Falcon 9 +SRB

On 6/8/2010 12:53 AM, Jochem Huhmann wrote:


What's odd is that someone hasn't realized that maybe one or only a few
turbopumps feeding multiple combustion chambers could both up
reliability and decrease overall weight, in much the way the
four-chambered Soviet RD-107/RD-108 engines and the twin-chambered
Titan1/II LR-87 engines worked.

But then a failing turbopump would take out more than one chamber. And a
layout with multiple engines that can't survive one failing turbopump is
the worst of all layouts. You'd be better off with one giant engine then.

That would be the idea, yes.
...or at least one big turbopump feeding all nine combustion chambers.


Unless there is going to be some big future demand for Falcon-1 boosters
with their single Merlin engines, SpaceX might want to look into that
concept also, as it might also cut overall engine cost for amount of
thrust generated.

OTOH if you still need to build smaller engines and turbopumps for the
second stage anyway, keeping two production lines producing smaller
numbers of different engines and turbopumps may be just more expensive
than having only one building large numbers.

Anyway, I think the Falcon 9 using exactly one kind of engine and one
tank diametre and the same domes in both stages is quite an elegant
design. Might be the easiest way to get into something like
mass-production for individual parts for something built in such small
numbers as launchers. Manufacturing larger numbers of the same parts
*must* be cheaper.

They seem to be going that route.
What's fascinating is that you could bundle up to _seven_ Falcon 9
booster modules into one massive first stage and stick a really large
second stage atop that using several Vacuum Merlins for power. That
would mean the first stage was powered by _sixty-three_ engines, and
resemble something like the first stage of the von Braun Ferry Rockets
as far as total number of engines goes.

Pat

Jochem

In article , jrfrank@ibm-
pc.borg says...

On 06/07/2010 09:54 PM, Alan Erskine wrote:
On 8/06/2010 1:57 AM, Frogwatch wrote:
SpaceX shows a falcon 9 heavy consisting of three identical falcon 9
segments. Of course, this is 27 engines. Would it be more reliable
to use the falcon 9 as a core and shuttle SRB strap ons?
Next, what are the plans for the payload of this falcon 9 that is in
orbit? Do they plan to de-orbit it to test the landing?

No, it would be less reliable as the SRB is a very (VERY) bad thing.
It's said that 50% of all shuttle crews can't read the instrument panel
whilst the SRB's are burning. That's due to vibration and that's
potentially fatal.

It's also said that 84.5% of all statistics are made up on the spot.

It would be interesting to find out if Alan's assertion has any truth
behind it. How about it Alan, care to back up your assertion with a
cite?

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?

Pat Flannery writes:

What's fascinating is that you could bundle up to _seven_ Falcon 9
booster modules into one massive first stage and stick a really large
second stage atop that using several Vacuum Merlins for power. That
would mean the first stage was powered by _sixty-three_ engines, and
resemble something like the first stage of the von Braun Ferry Rockets
as far as total number of engines goes.

Seems possible and very likely easier/cheaper to build (and test!) than
a similar sized first stage in one huge module. They should definitely
get a grip on that recovery problem then though ;-)


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

Pat Flannery wrote:

What's fascinating is that you could bundle up to _seven_ Falcon 9
booster modules into one massive first stage and stick a really
large second stage atop that using several Vacuum Merlins for
power. That would mean the first stage was powered by _sixty-three_
engines, and resemble something like the first stage of the von
Braun Ferry Rockets as far as total number of engines goes.

They would have to make sure they allocated at least 6 bits to
enumerate the first stage engine numbers in the flight control
software. Right now they can get by with just 5 since max engine
count is 27. It can be fascinating when trying to find room for just
one more bit

rick
--
firebug n, the idiot who tosses a lit cigarette out his car window
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

Pat Flannery wrote:

What's fascinating is that you could bundle up to _seven_ Falcon 9
booster modules into one massive first stage

Just curious here. Is there really a fundamental reason why seven
would be the maximum? If you have seven, I imagine that would be
a central booster surrounded by six, why could you not add two more,
is it necessary that they all be in direct contact with a central
booster? Not that I think that a Falcon 9x9 would be something sane
to do. I don't really consider a Falcon 9x7 to be sane, but if you
are going to do insane launchers why stop there?


Alain Fournier

On 6/8/2010 6:25 AM, Jeff Findley wrote:

The scary thing about those Aerojet SRB's is the amount of vibration
they produced. I'm not sure you'd ever be able to safely put people on
top of such a beast. These SRB's make the shuttle SRB's look like toys.

Wasn't this the test where the exhaust products took all the paint off
of the cars they settled on?

Pat

Pat Flannery writes:

Want to see something oddball?
This was Chelomei's UR-700 competitor for the N-1 Soviet moon rocket:
http://www.astronautix.com/lvs/ur700.htm
The individual engine/propellant tank modules were designed to be the
maximum size that could travel on the Soviet rail system (the N-1 had to
be built right at the launch site).
If that wasn't enough fun, there was also the UR-900 design for
launching manned Mars expeditions:
http://www.astronautix.com/lvs/ur900.htm

And if you want to see something even more oddball look at that concept
of a launcher consisting of bundles of extremely simple (pressure-fed)
modules, each with its own engine and about 0.27 m (10") across:
http://www.astronautix.com/lvs/otrag.htm

The smallest launcher (1 tonne LEO payload) would have had 48 of these
modules in the first stage...

Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

On 6/8/2010 5:38 PM, Alain Fournier wrote:
Pat Flannery wrote:

What's fascinating is that you could bundle up to _seven_ Falcon 9
booster modules into one massive first stage

Just curious here. Is there really a fundamental reason why seven
would be the maximum? If you have seven, I imagine that would be
a central booster surrounded by six, why could you not add two more,

If you take seven coins of identical diameter you will see that six of
them will neatly fit around the seventh at their center.
This keeps the assembly basically circular in shape, making it easier to
mount a second stage atop it.
Of course you could go with other arrangements, but it wouldn't be as
aerodynamic or compact.

is it necessary that they all be in direct contact with a central
booster?
Not that I think that a Falcon 9x9 would be something sane
to do. I don't really consider a Falcon 9x7 to be sane, but if you
are going to do insane launchers why stop there?

Want to see something oddball?
This was Chelomei's UR-700 competitor for the N-1 Soviet moon rocket:
http://www.astronautix.com/lvs/ur700.htm
The individual engine/propellant tank modules were designed to be the
maximum size that could travel on the Soviet rail system (the N-1 had to
be built right at the launch site).
If that wasn't enough fun, there was also the UR-900 design for
launching manned Mars expeditions:
http://www.astronautix.com/lvs/ur900.htm

Pat

On 9/06/2010 12:38 AM, Jeff Findley wrote:
In articleA9qdneQHMJFxKpDRnZ2dnUVZ_hKdnZ2d@giganews. com, jrfrank@ibm-
pc.borg says...

On 06/07/2010 09:54 PM, Alan Erskine wrote:
On 8/06/2010 1:57 AM, Frogwatch wrote:
SpaceX shows a falcon 9 heavy consisting of three identical falcon 9
segments. Of course, this is 27 engines. Would it be more reliable
to use the falcon 9 as a core and shuttle SRB strap ons?
Next, what are the plans for the payload of this falcon 9 that is in
orbit? Do they plan to de-orbit it to test the landing?

No, it would be less reliable as the SRB is a very (VERY) bad thing.
It's said that 50% of all shuttle crews can't read the instrument panel
whilst the SRB's are burning. That's due to vibration and that's
potentially fatal.

It's also said that 84.5% of all statistics are made up on the spot.

It would be interesting to find out if Alan's assertion has any truth
behind it. How about it Alan, care to back up your assertion with a
cite?

Jeff

Well.... it wasn't an assertion; it's "been said" - I don't remember who
said it.

However, look at all the vibration-absorbing systems needed by Orion.
That was because of the SRB problems.

On 9/06/2010 12:38 AM, Jeff Findley wrote:

It would be interesting to find out if Alan's assertion has any truth
behind it. How about it Alan, care to back up your assertion with a
cite?

Jeff

There's a more practical reason for not using the SRB - it's 40-year-old
technology.