Abstract: An abradable seal member, which can be a component of a rotary seal in juxtaposition with another member, includes a non-metallic abradable material comprising a halogenated hydrocarbon, for example Teflon material. Such a material, which preferably is porous, has a solids content of at least about 40 weight %, a heat of combustion of no more than about 4000 BTU per pound, the halogenated hydrocarbon being at least about 60 weight % halogen.

Abstract: A wheel comprising a plurality of wheel plies, each wheel ply including concentric inner and outer hoops and a plurality of circumferentially spaced spoke loops therebetween, wherein each of the spoke loops is entrapped within the hoops. In one embodiment the wheel comprises a laminate of alternating wheel plies and intermediate plies bonded together. A spoked frame comprising one or more of the wheels is provided, the frame including fairing means to substantially envelope the spokes and retain the individual wheels in their proper spacial relationship.