Author Topic: Gwynne Shotwell lecture at Stanford 11 Oct 2017  (Read 55543 times)

Offline wannamoonbase

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #80 on: 10/12/2017 01:46 pm »
-larger Raptor currently under construction

It seems unclear what she meant here. It could either mean a physically larger engine or a engine with upscaled capabilities with the same physical size.

Although the language isn't precise, it must be clear that she's talking about the BFR final scaled engine.  This is very good news and where they need to be going. 

The Mini Raptor was always a step for learning and testing.
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Offline Robotbeat

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #81 on: 10/12/2017 01:48 pm »
-larger Raptor currently under construction

It seems unclear what she meant here. It could either mean a physically larger engine or a engine with upscaled capabilities with the same physical size.

Although the language isn't precise, it must be clear that she's talking about the BFR final scaled engine.  This is very good news and where they need to be going. 

The Mini Raptor was always a step for learning and testing.
Doesnt make sense to call it a mini Raptor. It's most of the way to the one that will be used for BFR. It's a lower thrust development engine, just like Merlin 1D had.
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Online matthewkantar

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #82 on: 10/12/2017 02:10 pm »
If I understand correctly, the Boca Chica site will be BFR only? I guess that means they will be filing a new or amended EIS sometime?

Matthew

Offline SmallKing

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #83 on: 10/12/2017 02:18 pm »
If I understand correctly, the Boca Chica site will be BFR only? I guess that means they will be filing a new or amended EIS sometime?

Matthew
AFAIK, Falcon 9 will launch from Boca Chica NET later 2019
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Offline John Alan

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #84 on: 10/12/2017 02:24 pm »
If I understand correctly, the Boca Chica site will be BFR only? I guess that means they will be filing a new or amended EIS sometime?

Matthew
AFAIK, Falcon 9 will launch from Boca Chica NET later 2019

And in my opinion...
There will never be any RP-1 tank farms, or Falcon 9 GSE, HIF's, T/E's, or F9 hardware ever seen at Boca Chica for all eternity...
Yes... I am of the opinion a new EIS is in the works...
I also opine that the first BFR (the booster) static fire will be over that trench in Boca Chica on the actual Launch Mount...
Not 39a...Or anywhere else
My 2 cents on subtopic...  ;)

On edit... I am willing now to wager $$$ on this opinion with any one thinking otherwise... :)
Reference Texas launch pad thread... and suggest we take further talk of this over there...

On more edit... took it over here...
https://forum.nasaspaceflight.com/index.php?topic=43026.msg1735941#msg1735941
« Last Edit: 10/12/2017 02:45 pm by John Alan »

Offline Rocket Science

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #85 on: 10/12/2017 02:35 pm »
Quote
@SpaceX Prez @GwynneShotwell & @DFJSteve having fun onstage tonight talking all things Mars and #BFR (she clarified the F is for Falcon).

https://twitter.com/glydstone/status/918345583097556992

Emphasis mine.
That has been known since last year, courtesy of the Gallery section of SpaceX.com

I've never understood why folks designated some other F-word to the letter 'F'.
Probably because it's more of a "Pterodactyl in size" relative to the Falcon... ;D
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Offline vanoord

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #86 on: 10/12/2017 04:10 pm »
The likely location of the factory is a small lesson that what Elon says/tweets isn't necessarily what Gwynne Shotwell will enact as company policy!

It also opens up the possibility that the F9 production line will continue to run at least until BFR has entered service.

Offline vanoord

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #87 on: 10/12/2017 04:14 pm »
I've never understood why folks designated some other F-word to the letter 'F'.
Probably because it's more of a "Pterodactyl in size" relative to the Falcon... ;D

I think the joke is that the 'official' name is Big Falcon Rocket, but it can also be taken (by Elon in particular) as standing for Big F*****g Rocket.

The ambiguity is purposeful. No big deal.

Offline vaporcobra

Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #88 on: 10/12/2017 05:24 pm »
One attendee was absolutely adamant (https://www.reddit.com/r/spacex/comments/75ufq9/interesting_items_from_gwynne_shotwells_talk_at/do94w0z/) that Shotwell mentioned the construction of a larger Raptor, and that only makes sense. Minor upscaling is arguably necessary to reach the final figure of 1.7-1.9kN, can't be accomplished solely through higher chamber pressures.

I posted this earlier, but here is a picture showing sizes of the Demonstrator engine, the 2016 engine and the new smaller 2017 engine. The 2017 Raptor appears to be about a 15% scale up of the Demonstrator Raptor. Today I re-estimated the demonstrator engine exit diameter from the best picture we have. I think it is closer to .94 m which would make its expansion ratio closer to 25:1 instead of 26:1. I am also working up a Pc = 3000 psi engine.

John

Offline envy887

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #89 on: 10/12/2017 05:31 pm »
One attendee was absolutely adamant (https://www.reddit.com/r/spacex/comments/75ufq9/interesting_items_from_gwynne_shotwells_talk_at/do94w0z/) that Shotwell mentioned the construction of a larger Raptor, and that only makes sense. Minor upscaling is arguably necessary to reach the final figure of 1.7-1.9kN, can't be accomplished solely through higher chamber pressures.

I posted this earlier, but here is a picture showing sizes of the Demonstrator engine, the 2016 engine and the new smaller 2017 engine. The 2017 Raptor appears to be about a 15% scale up of the Demonstrator Raptor. Today I re-estimated the demonstrator engine exit diameter from the best picture we have. I think it is closer to .94 m which would make its expansion ratio closer to 25:1 instead of 26:1. I am also working up a Pc = 3000 psi engine.

John

I agree that's likely, but we can't know for certain without knowing the actual thrust and Pc of the demo Raptor.

Offline Kabloona

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #90 on: 10/12/2017 05:39 pm »
I've never understood why folks designated some other F-word to the letter 'F'.
Probably because it's more of a "Pterodactyl in size" relative to the Falcon... ;D

I think the joke is that the 'official' name is Big Falcon Rocket, but it can also be taken (by Elon in particular) as standing for Big F*****g Rocket.

The ambiguity is purposeful. No big deal.

In the construction and mechanical trades, sometimes the hammer one has in one's hand isn't producing the desired result, and a bigger hammer is needed. In those trades, the larger hammer is commonly referred to as a "BFH." And the F there does not mean Falcon.

So Elon/SpaceX has taken the "BFH" moniker and tongue-in-cheekily applied it to a rocket instead of a hammer, with the convenient happenstance that the "F" in BFR can be more ambiguous in polite company.

Just mentioning this for those who have never heard of a BFH.

Offline jpo234

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #91 on: 10/12/2017 05:43 pm »

It also opens up the possibility that the F9 production line will continue to run at least until BFR has entered service.
That's a known fact.
https://www.spaceintelreport.com/spacex-reassures-commercial-satellite-market-falcon-9-wont-soon-scrapped-bfr/
« Last Edit: 10/12/2017 05:44 pm by jpo234 »
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Online gongora

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #92 on: 10/12/2017 05:50 pm »
I've never understood why folks designated some other F-word to the letter 'F'.
Probably because it's more of a "Pterodactyl in size" relative to the Falcon... ;D

I think the joke is that the 'official' name is Big Falcon Rocket, but it can also be taken (by Elon in particular) as standing for Big F*****g Rocket.

The ambiguity is purposeful. No big deal.

In the construction and mechanical trades, sometimes the hammer one has in one's hand isn't producing the desired result, and a bigger hammer is needed. In those trades, the larger hammer is commonly referred to as a "BFH." And the F there does not mean Falcon.

So Elon/SpaceX has taken the "BFH" moniker and tongue-in-cheekily applied it to a rocket instead of a hammer, with the convenient happenstance that the "F" in BFR can be more ambiguous in polite company.

Just mentioning this for those who have never heard of a BFH.

If you go back 10 years you can find Elon talking about the BFE and BFTS as well, and even back then it had the dual-meaning ("Falcon" in public, but told in a way that made the double entendre obvious).

Offline vaporcobra

Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #93 on: 10/12/2017 06:03 pm »
One attendee was absolutely adamant (https://www.reddit.com/r/spacex/comments/75ufq9/interesting_items_from_gwynne_shotwells_talk_at/do94w0z/) that Shotwell mentioned the construction of a larger Raptor, and that only makes sense. Minor upscaling is arguably necessary to reach the final figure of 1.7-1.9kN, can't be accomplished solely through higher chamber pressures.

I posted this earlier, but here is a picture showing sizes of the Demonstrator engine, the 2016 engine and the new smaller 2017 engine. The 2017 Raptor appears to be about a 15% scale up of the Demonstrator Raptor. Today I re-estimated the demonstrator engine exit diameter from the best picture we have. I think it is closer to .94 m which would make its expansion ratio closer to 25:1 instead of 26:1. I am also working up a Pc = 3000 psi engine.

John

I agree that's likely, but we can't know for certain without knowing the actual thrust and Pc of the demo Raptor.

NASASpaceflight publicly quoted it at 1000kN days after the 2016 reveal, and I believe that came from L2 info. There's no reason to doubt that figure, its long been understood that the subscale Raptor is approximately the same size as Merlin 1D.

Offline Tulse

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #94 on: 10/12/2017 06:12 pm »
In the construction and mechanical trades, sometimes the hammer one has in one's hand isn't producing the desired result, and a bigger hammer is needed. In those trades, the larger hammer is commonly referred to as a "BFH." And the F there does not mean Falcon.
Many video games, especially first-person shooters (like Doom and Quake), have a huge, powerful gun called a "BFG".  Here too, the meaning of the "F" is pretty clear.

And, of course, there is the slang expression "BFD", short for the sarcastic phrase "Big F...... Deal".

More generally, the construction "Big F....... something" is pretty common in popular culture.  So I think it's clear that Elon is just being cheeky calling his rocket the BFR.

Offline vaporcobra

Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #95 on: 10/12/2017 06:19 pm »
Guys... the name is of literally zero consequence. It does not matter. Focus on the aspects related to rocketry rather than nominalism, the dead horse of BFR has been revived and killed many, many times at this point.

Offline envy887

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #96 on: 10/12/2017 06:27 pm »
One attendee was absolutely adamant (https://www.reddit.com/r/spacex/comments/75ufq9/interesting_items_from_gwynne_shotwells_talk_at/do94w0z/) that Shotwell mentioned the construction of a larger Raptor, and that only makes sense. Minor upscaling is arguably necessary to reach the final figure of 1.7-1.9kN, can't be accomplished solely through higher chamber pressures.

I posted this earlier, but here is a picture showing sizes of the Demonstrator engine, the 2016 engine and the new smaller 2017 engine. The 2017 Raptor appears to be about a 15% scale up of the Demonstrator Raptor. Today I re-estimated the demonstrator engine exit diameter from the best picture we have. I think it is closer to .94 m which would make its expansion ratio closer to 25:1 instead of 26:1. I am also working up a Pc = 3000 psi engine.

John

I agree that's likely, but we can't know for certain without knowing the actual thrust and Pc of the demo Raptor.

NASASpaceflight publicly quoted it at 1000kN days after the 2016 reveal, and I believe that came from L2 info. There's no reason to doubt that figure, its long been understood that the subscale Raptor is approximately the same size as Merlin 1D.

1000 kN and same physical size as Merlin D would mean the demo was full size but low pressure, about 15 bar MPa. If run at 20 bar MPa as Elon said the demo was running, it would produce more than 1000 kN. And at 25 bar MPa it would produce in the ballpark of the 1700 kN that Elon quoted in his presentation.
« Last Edit: 10/12/2017 11:19 pm by envy887 »

Offline vaporcobra

Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #97 on: 10/12/2017 07:36 pm »
Entirely possible that you're right, but I'd still suggest checking out the last several pages of this thread. livingjw demonstrates a pretty strong understand of rocket propulsion and backs up those charts and claims with data.

http://forum.nasaspaceflight.com/index.php?topic=41363.msg1733108#msg1733108

Offline FutureSpaceTourist

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #98 on: 10/12/2017 07:53 pm »
Quote
Reddit to the rescue!  Several people took notes, which I compiled here, with some photos too: https://www.flickr.com/photos/jurvetson/37659376821/. Thanks @glydstone!

https://twitter.com/dfjsteve/status/918560185383133184

Offline envy887

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Re: Gwynne Shotwell lecture at Stanford 11 Oct 2017
« Reply #99 on: 10/12/2017 08:57 pm »
Entirely possible that you're right, but I'd still suggest checking out the last several pages of this thread. livingjw demonstrates a pretty strong understand of rocket propulsion and backs up those charts and claims with data.

http://forum.nasaspaceflight.com/index.php?topic=41363.msg1733108#msg1733108

I trust John's analysis (and have independently confirmed some of them in RPA). But we've never had a solid source for both the chamber pressure and thrust, even in L2. John says so himself in that thread. Without knowing both values for the same operating configuration it's impossible to know exactly how large the engine is physically or what thrust it would get at the quote chamber pressures.

My interpretation is that the demo engine is physically smaller than Merlin D and gets 1000 kN at 20 bar MPa, and that when Shotwell said they were building a larger Raptor right now, when meant physically larger - not just higher pressure. The larger Raptor will run at 25 bar MPa and get 1700 kN at sea level, but it would also get more than 1000 kN at 20 bar MPa.

But it's also plausible that the demo runs at less than 20 to get 1000 kN, and the larger Raptor is the same physical size and just higher pressure.
« Last Edit: 10/12/2017 11:18 pm by envy887 »

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