Per tonight's discussion on the construction of Skywalker X8 drones:
EPO = Expanded (foamed) Polyolefin
Polyolefin covers a huge range of materials, so it's a remarkably
non-specific piece of information. Polypropylene and polyethylene
(polyester) are in this category and make up between half and two-thirds of
polyolefin production, but that leaves a big gap.
There was the question of heat-forming the material. These materials are
inherently thermoplastic, however they're also foamed so they'll be
difficult to heat to plasticity without just slagging them along the way.
Expanded foams tend to chip when milled, however they generally glue just
fine. Polyolefins are glueable with common cyanoacrylate glue.
*Extruded* foams are more compatible with milling but tend to be
As for RF characteristics the materials are all over the place. RFCafe
states that polyethylene can have a dialectric constant anywhere between
1.0 and 5.0. Polypropylene sits in the low 2's. Breakdown voltage of solid
PE and PP are generally about an order of magnitude better than that of
air. Foaming any of these will bring them closer to the RF characteristics
of dry air -- indeed most of the volume *is* air.
You could probably embed antennas into the bodies of the X8 rather easily,
especially if using a relatively forgiving design such as a 3-element yagi.