SpaceX (general discussion)

publiusr said:
Replace those four?

Were they in the same position as the ones that failed previously?

Maybe some kind of back pressure flow artifact at certain locations?

Or just bad engines?
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For me it’s a fact that firing so many of these new engines at the same time in such a close space is still a relatively new thing.
 
what a View
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View: https://www.youtube.com/watch?v=EZA-4_0D-W8
 
Something else I was thinking about.
Each Raptor has the same chirality, right?

Often--in automotive design--- if one pipe curls around part of the engine...it's mate on the other side has a corresponding bend as well to even flow out.

Alternating engine designs may be in order such as to even out flow?

With respect to the deluge plate.
The flower pattern seems to allow a "bald spot" at the center.

Might it be wise to have jets from the east end of the plate shoot westwards... and jets to the west aim eastwards...so that a grid is laid down?

A part of me thinks the current lay-outs might allow the plate to pop up...I'm probably wrong there.


Thoughts?
 
publiusr said:
Something else I was thinking about.
Each Raptor has the same chirality, right?

Often--in automotive design--- if one pipe curls around part of the engine...it's mate on the other side has a corresponding bend as well to even flow out.

Alternating engine designs may be in order such as to even out flow?

With respect to the deluge plate.
The flower pattern seems to allow a "bald spot" at the center.

Might it be wise to have jets from the east end of the plate shoot westwards... and jets to the west aim eastwards...so that a grid is laid down?

A part of me thinks the current lay-outs might allow the plate to pop up...I'm probably wrong there.


Thoughts?
Click to expand...
If you look at the engine layout there isn't an engine in the middle. (I wondered about the "bald spot" as well.)
 
Flyaway said:
For me it’s a fact that firing so many of these new engines at the same time in such a close space is still a relatively new thing.
Click to expand...
That doesn't seem a problem with Falcon Heavy...though that is broken in a line of threes.

Kerosene is much heavier than LOX..
and LOX...and that heavier than LH2.

LOX and liquid methane are a bit more on equal terms...might that explain recent methalox engine troubles across the board?

Perhaps the heavier of two propellants can help flow if it is much more dominant?

It might be interesting to do a program where you have two flows combine and by turning a dial...adjust the density of either two streams... and see what happens per pipe size.
 
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Flyaway said:
For me it’s a fact that firing so many of these new engines at the same time in such a close space is still a relatively new thing.
Click to expand...
Well, I think the Soviet N1 rocket had the same to some extent, and that had problems too.
 
publiusr said:
That doesn't seem a problem with Falcon Heavy...though that is broken in a line of threes.

Kerosene is much heavier than LOX..
and LOX...and that heavier than LH2.

LOX and liquid methane are a bit more on equal terms...might that explain recent methalox engine troubles across the board?

Perhaps the heavier of two propellants can help flow if it is much more dominant?

It might be interesting to do a program where you have two flows combine and by turning a dial...adjust the density of either two streams... and see what happens per pipe size.
Click to expand...
China recently reached orbit with a rocket using methalox engines.
spacenews.com

China’s Landspace reaches orbit with methane-powered Zhuque-2 rocket

China’s Landspace reaches orbit with methane-powered Zhuque-2 rocket Chinese private rocket firm Landspace achieved a global first late Tuesday by reaching orbit with a methane-fueled rocket.
spacenews.com spacenews.com

I am sure it has nothing to do with plumbing, or with mixing two streams of different density.
The LOX and LNG are not mixed in piping. The different molecules don't meet each other until they are in the combustion chamber at 300 bar and 3000 K (or whatever the exact conditions in a Raptor are).

During the test the water deluge system was turned on about 5 seconds before the engines were started. By that time all engines much have contained a lot of deluge water, some engines more than others.
Perhaps some engines had too much water in the combustion chamber and therefor did not ignite properly.
Just another possibility to consider.
 
publiusr said:
LOX and liquid methane are a bit more on equal terms...might that explain recent methalox engine troubles across the board?

Perhaps the heavier of two propellants can help flow if it is much more dominant?

It might be interesting to do a program where you have two flows combine and by turning a dial...adjust the density of either two streams... and see what happens per pipe size.
Click to expand...
Uhm, what?
 
I hadn't considered deluge water impingement...silly me thought that..maybe engines liked a count that added up to a prime, or something.

I always look out for that odd element...
 
https://twitter.com/x/status/1691546890318352385
View: https://twitter.com/jackkuhr/status/1691546890318352385


Just in: SpaceX has filed its final mishap investigation report to the FAA for its April 20 Starship flight test

The review is ongoing, the FAA told Payload today
Click to expand...

payloadspace.com

SpaceX Files its Starship Mishap Report to the FAA

SpaceX has filed a final mishap investigation report to the FAA for its April 20 Starship integrated flight test, the FAA told Payload on Tuesday. Submitting the report is an important regulatory step toward SpaceX launching Starship on its second orbital test flight, a milestone that will...
payloadspace.com payloadspace.com
 
Updates
SpaceX filed Testing for 31 August 2023, maybe second Launch Attempt ???
Next road closure also Coast Guard blocking launch corridor in Gulf of Mexico

The Productions tens are going down and Midbay is clean out - preparation for demolition ?
https://twitter.com/x/status/1691981094772466165
View: https://twitter.com/NASASpaceflight/status/1691981094772466165


The Hot staging Adapter is move to Booster 9
https://twitter.com/x/status/1692005802863632683
View: https://twitter.com/CSI_Starbase/status/1692005802863632683


Another large tank is deliver to the launch site
https://twitter.com/x/status/1689457063687073793
View: https://twitter.com/NASASpaceflight/status/1689457063687073793


https://twitter.com/x/status/1692270169261818238
View: https://twitter.com/CSI_Starbase/status/1692270169261818238
 
publiusr said:
That doesn't seem a problem with Falcon Heavy...though that is broken in a line of threes.

Kerosene is much heavier than LOX..
and LOX...and that heavier than LH2.
Click to expand...
No. LOX is heavier than water and kerosene floats on water. This is basic layman rocket science knowledge. Jesse, no wonder your posts don't make sense.

Methane is cryogenic and nothing like kerosene. Merlin is a gas generator cycle and Raptor is full-flow staged combustion
 
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On National Geographic channel I often watch "Massive Engineering Mistakes". In that series there have been several situations in which bridges and other structures collapsed because the geniuses that designed them did not use triangular bracing.

Now I see some geniuses at SpaceX make the same mistake, although they only had to look at the good old Vostok rocket (Gagarin's rocket) to see how it should be done. The Soyuz and Proton rockets still have it today.
 
Dagger said:
Now I see some geniuses at SpaceX make the same mistake, although they only had to look at the good old Vostok rocket (Gagarin's rocket) to see how it should be done.
Click to expand...

The Titan II, III and IV didn't use triangular bracing in their S1/S2 interstages and they worked just fine.
 
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Dagger said:
On National Geographic channel I often watch "Massive Engineering Mistakes". In that series there have been several situations in which bridges and other structures collapsed because the geniuses that designed them did not use triangular bracing.

Now I see some geniuses at SpaceX make the same mistake, although they only had to look at the good old Vostok rocket (Gagarin's rocket) to see how it should be done. The Soyuz and Proton rockets still have it today.
Click to expand...
Why don't aircraft fall out of the sky? They don't use "triangular bracing".
 
NMaude said:
The Titan II, III and IV didn't use triangular bracing in their S1/S2 interstages and they worked just fine.
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They had vertical bars for only half of the circumference. The other half of the circumference was solid plate and therefor not susceptible to collapse by lateral force.

Moreover the Titan rocket was not intended to be used over and over and over again like the booster of Starship.

sferrin said:
Why don't aircraft fall out of the sky? They don't use "triangular bracing".
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Look at how very old (especially pre-WW1) planes were constructed. They had triangular braces, or bracing by a lot of wires, to resist lateral forces. Later planes completely manufactured from metal sheets obviously don't need that.
Look also at the tail of an Alouette II helicopter, and others.

I expect that SpaceX will receive many comments on that design and will change this before Starship will be used for humans.
 
Michel Van said:
how small we humans are
F31cK_SWwAAjJmA
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With all those startups that produce nothing more than cgi (cheap one, by the way), it's good to see the good old American worker doing what his elders proudly did with the Empire state building 100 years ago: leading the way to a new industrial age.

Behold Eon and his minions!
 
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Now Dagger has a lot to be proud of.
Semyorka having come strap-ons burned on the pad for a long time without collapsing back in...1983 was it?

I might want a scaled up Proton/Saturn IB RLV with landing legs between the tanks.
 
Byeman said:
No. LOX is heavier than water and kerosene floats on water. This is basic layman rocket science knowledge. Jesse, no wonder your posts don't make sense.

Methane is cryogenic and nothing kerosene. Merlin is a gas generator cycle and Raptor is full-flow staged combustion
Click to expand...
That's fair...in retrospect--if the difference in weight were an issue---then it would likely show itself in individual Raptor tests.

But they don't seem to do well in groups.

Water hammer...a hostile acoustic environment then?
 
publiusr said:
Now Dagger has a lot to be proud of.
Semyorka having come strap-ons burned on the pad for a long time without collapsing back in...1983 was it?

I might want a scaled up Proton/Saturn IB RLV with landing legs between the tanks.
Click to expand...
Unworkable. And no need to to use old out dated designs as a basis.
 
Dagger said:
On National Geographic channel I often watch "Massive Engineering Mistakes". In that series there have been several situations in which bridges and other structures collapsed because the geniuses that designed them did not use triangular bracing.
Click to expand...
The Saturn V had no triangular bracing in interstage despite build from Alumium alloy
because most of it load is vertical, either mass of upper stage vs thrust of engine
and Starship is build from more stronger Steel !
img109.jpg


and Saturn V flew perfect.
View: https://www.youtube.com/watch?v=46BW5IfshCE
 
Byeman said:
Unworkable. And no need to to use old out dated designs as a basis.
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Different doesn’t mean outdated. By having legs between the tanks..there is less likelihood of them stoving the tanks in…as the tanks would not “feel” the legs.
 
Several forum members completely miss the point, although this is very basic stuff and should be known to every engineer.

When supporting a heavy load on an open structure with only vertical struts (like SpaceX is now trying to do) such structure is very sensitive to lateral forces. It does not take much to make it collapse sideways.
Such open structure needs triangular or diagonal bracing. Without sufficient triangles it will sooner or later collapse.
A rocket is subject to a lot of vibration and dynamic forces, especially around Max Q. Moreover it flies at an angle. Lateral forces due to slight movement of upper stage relative to booster are inevitable. The slightest twist could collapse the open structure.

The example of the Saturn V (and other US rockets) is not relevant as there the metal covers prevent sideways motion of the vertical struts.

In an open structure like Starship booster, Soyuz and Proton have, sufficient triangles must be included.
It has nothing to do with vertical strength of the struts or the metal used. People knew that already in the middle ages.

A quick fix of the present simplistic SpaceX design would be to add sufficient diagonal braces to create sufficient triangles. Before using this rocket for humans however a redesign should be considered.
I hope that somehow this messages gets through to Elon.
 
Dagger said:
Several forum members completely miss the point, although this is very basic stuff and should be known to every engineer.

When supporting a heavy load on an open structure with only vertical struts (like SpaceX is now trying to do) such structure is very sensitive to lateral forces.
Click to expand...
Look at the structure as a whole instead of individual elements.
 
Dagger said:
When supporting a heavy load on an open structure with only vertical struts (like SpaceX is now trying to do) such structure is very sensitive to lateral forces. It does not take much to make it collapse sideways.
Click to expand...
It doesn't have only vertical struts. there is an "X" riveted here and in five other places.
 

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Hi there,

Lots of answers and useful comments on hot staging and interstage structures on US and Soviet rockets including Titan, Soyuz, N1, on this quora link.
www.quora.com

Why did the Soviet N1 Moon rocket have sections that were exposed truss and not a solid skin?

Answer (1 of 4): The exposed trusses was a part of the interstage section between stages of the rocket. The Soviets/Russians and the US Western countries use two different methods to overcome the issue of ullage in the fuel tanks of liquid fueled rockets. The problem is that a rocket not under ...
www.quora.com www.quora.com

Hope this helps

A.
 
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publiusr said:
Different doesn’t mean outdated. By having legs between the tanks..there is less likelihood of them stoving the tanks in…as the tanks would not “feel” the legs.
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they are outdated and inefficient. Building 9 tanks where one will do the job,
There is no other hardware but tanks.The legs would have to still attach to tanks and the tanks would "feel" them.
There is no need to worry about stoving in the tanks, there have been over 100 landings.
 

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