Honeycomb

Hello to you all,

Where to get information about honeycomb used in the BD4 aircraft. Is this detailed in
the Jim Bede book "Build Your Own Airplane", if someone has the book ?

Thank you for your answer.

I'm not directly familiar with the specific BD4 honeycomb core but for most sandwich core information, you can get started with Hexcel Honeycomb online.
The two basic core materials are Aramid paper and aluminum core. The core in a sandwich structure carries shear strains between the face sheets and allows the face skins to develop maximum bending strength at low weight. The choice of core material depends on the required shear strength; Aramid has lower shear strength than aluminum. For most experimental planes, the Aramid has sufficient shear strength. If the structure requires high stiffness and shear, the choice of face skins comes into play. Glass skins are often molded with the core in a tool to make a structure with contour. Aluminum skins can be used also but much more difficult to mold into aerodynamic shapes. And on commercial aircraft with higher loading, carbon face skins are used to provide high stiffness and high strength at higher cost.
Foam cores are often used for lower strength applications but they have lower shear strengths. Aramid core comes in 3 possible forms; standard honeycomb that does not bend much into contours, overexpanded (ox core) core that can bend in one direction and flex core that can be wrapped around a sphere. Cost go up exponentially.
Bob H

Thank you Bob for answering my question. I'll try to have a look at Bede's book but your information is sufficient for me.