The company announces that it’s completed a hundred successful tests of its staged-combustion turbomachinery. It’s a little misleading to show a full-engine test, with shock diamonds, though. Also, they don’t say if there have been any failures. Particularly of the rapid-unscheduled-disassembly type.
Meanwhile, Aerojet Rockedyne continues to beg for money.
[Update a few minutes later]
George Sowers just tweeted to me that these were subscale tests, not full scale. Hopefully, that’s next.
It’s a little misleading to show a full-engine test
I don’t understand what you find misleading. Also, there’s nothing mentioned in the press release about turbomachinery, though I’ll concede since the engine cycle is heavily married to the turbomachinery design, it stands to reason they were using their turbopumps to press the propellants. Based on the press release, it seems to me these tests focused on injector geometry and performance.
They showed a full engine test, with shock diamonds coming from the nozzle.
The press release states it included a representative thrust chamber, so why is the presence of Mach diamonds perplexing?
Also, per Tory Bruno’s Twitter, full scale static tests to begin next fall.
https://twitter.com/torybruno/status/649515014701871104
The photo doesn’t seem to show a nozzle, just what appears to be the exit end of a combustion chamber. Looks as though adding the nozzle would give them a complete engine, but what is shown just looks like everything north of the nozzle.
I’m a bit confused by Mr. Sowers’s reported tweet. Key sentence in BO press release (emphasis mine):
The staged-combustion testing configuration included a representative BE-4 preburner and regeneratively cooled thrust chamber using multiple full-scale injector elements.
There is also a reference to “preburner and main combustion chamber sizing” as one of the main test series objectives.
I have no idea what the “injector elements” of the BE-4 will look like, but the only way to reconcile what is said in the release with what you report Sowers tweeted is if the test articles are sub-scale power heads that use full-size injector elements, just fewer than would be used in a full-scale BE-4. If that’s the case, though, it’s hard to see how sizing of the other powerhead elements of such a subscale engine would translate, straightforwardly, into specs for its full-scale counterpart given the notorious non-linear scaling effects of many rocket engine components due to cube-square effects, etc.
I’m pleased that BO is apparently making good progress on BE-4, but this press release is a bit more Delphic than I’d like; lamentably typical of BO, unfortunately.
I also speculate that the timing of the release may have something to do with reassuring technically ignorant Congresscritters that ULA was not smoking wacky-terbacky when it gave the primary engine contract for Vulcan to BO instead of the familiar and well-connected, yet hapless, Aerojet-Rocketdyne in the wake of the latter’s quixotic bid to purchase ULA.