Minuteman ICBM reaches Mach 1 at 60-ft above launcher?

Pat Flannery wrote:

Rand Simberg wrote:

Seems dubious to me. Unless I screwed up the calculation, that means
over 300 g acceleration (zero to 760 mph in sixty feet). I'm pretty
sure its liftoff T/W is nowhere near that...



The only one I can think of that would do that is the Sprint ABM.

HiBex could possibly pull it off, but not Sprint. Sprint was pokey
compared to HiBex.

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On or about Thu, 23 Oct 2003 04:21:49 GMT, James Oberg
made the sensational claim that:
It's an unladen AFRICAN swallow-foot.

Yes, but is it made of wood?

(Believe it or not, this is the second time tonight I've had to use that line.)
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LooseChanj wrote:

Yes, but is it made of wood?

(Believe it or not, this is the second time tonight I've had to use that line.)



The first was in relation to a drunken proposal to a woman dressed as
Lady Penelope at a Thunderbirds fan convention.
Tomorrow morning, you may use it again...assuming that it doesn't have
slivers in it.

Pat

"James Oberg" wrote in message .. .
It's an unladen AFRICAN swallow-foot.

Now, if we were talking about the European swallow-foot ...the numbers
would make sense!

(...sorry!)




"Mary Pegg" wrote in message
news
James Oberg wrote:

If S = 0.5 a t**2,
and V = at,

Then since S = 55 ft,

Is that the Babylonian foot or the Roman foot?


[ducks and runs]

h (Rand Simberg) wrote in message . ..
On 22 Oct 2003 10:30:13 -0700, in a place far, far away,
(Rusty B) made the phosphor on my monitor glow
in such a way as to indicate that:

I found a web page on Edwards Air Force Base website that describes
early captive silo test launches of the Minuteman ICBM.

In the article it is claimed that, "a Minuteman passes through Mach
1.0 by the time it travels its own length above the launcher."

A Minuteman I is 55.9-ft tall, A Minuteman III is 59.75-ft tall.

Can anyone verify this claim?

Seems dubious to me. Unless I screwed up the calculation, that means
over 300 g acceleration (zero to 760 mph in sixty feet). I'm pretty
sure its liftoff T/W is nowhere near that...

I did a little bit of digging: (Encyclopedia Astronautica)

Minuteman II & III liftoff thrust 210,000-lbs

Minuteman II weight - 73,000-lbs

Minuteman III weight - 78,000-lbs

I found a performance profile for the Minotaur rocket, which is made up
of the 1st and 2nd stages of the Minuteman II ICBM.

Minotaur Users Guide and Fact Sheet:

http://www.orbital.com/NewsInfo/Publ...taur_Guide.pdf

http://www.losangeles.af.mil/SMC/PA/...inotaur_fs.htm


Minotaur lift-off thrust 200,435-lbs

Minotaur weight - 67,000-lbs


For the Minotaur, 1st stage burn-out is at 61.3-seconds, velocity is 4,954-fps
(3,377.7-mph). That makes the average acceleration over the duration of
the burn 55.1-mph per second for 61.3-seconds. (Page 18 of Users Guide).

I know the rocket will accelerate more slowly at liftoff with a full fuel
load and quicker near burnout with most of the fuel load gone.

My guess is, coming out of the silo, the Minuteman is going 50 - 100-mph.

There may be some extra acceleration from the exhaust gases pushing
the missile out of the silo, but I don't think that would add 600-mph
to the velocity.


--
Rusty Barton - Antelope, California |
E-mail - |
Visit my Minuteman ICBM website at: |
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On 23 Oct 2003 13:45:39 -0700, in a place far, far away,
(Rusty B) made the phosphor on my monitor glow
in such a way as to indicate that:


Minotaur lift-off thrust 200,435-lbs

Minotaur weight - 67,000-lbs


For the Minotaur, 1st stage burn-out is at 61.3-seconds, velocity is 4,954-fps
(3,377.7-mph). That makes the average acceleration over the duration of
the burn 55.1-mph per second for 61.3-seconds. (Page 18 of Users Guide).

I know the rocket will accelerate more slowly at liftoff with a full fuel
load and quicker near burnout with most of the fuel load gone.

My guess is, coming out of the silo, the Minuteman is going 50 - 100-mph.

Yup. At two gs, and sixty feet, it would be doing almost the freeway
speed limit--60 mph.

--
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On Thu, 23 Oct 2003 05:46:04 GMT, Scott Lowther
wrote:

Pat Flannery wrote:

Rand Simberg wrote:

Seems dubious to me. Unless I screwed up the calculation, that means
over 300 g acceleration (zero to 760 mph in sixty feet). I'm pretty
sure its liftoff T/W is nowhere near that...



The only one I can think of that would do that is the Sprint ABM.

HiBex could possibly pull it off, but not Sprint. Sprint was pokey
compared to HiBex.


Sprint accelerated at 100 Gs, HiBex at 400 and HEDI at 200. There is
a video clip on the DVD Nukes In Space taken from a distance of a
Sprint launch and that thing is MOVING.

On 22 Oct 2003 16:52:39 -0700, in a place far, far away,
(R Neutron) made the phosphor on my monitor glow in
such a way as to indicate that:

I've heard similar claims about the shuttle, although not near as much
accelaration, I recall on occasion hearing 100 mph as it clears the
tower does anybody an accurate figure on this?

That actually sounds pretty accurate. It's just not very precise...

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
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On Thu, 23 Oct 2003 17:43:31 -0600, Scott Ferrin
wrote:

On Thu, 23 Oct 2003 05:46:04 GMT, Scott Lowther
wrote:

Pat Flannery wrote:

Rand Simberg wrote:

Seems dubious to me. Unless I screwed up the calculation, that means
over 300 g acceleration (zero to 760 mph in sixty feet). I'm pretty
sure its liftoff T/W is nowhere near that...



The only one I can think of that would do that is the Sprint ABM.

HiBex could possibly pull it off, but not Sprint. Sprint was pokey
compared to HiBex.


Sprint accelerated at 100 Gs, HiBex at 400 and HEDI at 200. There is
a video clip on the DVD Nukes In Space taken from a distance of a
Sprint launch and that thing is MOVING.

I looked up the stats for Sprint and Minuteman III.

http://www.paineless.id.au/missiles/Sprint.html

http://www.fas.org/nuke/guide/usa/icbm/lgm-30_3.htm


-Sprint takeoff weight 16,500-lbs.

-Sprint takeoff thrust 660,000-lbs - thrust to weight ratio 40 to 1.


-Minuteman III takeoff weight - 79,400-lbs.

-Minuteman III takeoff thrust 202,600-lbs - thrust to weight ratio
2.55 to 1.



--
Rusty Barton - Antelope, California |
E-mail - |
Visit my Minuteman ICBM website at: |
http://www.geocities.com/minuteman_missile |

On Thu, 23 Oct 2003 05:46:04 GMT, in a place far, far away, Scott
Lowther made the phosphor on
my monitor glow in such a way as to indicate that:

Pat Flannery wrote:

Rand Simberg wrote:

Seems dubious to me. Unless I screwed up the calculation, that means
over 300 g acceleration (zero to 760 mph in sixty feet). I'm pretty
sure its liftoff T/W is nowhere near that...



The only one I can think of that would do that is the Sprint ABM.

HiBex could possibly pull it off

Probably not. Too short...

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers: