Creating a fully-functional scale undercarriage is a task that few EIII modelers take on. I did, and I'm glad I did, because it forced me to learn a lot about how the original was built. In essence, this was an early version of independent suspension which incorporated the novel idea of putting the suspension (bungees) at the top instead of at the bottom. So the side legs are attached (via pivots) to bars inside the fuse, which can move up and down on a center pivot. This explains the slot for travel that you see on the side of real EIIIs (and which is missing on almost all model EIIIs). Then there is the basic "inverted V structure" on the bottom of the fuselage that supports the whole thing. This will need functional cross bracing on the model. Then you'll need to figure out how to "hinge" the side triangles on the center supporting beam. I used electrical lugs.

This is really WAY too much work to do on a sport scale model though.