Author Topic: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION  (Read 878465 times)

Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1620 on: 03/02/2016 03:02 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Nice tool, but it doesn't seem able to report wind speeds over 29 m/sec, unfortunately.

I selected the "10km" layer over the Cape and played with the "time" bar at the bottom. But I could not get the windspeed scale to exceed 29 m/sec. And the chart Elon tweeted yesterday showed about 70 m/sec at 10km. Obviously a big difference. So the tool seems to work better at lower altitude where wind speed is less.

I don't think it auto-scales to high wind speeds.  Looks like an opportunity for improvement.

Online whitelancer64

Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.

Length isn't the issue, width is. The Falcon 9 is 12 feet wide, which is the maximum allowable width for interstate transportation. Wider objects need special permissions and routes.

As for making it longer, rockets have little internal bracing, which makes making them long and skinny very problematic. The Falcon 9 is already longer than I personally am comfortable with, I worry about it bending or buckling in flight, especially if there is bad wind shear.
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Offline JamesH

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1622 on: 03/02/2016 03:17 PM »
Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.

Length isn't the issue, width is. The Falcon 9 is 12 feet wide, which is the maximum allowable width for interstate transportation. Wider objects need special permissions and routes.

As for making it longer, rockets have little internal bracing, which makes making them long and skinny very problematic. The Falcon 9 is already longer than I personally am comfortable with, I worry about it bending or buckling in flight, especially if there is bad wind shear.

I wonder if they would stop a launch due to predicted bad wind shear...oh, hold on......

As for wider loads, although possible, they take a lot longer to get anywhere and require permission. You really don't want than when you have to send as many cores by road as SpaceX are going to have to do.

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1623 on: 03/02/2016 03:18 PM »
IIRC somewhere on the site there was a post with rocket onboard cam video showing a Titan fighting heavy wind shear, you can see the center core skin buckling. But my search-fu fails me. Anyone else remember where it was?

A must see for anyone thinking "a bit windy up there, so what, just launch".
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Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1624 on: 03/02/2016 03:22 PM »
As for wider loads, although possible, they take a lot longer to get anywhere and require permission. You really don't want than when you have to send as many cores by road as SpaceX are going to have to do.

More than the 100,000 or so wide wind turbine loads than have been sent over the road in the last 10 years, just in the US?

Offline rsdavis9

I like the analogy for understanding wind shear.

You are in a plane travelling at altitude and you hit air bumps. You feel the plane go up and then down. You can see the wings flex (alot!). Air bumps when travelling horizontally is the same thing the rocket feels when travelling vertically through different speed winds.
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Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1626 on: 03/02/2016 03:31 PM »
Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.

Length isn't the issue, width is. The Falcon 9 is 12 feet wide, which is the maximum allowable width for interstate transportation. Wider objects need special permissions and routes.

And yet, wind turbine towers are generally 4.2m (13.75 feet) in diameter at the base, and we've shipped about 15,000 of them (in three sections) in the last 10 years.
« Last Edit: 03/02/2016 03:33 PM by Lee Jay »

Offline clegg78

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1627 on: 03/02/2016 03:36 PM »
IIRC somewhere on the site there was a post with rocket onboard cam video showing a Titan fighting heavy wind shear, you can see the center core skin buckling. But my search-fu fails me. Anyone else remember where it was?

A must see for anyone thinking "a bit windy up there, so what, just launch".

Wow I would love to see that if anyone can find that vid (even though its not really SpaceX relevant, still interesting to see)
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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1628 on: 03/02/2016 03:44 PM »
I don't know about Titan, but this video of the inaugural Atlas III shows a bit of the engine section bending with respect to the camera location starting at around 1:40 in the video:


Offline rsdavis9

I think an interesting thing to note is that ses-9 was designed when falcon  9 was much less capable. Evidence the 2.1 mt of chemical propellant. If you left off the chemical propellant couldn't the falcon 9 FT get ses-9 to a super synchronous orbit easily. And maybe have left over to help with plane change and circularization? Wouldn't it be better to do the plane and circularizationwith with the falcon 9 US?
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1630 on: 03/02/2016 04:16 PM »
As for wider loads, although possible, they take a lot longer to get anywhere and require permission. You really don't want than when you have to send as many cores by road as SpaceX are going to have to do.

More than the 100,000 or so wide wind turbine loads than have been sent over the road in the last 10 years, just in the US?

Obviously it can be done, but going bigger does make transport more difficult. Florida and Alabama prohibit nighttime transit of oversize loads on all roads, for example, and several other states have similar prohibitions. So those turbine towers may be taking twice as long to get where they're going than if they were the diameter of an F9.

SpaceX obviously did the trades and decided they didn't want to go bigger than F9's current diameter, and transport logistics had to be one of the factors in the trade.

The federal width limitation is 102 inches.  The Falcon 9 is already an oversize load.

http://forum.nasaspaceflight.com/index.php?topic=36065.msg1327928#msg1327928

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1631 on: 03/02/2016 04:23 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Nice tool, but it doesn't seem able to report wind speeds over 29 m/sec, unfortunately.

I selected the "10km" layer over the Cape and played with the "time" bar at the bottom. But I could not get the windspeed scale to exceed 29 m/sec. And the chart Elon tweeted yesterday showed about 70 m/sec at 10km. Obviously a big difference. So the tool seems to work better at lower altitude where wind speed is less.
If you click a point on the map it will display the values correctly.

Online whitelancer64

Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.

Length isn't the issue, width is. The Falcon 9 is 12 feet wide, which is the maximum allowable width for interstate transportation. Wider objects need special permissions and routes.

And yet, wind turbine towers are generally 4.2m (13.75 feet) in diameter at the base, and we've shipped about 15,000 of them (in three sections) in the last 10 years.

And what routes are they taking? They definitely are taking special routes, which is what I've been saying all along.
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Offline Kabloona

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1633 on: 03/02/2016 04:47 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Nice tool, but it doesn't seem able to report wind speeds over 29 m/sec, unfortunately.

I selected the "10km" layer over the Cape and played with the "time" bar at the bottom. But I could not get the windspeed scale to exceed 29 m/sec. And the chart Elon tweeted yesterday showed about 70 m/sec at 10km. Obviously a big difference. So the tool seems to work better at lower altitude where wind speed is less.
If you click a point on the map it will display the values correctly.

Ah, very good. So current wind speed over the Cape at 10km is given as 64 m/sec, dropping to 53 m/sec Friday at 7:00 pm local, for example.
« Last Edit: 03/02/2016 04:48 PM by Kabloona »

Offline Jim

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1634 on: 03/02/2016 04:47 PM »
I think an interesting thing to note is that ses-9 was designed when falcon  9 was much less capable. Evidence the 2.1 mt of chemical propellant. If you left off the chemical propellant couldn't the falcon 9 FT get ses-9 to a super synchronous orbit easily. And maybe have left over to help with plane change and circularization? Wouldn't it be better to do the plane and circularizationwith with the falcon 9 US?

No, F9 doesn't have the capability for GSO delivery

Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1635 on: 03/02/2016 04:53 PM »
Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.

Length isn't the issue, width is. The Falcon 9 is 12 feet wide, which is the maximum allowable width for interstate transportation. Wider objects need special permissions and routes.

And yet, wind turbine towers are generally 4.2m (13.75 feet) in diameter at the base, and we've shipped about 15,000 of them (in three sections) in the last 10 years.

And what routes are they taking? They definitely are taking special routes, which is what I've been saying all along.

F9 is a permitted load anyway, due to it being oversize.  So the route is based on the locality and the specifics of the load.  Same thing if it were a little bigger.

Offline Jim

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1636 on: 03/02/2016 04:53 PM »
IIRC somewhere on the site there was a post with rocket onboard cam video showing a Titan fighting heavy wind shear, you can see the center core skin buckling. But my search-fu fails me. Anyone else remember where it was?

A must see for anyone thinking "a bit windy up there, so what, just launch".

Wow I would love to see that if anyone can find that vid (even though its not really SpaceX relevant, still interesting to see)

http://forum.nasaspaceflight.com/index.php?topic=28702.msg888381#msg888381

Online eeergo

While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Nice tool, but it doesn't seem able to report wind speeds over 29 m/sec, unfortunately.

I selected the "10km" layer over the Cape and played with the "time" bar at the bottom. But I could not get the windspeed scale to exceed 29 m/sec. And the chart Elon tweeted yesterday showed about 70 m/sec at 10km. Obviously a big difference. So the tool seems to work better at lower altitude where wind speed is less.
If you click a point on the map it will display the values correctly.

Ah, very good. So current wind speed over the Cape at 10km is given as 64 m/sec, dropping to 53 m/sec Friday at 7:00 pm local, for example.

There's a very similar website that I watch regularly and offers more options: http://earth.nullschool.net/
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Online Lar

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1638 on: 03/02/2016 06:40 PM »
F9 is a permitted load anyway, due to it being oversize.  So the route is based on the locality and the specifics of the load.  Same thing if it were a little bigger.

Why are the tower bases shipped in three sections? I had always assumed that it was because that as you make things bigger (whether that be longer, or  wider) your possible routes go down and the level of special handling goes up.  (flag cars front and back, cable lifts, state police escorts etc etc)  Those sections you showed pictures of are using schnabels or similar tech. They're also really really strong, presumably, compared to a F9 which is pretty fragile.

I'm not totally clear what argument you're making any more. SpaceX presumably ran trades and chose the diameter and length of the F9 1.0  S1 for what they felt were good reasons.  When they wanted to increase the propellant load of S1 they went longer. Which had impacts on their GSE.  If they had went fatter, it would have disrupted their basic tooling for bending tank sections, AND impacted the GSE as well... so they didn't.

This latest change maybe they wanted to try to contain the amount of rebuilding of the Transporter Erector they had to do since they had already done that once.

Who knows? They ran the trades, they made their choices. Second guessing them now seems not all that much fun to me. but YMMV.
« Last Edit: 03/02/2016 06:42 PM by Lar »
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Offline Lee Jay

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Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1639 on: 03/02/2016 06:58 PM »
F9 is a permitted load anyway, due to it being oversize.  So the route is based on the locality and the specifics of the load.  Same thing if it were a little bigger.

Why are the tower bases shipped in three sections?

Because they're too heavy for crane lifting if you don't.  (There are other reasons as well).

Quote
I'm not totally clear what argument you're making any more.

It's simple.

Either they chose the length and diameter they did because they were totally confused about the logistics of road transport, or they chose those things for reasons having very little or nothing to do with road transport.

They don't seem stupid to me.
« Last Edit: 03/02/2016 06:58 PM by Lee Jay »

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