Author Topic: F9 Block 5 Updates and Discussion  (Read 313397 times)

Offline Urx

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Re: F9 Block 5 Updates and Discussion
« Reply #460 on: 02/18/2018 06:27 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

Offline IanThePineapple

Re: F9 Block 5 Updates and Discussion
« Reply #461 on: 02/18/2018 06:37 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

The non-roundness is caused by the wrapping holders being a specific shape (along with the raceways on the core).

The booster that was pictured from a bridge IS a Block 5, I don't know about the one in front of the HIF.

Online hkultala

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Re: F9 Block 5 Updates and Discussion
« Reply #462 on: 02/18/2018 07:57 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

No.

AFAIK the interstage of block 5 will be black. (probably just left unpainted, as carbon fiber as black natively).

Offline IanThePineapple

Re: F9 Block 5 Updates and Discussion
« Reply #463 on: 02/18/2018 08:17 PM »
AFAIK the interstage of block 5 will be black. (probably just left unpainted, as carbon fiber as black natively).

The nice black/grey pattern of woven carbon fiber will look nice

Offline niwax

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Re: F9 Block 5 Updates and Discussion
« Reply #464 on: 02/18/2018 09:23 PM »
AFAIK the interstage of block 5 will be black. (probably just left unpainted, as carbon fiber as black natively).

The nice black/grey pattern of woven carbon fiber will look nice

Are you sure of that? Carbon fiber is sensitive to UV light and starts to decompose and lose strength. On the other hand, it would be another cool in-your-face to other rocket manufacturers when the majority of rockets a typical person will see are reusable and obviously carbon fiber.
« Last Edit: 02/18/2018 09:25 PM by niwax »

Online wannamoonbase

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Re: F9 Block 5 Updates and Discussion
« Reply #465 on: 02/18/2018 10:04 PM »
AFAIK the interstage of block 5 will be black. (probably just left unpainted, as carbon fiber as black natively).

The nice black/grey pattern of woven carbon fiber will look nice

Are you sure of that? Carbon fiber is sensitive to UV light and starts to decompose and lose strength. On the other hand, it would be another cool in-your-face to other rocket manufacturers when the majority of rockets a typical person will see are reusable and obviously carbon fiber.

UV does like degrading carbon bonds.  However, it's not like these vehicles stay outside 24/7. 

Could save a few ounces of paint (maybe a pound or two).

Maybe it has a purpose, maybe its just a way of visually demonstrating that it's a new vehicle. 
Jonesing for a copy of 'Tales of Suspense #39'

Offline niwax

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Re: F9 Block 5 Updates and Discussion
« Reply #466 on: 02/18/2018 10:11 PM »
AFAIK the interstage of block 5 will be black. (probably just left unpainted, as carbon fiber as black natively).

The nice black/grey pattern of woven carbon fiber will look nice

Are you sure of that? Carbon fiber is sensitive to UV light and starts to decompose and lose strength. On the other hand, it would be another cool in-your-face to other rocket manufacturers when the majority of rockets a typical person will see are reusable and obviously carbon fiber.

UV does like degrading carbon bonds.  However, it's not like these vehicles stay outside 24/7. 

They penetrate the ozone layer for a heavy dose of UV and they do stand on the launch pad or next to it for days. One study I saw found 29% performance degradation after just 1000h of normal irradiation. Considering 10 flights between refurbishments that is not a lot and I don't think replacing the carbon fiber components is in scope for refurbishment anyways.
« Last Edit: 02/18/2018 10:22 PM by niwax »

Offline speedevil

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Re: F9 Block 5 Updates and Discussion
« Reply #467 on: 02/18/2018 10:19 PM »
They penetrate the ozone layer for a heavy dose of UV and they do stand on the launch pad or next to it for days. One study I saw found 29% performance degradation after just 1000h of normal irradiation. Considering 10 flights between refurbishments that is not a lot and I don't think replacing the carbon fiber components counts is in scope for refurbishment anyways.

Maybe it's all one plan!
Perhaps soot absorbs UV really well.

Offline Testraindrop

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Re: F9 Block 5 Updates and Discussion
« Reply #468 on: 02/18/2018 10:21 PM »
Maybe they will put some clear coat on the CF, like car manufacturers do...

Offline Stan-1967

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Re: F9 Block 5 Updates and Discussion
« Reply #469 on: 02/18/2018 11:19 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

Making the  Block 5 core into an octagon that still is only 3.7 m high & maintains road-transportability would give it more internal volume than a 3.7m diameter cylinder by 5.4%.  Not saying it's a good idea, just saying that the current F9 core supposedly is limited to 3.7m by transportation considerations.  An octagon with a diameter of 4m can be stacked so that it is only 3.7 meters in height, & would still fit under transportation constraints.

Offline rpapo

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Re: F9 Block 5 Updates and Discussion
« Reply #470 on: 02/18/2018 11:25 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

Making the  Block 5 core into an octagon that still is only 3.7 m high & maintains road-transportability would give it more internal volume than a 3.7m diameter cylinder by 5.4%.  Not saying it's a good idea, just saying that the current F9 core supposedly is limited to 3.7m by transportation considerations.  An octagon with a diameter of 4m can be stacked so that it is only 3.7 meters in height, & would still fit under transportation constraints.
Unfortunately, it would not have the same strength as a pressurized cylinder.
An Apollo fanboy . . . fifty years ago.

Offline Lars-J

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Re: F9 Block 5 Updates and Discussion
« Reply #471 on: 02/19/2018 04:29 AM »
Maybe they will put some clear coat on the CF, like car manufacturers do...

Right. There's a reason why most metal on rockets is painted, and it's not for adding strength - mostly to protect against the elements.

Offline lrk

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Re: F9 Block 5 Updates and Discussion
« Reply #472 on: 02/19/2018 06:15 PM »
I read somewhere on the forum that all Block 5 boosters will include the side-booster attachment hardware on the octaweb.  I thought that the major reason for switching to bolted octawebs was to make this easily configurable?  Can somebody comment on this? 

Offline rpapo

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Re: F9 Block 5 Updates and Discussion
« Reply #473 on: 02/19/2018 06:18 PM »
I read somewhere on the forum that all Block 5 boosters will include the side-booster attachment hardware on the octaweb.  I thought that the major reason for switching to bolted octawebs was to make this easily configurable?  Can somebody comment on this?
And here I thought/assumed that the transition from welded to bolted octaweb was simply a matter of making the whole thing more serviceable.
An Apollo fanboy . . . fifty years ago.

Online Semmel

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Re: F9 Block 5 Updates and Discussion
« Reply #474 on: 02/19/2018 06:20 PM »
I read somewhere on the forum that all Block 5 boosters will include the side-booster attachment hardware on the octaweb.  I thought that the major reason for switching to bolted octawebs was to make this easily configurable?  Can somebody comment on this?

Well the answer is right there (in my naive view as a software engineer). Since the Octoweb is bolted, not welded, the side-booster attachment hardware could just be bolted on. So not the actual attachment hardware needs to be there, just the holes in the octoweb where it is bolted on if it needs to be there. If they make the hard points accessible without deconstructing the whole thing, this should be possible in a day or two.

Offline lrk

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Re: F9 Block 5 Updates and Discussion
« Reply #475 on: 02/19/2018 11:21 PM »
I read somewhere on the forum that all Block 5 boosters will include the side-booster attachment hardware on the octaweb.  I thought that the major reason for switching to bolted octawebs was to make this easily configurable?  Can somebody comment on this?

Well the answer is right there (in my naive view as a software engineer). Since the Octoweb is bolted, not welded, the side-booster attachment hardware could just be bolted on. So not the actual attachment hardware needs to be there, just the holes in the octoweb where it is bolted on if it needs to be there. If they make the hard points accessible without deconstructing the whole thing, this should be possible in a day or two.

What I meant was that I read that all cores would have the hard points attached, at all times.  Why would they still have switched to (heavier) bolted octawebs if that is the case? 

Offline Kansan52

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Re: F9 Block 5 Updates and Discussion
« Reply #476 on: 02/19/2018 11:27 PM »
The above post on increasing serviceability seems to be a good reason for the bolted, not welded, frame.

Offline Stan-1967

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Re: F9 Block 5 Updates and Discussion
« Reply #477 on: 02/20/2018 02:33 PM »
Could the following images be the first one of Block 5?
https://i.redd.it/snje9xc7ei801.jpg and https://i.redd.it/youjp8a8slg01.jpg
IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?

Making the  Block 5 core into an octagon that still is only 3.7 m high & maintains road-transportability would give it more internal volume than a 3.7m diameter cylinder by 5.4%.  Not saying it's a good idea, just saying that the current F9 core supposedly is limited to 3.7m by transportation considerations.  An octagon with a diameter of 4m can be stacked so that it is only 3.7 meters in height, & would still fit under transportation constraints.
Unfortunately, it would not have the same strength as a pressurized cylinder.
I hate it when a bad idea keeps worming it's way inside my mind, so to get it out of my mind, I'll just point out the following about a block 5 core shaped as an octagon that fits a 3.7m diameter circumscribed circle within it:
1.  It is consistent with statements that Block 5 will be immediately recognizable on the pad
2.  it is consistent with the option to make a slightly larger S2.   The octagon formfactor could be made to include the interstage & adapt to S2.
3.  It is consistent with Musk saying a slightly larger fairing is under consideration.  If S2 is also octagonal, a new fairing would probably be preferred unless SpaceX thinks it OK to let the octagon vertices lay outside the fairing 3.7m diameter at the base of the PAF.
4.  It is consistent with the uprated payload to LEO & GTO.  It would enable adding about 15-17t of prop to S1, & additional optimization to S2.  The "fineness" ratio that F9 can support as a octagon will enable a further stretch of S2.
5.  An octagon still works with the existing octaweb, as each vertice of the octaweb will intersect the midpoint of each face of the octagon core.
6.  An octagon formfactor for the core is consistent with the need to make new landing legs. 

As to an octagon not being ideal for a pressurized container, this is obviously true, but I don't see that it would be a show stopper, & the core is not pressurized that high ( 40psi?  A COPV it is not).  SpaceX is optimizing for performance to GTO & re-use, so why let some compressive loads in the vertices get in the way of that?  Al-Li is perfectly capable of supporting compressive loads & bending moments.  That is what finite element analysis is for. 
« Last Edit: 02/20/2018 02:51 PM by Stan-1967 »

Offline speedevil

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Re: F9 Block 5 Updates and Discussion
« Reply #478 on: 02/20/2018 02:35 PM »
As to an octagon not being ideal for a pressurized container, this is obviously true, but I don't see that it would be a show stopper, & the core is not pressurized that high ( 40psi?  A COPV it is not).  SpaceX is optimizing for performance to GTO & re-use, so why let some compressive loads in the vertices get in the way of that?  Al-Li is perfectly capable of supporting compressive loads & bending moments.  That is what finite element analysis is for.

It could pop round on the pad, when filled at 40PSI, and collapse to an octagon for transport.
What a visionary idea!

Offline Jim

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Re: F9 Block 5 Updates and Discussion
« Reply #479 on: 02/20/2018 02:57 PM »

As to an octagon not being ideal for a pressurized container, this is obviously true, but I don't see that it would be a show stopper, & the core is not pressurized that high ( 40psi?  A COPV it is not).   


You are forgetting head pressure and acceleration.  An octagon is a non starter

Not going to work with composite interstages.

« Last Edit: 02/20/2018 02:59 PM by Jim »

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