Author Topic: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion  (Read 371312 times)

Offline RoboGoofers

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #420 on: 12/20/2017 07:13 PM »
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.

Offline groknull

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #421 on: 12/20/2017 07:31 PM »
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.

Conjecture:

Yellow saddle pieces do not fly*.  Diagonal struts (between the tangential ones) from side stages to the center stage stay with the side stages.  Possibly pull out of sockets on the center stage (fat section under tangential struts), then fold up against the side booster nose cone.  There is a small fairing on the inboard side of each side booster nose cone that might be a latch point**.

Edit: * may be an assembly jig or strap; ** or a vent, or more likely, a camera port.
« Last Edit: 12/20/2017 07:58 PM by groknull »

Offline Coastal Ron

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #422 on: 12/20/2017 07:41 PM »
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

Speculation: Having both on one side provides consistent lift characteristics? For instance, if the "bottom" of the stage in flight is the side with the feed lines, then the flat area of the feed lines may provide some level of aerodynamic lift when compared with a side that does not have feed lines.
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Online ugordan

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #423 on: 12/20/2017 07:45 PM »
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

What precisely do you mean by feed lines? To the best that my eye can see, they are identical cores, one simply rotated 180 degrees. Like Atlas V HLV would have done and unlike Delta IV Heavy.
« Last Edit: 12/20/2017 07:47 PM by ugordan »

Offline Lars-J

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #424 on: 12/20/2017 07:47 PM »
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

Speculation: Having both on one side provides consistent lift characteristics? For instance, if the "bottom" of the stage in flight is the side with the feed lines, then the flat area of the feed lines may provide some level of aerodynamic lift when compared with a side that does not have feed lines.

Are you seeing some other image than we are??  :o It is clear that one side booster is matches the rotation of the core, but the other one is rotated 180 degrees. Just look at the big racetrack piping on the right core.

You can also see the rotation in the engine view, by noting the color of the propellant attachments. Blue or Red. (for LOX or RP1)

Offline edkyle99

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #425 on: 12/20/2017 07:48 PM »
Interesting.  I had always heard that the Shuttle's intertank structure had to be so heavily built was because the upper attach points were where the thrust actually transferred into the stack.  On the Shuttle stack, anyway, most of the thrust transfer happened up top, not down below.  I also recall reading the same comment about the SRB connections on the Titan III and IV family.

Shuttle SRBs lifted from near their top ends.  Titan Stage-Zero solids lifted from the bottom, which appears to be the method used by Falcon Heavy, though with much different loads since the Titan core stage did not ignite on the ground.

 - Ed Kyle
« Last Edit: 12/20/2017 07:53 PM by edkyle99 »

Offline docmordrid

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #426 on: 12/20/2017 08:22 PM »
Elon Musk ✔ @elonmusk
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.
4:13 PM - Dec 20, 2017

https://twitter.com/elonmusk/status/943590152181448704
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Offline sevenperforce

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #427 on: 12/20/2017 08:36 PM »
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.
No, I'm talking about the white connector arms that are just barely angled and are attached at the center of those struts.

The piston is pulled into the sheath via hydraulics, which rotates the strut up.

Online cscott

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #428 on: 12/20/2017 08:58 PM »
Yellow saddle piece is part of the pusher mechanism to separate the boosters, I think. (Although I agree that the yellow piece itself will probably not fly.)

Online cscott

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #429 on: 12/20/2017 09:00 PM »
Someone on reddit pointed out what might be stitching errors or some kind of intentional editing.

https://i.imgur.com/PQSPi2z.png

These details along the raceway are lined up in one image, but not in the other. I'm guessing someone was just not paying attention when it came time to stitch, or left it to automated software and it got confused.
Yes, discussed earlier.  On the right on the uncropped version you can see the guy holding the yellow cable to trigger the camera... twice.  Consensus here was that there are three images stitched together; you can actually see the yellow command cord a third time at the bottom, but the photographer themself has been stitched away.
« Last Edit: 12/20/2017 09:04 PM by cscott »

Someone on reddit pointed out what might be stitching errors or some kind of intentional editing.

https://i.imgur.com/PQSPi2z.png

These details along the raceway are lined up in one image, but not in the other. I'm guessing someone was just not paying attention when it came time to stitch, or left it to automated software and it got confused.
Yes, discussed earlier.  On the right on the uncropped version you can see the guy holding the yellow cable to trigger the camera... twice.  Consensus here was that there are three images stitched together; you can actually see the yellow command cord a third time at the bottom, but the photographer themself has been stitched away.

The sep nodes for the second stage on the interstage are missing too
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Offline sevenperforce

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #431 on: 12/20/2017 09:59 PM »
Quote
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.

https://twitter.com/elonmusk/status/943590152181448704

Quote
Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket. It was 50% higher thrust with five F-1 engines at 7.5M lb-F. I love that rocket so much.

https://twitter.com/elonmusk/status/943592480926076928
Just add one core to the front of the core, another to the back, rotate 45 degrees, and redo the launch mount/reaction frame?  ;)
Nine Merlin 1Ds have just 12% more thrust than a single F1.

Offline Zed_Noir

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #432 on: 12/20/2017 10:09 PM »
Quote
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.

https://twitter.com/elonmusk/status/943590152181448704

Quote
Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket. It was 50% higher thrust with five F-1 engines at 7.5M lb-F. I love that rocket so much.

https://twitter.com/elonmusk/status/943592480926076928
Just add one core to the front of the core, another to the back, rotate 45 degrees, and redo the launch mount/reaction frame?  ;)

Yes, but think it will be easier to assemble you quint core LV on a new customized MLP inside the VAB and launch from LC_39B.

Of course that requires a new reinforced center core that can handle the stress of 4 strapped-on booster cores.

The Falcon Heavy should go with a new Raptor upper stage for increase performance instead of more cores. It will take less money and time. ;)



Offline Rocket Science

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #433 on: 12/20/2017 10:46 PM »
Well, there it is, in all its glory. From Elon's Twitter.
Welcome to the forum and spectacular first post!! 8)
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Offline Rocket Science

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #434 on: 12/20/2017 10:49 PM »
Can I just say how beautiful FH is?

Looks like titanium grid fins on the side boosters but aluminium on the central core.
Lol, ninja'd. Yes and lots of pusher hardware on display.

It seems odd to be using such old hardware on a maiden flight. It's so incongruous to how space flight normally works, that my mind struggles with it.
I like to use the word "proven" instead of "old" hardware... ;)
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Offline MATTBLAK

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #435 on: 12/21/2017 01:26 AM »
Possibly belongs in a cheerleading thread; but I reckon there's only one piece of music to dub to first (successful) flight footage of this monster... 

« Last Edit: 12/21/2017 01:47 AM by gongora »
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Offline TripD

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #436 on: 12/21/2017 01:42 AM »
Tweaked to bring out more details.

Offline sevenperforce

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #437 on: 12/21/2017 01:50 AM »
I wonder if the fairing will come off after booster sep but before core staging.

Offline deruch

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #438 on: 12/21/2017 01:54 AM »
A video with a view from the outside looking into the hangar (though unfortunately with bad window glare).

https://www.instagram.com/p/Bc7fyjWFPjB/


Edit: This was from earlier this week.
« Last Edit: 12/21/2017 05:10 AM by deruch »
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Online ZachS09

I wonder if the fairing will come off after booster sep but before core staging.

That's a possibility, but then again, fairing sep could occur after second stage engine start; just like the Delta IV Heavy.
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