Author Topic: F9 Block 5 Updates and Discussion  (Read 325255 times)

Offline TripleSeven

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Re: F9 Block 5 Updates and Discussion
« Reply #980 on: 07/29/2018 01:10 am »
B777's engines...which had been tested to near exhaustion but compressor stalled on the first flight. 


Wow.   What caused them to work on the ground and yet fail on the first flight?   

Seems to prove that ground testing is great, but flight testing is a must.

my point exactly...you can do all the ground testing you want to do the CFD etc...but in the end you have to fly.  the difference? in this case it was the modeling of the airflow over the fuselage with high lift devices on the wing and certain angles of attack, the solution was to immediately lower the AOA...that is why Boeing has great test pilots  (self serving compliment)  good night

Online meekGee

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Re: F9 Block 5 Updates and Discussion
« Reply #981 on: 07/29/2018 05:11 am »
B777's engines...which had been tested to near exhaustion but compressor stalled on the first flight. 


Wow.   What caused them to work on the ground and yet fail on the first flight?   

Seems to prove that ground testing is great, but flight testing is a must.

my point exactly...you can do all the ground testing you want to do the CFD etc...but in the end you have to fly.  the difference? in this case it was the modeling of the airflow over the fuselage with high lift devices on the wing and certain angles of attack, the solution was to immediately lower the AOA...that is why Boeing has great test pilots  (self serving compliment)  good night
Yup - but also shows that this issue was not about insufficient margins...  Margins don't necessary save you from design mistakes.  They are designed to comoensate for small residual uncertainties in A) load conditions and B) material properties.

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Offline speedevil

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Re: F9 Block 5 Updates and Discussion
« Reply #982 on: 07/29/2018 12:44 pm »
my point exactly...you can do all the ground testing you want to do the CFD etc...but in the end you have to fly.  the difference? in this case it was the modeling of the airflow over the fuselage with high lift devices on the wing and certain angles of attack, the solution was to immediately lower the AOA...that is why Boeing has great test pilots  (self serving compliment)  good night
Shuttle first flight had an anomaly driven by misprediction of reentry aerodynamics that if it had been of a similar magnitude in another direction could have caused loss of vehicle.
Solution for the next few flights was to hand-fly that portion, till the autopilot was taught the true value.

Offline IainMcClatchie

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Re: F9 Block 5 Updates and Discussion
« Reply #983 on: 07/29/2018 07:36 pm »
Well now that's pretty interesting.  Was this something to do with the wings being stalled at high AoA during initial reentry, and the circulation behind the wings having some sort of interaction with the tail?

Online Chris Bergin

Re: F9 Block 5 Updates and Discussion
« Reply #984 on: 07/29/2018 08:37 pm »
Back on topic guys (per report to mod alerts it's wandering).

All following posts will be about Block 5 of we'll have to trim it back. If you want to go off on a tangent, start a new thread, quote the post in question and respond to it there.

Online FutureSpaceTourist

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Re: F9 Block 5 Updates and Discussion
« Reply #985 on: 07/29/2018 10:15 pm »
Cross-posting as this seems best place for follow-up discussion:

This headline is accurate, some examples attached:

Quote
SpaceX Falcon 9 Block 5 rocketís drone ship return captured in stunning detail

By Eric Ralph
Posted on July 29, 2018

Teslarati photographer Pauline Acalin has captured SpaceXís first Falcon 9 Block 5 booster recovery in the best detail yet seen of the rocket upgrade, well-worn after its first successful launch of Iridium NEXT-7, July 25.

https://www.teslarati.com/spacex-falcon-9-block-5-rocket-droneship-photo-gallery/

Offline RotoSequence

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Re: F9 Block 5 Updates and Discussion
« Reply #986 on: 07/29/2018 11:09 pm »
Lots of little curiosities on the Merlins there. What's the green, copper-oxide looking stuff on the end of the nozzles? What's the protrusion on the side of the bell for? Why does one of the engines have a rivet or other fastener sticking out?
« Last Edit: 07/29/2018 11:09 pm by RotoSequence »

Offline Damon Hill

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Re: F9 Block 5 Updates and Discussion
« Reply #987 on: 07/29/2018 11:53 pm »
These are industrial rocket engines.  They don't have to be pretty, just rugged.

Offline freda

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Re: F9 Block 5 Updates and Discussion
« Reply #988 on: 07/30/2018 12:55 am »
Lots of little curiosities on the Merlins there...
Green color - left over TEA-TEB igniter sludge?
Protrusions - to prevent nozzles hitting each other when gimbaling.
Rivet - Unknown.

Offline envy887

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Re: F9 Block 5 Updates and Discussion
« Reply #989 on: 07/30/2018 02:01 am »
The "rivet" is probably the drain port for the regen cooled nozzle... There's quite a bit of RP-1 left in there after firing.

Online meekGee

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Re: F9 Block 5 Updates and Discussion
« Reply #990 on: 07/30/2018 02:18 am »
Reading the original story
(https://www.teslarati.com/spacex-falcon-9-block-5-rocket-droneship-photo-gallery/)

It is just pleasant to see how mature the B5 is.
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Offline wannamoonbase

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Re: F9 Block 5 Updates and Discussion
« Reply #991 on: 07/30/2018 03:23 am »
Reading the original story
(https://www.teslarati.com/spacex-falcon-9-block-5-rocket-droneship-photo-gallery/)

It is just pleasant to see how mature the B5 is.

The Block 5's look much cleaner than the older blocks.

No Octograbber on the west coast yet, but perhaps they won't be using the ASDS on the west coach much after they start RTLS flights.

The rest of this year's manifest is interesting.  Less GTO's, Iridium finishing up, DM-1, In-flight abort and Block 5 FH. 

They got a lot going on so we'll see just how smooth the Block 5 performs.
Needing a copy of 'Tales of Suspense #39'

Offline Fluke72

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Re: F9 Block 5 Updates and Discussion
« Reply #992 on: 07/30/2018 01:29 pm »
The "rivet" is probably the drain port for the regen cooled nozzle... There's quite a bit of RP-1 left in there after firing.

that's the answer... 3 gallons or so is left after shutdown. its a small allen head drain plug in a welded in boss.
former SpaceX technician

Offline yg1968

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Re: F9 Block 5 Updates and Discussion
« Reply #993 on: 07/30/2018 03:42 pm »
This has probably been discussed elsewhere but what are those and are they installed by humans (not robots)?

https://www.teslarati.com/f9-b1048-recovery-details-pauline-acalin-15c/
« Last Edit: 07/30/2018 03:44 pm by yg1968 »

Offline abaddon

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Re: F9 Block 5 Updates and Discussion
« Reply #994 on: 07/30/2018 03:44 pm »
This has probably been discussed elsewhere but what are those and are they installed by humans (not robots)?

https://www.teslarati.com/spacex-falcon-9-block-5-rocket-droneship-photo-gallery/#jp-carousel-80044
Those are the jacks that are welded in place by human crews to secure the booster to the drone ship deck.  The Roomba replaces this procedure, but is east-coast only to date.

Offline friendly3

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Re: F9 Block 5 Updates and Discussion
« Reply #995 on: 07/30/2018 08:51 pm »
This has probably been discussed elsewhere but what are those and are they installed by humans (not robots)?

https://www.teslarati.com/spacex-falcon-9-block-5-rocket-droneship-photo-gallery/#jp-carousel-80044
Those are the jacks that are welded in place by human crews to secure the booster to the drone ship deck.  The Roomba replaces this procedure, but is east-coast only to date.

Are you sure that they are welded?

Offline speedevil

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Re: F9 Block 5 Updates and Discussion
« Reply #996 on: 07/30/2018 08:54 pm »
Those are the jacks that are welded in place by human crews to secure the booster to the drone ship deck.  The Roomba replaces this procedure, but is east-coast only to date.

Are you sure that they are welded?
Welding is not an irreversible procedure. 30s can put down a bead that will provide many tons anchoring force.
A couple minutes with an angle grinder takes it back off.
There are other solutions, but welding stuff down is a common practice and is well understood, and 'just works'.

Offline Wolfram66

Re: F9 Block 5 Updates and Discussion
« Reply #997 on: 07/30/2018 09:15 pm »
Those are the jacks that are welded in place by human crews to secure the booster to the drone ship deck.  The Roomba replaces this procedure, but is east-coast only to date.

Are you sure that they are welded?
Welding is not an irreversible procedure. 30s can put down a bead that will provide many tons anchoring force.
A couple minutes with an angle grinder takes it back off.
There are other solutions, but welding stuff down is a common practice and is well understood, and 'just works'.


Just looking at the Teslarati photos above, the welded angle iron is very clearly visible

Offline TripleSeven

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Re: F9 Block 5 Updates and Discussion
« Reply #998 on: 07/30/2018 09:16 pm »
my point exactly...you can do all the ground testing you want to do the CFD etc...but in the end you have to fly.  the difference? in this case it was the modeling of the airflow over the fuselage with high lift devices on the wing and certain angles of attack, the solution was to immediately lower the AOA...that is why Boeing has great test pilots  (self serving compliment)  good night
Shuttle first flight had an anomaly driven by misprediction of reentry aerodynamics that if it had been of a similar magnitude in another direction could have caused loss of vehicle.
Solution for the next few flights was to hand-fly that portion, till the autopilot was taught the true value.

I vaguely recall that about the shuttle...but I was a child during the first flights :)

it sound "right" and expected actually, the shuttle was a ground breaker in terms of a lot of things but that included the region that the vehicle both reentered in and started to fly in...

but, and I am tired...and have another flight sequence tomorrow...just thinking about it...how did that work?

the autopilot takes direction from the same things that was giving cues to the pilot/commander to fly.  are you telling me that there were some early portions of teh shuttle reentry that were flown more or less from raw data?

an autopilot rate limit ?  anyway good night




Offline catdlr

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Re: F9 Block 5 Updates and Discussion
« Reply #999 on: 08/03/2018 12:28 am »
SpaceX - Block 5 Merlins - Remote Cap - 1047 08-02-2018


USLaunchReport
Published on Aug 2, 2018

Block 5 Merlins first of ten flights, Booster cap totally new and remote controlled. Does anyone know how thick the walls of Falcon 9 first stage? 3/4 in, 1 1/2 or more? Let us know in comments. Sorry! We missed Tekcom-4 Static Fire Test. We have a lot more footage of guys securing the Booster. Maybe next launch.

https://www.youtube.com/watch?v=iZVvt17BagY?t=001

Tony De La Rosa

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