Neil Armstrong has Died

Fred J. McCall wrote:

"Fevric J. Glandules" wrote:

So if the nominal flight plan left 441.7kg "in the tanks", Eagle
still had 79% of its "contingency" fuel left. Or if that's 441.7
usable, we're at 69%.

They were a few dozen seconds away from MANDATORY ABORT.

The ALSJ is proving enlightening.

102:43:21 NA takes manual control.
102:45:02 Duke calls 60 seconds til bingo
102:45:40 Contact.


And "a 'Bingo' fuel call which meant 'land in 20 seconds or abort.' So
if the count gets down to zero, Neil will have 20 seconds to land, if
he thinks he can get down in time. Otherwise, he will have to abort
immediately. If you're 50 feet up at 'bingo fuel' with all of your
horizontal rates nulled and are coming down to a good spot, you could
certainly continue to land. With your horizontal rates nulled at 70 to
100 feet, it would be risky to land - perhaps giving you a landing at
the limiting load of the landing gear. At anything over 100 feet,
you'd punch the abort button, say goodbye to the moon, and stew for
the rest of your life!"

So he was 20 seconds from "land within 20 seconds".

On Saturday, August 25, 2012 11:39:11 PM UTC-5, Stuf4 wrote:
...Clearly a bad week for Armstrong's.

....If it's the last thing I do, I will find out who you are, where you live, all your personal information, and I will disseminate it on every computer network, forum, newsgroup and mailing list, inviting ever 4chantard to datamine and totally ruin your life for the rest of your miserable existence. I'll even make sure you're put on a NAMBLA mailing list, just so you'll get what's coming to you, you pathetic, psychotic maladroit.

OM

In article ,
says...

"Fevric J. Glandules" wrote:

Fred J. McCall wrote:

"Fevric J. Glandules" wrote:

So if the nominal flight plan left 441.7kg "in the tanks", Eagle
still had 79% of its "contingency" fuel left. Or if that's 441.7
usable, we're at 69%.

They were a few dozen seconds away from MANDATORY ABORT.

The ALSJ is proving enlightening.

102:43:21 NA takes manual control.
102:45:02 Duke calls 60 seconds til bingo
102:45:40 Contact.


And "a 'Bingo' fuel call which meant 'land in 20 seconds or abort.' So
if the count gets down to zero, Neil will have 20 seconds to land, if
he thinks he can get down in time. Otherwise, he will have to abort
immediately. If you're 50 feet up at 'bingo fuel' with all of your
horizontal rates nulled and are coming down to a good spot, you could
certainly continue to land. With your horizontal rates nulled at 70 to
100 feet, it would be risky to land - perhaps giving you a landing at
the limiting load of the landing gear. At anything over 100 feet,
you'd punch the abort button, say goodbye to the moon, and stew for
the rest of your life!"

So he was 20 seconds from "land within 20 seconds".


Which would have given him around 15 seconds of trying to fly with
totally empty tanks. That usually doesn't work so well.

I think it's probably a given that the calls were not exact to the
second. Note that there are not 30 seconds between the 60 second call
and the 30 second call, for example....

Which would seem to indicate they were burning fuel at a higher rate
than the mission plans originally anticipated. I don't think that
should surprise anyone since Armstrong wasn't just hovering, but was
translating the LM (quite a bit) in order to find a safe place to land.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Fred J. McCall wrote:

Your myopia and inability to think are merely signs of your trollish
nature and, unfortunately for you, do nothing at all to alter our
present reality, where you merely look like an ignorant boob.

Fred,

I don't know what I've said to provoke this ad hominem. AFAIWC we
were having a civilised discussion wherein I was trying to find out
how much A11 differed from other missions. So if it's alright with
you I'll try and carry on in the same way.

So he was 20 seconds from "land within 20 seconds".

Which would have given him around 15 seconds of trying to fly with
totally empty tanks. That usually doesn't work so well.

Apollo by numbers has the following numbers for seconds of hover time
remaining for the six landings:
45, 103, 68, 103, 102, 117

So firstly, A11 wouldn't have been on empty tanks.

Secondly, that makes an average of 90: A11 had 50% of the average.
It's an outlier but it's not freakish.

Perhaps more to the point is how much time the CDR (and everyone else)
*thought* they had left.

A11 A12
Bingo-30: 45:31 32:28
Contact: 45:40 32:35
Time-to-go: 21 23

Much the same. A14 had contact 19 seconds after Bingo-60: 41 seconds.
The remaining flights never got as far as Bingo-60.

Fred J. McCall wrote:

"Fevric J. Glandules" wrote:

Apollo by numbers has the following numbers for seconds of hover time
remaining for the six landings:
45, 103, 68, 103, 102, 117

So firstly, A11 wouldn't have been on empty tanks.


And why are those numbers better than the "about 25 seconds of fuel"
that almost every source calls out?

Good question. This is the URL:
http://history.nasa.gov/SP-4029/Apol...ar_Landing.htm

I should think that the *main* reason is that anybody watching
the coverage or reading a raw transcript would assume that the
"Bingo" calls gave the time til the fuel ran out.

Some discussion he
http://www.apollohoax.net/forum/index.php?topic=189.0
which states that the low fuel sensor latched on early
due to "slosh" and it's that which starts the bingo call
countdown.

The above numbers don't at first sight match with the "usable fuel
remaining at cutoff" from the same source: 216, 386, 228.
http://history.nasa.gov/SP-4029/Apol...ant_Status.htm

The fuel slosh problem was fixed from A14 onwards.

So in fact, one way of reconciling the numbers is to assume that
the 45 seconds given in the first table is based on the (inaccurate)
bingo call - that is to say, roughly 21-til-bingo plus 20-for-abort.

Going by the fuel levels they probably had more like 65.

But as I said, the *important* number is how long the CDR *thought*
he had. Which was 20+ seconds til abort-or-descend, and another 20
to settle down with.

Those numbers don't seem to match your other numbers very well.

They're not my numbers, they're NASA's. And I think I'm making
some headway in reconciling them. I am not massaging things
to try and prove a point.

I think the achievements of the Apollo programme in general and
the Eagle crew in the particular are great enough that they do
not need artificially enhancing with inaccurate statements.

I'm sure NA himself would have preferred accuracy over hyperbole.

In article , lid says...

Fred J. McCall wrote:

Your myopia and inability to think are merely signs of your trollish
nature and, unfortunately for you, do nothing at all to alter our
present reality, where you merely look like an ignorant boob.

Fred,

I don't know what I've said to provoke this ad hominem. AFAIWC we
were having a civilised discussion wherein I was trying to find out
how much A11 differed from other missions. So if it's alright with
you I'll try and carry on in the same way.

So he was 20 seconds from "land within 20 seconds".

Which would have given him around 15 seconds of trying to fly with
totally empty tanks. That usually doesn't work so well.

Apollo by numbers has the following numbers for seconds of hover time
remaining for the six landings:
45, 103, 68, 103, 102, 117

Seconds of hover time remaining is only one metric and I don't feel it
is a good one.

Later missions just weren't the same. Improvements kept being made, so
it would not surprise me if later missions had larger fuel margins.
Larger fuel margins could mean larger "seconds of hover time remaining"
even if the pilot wasn't as skilled and used more fuel than Armstrong
would have.

You need to supply *a lot* more data than this one metric to make your
case, IMHO. The hardware and missions were so varied that this could
quickly turn into a huge thesis.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Jeff Findley wrote:

Later missions just weren't the same. Improvements kept being made, so
it would not surprise me if later missions had larger fuel margins.

AIUI A14 used the CSM to initiate descent so used less LM propellant
at that stage. Later machines packed more hardware and more fuel.

Larger fuel margins could mean larger "seconds of hover time remaining"
even if the pilot wasn't as skilled and used more fuel than Armstrong
would have.

Ah. This might explain some of the animosity kicking around.

This has got *nothing* to do with the individuals. Just the simple
questions - how much hover time did they *think* they had left on A11,
and how much did they *actually* have.

I have some proposed answers in the other post.

Fred J. McCall wrote:

further ad hominem attacks - why?

"Fevric J. Glandules" wrote:

I'm sure NA himself would have preferred accuracy over hyperbole.

I'm sure he would have. How much fuel did he say was left at
touchdown?

I don't know.

But you appear to be sticking to the '"about 25 seconds of
fuel" that almost every source calls out' as you put it.

If you're not, I don't know what we are arguing about.

However, I have shown with reference to the ALSJ and Apollo
by numbers, that:

- A11 was ~21 seconds from "Bingo", which was the land-within-
twenty-or-abort call (ALSJ)
- that this is *consistent* with the 45 second hover-time
remaining given in ABN
- that the Bingo countdown was started early due to tank 'slosh' (ALSJ)
- that the *actual* fuel + oxidiser quantities left were similar
to those on A14, which had had the tank slosh problem fixed [0]

and from this I have surmised that:
- the *actual* hover time was more of the order of 65 seconds

and I have hypothesised that:
- the commonly stated "about 25 seconds fuel remaining" is
very likely due to widespread misinterpretation of the
"bingo" calls.
- the hover time remaining given in ABN is based on the bingo calls.

[0] Consider these numbers.
"Remaining Hover" times for landings:
45, 103, 68, 103, 102, 117
Total usable fuel + ox left:
674, 1079, 628, 1055, 1128, 1225

It's fairly clear that a very rough approximation of hover time is
propellant / 10. Apart from A11 which had tank slosh trigger the
bingo call.

Refs:
http://history.nasa.gov/SP-4029/Apol...ar_Landing.htm
http://history.nasa.gov/SP-4029/Apol...ant_Status.htm

Fred J. McCall wrote:

"Fevric J. Glandules" wrote:

Fred J. McCall wrote:

further ad hominem attacks - why?

Because you keep saying silly things. You believe whatever
foolishness you care to and the rest of us will stick with reality.

Silly old ALSJ. Silly old nasa.gov.

No, Fred. If you want to dispute my claims then do so with facts
and references that are at least as authoritative as the above.
Not with ad hominem attacks. They merely reflect badly on you
and make your position weaker, not stronger.

And hell, I thought to begin with we might be on a mutual quest
to discover the facts. You seem determined to turn it into an
adversarial situation.

I am quite prepared to believe that A11 landed with 30 seconds
of fuel remaining: *IF* somebody comes up with *EVIDENCE* that is
stronger than the ALSJ and NASA's own numbers. Meanwhile all
the EVIDENCE so far is that A11 landed with at least 40 seconds of
usable fuel on board, and that the crew - both flight and ground -
thought this at the time, and that in fact they landed with more like
60 seconds of usable fuel on board.

None of which diminishes in the slightest the achievements of the
Apollo program or the memory of the first man on the moon.

On 12/09/2012 16:24, Fred J. McCall wrote:

I'm sure NA himself would have preferred accuracy over hyperbole.


I'm sure he would have. How much fuel did he say was left at
touchdown?

In 'First Man' he's quoted as saying that it was impossible to know. The
tanks were spherical and impossible to measure quantity accurately.

He also said that flying the LLTV it was 'normal' to land with about 15s
of fuel left.

Also, as long as the LM was below 100 feet it wouldn't matter if the
fuel ran out, it would land safely anyway - assuming it was in a
reasonably flat area.

Roughly speaking, four missions landed after consuming between 93 and
94% of their propellant. The other two consumed a bit more, exactly the
same amount - A11 & A14 (95.7%).

--

Brian W Lawrence
Wantage
Oxfordshire