Composite interior panels

[Daniel]

I would be interested to know what weights people are ending up with.

I tried a composite panel for the aft bulkhead, and once painted to match the rest of the interior - it weighed about the same as painted aluminium paneling. I was shocked, certainly not an intuitive result, but I weighed it twice and sure enough.

What's worse, is for all that extra work - composite isn't anywhere near as durable as aluminium.

For the floor in a "bush plane" you are going to get so much sand / gravel / debris inside, composite flooring would get all scratched up look a mess in just a few months - you'd end up covering it with carpet or deco-dot rubber mat anyway. Probably not a concern for a sealed airport traveler.

Your comments are spot on. I had the same shock when making my first part, the rear bulkhead. At 5 layers it is overbuilt. Add the clear UV durable coat and kevlar for 'safety' and it weighs more than aluminum. It was certainly a learning experience on how to approach composites.

I did do a weight comparison between my floor sections and the aluminum panels that came with the kit. It is far from an apples to apples comparison as the custom carbon panels cover a lot more than the kit provided panels. In fact, the kit is missing floor sections entirely under the flap handle and forward of the rudder pedals. Altogether the carbon panels weigh 1 pound less. How one builds the panel is key to keeping it light. Still the cost/effort to weight ratio is slim when using carbon in lue of aluminum. But reducing weight wasn't my only goal.

You are also correct about durability. I am fully aware that these surfaces will get scuffed up over time and am all good with that. In an effort to improve durability I used the kevlar as the top layer. Even so, I doubt they would age as well as aluminium.

Lastly, one of my goals with these panels was to shape them as to prevent sand, gravel or debris from getting to the belly of the airplane. I worked on small planes years ago and was shocked at how messy that area could get. From my point of view, I would rather have these on a bush plane for that reason.

[Battson]

Thanks for sharing that extra information. It sounds like we had exactly the same experience with the rear bulkhead.