They are hardware rich in that they have no fear of running out of hardware to test although it appears they would prefer to solve any issues that led to the issue before building a replacement.
When a component failed in an engine test, or in a component test, the UCR was generated. The first thing we had to determine was whether the latest configuration had failed, or whether it was something else that had already been replaced on the engine and the failure wasn’t useful. There was enough hardware richness that we had five engine test stands, running two shifts. [..] The attempt was to incorporate any corrective actions immediately, and put out kits for retrofit of everything in the field. The logbooks of which kits applied to which engines were pretty interesting.
I think for major problems we have always [...] established an investigation team[...] Today, we would not test for a period of time. I think on F-1 that was rare. We would continue testing while the investigation was going on.
Quote from: Lemurion on 07/28/2019 02:12 amThey are hardware rich in that they have no fear of running out of hardware to test although it appears they would prefer to solve any issues that led to the issue before building a replacement. One way to use hardware-richness is to speed development by not waiting until problems are solved to continue testing (which may uncover other problems). Fixing problems serially is an efficient use of resources, but comes at a risk to schedule. On Apollo, they used hardware richness to help complete the test campaign faster. From Remembering the Giants, a monograph about Apollo engines:QuoteWhen a component failed in an engine test, or in a component test, the UCR was generated. The first thing we had to determine was whether the latest configuration had failed, or whether it was something else that had already been replaced on the engine and the failure wasn’t useful. There was enough hardware richness that we had five engine test stands, running two shifts. [..] The attempt was to incorporate any corrective actions immediately, and put out kits for retrofit of everything in the field. The logbooks of which kits applied to which engines were pretty interesting. Quote I think for major problems we have always [...] established an investigation team[...] Today, we would not test for a period of time. I think on F-1 that was rare. We would continue testing while the investigation was going on.
I agree with your point, and that's definitely how SpaceX has approached Raptor development. Blue on the other hand seems to be focused more on getting it right than getting it done fast.
I don't expect we'll get any updates on the BE-4 until after it's fully ready to go.
Quote from: Lemurion on 07/28/2019 06:22 pmI agree with your point, and that's definitely how SpaceX has approached Raptor development. Blue on the other hand seems to be focused more on getting it right than getting it done fast.... ...I cheer for both, but part of my cheer for Blue Origin is that I hope they go faster...
The first stage will use new BE-4 booster engines. A single BE-4 engine consumes approximately 150,000 pounds (68,038 kilograms) of LNG and 500,000 pounds (226,796 kilograms) of LO2.
From the "Environmental assessment for launching Vulcan at CCAFS" document , (see Vulcan thread reply #946 & #948 ), we can read : QuoteThe first stage will use new BE-4 booster engines. A single BE-4 engine consumes approximately 150,000 pounds (68,038 kilograms) of LNG and 500,000 pounds (226,796 kilograms) of LO2. Does this mean that the mixture ratio equals 3.33 ?
Quote from: bombyx on 08/02/2019 04:09 pmFrom the "Environmental assessment for launching Vulcan at CCAFS" document , (see Vulcan thread reply #946 & #948 ), we can read : QuoteThe first stage will use new BE-4 booster engines. A single BE-4 engine consumes approximately 150,000 pounds (68,038 kilograms) of LNG and 500,000 pounds (226,796 kilograms) of LO2. Does this mean that the mixture ratio equals 3.33 ?CH4 + 2(O2) = CO2 + 2(H2O)16 g/mol + 2*14 g/mol so ideally that's about 28/16 = 1.75First of all, LNG is not pure CH4 so there are some longer chain hydrocarbons in the mix. If they really are doubling the O2 needed for combustion then my guess is they are doing that to eliminate any possibility of coking or soot formation. There may be some combustion temperature issues also. Disclaimer: I'm an embedded software developer with a degree in chemistry, but I'm no rocket scientist.
Blue Origin@blueorigin·18mBE-4 continues to rack up time on the test stand. Here’s a great shot of our full power engine test today #GradatimFerociter
That's great news for Blue.
Quote from: Lemurion on 08/03/2019 03:05 amThat's great news for Blue.And for ULA and for spaceflight in general.Now hopefully they can get some full duration runs in and see how the engine holds up.
Fantastic news that full power has finally been reached - a huge milestone. Here’s the photo from Blue’s tweet.
That means an O/F ratio of 3.3, plus or minus a bit. They only gave one and a half significant figures, and threw an "approximately" on it, so take that with a medium sized grain of salt.