Liberty Bell 7 attempted recovery

"Craig Fink" wrote in message
news
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.

That's a static analysis. What we're ignoring in the above analysis is the
effects of moving water (i.e. waves) on the capsule. It's entirely possible
that waves would make it far harder to "hold the capsule under water" than
the typical lay person (e.g. me) would think.

Anyone who's had experience in this area speak up. I've never personally
flown a helicopter while tethered to a large, metal object submerged several
feet in the ocean.

Jeff
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In message , 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?

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?


According to Tim Furniss's "Manned Spaceflight Log" the warning light
was actually a false alarm :-(
"Into Orbit" doesn't mention this, and I can't find any other
references.
Comments?
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Scott Lowther ) writes:
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.

This would be true, if the capsule were a neutrally bouant object,
at that depth, and had no inertail and mass inclination to sink any
deeper...

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.

Given that the helo holding Grissom's sinking capsule was seeing
no such reaction, but rather, was further sinking *along with
the sinking capsule*, this is proven wrong, by the events of that
afternoon.

What depth would you state was the natural bouant depth of a
Mercury capsule ?

Andre

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On Fri, 24 Sep 2004 14:19:53 -0400, Jeff Findley wrote:


"Craig Fink" wrote in message
news
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.

That's a static analysis. What we're ignoring in the above analysis is the
effects of moving water (i.e. waves) on the capsule. It's entirely possible
that waves would make it far harder to "hold the capsule under water" than
the typical lay person (e.g. me) would think.

Anyone who's had experience in this area speak up. I've never personally
flown a helicopter while tethered to a large, metal object submerged several
feet in the ocean.



The capsule actually sank just as they got it hooked to the helicopter.
Here's a picture with water gushing out of the hatch. So most of the water
came out, it's just the last bit that was below the opening that stayed
in the capsule.

http://grin.hq.nasa.gov/IMAGES/SMALL...002-000047.jpg

Craig Fink
Badnarik for President http://www.badnarik.org
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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.

The capsule actually sank just as they got it hooked to the
helicopter.
Here's a picture with water gushing out of the hatch. So most of the
water
came out, it's just the last bit that was below the opening that
stayed
in the capsule.

http://grin.hq.nasa.gov/IMAGES/SMALL...002-000047.jpg

Craig Fink

There was also a six foot wide, four foot high, landing bag full of
water attached to the bottom of Liberty Bell 7.


From "This New Ocean: A History of Project Mercury"

http://www.hq.nasa.gov/office/pao/Hi...201/ch11-8.htm

"As the first helicopter moved away from Grissom, it struggled
valiantly to raise the spacecraft high enough to drain the water from
the impact bag. Once the capsule was almost clear of the water, but
like an anchor it prevented the helicopter from moving forward. The
flooded Liberty Bell 7 weighed over 5,000 pounds, a thousand pounds
beyond the helicopter's lifting capacity. The pilot, watching his
insistent red warning light, decided not to chance losing two craft in
one day. He finally cast loose, allowing the spacecraft to sink
swiftly. Martin Byrnes, aboard the carrier, suggested that a marker be
placed at the point so that the capsule might be recovered later. Rear
Admiral J. E. Clark advised Byrnes that in that area the depth was
about 2,800 fathoms."



- Rusty Barton

On Fri, 24 Sep 2004 13:51:33 -0500, Michael Gardner
wrote:

The capsule would weight less submerged.

I would suspect the problem wasn't that it couldn't hold up the
submerged capsule - but the hazards of flying tethered. That capsule,
mostly underwater, would be one hell of a water anchor.

That's a very good point. The capsule under the water would not be
very mobile, which might make a dangerous situation for the 'copter.


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On 24 Sep 2004 12:31:12 -0700, (Rusty B)
wrote:

http://www.hq.nasa.gov/office/pao/Hi...201/ch11-8.htm
- Rusty Barton

You're always good with the links! Either you are very good at
finding them or you have a very good memory for where the appropriate
material is.

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From what Jim Lewis has told me, he had planned to simply drag the capsule
to the carrier keeping it submerged all the time (and have them attach a
line to it). He apparently felt he could do this. However, when he observed
the "chip warning light," he elected to jettison to spacecraft as that
indicated that his engine was going to fail.

C. Newport

I think I once estimated the submerged weight of Liberty Bell 7 at less than
1,600 lbs (it was about 2,300 lbs. in air in the landing configuration). I
did this on a flight from Washington to Colorado Springs, CO, with nothing
better to do..

C. Newport

has any effort been made to return and recover the hatch?
HAVE A GREAT DAY!