Poll

When will full-scale hot-fire testing of Raptor begin?

Component tests - 2017
3 (0.8%)
Component tests - 2018
19 (5.3%)
Integrated tests -  2017
16 (4.5%)
Integrated tests -  2018
227 (63.4%)
Integrated tests -  2019
64 (17.9%)
Raptor is not physically scaled up
25 (7%)
Never
4 (1.1%)

Total Members Voted: 358


Author Topic: Super Heavy (ITS-BFR) Propulsion – The evolution of the SpaceX Raptor engine  (Read 365489 times)

Offline QuantumG

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1080 on: 07/17/2018 11:49 PM »
Yup, in Sutton you'll see a similar description.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Hitech

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1081 on: 07/18/2018 01:52 PM »
I would have thought that the illustration would have made it clear I was referring to rocket engines. But i like your clarification.

Offline TomH

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1082 on: 07/18/2018 11:17 PM »
I would have thought that the illustration would have made it clear I was referring to rocket engines. But i like your clarification.

Not quite sure to whom that is addressed, but my post was in response to:

Says jets in the text you gave, is this a translation issue?

Offline Hitech

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1083 on: 07/19/2018 12:55 AM »
Just a general reply to the subject matter...

Offline Hitech

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1084 on: 07/19/2018 01:01 AM »
I do see an new vertical test stand under construction east of the Merlin vertical stand (and "milk stool") .The flame trench and water tower as well as some small building are sprouting out of the ground. Perhaps that is the suppressed Raptor stand.

Offline edzieba

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1085 on: 07/19/2018 04:11 PM »
All signs point to the new stand being an S2 test stand (to move it away from the individual Merlin test stands). The Raptor test stand is the existing Raptor test stand.

Offline testguy

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1086 on: 07/19/2018 04:49 PM »
I believe the purpose is still under debate.  L2 could provide additional insight.

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1087 on: 07/19/2018 06:40 PM »
I would have thought that the illustration would have made it clear I was referring to rocket engines. But i like your clarification.

Not quite sure to whom that is addressed, but my post was in response to:

Says jets in the text you gave, is this a translation issue?
I got it now. In my defense, the stuff at the left doesn't look very "engine-ey" in that the (apparent) bell seems smaller than the (apparent) combustion chamber.
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Offline alang

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1088 on: 07/21/2018 01:48 PM »
I would have thought that the illustration would have made it clear I was referring to rocket engines. But i like your clarification.

Not quite sure to whom that is addressed, but my post was in response to:

Says jets in the text you gave, is this a translation issue?
I got it now. In my defense, the stuff at the left doesn't look very "engine-ey" in that the (apparent) bell seems smaller than the (apparent) combustion chamber.

A RAH fan like you might remember when some people called rocket engines "jets" in English.

Offline TomH

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1089 on: 07/21/2018 03:36 PM »
This issue is known as denotation vs. connotation. The denotation is the original literal meaning of a word. The connotation is the way people use it in common vernacular. The present connotation of jet obviously is an airplane powered by turbojet or turbofan engines.

The denotation of hot is high temperature and cold is low temperature. Following a rock concert by a female performer, two young teenage boys were heard saying, Wow, she was really cool. I agree, said the other, she was so hot! A third boy, named Sheldon, exclaimed, Well hold on just a minute here; I didn't see either of you go take her temperature!

Now, back to our regularly scheduled program.
« Last Edit: 07/22/2018 08:41 PM by TomH »

Offline deruch

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1090 on: 07/22/2018 01:37 PM »
This issue is known as denotation vs. connotation. The denotation is the original literal meaning of a word. The connotation is the way people use it in common vernacular. The present connotation of jet obviously is an airplane powered by turbojet or turbofan engines.

You run into this issue a lot when engaging in technical discussions, where one participant may use one meaning and others use the other (or they may not be familiar with the technical usage, etc).
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Offline Davidthefat

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1091 on: 07/25/2018 07:21 PM »
Is the Isp stated is their actual test data, or the theoretical Isp that they are working toward?

Offline Hitech

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1092 on: 08/03/2018 01:18 AM »
I would think the latter...

Offline Davidthefat

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1093 on: 08/03/2018 06:26 PM »
I would think the latter...

I am confused as the Wiki shows 2 different Vac Isp's. Is 356s the Isp reached, or is it due to a redesign from the previous announcement?

Offline envy887

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1094 on: 08/03/2018 10:28 PM »
I would think the latter...

I am confused as the Wiki shows 2 different Vac Isp's. Is 356s the Isp reached, or is it due to a redesign from the previous announcement?

SL engines have a different vac ISP than vac engines do.

Offline Hitech

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1095 on: 08/04/2018 02:24 PM »
If they manage to operate at the MC pressures and  desired mixture ratios, then the
 chemistry and thermodynamics dictates the ISP, low MC pressure equals lower ISP.

Offline Ultrafamicom

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1096 on: 09/18/2018 03:27 AM »
Does today's test video show a full scale Raptor running?

Online Lars-J

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1097 on: 09/18/2018 05:22 AM »
Does today's test video show a full scale Raptor running?

That’s my assumption. It looked like a different test stand (?), so I assume it was the full size engine. I hope we get some clarification.

Offline Rocket Surgeon

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1098 on: 09/18/2018 06:05 AM »
Does today's test video show a full scale Raptor running?

That’s my assumption. It looked like a different test stand (?), so I assume it was the full size engine. I hope we get some clarification.

With the new chamber pressure and thrust details, does any one have any good ideas on what the new ISP might be if it changes at all?

Online yokem55

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Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #1099 on: 09/18/2018 06:46 AM »
I have a feeling that they ran into a big issue with designing the vacuum regen cooled nozzle.

It needed to be very large while still being light enough to not chew up the ISP gains, and still able to handle the thermal flux of the exhaust, which previously Elon has described as 'nuts'.

Punting on RaptorVac was probably the best way forward for now.

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