Maximum Rate Shuttle Launches

On Jun 15, 5:44 pm, "Ed Ruf (REPLY to E-MAIL IN SIG!)"
wrote:
On Tue, 12 Jun 2007 04:42:15 -0700, in sci.space.policy Ian Parker

wrote:
[...]
As for Fred's ascertain that wind tunnel test can be used to anchor all
calculations, this is a again a less than informed position as presented.
These are not performed at true scale, or true enthalpy conditions. Scaling
wind tunnel data is not at al trivial. One has to account for different BL
transition, real gas heating effects, chemistry, etc.

Reynolds number is one the things people have to keep an eye on,
right?

/dps

snidely wrote:

:On Jun 15, 5:44 pm, "Ed Ruf (REPLY to E-MAIL IN SIG!)"
wrote:
: On Tue, 12 Jun 2007 04:42:15 -0700, in sci.space.policy Ian Parker
:
: wrote:
:[...]
: As for Fred's ascertain that wind tunnel test can be used to anchor all
: calculations, this is a again a less than informed position as presented.
: These are not performed at true scale, or true enthalpy conditions. Scaling
: wind tunnel data is not at al trivial. One has to account for different BL
: transition, real gas heating effects, chemistry, etc.
:

I'll simply note that I made no such "ascertain" [sic].

:
:Reynolds number is one the things people have to keep an eye on,
:right?
:

Among many other things.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

"Ed Ruf (REPLY to E-MAIL IN SIG!)" wrote:

:On Wed, 20 Jun 2007 15:18:50 GMT, in sci.space.policy
Henry Spencer) wrote:
:
:In article ,
:Fred J. McCall wrote:
::...When the Shuttle was built everyone who did not have what
::were then supercomputers simply stuck their fingers into the air.
:
:Hint: You still build scale models and stick them in wind tunnels to
:validate your simulation.
:
:But, it is a lot more than just doing full scale CFD and doing subscale
:wind tunnel tests. One also needs to do a lot of CFD on the wind tunnel
:configurations themselves as well and other analysis which helps give
:confidence in your full scale solutions and your scaling techniques
:applied to subscale wind tunnel data.
:

Well, DOH!


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

In article .com,
Ian Parker wrote:
One other aspect of competition. ProEngineer has a JLink interface. If
NASA managed to sort out licenses this could be given to bright high
school kids and undergraduates. A lunar robot fabricator could be
designed and tested without bending metal.

And if it worked at all, it would probably stop doing so within a few days
on the Moon. (Hint: the professional vehicle engineers and mining
engineers think the MTBF of *NASA-designed* vehicles and mining equipment
on the lunar surface is likely to be measured in days. Why? Because the
aerospace engineers are grossly over-optimistic about their ability to
solve difficult problems -- like lunar dust -- on paper/screen without
ever testing in the field.)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

I wrote:
...(Hint: the professional vehicle engineers and mining
engineers think the MTBF of *NASA-designed* vehicles and mining equipment
on the lunar surface is likely to be measured in days. Why? Because the
aerospace engineers are grossly over-optimistic about their ability to
solve difficult problems -- like lunar dust -- on paper/screen without
ever testing in the field.)

After posting this, I got mail from a friend who'd seen what happened when
an aerospace company ventured into work along those lines (on Earth). I
probably shouldn't repeat the details, but a reasonable one-line summary
is: "you're way too optimistic -- that's the mean time to catastrophic
probably-unrepairable failure, not just the MTBF".
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |