Trajectory Analysis

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

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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

"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

"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

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.

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

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

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

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

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.

"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 y0

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 ti
plot(MX(t),MY(t))
hold on;
t=t+1;
end