Jet Effect FAQ
swe...@mailhost.tcs.tulane.edu
John McAdams wrote:
>
> On 2 Apr 1998 19:37:42 -0600, swe...@mailhost.tcs.tulane.edu wrote:
>
> >e-p...@usa.net wrote:
> >>
>
> >>
> >> Once the head ruptures matter pressurized by the bullet is expelled.
> >> Alvarez calls this expelled matter a jet.
> >
> >You have it essentially right. Alvarez's equations, as Snyder points out,
> >assume a bullet that has completely stopped in the head. This didn't
> >happen. He also used HUNTING AMMO. This is the single biggest
> >determining factor in producing a jet, according to Snyder. The only
> >person to have ever achieved the jet effect with FMJ ammo is Lattimer.
> >There have been a number of problems pointed to in Lattimer's work: his
> >skull simulant doesn't accurately reflect the weight of the human head, he
> >uses a ladder to brace his skulls and this ladder clearly moves with the
> >shot, his brain simulant isn't entirely justified-- paint.
>
> My recollection was that it was paint *mixed* with pig brains --
> although my copy of KENNEDY AND LINCOLN is at work.
>
> As for the ladder: what it does in *one* of the shots is tip forward,
> while the skull flies backward off the ladder.
>
> This makes a lot of sense. The bullet imparts some forward momentum
> to the skull and ladder, but then the jet effect rockets the skull
> backward off the ladder.
If you just said what I think you said then you are conceding that what
Lattimer demonstrated was a "billiard-ball" effect not a jet-effect, and
for that matter, something that COULDN'T have occured on November 22.
What do you think served the role of the ladder on that day, JFK's
collar bone?
>
> Kennedy's head, you will remember, moved forward between Z-312 and
> Z-313. Apparently, the bullet imparted a bit of forward momentum to
> his head, before the -- whatever -- caused him head to move "back and
> to the left."
Art Snyder has proved with computer simulations and Ron Hepler has
observed independently that some of the forward motion is due to an
optical illusion. Sturdivan wrote you a post over a year ago where he
says the exact same thing that Snyder does-- physically, a jet effect
would be faster than we see in the Z-film. Sturdivan added that
Lattimer makes assumptions about the relationship of the ejecta to the
exit wound that isn't consistent with the known facts. Do you want me
to cite this passage back to you?
>
> >Thus we are
> >not surprised to find that everyone else who has conducted independent
> >experiments to verify Lattimer's or before Lattimer has achieved different
> >results-- Doug DeSalles used melons that more closely reflected the weight
> >of the human skull; he couldn't get a jet effect. Art Snyder did his
> >experiments; he could only achieve a jet effect with hunting ammo. The
> >Army Wound Ballistics people also tried and never achieved jet effect.
> >But, as I will explain later on, EVEN if the jet effect is possible, there
> >are VERY GOOD reasons to believe it didn't happen in this case.
> >
> >
>
> It doesn't seem that hard to achieve.
>
> Richard Trott got it with melons:
>
> http://mcadams.posc.mu.edu/melon-sh.mpg
>
> http://mcadams.posc.mu.edu/melon2.mpg
>
> But irregardless of what happens with melons, the best experiments are
> Lattimer's who used a gun like Oswald's, ammo like Oswald's, and human
> skulls.
No. The best experiments were the ones using skulls, Oswald's gun and
ammo that were conducted by SEVERAL bona fide wound ballistics experts
for the government. They got different results from Lattimer-- why?
For that matter, why did everyone else. No jet effect without hunting
rounds.
>
> >> Does this prove LHO made the head shots?
> >>
> >> Certainly not. I believe it shows JFKs movement in 313 and following
> >> frames could be caused by a shot from the rear. The movement of JFK
> >> seen in the Z film does not prove a shot hit JFK from the front.
> >>
> >
> >Snyder, a physicist who specializes in this particular area of physics,
> >and Larry Sturdivan, a physicist AND wound ballistics expert, both AGREE
> >on one thing: the jet effect occurs too quickly to be what we see in the
> >Z-film. I can cite you passages from both.
> >
>
> Then if the "back and to the left" movement occurs too slowly to be a
> jet effect, doesn't it *also* occur too slowly to be the result of a
> bullet hitting JFK from the right front?
>
> >Sturdivan implies in some other posts that Lattimer's jet effect
> >experiments, as well as others, assume a relationship between the jet and
> >the exit wound that did NOT exist on November 22, 1963. EVEN LATTIMER,
> >who has done the only real replication of the phenomenon, using the actual
> >ammo, hangs his hat on a neuromuscular spasm-- not the jet effect.
> >
>
> Huh? In KENNEDY AND LINCOLN, he documents the jet effect, and also
> mentions a neuromuscular spasm. I don't see him coming down on either
> side.
>
> BTW, what is happening to JFK certainly looks to me more like a
> neuromuscular spasm than *either* a jet effect or a bullet hitting
> from the right front.
The HSCA proposed some things based on goat neurophysiology that are in
fact impossible in humans-- like super-quick decerebrate rigidity.
Much of the same problems come with postulating a human neuromuscular
reaction based on what you see with a goat. Mantik cites studies where
neuromuscular reactions are found to occur, almost always, either at the
time of death (1pm CST) or shortly thereafter in humans. Not only do
you not have such a delay here, you have a spasm occuring with
UNPRECEDENTED speed, close to an eyeblink.
>
> I have a neat little film clip showing this:
>
> http://mcadams.posc.mu.edu/goat.rm
>
> .John
e-p...@usa.net
A qualitative look at the jet effect process as it relates to JFK.
(mostly in response to Dave Wimp and Ron Hepler's questions)
1) How does the jet form?
The bullet carries a lot of energy. Only a small amount of this
energy directly pushes the head forward for the simple reason that
the skull breaks well before the bullet has given up all but a
fraction of it's energy. This is the cart and handle example.
The Alvarez equation for the % of the bullets KE that is converted
into forward momentum of the head, namely f = mass bullet/mass head.
The remainder of the energy (approximately 98% of the bullets KE)
goes into a number or sinks. The most obvious is the bullet itself
which exits the head (atleast some portion exits the head) and
carries off energy.
Another sink is the mass that is accelerated by the pressure pulse
of the bullet. I have posted a citation showing bullets can create
tremendous pressures inside the body - up to 3000 psi. If the head
were large enough or dense enough this pressure would be contained
as in a ballistic pendulum and simply deform the inside of the skull.
But heads don't always contain the pressure:
...In contrast to the effect in elastic tissue,
temporary cavitation can contribute substantially
to wounding of inelastic tissue, such as the brain.
This is the case in penetrating gunshot wounds to
the head.
Most important, wounding resulting from temporary
cavitation is greatly augmented by the confined space
provided by the unyielding walls of the skull. Bone
contact and enhanced effects of temporary cavitation
result in an enlarged zone of disintegrated tissue and
in high intracranial peak pressures.
Depending on ballistic and anatomical parameters, the
intracranial effect varies from slightly more severe
injury than in isolated soft tissue to an "explosive"
type of injury with comminuted fractures of the skull
and laceration of the brain.
International Journal of Legal Medicine 1995;108(2):53-61
Once the head ruptures matter pressurized by the bullet is expelled.
Alvarez calls this expelled matter a jet.
2) How does the jet move the head?
This one I believe everyone agrees on. Newtons 3rd law says the momentum
carried forwards out of the head by the jet must be matched by a backwards
momentum of the head. The cup filled with water example shows this on a
much safer scale than a home headshot experiment.
3) Have jets been seen and photographed?
I believe the Z film shows matter blown upwards and forwards
(2 o'clock to Mr. Z's position) from JFKs head. I understand alot
of CTers suspect the Z film has been edited, airbrushed or otherwise
faked.
The Alvarez paper shows 16 frames of a 24 frame/sec film of a melon
shot with a rifle bullet. A jet is blown out away from the shooter,
the melon then flies 2 or 3 feet away from the jet, towards the shooter.
Lattimer shot skulls filled with ballistic gelatine and filmed jets
away from the shooter and the skull moving towards the shooter. I have
not personally seen these photos/film.
Ron Hepler and Dave Wimp tell me Art Snyder has film of melons shot
by a rifle bullet, some of which show jets and move towards the shooter.
Some don't. Again I have not seen these photos/film and I know nothing
about the details of Snyders setup.
4) Do I believe this stuff?
Yes I do. I was a sceptic before I read the Alvareez paper and started
pushing the numbers around. Ron and Dave have asked me a number of
excellent questions that had me running back to the books to try and
answer. I have learned or relearned some good physics the past few weeks.
I have no doubt more questions will be raised by this post. I hope it
answered some.
Does this prove LHO made the head shots?
Certainly not. I believe it shows JFKs movement in 313 and following
frames could be caused by a shot from the rear. The movement of JFK
seen in the Z film does not prove a shot hit JFK from the front.
Elliot
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
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R.T.DeLoria
Elliot:
One aspect that you may have failed to consider is JFK head/neck can be
compared to an extremity such as an arm. Note that in frames 241-250 how
abruptly Connally's wrist reacts to the bullet striking it on the back
side. The wrist, hand and arm are torn from in front of his body as if a
rope were attached to it and pulled. The presidents head reacted in much
the same way.
As the bullet entered the skull and "caught" the bullet; his head and neck
were subsequently propelled violently backwards from the impact of the
shot. Had the president been struck from behind as the WC stated he would
have slumped immediately forward into his wife's lap.
Also; notice that when the force of the bullet ceased; the presidents
shoulders continued to fall backwards until his neck muscles suddenly
weakened, causing him slumped leftward toward his wife.
" a paradox of unanswered questions, habored in the annex of time..."
Robin
swe...@mailhost.tcs.tulane.edu
You have it essentially right. Alvarez's equations, as Snyder points out,
assume a bullet that has completely stopped in the head. This didn't
happen. He also used HUNTING AMMO. This is the single biggest
determining factor in producing a jet, according to Snyder. The only
person to have ever achieved the jet effect with FMJ ammo is Lattimer.
There have been a number of problems pointed to in Lattimer's work: his
skull simulant doesn't accurately reflect the weight of the human head, he
uses a ladder to brace his skulls and this ladder clearly moves with the
shot, his brain simulant isn't entirely justified-- paint. Thus we are
not surprised to find that everyone else who has conducted independent
experiments to verify Lattimer's or before Lattimer has achieved different
results-- Doug DeSalles used melons that more closely reflected the weight
of the human skull; he couldn't get a jet effect. Art Snyder did his
experiments; he could only achieve a jet effect with hunting ammo. The
Army Wound Ballistics people also tried and never achieved jet effect.
But, as I will explain later on, EVEN if the jet effect is possible, there
are VERY GOOD reasons to believe it didn't happen in this case.
>
Snyder, a physicist who specializes in this particular area of physics,
and Larry Sturdivan, a physicist AND wound ballistics expert, both AGREE
on one thing: the jet effect occurs too quickly to be what we see in the
Z-film. I can cite you passages from both.
Sturdivan implies in some other posts that Lattimer's jet effect
experiments, as well as others, assume a relationship between the jet and
the exit wound that did NOT exist on November 22, 1963. EVEN LATTIMER,
who has done the only real replication of the phenomenon, using the actual
ammo, hangs his hat on a neuromuscular spasm-- not the jet effect.
> Elliot
David Wimp
swe...@mailhost.tcs.tulane.edu wrote:
> You have it essentially right. Alvarez's equations, as Snyder points
> out,
> assume a bullet that has completely stopped in the head. ...
Would this mean that what is happening is better described as an
explosion? Any chance that what happens in watermelons is, in part,
caused by a steam blowout? Anybody try reinforcing the rind of the melon
to give it a strength closer to that of a skull?
--
Dave
Define thine enemy and speak for him!
John McAdams
On 2 Apr 1998 19:37:42 -0600, swe...@mailhost.tcs.tulane.edu wrote:
>e-p...@usa.net wrote:
>>
>>
>> Once the head ruptures matter pressurized by the bullet is expelled.
>> Alvarez calls this expelled matter a jet.
>
>You have it essentially right. Alvarez's equations, as Snyder points out,
>assume a bullet that has completely stopped in the head. This didn't
>happen. He also used HUNTING AMMO. This is the single biggest
>determining factor in producing a jet, according to Snyder. The only
>person to have ever achieved the jet effect with FMJ ammo is Lattimer.
>There have been a number of problems pointed to in Lattimer's work: his
>skull simulant doesn't accurately reflect the weight of the human head, he
>uses a ladder to brace his skulls and this ladder clearly moves with the
>shot, his brain simulant isn't entirely justified-- paint.
My recollection was that it was paint *mixed* with pig brains --
although my copy of KENNEDY AND LINCOLN is at work.
As for the ladder: what it does in *one* of the shots is tip forward,
while the skull flies backward off the ladder.
This makes a lot of sense. The bullet imparts some forward momentum
to the skull and ladder, but then the jet effect rockets the skull
backward off the ladder.
Kennedy's head, you will remember, moved forward between Z-312 and
Z-313. Apparently, the bullet imparted a bit of forward momentum to
his head, before the -- whatever -- caused him head to move "back and
to the left."
>Thus we are
>not surprised to find that everyone else who has conducted independent
>experiments to verify Lattimer's or before Lattimer has achieved different
>results-- Doug DeSalles used melons that more closely reflected the weight
>of the human skull; he couldn't get a jet effect. Art Snyder did his
>experiments; he could only achieve a jet effect with hunting ammo. The
>Army Wound Ballistics people also tried and never achieved jet effect.
>But, as I will explain later on, EVEN if the jet effect is possible, there
>are VERY GOOD reasons to believe it didn't happen in this case.
>
>
It doesn't seem that hard to achieve.
Richard Trott got it with melons:
http://mcadams.posc.mu.edu/melon-sh.mpg
http://mcadams.posc.mu.edu/melon2.mpg
But irregardless of what happens with melons, the best experiments are
Lattimer's who used a gun like Oswald's, ammo like Oswald's, and human
skulls.
>> Does this prove LHO made the head shots?
>>
>> Certainly not. I believe it shows JFKs movement in 313 and following
>> frames could be caused by a shot from the rear. The movement of JFK
>> seen in the Z film does not prove a shot hit JFK from the front.
>>
>
>Snyder, a physicist who specializes in this particular area of physics,
>and Larry Sturdivan, a physicist AND wound ballistics expert, both AGREE
>on one thing: the jet effect occurs too quickly to be what we see in the
>Z-film. I can cite you passages from both.
>
Then if the "back and to the left" movement occurs too slowly to be a
jet effect, doesn't it *also* occur too slowly to be the result of a
bullet hitting JFK from the right front?
>Sturdivan implies in some other posts that Lattimer's jet effect
>experiments, as well as others, assume a relationship between the jet and
>the exit wound that did NOT exist on November 22, 1963. EVEN LATTIMER,
>who has done the only real replication of the phenomenon, using the actual
>ammo, hangs his hat on a neuromuscular spasm-- not the jet effect.
>
Huh? In KENNEDY AND LINCOLN, he documents the jet effect, and also
mentions a neuromuscular spasm. I don't see him coming down on either
side.
BTW, what is happening to JFK certainly looks to me more like a
neuromuscular spasm than *either* a jet effect or a bullet hitting
from the right front.
I have a neat little film clip showing this:
http://mcadams.posc.mu.edu/goat.rm
.John
e-p...@usa.net
In article <35242F1B...@netheaven.com>,
del...@netheaven.com wrote:
>
> Elliot:
>
> One aspect that you may have failed to consider is JFK head/neck can be
> compared to an extremity such as an arm. Note that in frames 241-250 how
> abruptly Connally's wrist reacts to the bullet striking it on the back
> side. The wrist, hand and arm are torn from in front of his body as if a
> rope were attached to it and pulled. The presidents head reacted in much
> the same way.
>
> As the bullet entered the skull and "caught" the bullet; his head and neck
> were subsequently propelled violently backwards from the impact of the
> shot. Had the president been struck from behind as the WC stated he would
> have slumped immediately forward into his wife's lap.
>
> Also; notice that when the force of the bullet ceased; the presidents
> shoulders continued to fall backwards until his neck muscles suddenly
> weakened, causing him slumped leftward toward his wife.
>
> " a paradox of unanswered questions, habored in the annex of time..."
>
> Robin
Hi Robin,
I've tried to take the forward motion from the bullet and the backwards motion
from the jet into account. You might want to look at my original post "The
Alvarez Model of the Head Snap" for the details. You'll see not everyone
agrees with my position!
e-p...@usa.net
In article <3522A3...@mailhost.tcs.tulane.edu>,
swe...@mailhost.tcs.tulane.edu wrote:
>
> You have it essentially right. Alvarez's equations, as Snyder points out,
> assume a bullet that has completely stopped in the head. This didn't
> happen. He also used HUNTING AMMO. This is the single biggest
> determining factor in producing a jet, according to Snyder.
Melons are a lot softer then skulls. It makes sense to me you'd want a bullet
that could expand on impact in a melon the way a FMJ can expand on impacting a
skull.
> The only
> person to have ever achieved the jet effect with FMJ ammo is Lattimer.
> There have been a number of problems pointed to in Lattimer's work: his
> skull simulant doesn't accurately reflect the weight of the human head, he
> uses a ladder to brace his skulls and this ladder clearly moves with the
> shot, his brain simulant isn't entirely justified-- paint.
Does the ladder move in every shot that has the skulls moving?
> Thus we are
> not surprised to find that everyone else who has conducted independent
> experiments to verify Lattimer's or before Lattimer has achieved different
> results-- Doug DeSalles used melons that more closely reflected the weight
> of the human skull; he couldn't get a jet effect. Art Snyder did his
> experiments; he could only achieve a jet effect with hunting ammo.
As I said above it seems logical you might need a slightly different input to
a melon to get it to react like a skull. Did DeSalles use FMJs and hunting
rounds? Did he tape the melons to give them some elastic `skin'?
> The Army Wound Ballistics people also tried and never achieved jet effect.
Do you know where I can get the set up and results of these tests?
The momentum from the bullet and the momentum from the jet should be acting at
the same time shouldn't they? If the jet doesn't have time to move JFK back
and left how can the bullet?
The main reason I got into this whole subject were the CT posts claiming the
motion of JFK following 313 proves a shot from the front. If his reactions are
too quick to be a reaction to imparted momentum then this claim would be
baseless.
> Sturdivan implies in some other posts that Lattimer's jet effect
> experiments, as well as others, assume a relationship between the jet and
> the exit wound that did NOT exist on November 22, 1963. EVEN LATTIMER,
> who has done the only real replication of the phenomenon, using the actual
> ammo, hangs his hat on a neuromuscular spasm-- not the jet effect.
>
Can you be more specific regarding the relationship between the jet and exit
wound? I'm no Dr. but it seems to me every skull ruptured by a bullet is going
to be somewhat unique.
John McAdams
Anyone who wants to see this process can hit:
http://mcadams.posc.mu.edu/gel1.rm
http://mcadams.posc.mu.edu/gel2.rm
>Once the head ruptures matter pressurized by the bullet is expelled.
>Alvarez calls this expelled matter a jet.
>
>
>2) How does the jet move the head?
>
>This one I believe everyone agrees on. Newtons 3rd law says the momentum
>carried forwards out of the head by the jet must be matched by a backwards
>momentum of the head. The cup filled with water example shows this on a
>much safer scale than a home headshot experiment.
>
>
>3) Have jets been seen and photographed?
>
>I believe the Z film shows matter blown upwards and forwards
>(2 o'clock to Mr. Z's position) from JFKs head. I understand alot
>of CTers suspect the Z film has been edited, airbrushed or otherwise
>faked.
>
>The Alvarez paper shows 16 frames of a 24 frame/sec film of a melon
>shot with a rifle bullet. A jet is blown out away from the shooter,
>the melon then flies 2 or 3 feet away from the jet, towards the shooter.
>
>Lattimer shot skulls filled with ballistic gelatine and filmed jets
>away from the shooter and the skull moving towards the shooter. I have
>not personally seen these photos/film.
>
This look at this:
http://mcadams.posc.mu.edu/skull.rm
>Ron Hepler and Dave Wimp tell me Art Snyder has film of melons shot
>by a rifle bullet, some of which show jets and move towards the shooter.
>Some don't. Again I have not seen these photos/film and I know nothing
>about the details of Snyders setup.
>
>
>4) Do I believe this stuff?
>
>Yes I do. I was a sceptic before I read the Alvareez paper and started
>pushing the numbers around. Ron and Dave have asked me a number of
>excellent questions that had me running back to the books to try and
>answer. I have learned or relearned some good physics the past few weeks.
>I have no doubt more questions will be raised by this post. I hope it
>answered some.
>
>
>Does this prove LHO made the head shots?
>
>Certainly not. I believe it shows JFKs movement in 313 and following
>frames could be caused by a shot from the rear. The movement of JFK
>seen in the Z film does not prove a shot hit JFK from the front.
>
>
In fact, I think the "back and to the left" movement was more the
result of a neuromuscular spasm than a jet effect. See:
http://mcadams.posc.mu.edu/goat.rm
But the jet effect is real enough.
.John