Originally posted by sardion2000
Incorrect. The thin skins of Aerostats are Transparent to RADAR I believe.
True enough, the skins can be quite thin and radar transparent. However, one must consider the structural elements (beams, girders or thier cousins)
needed to keep even a helium displacement body from collapsing inward upon itself. Plenty of RAM, exotic materials or well shaped carbon fiber
composites would be needed here. Likely, a combination would be better suited to such a problem.
Consider how difficult it is to design the external structure of the B-2. Now, make it's skin completely transparent to radar. Finally, consider
all of the internal bulkheads, spars, etc... which will reflect radar waves any which way - while retaining thier structural qualities.
With a transparent skin, the hull of the aircraft can be nearly radar transparent - but how do you design structural elements which reflect radar away
from its source from every angle, even from within the aircraft?
Likely, more mass would be needed for either shape based or material based solutions to this problem. Again, a combination of techniques is likely,
in which case the total mass increases even further. and the size of the helium displacement or vacuum body would increase quite quickly. Requiring
more structure... repeat this problem ad infinitum, and you have to think of something else to get to a stealth aerostat.
Such as an aerogel-like skin or inner layers of skin which, instead of being transparent to radar, absorbs it. Traditional materials would weigh
entirely too much for such a skin. But, if an aerogel laminate were made with a radar absorbant material and succesive layers of atmospheric
gas-rich and -starved (vacuum) material, then a "shell" could succeed the girders-and-beams paradigm necessary for the outer structure, and provide
the skin as well. Pressure differentials between the inner vacuum and the outer atmosphere could be mitigated by the succesive layers of aerogel
material, while providing RAM properties as well.
Plasma can come into play here as well, since we're not talking about high speeds. Indeed, between an inner and outer hull on such a craft, a plasma
based system might just be able to hide any "unstealthy" structural elements as well as the skin of the craft as well.
Either way, the nearly transparent to radar nature of aerostat skins are not necessarily helpfull. A bit more ingenuity is needed.
[edit on 6-7-2006 by TheeStateMachine]