Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: $Revision: 1.6.2.16 $; site pbear.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!bbnccv!pbear!peterb From: peterb@pbear.UUCP Newsgroups: net.columbia Subject: Re: Re: Columbia's Tiled Damaged by Rain Message-ID: <900002@pbear.UUCP> Date: Mon, 19-Aug-85 18:48:00 EDT Article-I.D.: pbear.900002 Posted: Mon Aug 19 18:48:00 1985 Date-Received: Fri, 23-Aug-85 20:11:41 EDT References: <199@mot.UUCP> Lines: 30 Nf-ID: #R:mot:-19900:pbear:900002:000:1598 Nf-From: pbear!peterb Aug 19 18:48:00 1985 I think if the shuttle's exterior skin was made from titanium, then it would weigh quite a bit, and would change its flight charecteristics from "a set of car keys" to a brick. Sure in the second generation the added weight can be designed into it, but still what are you going to do with all the heat the the titanium stores? I remember reading a while back about a writer's ride in the blackbird, and as he was leaving he asked the pilot what the burning smell was. The pilot pointed out that since the titanium heted up, they had to use insulation on the inside of the aircraft to preserve avionics, hydralics, and wiring and conrtol cables from the extreme heat. That is also why blackbirds are painted black: so the black surface radiates heat faster than any other color. So if a second generation shuttle was made of titanium, you would also have to design in expansion factors for titanium, and insulate everything on the inside from the extreme heat. The tiles are a perfect choice for heat insulation. You can hit a tile with a blowtorch until it starts to turn orange, and then after removing the torch, 30 seconds later you can handle it safely. Also (depending on the thickness) the heat would not travel through the tile. This is because the tile is almost like pumice: it has many little air pockets and is extremely light. But the cost of insulation and lightness is in its being brittle and soft. Water particles travelling at high speed can easily fracture the surface of the tile and slowly cause it to wear down. Peter Barada {ihnp4!inmet|{harvard|cca}!ima}!pbear!peterb