Liberty Bell 7 attempted recovery

We all know that the helicopter was unable to lift the water-filled
Liberty Bell 7 out of the ocean. But would it have been possible
for the helicopter to stay hooked on to LB7, even if it was under
water, and hold it until a ship could get close enough to attach a
line?

Related question: when a helicopter cuts the cable, how do they do
that? Is there some sort of built in mechanism to cut it, do they use
manual cutters, or what?

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In article ,
Jud McCranie wrote:

We all know that the helicopter was unable to lift the water-filled
Liberty Bell 7 out of the ocean. But would it have been possible
for the helicopter to stay hooked on to LB7, even if it was under
water, and hold it until a ship could get close enough to attach a
line?

Well, the 'copter's own weight plus that of the capsule and water was
more than the 'copter could keep in the air. Just supporting the
capsule and water wouldn't take all that much less power than lifting it
slowly out. So unless the capsule reached neutral buoyancy somewhere
close to the surface, the answer is no. It would continue to sink,
pulling the 'copter into the water with it.

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net

On Fri, 24 Sep 2004 10:18:18 -0500, Herb Schaltegger
wrote:

Well, the 'copter's own weight plus that of the capsule and water was
more than the 'copter could keep in the air. Just supporting the
capsule and water wouldn't take all that much less power than lifting it
slowly out.

But if the capsule was submerged, the helicopter doesn't have to
support the weight of the water inside.

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Jud McCranie ) writes:
On Fri, 24 Sep 2004 10:18:18 -0500, Herb Schaltegger
wrote:

Well, the 'copter's own weight plus that of the capsule and water was
more than the 'copter could keep in the air. Just supporting the
capsule and water wouldn't take all that much less power than lifting it
slowly out.

But if the capsule was submerged, the helicopter doesn't have to
support the weight of the water inside.

You would be correct, *if* the capsule was submerged *and* now
neutrally boyant ( I can never spell that right ! ).

But, with the capsule trying to sink farther, it then takes power
from the helo to keep it from accomplishing that further sinking.

Had the capsule had, say, ballast tanks, such that it could hover
at a depth of, say, 15 feet, your comment would have merit.

But, trying to hang onto a *sinking* object, be it a small space
capsule or a large ship, is a recipe for joining the sinking
object under the seas.

Andre

--
" I'm a man... But, I can change... If I have to... I guess. "
The Man Prayer, Red Green.

In article ,
Jud McCranie writes:
We all know that the helicopter was unable to lift the water-filled
Liberty Bell 7 out of the ocean. But would it have been possible
for the helicopter to stay hooked on to LB7, even if it was under
water, and hold it until a ship could get close enough to attach a
line?

Maybe, maybe not - The Mercury capsule with its landing bag was
already at the limit of what an H-34/HUS-1 (The helicopter type
involved) could lift. While it may not require as much effort to keep
the capsule suspended under water as it would have to lift it, you'd
have to arrest the capsule's sinking, and maintain it. The engine on
the helicopter, a Wright R1820-84, was a pretty highly stressed beast
by that time in its life (The basic engine had grown from 750 HP in
the 1930s to more than 1500 HP in the late 1950s), and had a
reputation for coming apart if its limits were exceeded. They'd
already exceeded the Maximum pPower time limit of 5 minutes while
trying to keep the capsule at the surface, and the Chip Light, which
is an indicator that bits of metal are flaking away in the engine or
transmission, was illiminating. On a helicopter, Chip Lights are
serious - if the transmission fails, you don't even get teh chance to
autorotate - you plummet like a badly streamlined rock.
Since it was taking more than Maximum Power to maintiain their hover
with the capsule, and they'd reached the point where things were going
t break, reducing power wasn't going to help.

With a helicopter already attached to the capsule, it wouldn;t have
been possible to hook another helicopter on - they'd have fouled each
other's cables with their rotors. I don't think they could have been
able to get any sort of boat that could hold the capsule even under
water near it in time, either.

So, they were left with a choice - hang onto the capsule and lose
both the capule and the helicopter, and perhaps the helicopter crew,
or jettison the capsule. Either way, the capsule goes to the bottom.

Related question: when a helicopter cuts the cable, how do they do
that? Is there some sort of built in mechanism to cut it, do they use
manual cutters, or what?

There are several methods - an electrical solenoid at the hook end,
for normal releases, and an explosive-driven guillotine that's part of
the winch. They're activated by switches on the cyclic control stick.
When a helicopter has to drop a sling load, it needs to do so fast,
The usual problems are if a load starts swinging, or gets tangled up
in something. In any case, there isn't time to play games with bolt
cutters.


--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

On Fri, 24 Sep 2004 10:13:50 -0400, Jud McCranie wrote:

We all know that the helicopter was unable to lift the water-filled
Liberty Bell 7 out of the ocean. But would it have been possible for
the helicopter to stay hooked on to LB7, even if it was under water, and
hold it until a ship could get close enough to attach a line?





You are correct. They could have hovered holding onto the Liberty Bell
underwater. After the capsule sinks, it is going to weigh less by the
amount of water that it displaces. So, if the helicopter could have lifted
the empty capsule, it would have been much easier to hover with the
capsule underwater. The capsule was not going to pull the helicopter
under.

Craig Fink
Badnarik for President http://www.badnarik.org
http://www.metrowestdailynews.com/ar...rticleid=78317
Badnarik and others, coming to a PBS program near you! Sept 29th, or 30th.
Don't go to the polls as ignorant as CNN, MSNBC, FOXNEW,... would like you
to be.

On Fri, 24 Sep 2004 12:05:58 -0400, (Peter
Stickney) wrote:

So, they were left with a choice - hang onto the capsule and lose
both the capule and the helicopter, and perhaps the helicopter crew,
or jettison the capsule.

Well, at that point, with the helicopter already stressed by
attempting to lift the capsule plus water, they've obviously got to
let it go.

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"Craig Fink" wrote in message
news

You are correct. They could have hovered holding onto the Liberty Bell
underwater. After the capsule sinks, it is going to weigh less by the
amount of water that it displaces. So, if the helicopter could have lifted
the empty capsule, it would have been much easier to hover with the
capsule underwater. The capsule was not going to pull the helicopter
under.

File this under hearsay, but back when I was doing some aerial marine mammal
survey work, a pilot told me that they don't like to hover over water too
long as the spray builds up electrical charges or some such stuff.

Andre Lieven wrote:

Jud McCranie ) writes:
On Fri, 24 Sep 2004 10:18:18 -0500, Herb Schaltegger
wrote:

Well, the 'copter's own weight plus that of the capsule and water was
more than the 'copter could keep in the air. Just supporting the
capsule and water wouldn't take all that much less power than lifting it
slowly out.

But if the capsule was submerged, the helicopter doesn't have to
support the weight of the water inside.

You would be correct, *if* the capsule was submerged *and* now
neutrally boyant ( I can never spell that right ! ).

But, with the capsule trying to sink farther, it then takes power
from the helo to keep it from accomplishing that further sinking.

It would have been easier for the helicopter to hold the capsule underwater at
a set depth than to hover with it in the air. The effective weight of the
capusle underwater woudl be slightly less than in the air, due to the minimal
bouancy provided there compared to the virtually none provided in air.

On Fri, 24 Sep 2004 12:05:58 -0400, Peter Stickney wrote:

In article ,
Jud McCranie writes:
We all know that the helicopter was unable to lift the water-filled
Liberty Bell 7 out of the ocean. But would it have been possible for
the helicopter to stay hooked on to LB7, even if it was under water,
and hold it until a ship could get close enough to attach a line?

Maybe, maybe not - The Mercury capsule with its landing bag was already
at the limit of what an H-34/HUS-1 (The helicopter type involved) could
lift. While it may not require as much effort to keep the capsule
suspended under water as it would have to lift it, you'd have to arrest
the capsule's sinking, and maintain it. The engine on the helicopter, a
Wright R1820-84, was a pretty highly stressed beast by that time in its
life (The basic engine had grown from 750 HP in the 1930s to more than
1500 HP in the late 1950s), and had a reputation for coming apart if its
limits were exceeded. They'd already exceeded the Maximum pPower time
limit of 5 minutes while trying to keep the capsule at the surface, and
the Chip Light, which is an indicator that bits of metal are flaking
away in the engine or transmission, was illiminating. On a helicopter,
Chip Lights are serious - if the transmission fails, you don't even get
teh chance to autorotate - you plummet like a badly streamlined rock.
Since it was taking more than Maximum Power to maintiain their hover
with the capsule, and they'd reached the point where things were going t
break, reducing power wasn't going to help.



If they weren't at max power for more than 5 minutes trying to lift tons
of water, they wouldn't have broken the transmission. They could have
throttled back, let the capsule sink. The capsule underwater weights quite
a bit less than an empty capsule.

For example, aluminum has a specific gravity of 2.7, underwater it's going
to weight (2.7 - 1.03)/2.7 = .62 So, aluminum weight 38% less underwater.
It's not nearly as good for more dense metals, but I can imagine there
might have been empty tanks, and other things that hold air.

Craig Fink
Badnarik for President http://www.badnarik.org
http://www.metrowestdailynews.com/ar...rticleid=78317
Badnarik and others, coming to a PBS program near you! Sept 29th, or 30th.
Don't go to the polls as ignorant as CNN, MSNBC, FOXNEW,... would like you
to be.