Last time we filled the core and glued the face sheet in one shot, which was extremely stressfull. It takes ages to mix enough filling material, and having a wating face sheet that is slowly but surely curing does not make it easier. This time we will do it in two steps and started today to mark the places to fill: