Author Topic: Blue Origin's BE-4 Engine  (Read 175594 times)

Offline Space Ghost 1962

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Re: Blue Origin's BE-4 Engine
« Reply #520 on: 01/08/2018 10:35 PM »
Nice progress to see Blue!

You can see clear improvements across all aspects of engine operation visible.

...

Can you describe the 'improvements' that you see?
Compare the video's side by side.

First is "trimmed" so you don't see start-up/shutdown. Second you do. Perhaps because both did not appear ideal?

Second showed nothing but an appropriate start-up/shutdown for those absences.

First has artifacts visible that show unreacted in flow (saps iSP) and irregular, lower thrust. Not visible in second.

Second has some throttling and mach diamonds appearing well defined as changing. First was less defined and at a constant thrust level. Changing thrust on a LRE risks combustion instability. (Many LRE didn't have much/any throttle capability.)

In short, the second appropriately characterizes what the BE-4 has been represented to be - a throttleable, restartable ORSC engine. Unlike the prior, which just showed it to be a LRE that can function as one.

And, like with what the first showed of operation, all elements of the second including operation, show across the board effective improvement from the first.

So what's missing? Duration, thrust levels, operating/starting/shutdown conditions, wear assessment, ... these come eventually.

What they are telling us in this video is that they made the engine they told us they would and it works as designed.

What they can't yet tell us is when it becomes a viable propulsion system for use by a LV.

Offline daveklingler

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Re: Blue Origin's BE-4 Engine
« Reply #521 on: 01/09/2018 01:43 AM »
AFAIK It's still the only cryogenic SC (of any variant) to be developed in the US (before Blue and SX).

No.  Pratt & Whitney developed a series of hydrolox high-pressure staged-combustion engines to airline engine reusability standards during the 1960's.

According to the book, "Advanced Engine Development at Pratt and Whitney", credit for original invention of the staged combustion engine goes to John Chamberlain at P&W.  While studying ways to increase combustion chamber pressure on the RL-10, Chamberlain thought of burning a little oxygen in the hydrogen working fluid before the turbine. They began testing the concept successfully in 1960.

P&W went on to develop a series of hydrolox staged combustion engines for, or so they thought, the coming wave of NASA's reusable rockets.  Beginning in the late 1950's, P&W developed the 10K, 50K, RL20 (225Klbs thrust), 250K and 350K engines to airline-standards of reusability. Along the way, Chamberlain also invented transpiration cooling for rocket engines, and by mid-1963, the 10K chamber was up to 3300 PSI.  The 5600 psi turbopumps for the 350K engine were complete by mid-1967, and they reached 6700 PSI for the 250K engine's turbopump.

All of these engines were developed for essentially unlimited reusability in reusable space transports over a little over a decade with a view toward the SSME. Despite the fact that they had never done any work in high-pressure reusable staged-combustion engines, Rocketdyne was given the contract for the SSME anyway and P&W was forced to send Rocketdyne their development notes.  P&W was later asked by NASA to return and make the SSME work and ended up working on it quietly through the end of the Shuttle program.
« Last Edit: 01/09/2018 02:01 AM by daveklingler »

Offline Chasm

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Re: Blue Origin's BE-4 Engine
« Reply #522 on: 01/09/2018 03:45 AM »

Quote from: Chris Bergin in said short article

Interestingly, L2 information notes Blue Originís BE-3E engine is making progress in a trade study being conducted at NASAís Marshall Space Flight Center (MSFC) for use on the Space Launch Systemís Exploration Upper Stage (EUS).

Marking the tests, and throwing in just the slightest bit of eyebrow-raising and tree-shaking I see ;)

Yes, what is the BE-3E. Previously we only heard about the BE-3U being worked on.

Online Lars-J

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Re: Blue Origin's BE-4 Engine
« Reply #523 on: 01/09/2018 03:51 AM »

Quote from: Chris Bergin in said short article

Interestingly, L2 information notes Blue Originís BE-3E engine is making progress in a trade study being conducted at NASAís Marshall Space Flight Center (MSFC) for use on the Space Launch Systemís Exploration Upper Stage (EUS).

Marking the tests, and throwing in just the slightest bit of eyebrow-raising and tree-shaking I see ;)

Yes, what is the BE-3E. Previously we only heard about the BE-3U being worked on.

They are the same engine. (or it is a very close cousin, like the RL-10 variants)
« Last Edit: 01/09/2018 05:18 AM by Lars-J »

Online J-V

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Re: Blue Origin's BE-4 Engine
« Reply #524 on: 01/09/2018 06:11 AM »
Can anyone estimate from the mach diamonds in the new video what is the throttle range used in the test? I mean we don't know if the maximum used is 100% (probably not), but is the highest thrust e.g. 2x the minimum thrust used during the test?

Offline Boost

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Re: Blue Origin's BE-4 Engine
« Reply #525 on: 01/09/2018 11:09 PM »
All real booster engines are overexpanded at sea level, many have the exit pressure at about 0.6 atm. This improves overall performance during flight.
Was it even the case for the Shuttle SRB ? They seem slightly underexpanded since liftoff.

Offline Chasm

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Re: Blue Origin's BE-4 Engine
« Reply #526 on: 01/10/2018 05:03 AM »
YT version of the BE-4 test video


Offline Chasm

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Re: Blue Origin's BE-4 Engine
« Reply #527 on: 01/10/2018 05:09 AM »
Yes, what is the BE-3E. Previously we only heard about the BE-3U being worked on.

They are the same engine. (or it is a very close cousin, like the RL-10 variants)

Perhaps fixed vs extensible nozzle.
Looking at the Orbital ATK articles again the contract was "for development of [...], and an extendable nozzle for Blue Origin's BE-3U/EN upper stage engine."

Offline Nilof

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Re: Blue Origin's BE-4 Engine
« Reply #528 on: 01/10/2018 11:59 PM »
Maybe E for expendable, just like the upper stage it will be used on? Which would imply that Blue would be considering reuse for their own upper stage.
« Last Edit: 01/11/2018 12:00 AM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

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