Shuttle Drag Chute

On Aug 26, 12:28 pm, wrote:
FRom The Ascent, Entry, Landing Flight Procedure Manual:

Drag Chute Deploy
Nominal chute deploy by definition (assuming WOW) is 195 KEAS. Early
chute deploy is after main gear
touchdown and before nominal chute deploy. Late chute deploy is after
weight on nose gear. Emergency chute
deploy indicates the chute should not be deployed unless the Commander
determines it is required.
If the drag chute aggravates lateral directional controllability on
the runway, it should be jettisoned immediately.
Nominal drag chute jettison is done at 60 KGS.



WHHOOOAAAAA . . . . where could one find a copy of the Ascent, Entry,
Landing Flight Procedure Manual? Is the text available anywhere on
line?

My initial google search only found places where I could buy it, which
I am probably willing to do but free is better.

Take care . . .

John

Take care . . .

On Wed, 22 Aug 2007 04:43:23 -0700, John wrote:

That's why I put up with NASA TV on the web. . . with all of
its issues . . . unless CSPAN is covering. Where i live now there is
no NASA channel on the cable line up.

take care . . .

John

I am so very thankful for Dish Network having the NASA channel.
Years ago I installed a big C Band dish just so I could get NASA. I
plan to go back to C Band just as soon as I can afford it.
Jim in Houston.

Contrary to popular opinion RN does not mean Real Nerd!
Teddy Roosevelt's mother said: "Fill what is empty,
empty what is full, and scratch where it itches"

--
Posted via a free Usenet account from http://www.teranews.com

On Aug 26, 12:28 pm, wrote:
FRom The Ascent, Entry, Landing Flight Procedure Manual:

Drag Chute Deploy
Nominal chute deploy by definition (assuming WOW) is 195 KEAS. Early
chute deploy is after main gear
touchdown and before nominal chute deploy. Late chute deploy is after
weight on nose gear. Emergency chute
deploy indicates the chute should not be deployed unless the Commander
determines it is required.
If the drag chute aggravates lateral directional controllability on
the runway, it should be jettisoned immediately.
Nominal drag chute jettison is done at 60 KGS.

"Early chute", for practical purposes means "deploy the chute
immediately upon main gear touchdown". There is at least one
astronaut who likes to experiment with deploying the chute earlier
than early. That is to say, hit the chute arm and deploy buttons
*prior* to touchdown This will shorten the ground roll, but if done
too early it risks controllability problems, primarily due to the
pitching moments that a disreefed chute can induce on the orbiter.


~ CT

From John ):
On Aug 21, 9:11 pm, "James R. Jones" wrote:

Just curious if it was just me or did it seem the drag chute deployment
was late today. I thought I had read somewhere that the drag chute was
not only to help slow the shuttle, but it was also to help hold the nose
high for longer so it could be eased down with without it hitting the
pavement so hard. The drag chute didn't deploy today until the nose gear
was all the way down on the pavement.

The timing of the chute deploy is designed so that disreefing will
give the maximum pitch up force at the moment of slap down (WONG).

There is an old statement made here by Henry Spencer saying that
pilots hold up the nose as long as possible in order to minimize the
loads on the main gear tires that happens with the negative alpha
caused by having a short nose strut.

That is an inaccurate statement. Yes, the loads on the main tires do
peak at slapdown, but if you wait to long, then you are lacking aero
forces that will enable a gentle slapdown and you will end up spiking
the nose strut (potential failure there as well).

So the derotation is an optimization of main gear tire loads as well
as nose gear strut loads. The chute deploy and disreefing helps to
offload nose strut forces at slapdown.

An engineering solution that has been worked up (and subsequently
canceled) was an extended nose gear strut. A long nose strut would
mean that the shuttle would not be pointed so far down in the three-
point stance, and the wings would not be pushing so hard down on the
mains. This solution had problems of its own. I suspect that one of
them, aside from cost and weight, is the reliability of a much more
complex gear deploy system.

Part of the reason may have been the crosswind. I heard a call for a
late drag chute because of a crosswind procedure (never caught its
precise name). The idea is probably to get the nose gear down without
too much delay and increase steering authority for the remaining roll-
out.

The Crosswind DTO has nothing to do with getting the nose down earlier
or increasing steering authority. It is simply a flight test data
point, that the program has been chasing for decades, to just gather
data on the handling qualities of the orbiter in a two-point stance
with an excitation of the lateral-directional mode (in a crosswind).
My understanding as to why the chute is not deployed during that phase
is because the chute forces will corrupt, or at least interfere with,
that data.


~ CT

On Sun, 02 Sep 2007 09:15:25 -0700,
wrote:

On Aug 26, 12:28 pm, wrote:
FRom The Ascent, Entry, Landing Flight Procedure Manual:

Drag Chute Deploy
Nominal chute deploy by definition (assuming WOW) is 195 KEAS. Early
chute deploy is after main gear
touchdown and before nominal chute deploy. Late chute deploy is after
weight on nose gear. Emergency chute
deploy indicates the chute should not be deployed unless the Commander
determines it is required.
If the drag chute aggravates lateral directional controllability on
the runway, it should be jettisoned immediately.
Nominal drag chute jettison is done at 60 KGS.

"Early chute", for practical purposes means "deploy the chute
immediately upon main gear touchdown". There is at least one
astronaut who likes to experiment with deploying the chute earlier
than early. That is to say, hit the chute arm and deploy buttons
*prior* to touchdown This will shorten the ground roll, but if done
too early it risks controllability problems, primarily due to the
pitching moments that a disreefed chute can induce on the orbiter.


~ CT
Thanks for the info, finally ;-) This and your other post in this
thread today clears many questions I had.
Regards
Jim in Houston.

Contrary to popular opinion RN does not mean Real Nerd!
Teddy Roosevelt's mother said: "Fill what is empty,
empty what is full, and scratch where it itches"

--
Posted via a free Usenet account from http://www.teranews.com