22 Dec 2024, 01:57 [ UTC - 5; DST ]
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Username Protected
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Post subject: Re: Spacex Starship OFT Posted: 20 Nov 2024, 15:01 |
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Joined: 07/19/10 Posts: 2984 Post Likes: +1407 Company: Keller Williams Realty Location: Madison, WI (91C)
Aircraft: 1967 Bonanza V35
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Username Protected wrote: In orbit travel plaza? Orbit the Earth? Really? Wow!
What is so surprising? We already have space station up there. We ship supplies up there 3-4 times a year, We shuttle people up and down 4-5 times a year, Heck, we already ship tourists up and down (Axiom) all we need is scale. With Starship cost of launch in 2-3mln/launch range (~800k for propelant and ~2mln for hardware) and capacity to shuttle 100 people/time it comes down to $20-30k/seat. Jumpseats (small crew space on otherwise cargo missions) should be even cheaper.
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Post subject: Re: Spacex Starship OFT Posted: 21 Nov 2024, 14:25 |
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Joined: 04/26/13 Posts: 21251 Post Likes: +21301 Location: Columbus , IN (KBAK)
Aircraft: 1968 Baron D55
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Username Protected wrote: Hmm, then it is overbuilt. Exactly my thoughts. I'm expecting they will push to failure on one of the next flights. The exceedence was pitch attitude. They had models that indicated that they could go to a slightly negative pitch angle and still recover and land. If it couldn’t, it would have belly flopped into the water. But it could, and did.
It wasn’t a strength issue.
_________________ My last name rhymes with 'geese'.
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Post subject: Re: Spacex Starship OFT Posted: 21 Nov 2024, 15:34 |
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Joined: 07/19/10 Posts: 2984 Post Likes: +1407 Company: Keller Williams Realty Location: Madison, WI (91C)
Aircraft: 1967 Bonanza V35
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Username Protected wrote: I thought it was interesting that on the Starship, only the 3 center engines of the 33 total engines gimballed, and on the Saturn V, only the center engine of the 5 gimballed. There is way more gimballing than just the 3: https://youtu.be/gY-UbmBpxAo?si=BfgyCfhuczcDFEir&t=20the middle ring moves as well, the outside ring is stationary.
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Post subject: Re: Spacex Starship OFT Posted: 21 Nov 2024, 18:50 |
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Joined: 04/26/13 Posts: 21251 Post Likes: +21301 Location: Columbus , IN (KBAK)
Aircraft: 1968 Baron D55
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Username Protected wrote: I would think a challenge of all the gimbaling to steer and maintain attitude is probably the risk of overcontrolling. By limiting the number of engines that gimbal they probably have more than enough authority and reduced risk of overcontrol. Also less complexity and weight. The best part is no part.
_________________ My last name rhymes with 'geese'.
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Post subject: Re: Spacex Starship OFT Posted: 21 Nov 2024, 18:51 |
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Joined: 07/19/10 Posts: 2984 Post Likes: +1407 Company: Keller Williams Realty Location: Madison, WI (91C)
Aircraft: 1967 Bonanza V35
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Username Protected wrote: I would think a challenge of all the gimbaling to steer and maintain attitude is probably the risk of overcontrolling. By limiting the number of engines that gimbal they probably have more than enough authority and reduced risk of overcontrol. The outside engines are never used again except for initial ascent, there is zero need to wast several thousand pounds for the gimballing hardware for engines that don't need that.
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Post subject: Re: Spacex Starship OFT Posted: 21 Nov 2024, 22:02 |
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Joined: 12/10/07 Posts: 33569 Post Likes: +12579 Location: Minneapolis, MN (KFCM)
Aircraft: 1970 Baron B55
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Username Protected wrote: I still can't get gimballing straight in my mind, the amount of power required to move a nozzle, it hurts to even think about it. If the pivot point is well located the force required to move the nozzle would mostly be due to friction in the actuators. Of course with 280 tons of thrust that friction might be significant.
_________________ -lance
It's easier to fool people than to convince them that they have been fooled.
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Post subject: Re: Spacex Starship OFT Posted: 22 Nov 2024, 00:02 |
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Joined: 07/22/14 Posts: 9925 Post Likes: +18600 Company: Mountain Airframe LLC Location: Mena, Arkansas
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Username Protected wrote: Do a close up and look at the engines, inside the thrust chambers (nozzles). Some of the injector plates look different, like some are burning differently.
Hmph.
And I'm so used to seeing "tail feathers" on rockets... I think they all look like a litter of baby Pac-Men, some a bit more ripe than others. Hmph.
_________________ If a diligent man puts his energy into the exclusive effort, a molehill can be made into a mountain
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Post subject: Re: Spacex Starship OFT Posted: 22 Nov 2024, 08:51 |
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Joined: 04/26/13 Posts: 21251 Post Likes: +21301 Location: Columbus , IN (KBAK)
Aircraft: 1968 Baron D55
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Username Protected wrote: Do a close up and look at the engines, inside the thrust chambers (nozzles). Some of the injector plates look different, like some are burning differently.
I see that. Some of the dark spots appear to not be aligned with a nozzle. I’m thinking it’s an optical distortion.
_________________ My last name rhymes with 'geese'.
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Post subject: Re: Spacex Starship OFT Posted: 22 Nov 2024, 08:57 |
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Joined: 03/23/08 Posts: 7370 Post Likes: +4038 Company: AssuredPartners Aerospace Phx. Location: KDVT, 46U
Aircraft: IAR823, LrJet, 240Z
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You can see the different colors on all the images. Including in the gimbal test video. I posted the same question on the curated FB group the other day. I think the consensus is accumulated run time or slightly different process / material. Ch4 doesn’t get sooty like RP1 and they run a “pretty high” EGT
_________________ Tom Johnson-Az/Wy AssuredPartners Aerospace Insurance Tj.Johnson@AssuredPartners.com C: 602-628-2701
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