Author Topic: Blue Origin's BE-4 Engine  (Read 61374 times)

Online FutureSpaceTourist

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Re: Blue Origin's BE-4 Engine
« Reply #200 on: 03/20/2017 07:07 PM »
I must admit though that I feel more comfortable with SpaceX's (forced) simpler and more iterative approach.

Why?

Because I think there's quite a learning curve to building a successful orbital vehicle. So having a first orbital vehicle that's more capable (in terms of payload and re-use) than many other existing LVs feels riskier. SpaceX learnt some hard lessons with F1, will Blue do something similar with NG?

They obviously think NS has taught them enough and maybe they will have a very incremental test approach with NG. I guess I'm nervous about how easily their BE-3 and NS experience extrapolates to BE-4 and NG.
« Last Edit: 03/20/2017 07:08 PM by FutureSpaceTourist »

Online LouScheffer

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Re: Blue Origin's BE-4 Engine
« Reply #201 on: 03/20/2017 07:28 PM »
Quote from: Underappreciated Engine Components – Bearings
[Hydrostatic bearings...]

Why do we go to all this trouble instead of just using traditional bearings? Engine life. We’re relentlessly focused on reusability, and properly designed hydrostatic bearings offer the potential for longer engine life without refurbishment. This is one of the many engineering decisions we’ve made that we hope will lead to reusability – not just in principle – but to practical, operational reusability. If “reusability” requires significant refurbishment, inspection, and re-validation between flights, then it simply won’t lead to the far lower launch costs we need to achieve our vision of millions of people living and working in space.

For comparison, the SSME pump bearings were specified to have a 7.5 hour (450 minute) life before refurbishement..  That's on the order of 100 flights of a first stage.  So if the goal is to have a longer life, they must be planning lots of uses.  But it also seem to me (though I am certainly not a bearing engineer) that these might be easier to build and inspect, which might be part of their appeal.

Online FutureSpaceTourist

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Re: Blue Origin's BE-4 Engine
« Reply #202 on: 03/20/2017 07:33 PM »
Quote
@spacecom Hydrostatic bearings were one of the innovations that led us to pick the engine.  Thrilled to see them working 😌

https://twitter.com/george_sowers/status/843919844135260161

Offline Toast

Re: Blue Origin's BE-4 Engine
« Reply #203 on: 03/20/2017 08:31 PM »
In what way? We must differentiate between iterations in the design phase and development after the first generation of flight ready engines.

I agree that improvements on capability should be a lot easier on BE-4 than on Raptor, just like interations were frequent and significant for Merlin. Raptor seems much harder to improve capabilities.

But iterations during design are a totally different thing.

Sorry if I wasn't very clear, I meant it in the sense you did--improvements after the initial design. A big part of Merlin's success was it's relative simplicity, which allowed SpaceX to manufacture it quickly and incorporate more frequent changes. Similarly, I think BE-4's simpler engine cycle will make design modifications easier in the future in comparison to Raptor's more complicated full-flow staged combustion design.

Online AncientU

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Re: Blue Origin's BE-4 Engine
« Reply #204 on: 03/20/2017 10:10 PM »
Great post. Nice to see great engineering that Blue are doing.

Looks like we have entered a (welcome) new era of openness from Jeff Bezos and Blue Origins!
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Offline TrevorMonty

Re: Blue Origin's BE-4 Engine
« Reply #205 on: 03/20/2017 10:50 PM »
In what way? We must differentiate between iterations in the design phase and development after the first generation of flight ready engines.

I agree that improvements on capability should be a lot easier on BE-4 than on Raptor, just like interations were frequent and significant for Merlin. Raptor seems much harder to improve capabilities.

But iterations during design are a totally different thing.

Sorry if I wasn't very clear, I meant it in the sense you did--improvements after the initial design. A big part of Merlin's success was it's relative simplicity, which allowed SpaceX to manufacture it quickly and incorporate more frequent changes. Similarly, I think BE-4's simpler engine cycle will make design modifications easier in the future in comparison to Raptor's more complicated full-flow staged combustion design.
I don't think Blue will be modifying BE4 for improved performance. Increased reliability and easier maintenance yes.

Both NG and Vulcan (ACES) will have enough performance for most satellites without needing SRBs.

Offline russianhalo117

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Re: Blue Origin's BE-4 Engine
« Reply #206 on: 03/21/2017 12:51 AM »
I must admit though that I feel more comfortable with SpaceX's (forced) simpler and more iterative approach.

In a way, the BE-4 is more of a simple, iterative approach than SpaceX's Raptor design. Raptor is a bleeding-edge engine that relies on a lot of new technologies and designs, while the BE-4 is relatively simple, as far as staged-combustion engines go. That should make the BE-4 a lot easier to iterate on than the Raptor.
do you have proof for your statements as FFSC is not new and has been tested but not flown because of challenges from previous manufacturing techniques and others.
First ever FFSC to complete testing was the RD-270 for the cancelled UR-700 and UR-900 programmes. Next was integrated powerhead demonstrator (IPD) by Rocketdyne and last up and in testing is Raptor.

Online envy887

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Re: Blue Origin's BE-4 Engine
« Reply #207 on: 03/21/2017 02:21 AM »
I must admit though that I feel more comfortable with SpaceX's (forced) simpler and more iterative approach.

In a way, the BE-4 is more of a simple, iterative approach than SpaceX's Raptor design. Raptor is a bleeding-edge engine that relies on a lot of new technologies and designs, while the BE-4 is relatively simple, as far as staged-combustion engines go. That should make the BE-4 a lot easier to iterate on than the Raptor.
do you have proof for your statements as FFSC is not new and has been tested but not flown because of challenges from previous manufacturing techniques and others.
First ever FFSC to complete testing was the RD-270 for the cancelled UR-700 and UR-900 programmes. Next was integrated powerhead demonstrator (IPD) by Rocketdyne and last up and in testing is Raptor.

The level of integration used in Raptor is new, thanks to additive manufacturing. And the chamber pressure is new.

BE-4 has a more modular design and lower chamber pressure. Though some things are new with it as well.

Offline Dante80

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Re: Blue Origin's BE-4 Engine
« Reply #208 on: 03/21/2017 05:29 AM »

do you have proof for your statements as FFSC is not new and has been tested but not flown because of challenges from previous manufacturing techniques and others.
First ever FFSC to complete testing was the RD-270 for the cancelled UR-700 and UR-900 programmes. Next was integrated powerhead demonstrator (IPD) by Rocketdyne and last up and in testing is Raptor.

Both engines are new, and there is a lot of risk to retire and work to be done before we see them fly. The difference between the two simply lies on the design goals that each company has decided to pursue.

And the design goals for Raptor are simply ridiculous.
« Last Edit: 03/21/2017 05:30 AM by Dante80 »

Offline TrevorMonty

Re: Blue Origin's BE-4 Engine
« Reply #209 on: 03/21/2017 08:31 AM »
Trying estimate BE4 annual production rate, here my guesses.
One NG per year till they have fleet of 4 =7 engines.
 1 per flight for 2nd stage allow 6 flights = 6 engines.
Vulcan 5 flights = 10 engines.
Total 23.
When fleet of NG are ready they would start on NA at 21 engine per booster +3 for reuseable 2nd stage. One every 2 years so 12 engines. NB reusable NG 2nd stage maybe flying with few expendable so 4-6 a year. Vulcan maybe up to 10 flights but they should be recovering engines.

20 a year for next 10yrs is not unrealistic.

Online AncientU

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Re: Blue Origin's BE-4 Engine
« Reply #210 on: 03/21/2017 12:25 PM »
In what way? We must differentiate between iterations in the design phase and development after the first generation of flight ready engines.

I agree that improvements on capability should be a lot easier on BE-4 than on Raptor, just like interations were frequent and significant for Merlin. Raptor seems much harder to improve capabilities.

But iterations during design are a totally different thing.

Sorry if I wasn't very clear, I meant it in the sense you did--improvements after the initial design. A big part of Merlin's success was it's relative simplicity, which allowed SpaceX to manufacture it quickly and incorporate more frequent changes. Similarly, I think BE-4's simpler engine cycle will make design modifications easier in the future in comparison to Raptor's more complicated full-flow staged combustion design.
I don't think Blue will be modifying BE4 for improved performance. Increased reliability and easier maintenance yes.

Both NG and Vulcan (ACES) will have enough performance for most satellites without needing SRBs.

There is more to the envisioned role for NG than satellites*.

*In NG's early days, satellite constellations will be launched (hopefully).  Their first launches will be for OneWeb, for instance, with 80 satellites per launch.  With a constellation of small sats, there is no longer a 'satellite' based performance requirement as the constellation launches are almost 'infinitely' divisible payloads... more like propellant than today's GTO payloads.
« Last Edit: 03/21/2017 12:34 PM by AncientU »
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Offline Jim

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Re: Blue Origin's BE-4 Engine
« Reply #211 on: 03/21/2017 01:20 PM »
With a constellation of small sats, there is no longer a 'satellite' based performance requirement as the constellation launches are almost 'infinitely' divisible payloads... more like propellant than today's GTO payloads.

Wrong.  GSO comsats will still drive LV performance and fairing sizing.

Offline Toast

Re: Blue Origin's BE-4 Engine
« Reply #212 on: 03/21/2017 01:54 PM »
do you have proof for your statements as FFSC is not new and has been tested but not flown because of challenges from previous manufacturing techniques and others.

I think you're interpreting my statement a bit more rigidly than I intended it. All I meant was that oxygen-rich staged combustion in the BE-4 is a simpler cycle than the full flow staged combustion in Raptor. It is, in the words of Bezos, a "medium-performing version of a high-performing architecture". Bezos contends (and I generally agree) that fighting for that extra bit of Isp makes the engine significantly more complex and expensive, and complexity means that the design, manufacturing, and future upgrades are more difficult. I'm not saying that BE-4 is without challenges (or conversely, that Raptor or FFSC in general is not a good engine design or not worth the extra effort), just that I think that the BE-4 approach will probably provide for easier manufacturing and upgrading as compared to a more complicated cycle.

Offline strangequark

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Re: Blue Origin's BE-4 Engine
« Reply #213 on: 03/21/2017 02:30 PM »
Depends. SpaceX is pushing FFSC to the max, to try to hit that 4500psia chamber pressure. You could dial it back, match BE-4's 2000psia chamber pressure, while having markedly lower turbine inlet temperatures and eliminating the interpropellant seal package. Doing very, very rough scaling calcs, you could probably hit the same chamber pressure with a turbine inlet of 500-600°F, versus something around 1200-1400°F.
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Offline baldusi

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Re: Blue Origin's BE-4 Engine
« Reply #214 on: 03/21/2017 05:28 PM »
I think that you have to understand the difference between using unproven technologies and an unproven cycle. The FFSC is a bit more complicated, yes. But not as much as people have stated. The power balance is much simpler, you don't have to worry about interseals, and you can scale the cycle up and down in Pc/thrust and/or O/F as you want.
Regarding the technologies, both companies are making heavy use of FEM, 3D printing and new hot-oxygen resistant alloys. Blue even has implemented hydrostatic bearing. So, I don't think we know enough regarding the specifics of each to say that Blue has lower technologies risk. It's probable that they have lower rocket cycle risk. But again, there's so little experience with FFSC, that it might just happen to be an "easier" cycle in the long run, albeit initially more expensive.
What we know for sure is that Raptor will be a performance curve-breaking design without a schedule pressure, while BE-4 will be a "good enough" design with a very strict schedule. And that is what I think it's the actual difference: the requirements. SpaceX accepted a lot risks and aggressive requirements because they are not on a clock. And BE-4 tried to curb risk as much as possible to cover their reduced schedule margin.

Offline sdsds

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Re: Blue Origin's BE-4 Engine
« Reply #215 on: 03/21/2017 08:04 PM »
[...] the actual difference: the requirements. SpaceX accepted a lot risks and aggressive requirements because they are not on a clock. And BE-4 tried to curb risk as much as possible to cover their reduced schedule margin.

Thank-you, this is very good analysis. Risk tolerance and ways to reduce risk always seem like vital topics in innovative engineering projects!

A minor point: I think you over-state the case slightly by saying they tried to reduce risk "as much as possible." Just slightly differently phrased: I bet they tried to reduced risk only as much as needed to meet the schedule requirement!
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Offline Space Ghost 1962

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Re: Blue Origin's BE-4 Engine
« Reply #216 on: 03/21/2017 08:50 PM »
SpaceX accepted a lot risks and aggressive requirements because they are not on a clock. And BE-4 tried to curb risk as much as possible to cover their reduced schedule margin.
Exactly. For the initial success.

BTW, none of these engine designs have advanced to the point of reliability/wear/reuse. The first indications of this will come at the earliest after major firings of these engines. Then we'll see the remediations of each design, how well they work against design goals. That's when you know what you've gotten.

BE4 is a fast to market, low development risk engine. Raptor is an all out, long ranged gamble. AR1 is a RD180 "good enough" rival. Of the three, the first two have far more riding on what follows than the third does.

Offline baldusi

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Re: Blue Origin's BE-4 Engine
« Reply #217 on: 03/22/2017 10:52 AM »
Well, I hope that Raptor will be as important as the V-2 and RD-170 engines. Both had such a legacy that dominated for decades the rocket engine design. Blue is not still ready to make such a breakthough, yet. BE-4, I think, will be their RD-107/Merlin 1 workhorse engine. I expect it to be extremely successful. But for really bleeding edge engine, I expect the next engine, probably to be used on the New Armstrong.

Offline TrevorMonty

Re: Blue Origin's BE-4 Engine
« Reply #218 on: 03/22/2017 03:31 PM »
Well, I hope that Raptor will be as important as the V-2 and RD-170 engines. Both had such a legacy that dominated for decades the rocket engine design. Blue is not still ready to make such a breakthough, yet. BE-4, I think, will be their RD-107/Merlin 1 workhorse engine. I expect it to be extremely successful. But for really bleeding edge engine, I expect the next engine, probably to be used on the New Armstrong.
The BE4 should be good enough for NA, will just need more >20. By using BE4, NA will fly with a proven engine and production of NA can start as soon as NG fleet as been built.


Offline Wolfram66

Re: Blue Origin's BE-4 Engine
« Reply #219 on: 03/22/2017 03:52 PM »
I think that you have to understand the difference between using unproven technologies and an unproven cycle. The FFSC is a bit more complicated, yes. But not as much as people have stated. The power balance is much simpler, you don't have to worry about interseals, and you can scale the cycle up and down in Pc/thrust and/or O/F as you want.
Regarding the technologies, both companies are making heavy use of FEM, 3D printing and new hot-oxygen resistant alloys. Blue even has implemented hydrostatic bearing. So, I don't think we know enough regarding the specifics of each to say that Blue has lower technologies risk. It's probable that they have lower rocket cycle risk. But again, there's so little experience with FFSC, that it might just happen to be an "easier" cycle in the long run, albeit initially more expensive.
What we know for sure is that Raptor will be a performance curve-breaking design without a schedule pressure, while BE-4 will be a "good enough" design with a very strict schedule. And that is what I think it's the actual difference: the requirements. SpaceX accepted a lot risks and aggressive requirements because they are not on a clock. And BE-4 tried to curb risk as much as possible to cover their reduced schedule margin.
What happens if there is cavitation in LOX or LNG flow supplying the hydrostatic bearings?

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