Poll

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

Component tests - 2017
3 (0.6%)
Component tests - 2018
21 (4.2%)
Integrated tests -  2017
19 (3.8%)
Integrated tests -  2018
237 (47.2%)
Integrated tests -  2019
180 (35.9%)
Raptor is not physically scaled up
32 (6.4%)
Never
10 (2%)

Total Members Voted: 502


Author Topic: SpaceX Raptor engine (Super Heavy/Starship Propulsion) - General Thread 1  (Read 797934 times)

Offline jpo234

  • Full Member
  • ****
  • Posts: 1938
  • Liked: 2129
  • Likes Given: 1847
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #300 on: 09/05/2017 06:18 pm »



Here is pretty good video that explains (among other things) Full Flow Staged Combution cycle:


Another one I found very enlightening:
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #301 on: 09/06/2017 11:10 am »
Ok maybe I over-complex the thinking process  ;) ;) ;)

Titus

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 36422
  • Minnesota
  • Liked: 20786
  • Likes Given: 10796
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #302 on: 09/06/2017 01:07 pm »
In the pre burner. Liquid because supercritical gas.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #303 on: 09/07/2017 03:01 pm »
I'm trying to find pintle injector for gasified propellant, not much result...

An interesting find is patent by JAXA, I guess it's something to do with JAXA's LE-X engine development.
https://www.google.com/patents/US7703274


Titus

Offline Dave G

  • Senior Member
  • *****
  • Posts: 3231
  • Liked: 2126
  • Likes Given: 2021
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #304 on: 09/10/2017 06:53 pm »
Where does SpaceX test this sub-scale engine?  Will they attempt to see what it's maximum thrust can be?

Also, can they test a full scale engine at McGregor?  Or do they need Stennis? 
SpaceX tests their subscale Raptor at their McGregor test facility in Texas. I think that they will also test the full size Raptor at McGregor as well.

RAPTOR TEST EQUIPMENT ENGINEER: McGregor, TX
http://www.spacex.com/careers/position/211014

Quote
RESPONSIBILITIES:
• Engineering, design, analysis, material/component selection and procurement, construction, activation, and maintenance of test stands, tooling, and supporting infrastructure
• Provide support and direction to technicians during construction, activation, and maintenance of stands and equipment
• Support testing campaigns by operating ground propellant systems, reviewing data for system health, and modifying equipment or procedures as necessary
• Develop novel ways to streamline site-wide processes and increase the reliability and efficiency of testing operations
• Perform any additional tasks that ensure efficient and effective testing, as required
• It is sometimes necessary to perform hands-on work in all environments (heat, cold, rain), occasionally in tight quarters or at heights

BASIC QUALIFICATIONS:
• Bachelor’s degree in mechanical engineering, aerospace engineering or other engineering discipline

PREFERRED SKILLS AND EXPERIENCE:
• Master’s degree in mechanical or aerospace engineering
• 3+ years of relevant experience in an industrial setting
• Fundamental understanding, intuition, and aptitude of fluid and/or structural design and analysis
• Creative ability to imagine and design from scratch, while retaining low cost, reliability, efficiency, and maintainability
• Experience where quick-thinking and problem solving plays a critical role
• Good response to challenges posed by short deadlines
• Ability to work in a high-concentration, high-stress environment, under possible extended work hours
• Acute attention to detail, ability to see interactions with other systems to avoid problems
• Intermediate skill level using Windows Operating Systems
• Intermediate skill level using Microsoft Office
• Intermediate skill level using CAD (NX a plus)
• Experience with high pressure and cryogenic fluid systems and components
• Experience producing drawings for welders and machine shop fabrication
• Machining, welding, other fabrication techniques, and general hands-on experience
• Experience in FEA or CFD modeling and analysis, with ability to verify by simplified hand calculations
• Piping and pressure vessel design experience per ASME code, work with flanges, gaskets, fasteners
• Instrumentation, testing, data review and analysis, verification against a model

ADDITIONAL REQUIREMENTS:
• General physical fitness is required for some work areas, flight hardware typically is built in tight quarters and physical dexterity is required
• Physical effort including standing, lifting and carrying light weight such as materials or equipment. Must lift up to 30 pounds unassisted
• Occasionally exposed to work in extreme outdoor environments- heat, cold, rain
• Work performed in an environment requiring exposure to fumes, odors, and noise
• Must be available to work extended hours and weekends, which varies depending on site operational needs, flexibility required
« Last Edit: 09/10/2017 06:53 pm by Dave G »

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #305 on: 09/29/2017 08:46 am »
Based on IAC 2017, we are now looking at much smaller Raptor, roughly 60% of IAC 2016.

31 engines with 5400mT thrust. That's 1707kN per engine.
And the chamber pressure now down to 250bar

IAC 2016, it was 300bar, 3050kN
« Last Edit: 09/29/2017 08:46 am by titusou »

Offline Welsh Dragon

  • Full Member
  • ****
  • Posts: 669
  • Liked: 1031
  • Likes Given: 116
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #306 on: 09/29/2017 08:55 am »
Still thinking they'll go up to 300 eventually.

Offline DJPledger

  • Full Member
  • ****
  • Posts: 757
  • Liked: 431
  • Likes Given: 29418
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #307 on: 09/29/2017 09:07 am »
Based on IAC 2017, we are now looking at much smaller Raptor, roughly 60% of IAC 2016.

31 engines with 5400mT thrust. That's 1707kN per engine.
And the chamber pressure now down to 250bar

IAC 2016, it was 300bar, 3050kN
So looks like what was termed subscale Raptor that is undergoing testing is now the size of Raptor they will use. Saves a lot in dev. costs over IAC2016 size Raptor but I still think they still should have bit the bullet and gone with a larger Raptor to reduce booster engine no.

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #308 on: 09/29/2017 09:11 am »
Still thinking they'll go up to 300 eventually.
Surely they will, but 250bar->300bar only give thrust change as 1700kN to 2000kN
Thrust is mainly determined by prop flow rate.

Maybe SpaceX decide to go with test engine's "sub scale" size, instead of make it "full sized" ?

Titus

Offline jpo234

  • Full Member
  • ****
  • Posts: 1938
  • Liked: 2129
  • Likes Given: 1847
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #309 on: 09/29/2017 09:11 am »
Saves a lot in dev. costs over IAC2016 size Raptor but I still think they still should have bit the bullet and gone with a larger Raptor to reduce booster engine no.

Still early days for Raptor.
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #310 on: 09/29/2017 09:17 am »
Based on IAC 2017, we are now looking at much smaller Raptor, roughly 60% of IAC 2016.

31 engines with 5400mT thrust. That's 1707kN per engine.
And the chamber pressure now down to 250bar

IAC 2016, it was 300bar, 3050kN
So looks like what was termed subscale Raptor that is undergoing testing is now the size of Raptor they will use. Saves a lot in dev. costs over IAC2016 size Raptor but I still think they still should have bit the bullet and gone with a larger Raptor to reduce booster engine no.
That maybe true of the goal is reaching the original ITS(IAC2016) capability.

But with BFR(IAC2017) capability target, the original "IAC2016 full sized" Raptor will make the 2nd stage... either throttle-able down to 10% (not likly I think)... or cutdown engine number from 4+2 to 3+1... which will drop the redud-backup capability.

Or you use 2 different sized Raptor, not an idea solution I guess.

Interesting changes anyway.
Titus

Offline JamesH65

  • Full Member
  • ****
  • Posts: 1502
  • Liked: 1571
  • Likes Given: 9
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #311 on: 09/29/2017 09:30 am »
Based on IAC 2017, we are now looking at much smaller Raptor, roughly 60% of IAC 2016.

31 engines with 5400mT thrust. That's 1707kN per engine.
And the chamber pressure now down to 250bar

IAC 2016, it was 300bar, 3050kN
So looks like what was termed subscale Raptor that is undergoing testing is now the size of Raptor they will use. Saves a lot in dev. costs over IAC2016 size Raptor but I still think they still should have bit the bullet and gone with a larger Raptor to reduce booster engine no.

Engines are now reliable (or can be made so), so no need to worry about the number of them being a source of failure.

Offline Dante80

  • Full Member
  • ****
  • Posts: 888
  • Athens : Greece
  • Liked: 816
  • Likes Given: 508
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #312 on: 09/29/2017 10:57 am »
The test data given was a bit of a surprise to me. I had no idea they had progressed so much already!

Offline schaban

  • Full Member
  • *
  • Posts: 180
  • Liked: 53
  • Likes Given: 130
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #313 on: 09/29/2017 01:51 pm »
I'm pretty sure this version of the Raptor will eventually produce 3 MN. Initially Merlin 1D had ~70% of block 5 levels; here's the difference is roughly the same.

Offline wannamoonbase

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 4866
  • Denver, CO
    • U.S. Metric Association
  • Liked: 2602
  • Likes Given: 3308
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #314 on: 09/29/2017 01:59 pm »
The test data given was a bit of a surprise to me. I had no idea they had progressed so much already!

Appears they need more or larger tanks if they can only get a 40 sec run.  They’ll need a lot more time running the Raptor.

The blue exhaust and shock diamonds were fantastic. 

Still have a hard time imagining 31 of them on a vehicle. 
Superheavy + Starship the final push to launch commit!

Offline envy887

  • Senior Member
  • *****
  • Posts: 7992
  • Liked: 6532
  • Likes Given: 2927
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #315 on: 09/29/2017 01:59 pm »
The test data given was a bit of a surprise to me. I had no idea they had progressed so much already!

Appears they need more or larger tanks if they can only get a 40 sec run.  They’ll need a lot more time running the Raptor.

The blue exhaust and shock diamonds were fantastic. 

Still have a hard time imagining 31 of them on a vehicle.

Elon said that the tanks limited them to 100 seconds of run time.

Offline ZachF

  • Full Member
  • ****
  • Posts: 1389
  • Immensely complex & high risk
  • NH, USA, Earth
  • Liked: 2226
  • Likes Given: 444
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #316 on: 09/29/2017 02:04 pm »
Looking at the size of the nozzle diameters, it looks like RaptorVac had the expansion ratio dropped from ~200 around 120-140. would explain the slightly larger drop in ISP than the SL version (375 from 381, vs 330 from 334)

SL is probably similar to old Raptor, maybe slightly less (37 vs 40)

(2.4^2 / 1.3^2 = 3.41)
(3.41 x 37 = 126)

Mixture ratio was also changed from 3.8:1 to 3.6:1. (860/240) Probably result of lower (250bar) chamber pressure.
« Last Edit: 09/29/2017 02:06 pm by ZachF »
artist, so take opinions expressed above with a well-rendered grain of salt...
https://www.instagram.com/artzf/

Offline Semmel

  • Senior Member
  • *****
  • Posts: 2168
  • Germany
  • Liked: 2416
  • Likes Given: 11786
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #317 on: 09/29/2017 02:12 pm »
For my personal understanding, is it correct that the change in mixture ratio makes the combustion colder, hence less pressure and ISP?

Also, can someone please explain to me why they are going oxygen rich instead of fuel rich? I always thought a fuel rich environment would create lighter combustion elements, hence higher ISP for the same chamber temperature and pressure. Is that wrong?

@ edit: Sorry, my mistake. Raptor actually operates fuel rich. My parsing of the ratio numbers were wrong.
« Last Edit: 09/29/2017 02:46 pm by Semmel »

Offline ZachF

  • Full Member
  • ****
  • Posts: 1389
  • Immensely complex & high risk
  • NH, USA, Earth
  • Liked: 2226
  • Likes Given: 444
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #318 on: 09/29/2017 02:17 pm »
I'm pretty sure this version of the Raptor will eventually produce 3 MN. Initially Merlin 1D had ~70% of block 5 levels; here's the difference is roughly the same.

Probably not.

This engine, if it's maxed out to IAC2016 (chamber pressure increase from 250bar to 300bar, slight increase in ER, increase in O:F ratio) specs could probably hit a little over 2MN.

The original Raptor needed a ~1.7m bell diameter to hit 3MN.

The original Merlin engine only hit ~67bar. The current M1DFT is probably around 110bar, a ~65% increase.
artist, so take opinions expressed above with a well-rendered grain of salt...
https://www.instagram.com/artzf/

Offline titusou

  • Member
  • Posts: 59
  • Tokyo
  • Liked: 86
  • Likes Given: 0
Re: ITS Propulsion – The evolution of the SpaceX Raptor engine
« Reply #319 on: 09/29/2017 02:28 pm »
For my personal understanding, is it correct that the change in mixture ratio makes the combustion colder, hence less pressure and ISP?

Also, can someone please explain to me why they are going oxygen rich instead of fuel rich? I always thought a fuel rich environment would create lighter combustion elements, hence higher ISP for the same chamber temperature and pressure. Is that wrong?
Graph is easier to explain :)
(using Rocket Propulsion Analysis :))

Titus

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1