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HST repair delayed; Ares 1-X launch slips
Rick Jones wrote: Wish I fully understood it I wonder what is done in Merlin-1C/Falcon[19] wrt the issue? It will make your scrotum vibrate painfully; that's all I had to understand to rule out any flights on a large rocket for me. :-D Seriously, it generally occurs with larger engines or clusters of engines; so Falcon 9 would probably be more prone to it than Falcon 1, as all nine engines firing at once could generate interesting harmonic effects among them. Saturn I apparently didn't have many pogo problems though, and that's probably about the closest analogy to Falcon 9 in design, at least as far as clustered engines go. Pat |
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HST repair delayed; Ares 1-X launch slips
Fred J. McCall wrote:
Ian Parker wrote: : :I have just read an article in the Times which says that Apollo/saturn :veterans are being drafted in to sort out the Ares problems. : Which "Times" and could we have a real cite to that? Regardless of which Times, it's partially true. Apollo/Saturn veterans are involved in Constellation, but they've been involved since the beginning, not just "to sort out the Ares problems." You do realize that "Apollo/Saturn veterans" would be in their 80's or older by now, right? Not all of them. Some are in their late 60s and early 70s. Some never even retired. Al Pennington (Apollo INCO and shuttle flight director) is working Constellation, for example. So are John Young and T. K. Mattingly. |
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HST repair delayed; Ares 1-X launch slips
On Fri, 31 Oct 2008 17:37:37 -0600, Pat Flannery
wrote: Saturn I apparently didn't have many pogo problems though, and that's probably about the closest analogy to Falcon 9 in design, at least as far as clustered engines I wonder if that had something to do with all the different prop tanks in Stage 1. Brian |
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HST repair delayed; Ares 1-X launch slips
Brian Thorn wrote: I wonder if that had something to do with all the different prop tanks in Stage 1. The odd design of the Saturn I first stage was due to the fact that they wanted it to be built as quickly as possible and at low cost. They already had the tooling to make Redstone and Jupiter missile tankage, so the first stage consisted of a stretched Jupiter tank surrounded by eight stretched Redstone tanks. The Jupiter tank and four alternating Redstone tanks held LOX; the other four held kerosene. Although clunky from a weight versus propellant capacity way of doing things, it really sped up the development time of the booster and cut R&D costs a lot. The initial versions of Saturn I were ready to go in such a hurry that NASA didn't have any payloads designed to put on them at first. Pat |
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HST repair delayed; Ares 1-X launch slips
On Sun, 02 Nov 2008 09:56:23 -0600, OM
wrote: I wonder if that had something to do with all the different prop tanks in Stage 1. The odd design of the Saturn I first stage was due to the fact that they wanted it to be built as quickly as possible and at low cost. ...Actually, what I think Brian was referring to was the lack of severe pogo, which IIRC was worked out to have been due to all that tankage acting as dampeners for the harmonics that otherwise would have had more free range had the Saturn I first stage been, say, two big wide tanks instead of nine smaller, thin ones. Yes, that's what I was after. But I don't know if that is actually true. Brian |
#16
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HST repair delayed; Ares 1-X launch slips
Brian Thorn wrote: Yes, that's what I was after. But I don't know if that is actually true. I don't know if multiple propellant tanks would help or not, it would certainly cut down propellant sloshing a great deal, but that problem was already addressed many years ago around the time that the Jupiters started going out of control as their propellants started shifting during launch. From the article on pogo, it seems to imply that the root problem is pressure spikes in the turbopump plumbing. Here's a image of the pogo suppressor on the SSME: http://www.engineeringatboeing.com/a...ges/pogo5.jpeg (That's from here, BTW: http://www.engineeringatboeing.com/articles/pogo.htm ) I've been looking at photos and drawings of the Merlin engine showing a similar structure, but haven't spotted one yet. Pat |
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