Posted by Marc Martin on
URL: https://www.shado-forum.com/Conflict-episode-tp1490213p1490217.html

I've been thinking a bit more about about this flight path angle
thing in CONFLICT. It's quite possible that what they are calling
"flight path" in UFO is actually what the aerospace industry calls
"angle of attack". If this is true, then what we see in UFO makes a
lot more sense.

The angle of attack is the angle between the direction you are
travelling and the direction of the longitudinal axis of your
vehicle. So if you are travelling at an angle of -45 degrees and
your vehicle is pointed at -35 degrees, then your vehicle's angle of
attack is +10 degrees. In an airplane, the angle of attack is used
to generate lift, an upwards force which keeps it up in the air.

In UFO, the angle of attack of the lunar module is a critical factor
in slowing it down from "space speeds" to "earth speeds". The
shallower you fly, the higher the angle of attack (like the 8 degrees
we saw on the gauge), and the flat surface of the bottom of the lunar
module would generate more lift, which *could* cause the lunar
modules to "skip" like a rock thrown into the water at a shallow
angle. A steeper reentry would cause a lower angle of attack (like
the 3 degrees we saw on the gauge), and the flat surface on the
bottom would not generate as much lift, which means the lunar module
would not slow down enough during reentry, and the high speeds and
would cause the vehicle to overheat and burn up in the Earth's
atmosphere.

I should stress again, that although the lunar module could indeed
"skip" like a rock thrown in the water, it would never be flung back
into space due to this lift, just like a rock would never get flung
high into the air by skipping on the water.


Pam writes:
>This info seemed esp important to the
>astronauts of Apollo 13 when they were trying to get back home with limited
>power source and limited computer ability.

Yes, but on Apollo 13, I think that critical angle was indeed the
"flight path angle", which determined whether their trajectory would
successfully make it into the Earth's atmosphere, or whether they
would miss the atmosphere entirely and be stuck in space. Such a
thing is determined when you're still far out in space, not when
you're a minute from reentry. On Apollo 13, the concern was with the
direction the vehicle was travelling. On UFO, the concern was with
the direction the vehicle was pointing. Two different things.

So, I guess the gauge really *does* make sense if you think of these
angles as "angles of attack", and not "flight path angles".

Ron, are you sorry that you brought this subject up? :-)

--
Marc Martin, [hidden email]
(who once had a job calculating reentry trajectories of future space vehicles)