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ULA launch and discussion thread


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On 4/9/2019 at 7:22 PM, MaverickSawyer said:

You do remember that the RL-10 as it flies today is hands-down one of the most manual labor intensive engines made? I mean, it's brazed tube construction for the chamber and nozzle. Parts may be cheap, but the skilled labor to actually do the construction isn't. I'm not entirely sure you can do a furnace braze on that or not. I'll have to ask a contact of mine with some experience in such matters...

*brandishes Sutton*

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P&W used formed, double tapered, and flattened 347 stainless-steel tubes for the cooling jacket of the thrust chamber and the nozzle. It is basically similar to the tubular TC concepts developed years earlier by RMI, Aerojet, or Rocketdyne. P&W used the same subcontractor (LeFiel) who already had experience with double tapered tubes. Type 347 stainless steel was the tube material, which has good elongation properties, can be brazed, and is rust resistant. Silver was the brazing material. Brazing was done for 20 h in a special furnace with a reducing atmosphere (to prevent oxide contamination). The tubes and external rings were assembled and held in the furnace by a special rotary fix-ture. Because the TC axis was horizontal in the furnace, the TC was rotated slowly to prevent distortion and achieve an even distribution of the brazing material. 

 

Edited by DDE
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9 hours ago, Racescort666 said:

Sounds like they're the only game in town too: http://www.lefiell.com/2rocket_engine.html 

You would think that with having the market cornered and being able to dictate the price of the heinously expensive tubes, they'd be able to afford a better website.

Are you kidding?

This is the peak of web design. Nothing will ever top this.

ani_globe4b.gif

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11 hours ago, Racescort666 said:

Sounds like they're the only game in town too

No, apparently they have to compete with golf club companies, because that’s where Rocketdyne originally went to get their tubes bent.

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12 hours ago, Racescort666 said:

Sounds like they're the only game in town too: http://www.lefiell.com/2rocket_engine.html 

You would think that with having the market cornered and being able to dictate the price of the heinously expensive tubes, they'd be able to afford a better website.

does every major liquid rocket engine include merlin, because I thought that was all manufactured in house?

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26 minutes ago, insert_name said:

does every major liquid rocket engine include merlin, because I thought that was all manufactured in house?

Merlin doesn't use brazed-tube construction, so it's not applicable anyways. BE-4 also will not be using brazed tube.

However, for a long time, that has been the go-to method for any regeneratively cooled engine built in the US. H-1, F-1, J-2, RL-10, LR87/91, RS-25... All the big ones. Smaller stuff like the AJ-10 family, which includes the SPS engine from Apollo and the OMS engines off the shuttle, notably did not use brazed tube, or did so only for small sections, with the OMS using electroforming to close out machined channels in the chamber. Not sure if the Agena engine used brazed tube.

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  • 2 weeks later...
On 4/30/2019 at 8:32 AM, MaverickSawyer said:

Merlin doesn't use brazed-tube construction, so it's not applicable anyways. BE-4 also will not be using brazed tube.

However, for a long time, that has been the go-to method for any regeneratively cooled engine built in the US. H-1, F-1, J-2, RL-10, LR87/91, RS-25... All the big ones. Smaller stuff like the AJ-10 family, which includes the SPS engine from Apollo and the OMS engines off the shuttle, notably did not use brazed tube, or did so only for small sections, with the OMS using electroforming to close out machined channels in the chamber. Not sure if the Agena engine used brazed tube.

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Figure 7.11-7 shows the Agena engine, and a flow diagram is shown in Fig. 7.11-8. It has a unique aluminum (6061 T6) thrust chamber (oxidizer cooled) with a relatively thick wall, which contains long drilled holes (inclined to the axis) as cooling passages. Straight holes can be drilled into a double curved
nozzle-throat section of the cooling jacket as can be seen in Fig. 7.11-9. Some versions had a five-compartment injector baffle to prevent the occurrence of unstable combustion. The radiation-cooled nozzle-exit section (between area ratio of 12 and 45) is made of titanium reinforced externally with molybdenum stringers and hoops, which can be seen as an egg-crate pattern in Fig. 7.11-7.

As to RS-25, an image I remember made me look up, and

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For this reason a copper-alloy inner wall, and a milled channel design is used in the cooling jacket at the chamber and nozzle-throat region. This milling operation is seen in Fig.4.3-6. The copper alloy was developed by Rocketdyne to obtain higher
strength at elevated temperatures, yet retain some of the good conductivity of copper.

 

Edited by DDE
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3 hours ago, Racescort666 said:

Were there supposed to be pictures with this? Those descriptions make me want to see what they're describing.

Screenshot of a poorly-scanned PDF, so pardon me.

2463rko.jpg

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On 5/9/2019 at 7:35 PM, MaverickSawyer said:

Okay, so RS-25 used a milled and closed-out solid thrust chamber, with the nozzle extension being brazed or welded tube. Huh. Kind of an intermediate step between the older and newer technologies.

Milled channels aren’t a newer technology, but more of an augmentation. RD-170 similarly uses a milled throat but classic vacuum-brazed corrugated bronze sheets with steel outer wall for everything else.

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Looks like ULA is moving another step closer to engine reuse when they accepted an inflatable heat shield test contract in-flight over Kerbin Earth: https://spaceflightnow.com/2019/05/13/nasa-ula-find-launch-opportunity-for-inflatable-heat-shield-demonstrator/

Seriously though, this sounds like the most Kerbal plan ever since they're planning on catching the thing mid-air with a helicopter. I love it.

Figured I'd add their graphic for smart reuse because it's very similar.

recovery.jpg

Edited by Racescort666
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On 5/13/2019 at 11:42 PM, Racescort666 said:

Seriously though, this sounds like the most Kerbal plan ever since they're planning on catching the thing mid-air with a helicopter. I love it.

Where have we seen that before?

02_-5.jpg

[REDACTED]

And that wasn’t even the crazy one.

1045c.jpg

1045b.jpg

http://www.thespacereview.com/article/1045/1

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