a space shuttle question for every body

[catfan]

o k so i have a space shuttle question for every body. what are the dimensions for the black and the white tiles used on the shuttle. and when i mean black i mean what on the belly like when they are made. what are the dimensions any body know??

[Jay Chladek]

o k so i have a space shuttle question for every body. what are the dimensions for the black and the white tiles used on the shuttle. and when i mean black i mean what on the belly like when they are made. what are the dimensions any body know??

The tile shapes and dimensions can vary depending on where they are on the orbiter. Plus, the thickness can vary as well depending on how much heat load they see. But the average dimensions of square HRSI (black) tiles is 6 by 6 inches and the average dimension of square LRSI (white) tiles is 8 by 8 inches. Even though LRSI tiles tend to be larger in most dimensions, HRSI tiles are thicker due to their heat loads. No two tiles on the shuttle are exactly the same as they have a specific place where they go. A computerized milling machine shapes new tiles to the proper dimensions if one is needed and these are cataloged with an individual serial number stamped to the tile.

Edited December 12, 2010 by Jay Chladek

[David Hingtgen]

That reminds me, about every tile being unique---does that mean there is no perfectly flat surface on the shuttle, where you could use many perfectly square, identical tiles in an area? I always figured the sides of the fuselage, just under the bay doors, could have a "standardized" tile or something.

Edited December 12, 2010 by David Hingtgen

[niart17]

That reminds me, about every tile being unique---does that mean there is no perfectly flat surface on the shuttle, where you could use many perfectly square, identical tiles in an area? I always figured the sides of the fuselage, just under the bay doors, could have a "standardized" tile or something.

Perfectly flat is a relative term. If you look at some of the construction prints of the shuttles they are measured in .0001". That is some really really tight dimensioning. The company I work for deals in the .001" and that isn't really noticable to the naked eye. So it may be "flat" according to some measurments, but to be totally sure, they are numbered individually.

Bill

[spaceflightengineer]

The thinnest tiles were the LRSI that used to line the sides of the fuselage and payload bay doors, though there were HRSI on the belly- just about centered under the crew module that were as thin- 3/4 inch and less! Some interesting points and info regarding tile operations (though not truly modeling info)- the original placement of tiles on the belly or bottom of the orbiters were emplaced as "arrays"- literally groups on trays bonded with the type silicon RTV and cured under vacuum. These arrays were in effect the same on all vehicles as the dimensions of the aluminum skin for the lower surface was the most reliable for meeting intended dimensions. All 5 space worthy orbiters had these arrays. Then the "fun" began- making the close out tiles between arrays. Early on in the program foam material that had similar characteristics to actual TPS was HAND sanded to fit. "Fitting" had to take into account the expansion gaps and the felt SIP or strain isolation pad eventually attached (again with RTV) to the bottom of the tile. That felt remained constant in thickness. The hand made foam model or prototype for the tile was then placed on a numerically controlled machine ("NMC"). And while an arm went around tracing the surface of the foam tile, a raw piece of tile material was being ground to match. Those tiles would be coated on the upper surface and down the sides to about 2/3rds (the bottom third of the tile sides allowed the heat inside to vent) and the coating- glass based, baked to bond. Then the SIP was attached and then the Tile with SIP attached to the orbiter space it was designed for. Distances between the tile's sides and adjacent tiles had to be certain amount- and cut up IBM cards were stacked to achieve and maintain those. Tiles were bonded under vacuum- a plastic sheet attached around the tile to seal tight using a gray putty like material (at one time referred to euphemistically as "monkey poop"). Curing took, if I recall properly, 72 hours. The vacuum helped shorten the time if it were in ambient air and also helped with outgassing dispersion. Then tiles would under go pull tests with a similar vacuum device.

Later, LASER scanners were developed to scan the tile space, and then feed the stored dimensions, biased for SIPs and gaps directly into the NMCs. Some of you may recall that when Columbia (OV-102) first got shipped, not totally finished, to KSC, that the media reported "tile" flying off the orbiter- punctuating the media's penchant for negative reporting about the shuttle back then. Sorry, but the "tile" flying off were the foam temp tiles- placed on the orbiter in an attempt to reduce drag and maintain a smooth airflow. It turned out that bonding of the foam tiles just didn't occur well with the RTV. That foam tended to have a chalkiness that RTV couldn't "bite". BTW- two type RTVs were used on the orbiter- for two temperature regimes. I always found it interesting that the RTVs did bond so well to the bottom of the tiles, as that raw material also had a chalky surface.

Removal of tiles was done with a sort of device similar to heated nichrome wire we all have used for styrene cutting. It just had to be pulled under the RTV- as they'd try to save and reuse tiles when it was being removed for reasons of access to panels and such. Some tiles would be broken from debris (usually runway) and if bad enough would be broken off (with super care to not injure the tiles around it). I still have white surface glass from low temp tiles off of Challenger after STS-8 that I want to work into a model some day. (It would have been swept up and tossed).

I used to have to get tile removed frequently for antenna access or change out. Once the AFRSI went over the upper surfaces of the Crew Module/upper forward fuselage it made things a bit easier for the tile folks (nicknamed "puzzle workers"), though stenciling the antenna coupler alignment marks are a tad more difficult on slightly lumpy quilted fabric.

The largest tiles I was aware of were on the ends/tops of the inboard horizontal aero surfaces where they faced the fuselage and some on the ends/tops of the body flap. The end "tiles" for those inboard horiz aero surfaces on Columbia were ablative pieces, NOT reusable TPS tiles, though they seemed to hold up for multiple missions and weren't swapped out often. Also the SILTS pod, placed atop that orbiter after STS-9 had the oddest TPS tiles. The pod resembled a torpedo and the front had to have basically a 180 sphere covered with like-shaped tile. Only complicating that were two cut outs for infrared cameras- one pointing at the orbiter's nose region and one to the port wing leading edge. (Here's a weirdness of my particular mind: the pod always reminded me of the comic book version of the ship baby Kal-El was sent from Krypton to earth in, in Superman comics- especially with the top removed (allowing a view of the compartment the cameras and support gear sat in).

Bruce P.

The tile shapes and dimensions can vary depending on where they are on the orbiter. Plus, the thickness can vary as well depending on how much heat load they see. But the average dimensions of square HRSI (black) tiles is 6 by 6 inches and the average dimension of square LRSI (white) tiles is 8 by 8 inches. Even though LRSI tiles tend to be larger in most dimensions, HRSI tiles are thicker due to their heat loads. No two tiles on the shuttle are exactly the same as they have a specific place where they go. A computerized milling machine shapes new tiles to the proper dimensions if one is needed and these are cataloged with an individual serial number stamped to the tile.

[catfan]

OK so what my idea is. is this i have a 1/72 shuttle and i want to re tile the hole thing using ever green strips but i don't know what sizes to buy for the white and the black tiles. am i crazy. yes but i just think it will be so cool looking better than what there right now.

[K2Pete]

OK so what my idea is. is this i have a 1/72 shuttle and i want to re tile the hole thing using ever green strips but i don't know what sizes to buy for the white and the black tiles. am i crazy. yes but i just think it will be so cool looking better than what there right now.

Yeah, you're crazy ... but what the heck eh?

I'd say you're just gonna be estimating those 30,000 or so, tiles anyways, so it shouldn't matter what 'sizes' to use. Buy some sheet, and cut 'em all out!

By the bye, take a look at Phil's Shuttle. He did it the way you want to. And he did a spec-tack-u-lar job!! :)

http://www.astrazoic.com/Space-Shuttle-Discovery.html

And you're absolutely correct that " ... it will be so cool looking better than what there right now."

We'll be watchin' for your version!!

Pete

[Jay Chladek]

You aren't crazy as I have thought about doing the same thing myself. I would use very thin Evergreen strips of the right width cross hatched for the individual tiles and glue them on two at a time. Doing the math though, it would take about two months to do it, doing say 1000 tiles a day (ten strips with 100 tiles each) everyday for a Columbia model (maybe half that time for Discovery thru Endeavour and using tape for the FRSI and AFRSI blankets as they have only about 32,000 tiles compared to Columbia's original 55,000 or so). Here we don't have to worry about the thickness of the tiles since the model has already been profiled at the right shape while on real shuttles, the tiles help form the final exterior contour shape of the orbiter. One would likely make pretty rapid progress with the tiles on the bottom and the sides, but ones in areas with oddball contours would likely slow the process up a bit.