Re: Trajectory Analysis

[OM]

On Mon, 14 Jul 2003 23:53:53 -0500, "Jon Berndt" >
wrote:

>
>1070:PRINT "SPEED AT IMPACT ";IMPACTA;" MPH"

1075: PRINT "YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL ALIKE!"


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

[Pat Norton]

Jon Berndt wrote:
>480:WIND1=WINDC*6080/3600

This equation attempts (but fails) to convert knots into feet per
second. A nautical mile is not 6080 feet, it is 1852 metres precisely
(1852/0.3048 ft).

So the equation should be:
480:WIND1=WINDC*(1852/0.3048)/3600

[Jon Berndt]

"Pat Norton" > wrote in message

> Jon Berndt wrote:
> >480:WIND1=WINDC*6080/3600
>
> This equation attempts (but fails) to convert knots into feet per
> second. A nautical mile is not 6080 feet, it is 1852 metres precisely
> (1852/0.3048 ft).
>
> So the equation should be:
> 480:WIND1=WINDC*(1852/0.3048)/3600

NOTE: This was not my program. The web site I found it at claimed it came
from the NTSB then to the FAA. I had a longer chance to look at it this
morning and found it riddled with flaws.

This evening I devised what I think is a better tool, anyhow. It's not
optimal, but it's an Excel spreadsheet. Inputs are weight, projected area,
drag coefficient, initial velocity, flight path angle, and altitude, and
perhaps a few other things.

A question I have is one that maybe Danil can answer: how far downrange did
the crew cabin land?

Jon

[Charleston]

"Jon Berndt" > wrote in message
...
> "Charleston" > wrote in message news:AO1Ra.17666

> By the way - perhaps the higher velocity in the range you gave yesterday
> wasn't too far off ...

I think you will find it is closer to the lower velocity than the upper
velocity if you use all available data. Run a calculation to determine
impact time:-)

Daniel

[Jo Stoller]

Pat Norton wrote:
>This equation attempts (but fails) to convert knots into
>feet per second.

That is a symptom of one of the other problems with the program. The
calculations would be simpler in meters and kg, instead of slugs and
cubic feet etc.

[Michael Shaffer]

LOL, where is that from, it sounds familiar? Is it from that old BBS game?

OM wrote:
> On Mon, 14 Jul 2003 23:53:53 -0500, "Jon Berndt" >
> wrote:
>
>
>>1070:PRINT "SPEED AT IMPACT ";IMPACTA;" MPH"
>
>
> 1075: PRINT "YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL ALIKE!"
>
>
> OM
>

[Herb Schaltegger]

In article >,
jeff findley > wrote:

> Michael Shaffer > writes:
> >
> > LOL, where is that from, it sounds familiar? Is it from that old BBS game?
> >
> > OM wrote:
> > > On Mon, 14 Jul 2003 23:53:53 -0500, "Jon Berndt" >
> > > wrote:
> > >
> > >
> > > 1075: PRINT "YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL ALIKE!"
>
> Sounds like an "old school" text based adventure game. Zork, perhaps?
>
> Jeff

I thought it was the old Unix "Adventure" text game. But it's been a
LOOONG time since I played it or Zork, so I don't remember for certain,
either.

--
Herb Schaltegger, Esq.
Chief Counsel, Human O-Ring Society
"I was promised flying cars! Where are the flying cars?!"
~ Avery Brooks

[OM]

On 16 Jul 2003 11:04:35 -0400, jeff findley
> wrote:

>Michael Shaffer > writes:
>>
>> LOL, where is that from, it sounds familiar? Is it from that old BBS game?
>>
>> OM wrote:
>> > On Mon, 14 Jul 2003 23:53:53 -0500, "Jon Berndt" >
>> > wrote:
>> >
>> >
>> > 1075: PRINT "YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL ALIKE!"
>
>Sounds like an "old school" text based adventure game. Zork, perhaps?

....Oh, you kids and your Quake-based universes :-P. The "maze of
twisty little passages" comes from the progenitor of all adventure
games, "Colossal Cave". More commonly known as "Adventure", it
predates "Zork" (*) and set the standard for text adventures - lavish
descriptions and terse commands. Here's a couple of links that might
interest you:

The Colossal Cave Adventure Page:
http://www.rickadams.org/adventure/

Don Woods' Homepage:
http://www.icynic.com/~don/

OM


(*) Zork actually started out on a mainframe, just like Colossal Cave,
and was actually the first software program I ever pirated. When I was
in my first junior year in college, we swiped a copy from TAMU's 308x
clunker and actually got the damn thing to run on a CDC6600! It was
essentially Zork's 1-3 combined with a bunch of filler stuff left out.


--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

[David Higgins]

OM wrote:

> ...Oh, you kids and your Quake-based universes :-P. The "maze of
> twisty little passages" comes from the progenitor of all adventure
> games, "Colossal Cave". More commonly known as "Adventure" [...]

I first played Adventure back in 1977 or so using a
rehost of the Fortran variants into a Datacraft/Harris
Slash 7, a (wait for it) 24-bit minicomputer.

[David Harper]

"Jon Berndt" > wrote in message >...
> Anyone have a basic compiler? This might be an interesting program to move
> to "C". It's from this site:
>
> http://proairshow.com/aircraft_debris.htm
>
> TRAJECTORY ANALYSIS FOR AIRCRAFT DEBRIS
>
>
>
>
> COMPUTER PROGRAM

This one's a little shorter and simpler. Similar approach, but
different methods. For MATLAB. Some of the data I got from some
obscure NASA archive. I wrote it back in Feb, but forgot about it
until you posted that one. This is for a piece of debris approximated
as a sphere of aluminum with a mass of 50kg, although you can play
around with the values. Plot MAX at the end; this theoretical piece
of debris would have hit about 16 g's.

Of course it's just a program, but it gives some interesting insight
as to the mechanics involved.

-----------------------------------------------------------------

g=9.8;
m=50;
density=2.7*10^3;
volume=m/density;

%object is a sphere
r=(volume/(4/3*pi))^(1/3);
FA=pi*r^2;

%Atmospheric density table

AD=[0.00007
0.00014
0.00028
0.00053
0.00097
0.00188
0.00385
0.00821
0.01801
0.02660
0.03946
0.05881
0.08803
0.13058
0.19367
0.28726
0.41271
0.55663
0.73612
0.95686
1.22500];

%Atmospheric density lookup index

AA=[70000
65000
60000
55000
50000
45000
40000
35000
30000
27500
25000
22500
20000
17500
15000
12500
10000
7500
5000
2500
0];

%Drag coefficient index as a function of Mach number/velocity
%NASA empirical data from some old archive I found

CD=[.41
1.05
.9
.9];

%Drag coefficent lookup index, from the same obscure archive.

CDV=[0
2
5
20]*300;

%initial X and Y velocities

vx=12500*5280/3600/3.27;
vy=0*5280/3600/3.27;

%initial X and Y positions

y=65000;
x=0;
i=1;


%MX=X-position Matrix
%MY=Y-position Matrix
%MVX=X-velocity Matrix
%MVY=Y-velocity Matrix
%MC=drag coefficent index
%MAD=air density index
%MFX=X-direction forces
%MFY=Y-direction forces
%MAX=X-direction accelerations
%MAY=Y-direction accelerations

while y>0

MX(i)=x;
MY(i)=y;
MVX(i)=vx;
MVY(i)=vy;

c=interp1(CDV,CD,(vx^2+vy^2)^.5);
MC(i)=c;
air_density=interp1(AA,AD,y);
MAD(i)=air_density;
fx=-.5*c*FA*air_density*(vx^2);
fy=.5*c*FA*air_density*(vy^2)-m*g;
ax=fx/m;
ay=fy/m;
x=x+(2*vx+ax)/2;
y=y+(2*vy+ay)/2;
vx=vx+ax;
vy=vy+ay;

MFX(i)=fx;
MFY(i)=fy;

MAX(i)=ax;
MAY(i)=ay;

i=i+1;
end

%PLOT of trajectory

t=1;
while t<i
plot(MX(t),MY(t))
hold on;
t=t+1;
end

[Reed Snellenberger]

David Higgins > wrote in news:XMmRa.58127
:

>
>
> OM wrote:
>
>> ...Oh, you kids and your Quake-based universes :-P. The "maze of
>> twisty little passages" comes from the progenitor of all adventure
>> games, "Colossal Cave". More commonly known as "Adventure" [...]
>
> I first played Adventure back in 1977 or so using a
> rehost of the Fortran variants into a Datacraft/Harris
> Slash 7, a (wait for it) 24-bit minicomputer.
>
>

Zork *did* contain at least a couple of these mazes -- one is under the
house, and is where the thief hangs out.

I played Adventure on a PDP-11/34 (thanks, DECUS) - fall, 1977. I'm
pretty sure it was a binary, though, since I can't remember actually
building it. Just wasted a lot of time between RSX-11M sysgens :-(

My *first* computer game was a round of chess at the system console of a
CDC 6500 in 1972. I lost, as usual (my chess rating is near room
temperature) but enjoyed the experience nonetheless. This was an
especially cool machine -- styling was right out of "Forbidden Planet",
with a pair of circular CRTs at the center of the console.

(waiting for Henry to chime in, telling us he *wrote* that chess program
using an early regex parser)

--
Reed Snellenberger

[OM]

On Thu, 17 Jul 2003 02:13:59 GMT, Reed Snellenberger
> wrote:

>(waiting for Henry to chime in, telling us he *wrote* that chess program
>using an early regex parser)

....Knowing Henry, he *wrote* the parser :-)


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

[Jon Berndt]

"cndc" > wrote in message

> You may want to take a look at this page:
>
> http://proairshow.com/thanks_to_the_efforts_of_enginee.htm
>
> Elizabeth

Thanks. Darn, I missed that. I already "rolled my own".

Jon