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#1440
by
ulm_atms
on 25 Jan, 2018 01:36
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Falcon Heavy = 5,100,000 lbf
Saturn V = 7,891,000 lbf
That video made me think about something.
I know the pad/trench was built for around 15Mlbs thrust (Nova class) Since it now only seems to have one output side instead of two, can it still support that much power?
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#1441
by
fthomassy
on 25 Jan, 2018 02:34
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Of course there are many ways to interpret igniting two at a time. My take is two at a time on each core except three the last time. So on each core 2+2+2+3. If you look at the static fire plume you can convince yourself that might be the case. I'm hoping the SpaceX webcast will have lots of factoids like that on launch day!!
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#1442
by
darkenfast
on 25 Jan, 2018 03:00
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Falcon Heavy = 5,100,000 lbf
Saturn V = 7,891,000 lbf
That video made me think about something.
I know the pad/trench was built for around 15Mlbs thrust (Nova class) Since it now only seems to have one output side instead of two, can it still support that much power?
Since NASA's SLS will also be using just one side over at 39B, I think we can assume that it can. I would guess that years of data collection and experience with Saturn and Shuttle provided the confidence for that change.
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#1443
by
catdlr
on 25 Jan, 2018 03:54
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Saturn V vs FH Exhaust Flumes Comparison
Jay DeShetler
Published on Jan 24, 2018
Saturn V vs FH Exhaust Flumes Comparison
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#1444
by
su27k
on 25 Jan, 2018 04:11
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Falcon Heavy = 5,100,000 lbf
Saturn V = 7,891,000 lbf
Why does Saturn V has much more flames, while FH has larger vapor cloud? Different flame trench design? Or it's just SpaceX uses more water deluge?
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#1445
by
Nomadd
on 25 Jan, 2018 04:24
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#1446
by
catdlr
on 25 Jan, 2018 04:28
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Here is a three-way comparison adding the space Shuttle launch video to Jay DeShetler video.
Falcon Heavy, Saturn V and Shuttle launch comparison
CATDRL2
Published on Jan 24, 2018
Exhaust Comparisons for Falcon Heavy, Saturn V and Space Shuttle.
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#1447
by
llanitedave
on 25 Jan, 2018 04:46
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Falcon Heavy = 5,100,000 lbf
Saturn V = 7,891,000 lbf
Why does Saturn V has much more flames, while FH has larger vapor cloud? Different flame trench design? Or it's just SpaceX uses more water deluge?
The pictures aren't quite equivalent, since the Saturn V has already lifted off, and its plume is impinging on the top of the pad and platform, anot just confined to the flame trench.
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#1448
by
alhenry1231
on 25 Jan, 2018 05:29
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Spacex static fire video appears to be edited as Chris stated on his twitter.
-Spacex video appears to show brighter plume around the same time Chris’ stream starts the popping, between 6-7 seconds into static fire venting sounds are heard.
-Chris video coincides with Spacex video until 6-7 seconds when the crackling is heard and continues through about 11 seconds.
Is it just location of viewing changing acoustics? Or is Spacex editing out some video?
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#1449
by
Danrar
on 25 Jan, 2018 06:37
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I wonder if the center core will be recovered if they launch so close to GovSat. SpaceX is gonna need more barges.
If they can only recover one, then based on the value of the engineering data, recover FH and dump the Block 3/4 core they don't need.
Exactly. The FH core is just so much more valuable. Not to mention GovSat will use B1032. They won't be needing that back anyway.
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#1450
by
ludovic_f
on 25 Jan, 2018 12:05
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Spacex static fire video appears to be edited as Chris stated on his twitter.
-Spacex video appears to show brighter plume around the same time Chris’ stream starts the popping, between 6-7 seconds into static fire venting sounds are heard.
-Chris video coincides with Spacex video until 6-7 seconds when the crackling is heard and continues through about 11 seconds.
Is it just location of viewing changing acoustics? Or is Spacex editing out some video?
SpaceX Youtube video (available in HD at 50 fps) doesn't look like it's been edited at all.
Until t+10s in the video we have the close-up FH view. The static starts and then we switch to the wider view until
the end of the video (within that same second).
Edit: until at t+21s when the view switch to even further away so that we can see the splendid plume devellop in the dark blue Florida sky.
You can see the exhaust flame light up the exhaust plume from ~ t+14s until ~t+17s when the static seem to be completed (sound and lack of additional output from the flame trench seem to confirm this).
I'd guesstimate that by t+18s the static is done and over view. Which give 8s max, and closer to the usual 7s duration!
Is it possible that SpaceX planned for a 12s burn but programmed it to terminate if good thrust was achieve on all 27 engines?
Or is it plausible that they changed there mind on the duration, or (but that's the least likely cause
) that Chris B or Chris G had ... incorrect data?
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#1451
by
alhenry1231
on 25 Jan, 2018 12:32
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Spacex static fire video appears to be edited as Chris stated on his twitter.
-Spacex video appears to show brighter plume around the same time Chris’ stream starts the popping, between 6-7 seconds into static fire venting sounds are heard.
-Chris video coincides with Spacex video until 6-7 seconds when the crackling is heard and continues through about 11 seconds.
Is it just location of viewing changing acoustics? Or is Spacex editing out some video?
SpaceX Youtube video (available in HD at 50 fps) doesn't look like it's been edited at all.
Until t+10s in the video we have the close-up FH view. The static starts and then we switch to the wider view until the end of the video (within that same second).
Edit: until at t+21s when the view switch to even further away so that we can see the splendid plume devellop in the dark blue Florida sky.
You can see the exhaust flame light up the exhaust plume from ~ t+14s until ~t+17s when the static seem to be completed (sound and lack of additional output from the flame trench seem to confirm this).
I'd guesstimate that by t+18s the static is done and over view. Which give 8s max, and closer to the usual 7s duration!
Is it possible that SpaceX planned for a 12s burn but programmed it to terminate if good thrust was achieve on all 27 engines?
Or is it plausible that they changed there mind on the duration, or (but that's the least likely cause ) that Chris B or Chris G had ... incorrect data?
Bold Mine
The 7-8 second duration is the part in question by me.
Apologies on my video mashup loosing so much quality I was only using my iphone and had to convert and compress a lot.
My hope was that it would overlay Chris G's vantage point with the vantage point SpaceX recorded from.
There appears to be clear sound in Chris' stream from First loud crack for 11 seconds and Spacex 7-8 seconds.
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#1452
by
Robotbeat
on 25 Jan, 2018 12:58
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I think the firing duration seemed longer than the official Twitter and Instagram videos but shorter than 12 seconds.
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#1453
by
Ben the Space Brit
on 25 Jan, 2018 13:04
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Assuming more than is probably justifiable, how close can SpaceX launch GovSat-1 and Falcon Heavy, assuming optimum range turn-around times? Do they have a minimum turn-around time of MCC-X?
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#1454
by
Jim
on 25 Jan, 2018 13:18
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Assuming more than is probably justifiable, how close can SpaceX launch GovSat-1 and Falcon Heavy, assuming optimum range turn-around times? Do they have a minimum turn-around time of MCC-X?
MCC-X does not control launches. The LCC at the Cape does. MCC-X monitors launches (except those with Dragon onboard)
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#1455
by
old_sellsword
on 25 Jan, 2018 13:20
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Assuming more than is probably justifiable, how close can SpaceX launch GovSat-1 and Falcon Heavy, assuming optimum range turn-around times? Do they have a minimum turn-around time of MCC-X?
MCC-X does not control launches. The LCC at the Cape does. MCC-X monitors launches (except those with Dragon onboard)
But it’s still a necessary part of the launch process, right?
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#1456
by
Rocket Science
on 25 Jan, 2018 13:22
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I think the firing duration seemed longer than the official Twitter and Instagram videos but shorter than 12 seconds.
I see about 6-7 seconds or so from the SpaceX video, all of it good though!
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#1457
by
Nomadd
on 25 Jan, 2018 13:30
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They could have seen some unexpected loads or movement on the pad after 8 seconds or so that wouldn't be a factor on a launch, with no pressing reason to fire any longer.
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#1458
by
alexterrell
on 25 Jan, 2018 13:34
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Of course there are many ways to interpret igniting two at a time. My take is two at a time on each core except three the last time. So on each core 2+2+2+3. If you look at the static fire plume you can convince yourself that might be the case. I'm hoping the SpaceX webcast will have lots of factoids like that on launch day!!
If I were designing it, I'd want initially aim to keep the firings balanced - hence 2 at a time would make sense. If we call the boosters A and C, and the core B, then something like:
A1+C9, A9+C1, B1+B9, A2+C8, A8+C2, B2+B8, .........., A5+B5+C5.
That doesn't quite tie up with the sound waves, maybe:
A1+C9, A9+B1+B9+C1, A2+C8 ........
So 2 at a time or 4 at a time, but not 3 at a time, except for the centre 3 engines.
Generally I'd want the boosters to be firing slightly ahead of the core.
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#1459
by
.Scott
on 25 Jan, 2018 13:45
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Why does Saturn V has much more flames, while FH has larger vapor cloud? Different flame trench design? Or it's just SpaceX uses more water deluge?
It's the engines themselves.
I immediately noticed those much shorter flames from the Falcons the first time I saw one.
You can sometimes also spot a Mach diamond or two.
It indicates how much more efficient the Falcon boosters are than what we had 40 years ago.
) that Chris B or Chris G had ... incorrect data?