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The Entire History of Soviet Rocket Engines

everydayastronaut.com

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Re: The Entire History of Soviet Rocket Engines

#31

Post by simplicio »

wedn3sday wrote: post #19
KMag wrote: post #4

Earlier quoted context omitted.

I'd love some way to expose an allow-list-restricted subset of YouTube to my 7 y.o. nephew. A couple of days ago, he noticed that his twisty balloons get cold when they deflate, which opened up a huge learning opportunity for adiabatic compression/expansion, Sterling cryocoolers, etc. YouTube search is broken on Grandpa's smart TV and as soon as Grandpa handed him the tablet to do a YouTube search, he was off watchin…

Unfortunately the only metric that youtube cares about is watch time, so they're never going to introduce a feature that could reduce that. They _want_ to suck people into meaningless trivial nonsense since thats what keeps them watching more.

Not sure its that obvious it'd reduce watch time. If you could let your kid watch YouTube with less supervision, presumably some people would allow their kids to watch more YouTube, and more YouTube would be watched.

Re: The Entire History of Soviet Rocket Engines

#32

Post by schlupa »

bayesian_horse wrote: post #10

I heard that originally the Russians wanted to fuel their rockets with pure alcohol. But they abandoned that when they discovered the fuel would too often disappear before launch...

This was a real issue with the V2 rocket as related in Irving's book 'The Mare's Nest'.

Re: The Entire History of Soviet Rocket Engines

#33

Post by JanSolo »

MichaelMoser123 wrote: post #9

https://www.gazeta.ru/science/2021/08/27_a_13919672.shtml Here is an article in Russian about the effects of sanctions on RD-180 engines (these were powering the Atlas rockets run by ULA). it mentions a few interesting details: Energomash is loosing a third of its income, they will likely have to close down production of that engine, and that they won't be able to resume production of the engine in the future. This m…

What's notable is that the Russians were not able to exploit the huge lead that they had built in rocket engine technology. The RD-170 series of engines (RD-180, RD-190, etc) were so ahead of their time. Imagine if they had focused on reusability instead of aping NASA's foolish shuttle ideas.

A reusable Zenit or Energia would have been a real game-changer back in the 80s. Russian launches would have cost a fraction of what they were in the west. With cheap launch costs, MIR would likely have been maintained and expanded; maybe even to this day. The ISS would likely not exist since one of its primary goals was to engage the Russian space industry and prevent it decaying away to nothing. With Russian primacy in space, perhaps we'd see more of the 'exotic' Russian space ideas realized... like Kliper, TKS & Polyus.

Re: The Entire History of Soviet Rocket Engines

#34

Post by p_l »

lkozma wrote: post #13
jacquesm wrote: post #8

Earlier quoted context omitted.

The Soviets royally sucked in the computation department but were absolute masters at the materials sciences. To some extent this is still the case today.

> The Soviets royally sucked in the computation department To add more nuance, there is an essay [1] telling the history of early maximum flow algorithms and includes this small anecdote: [An] American asked: ".. how were you able to perform such an enormous amount of computing with your weak computers" to which the Russian responded: "we used better algorithms". There is some truth to that, besides maximum flow, sim…

While not unknown in the west in the past, "better algorithms" are in a way a dying breed in aerospace - these days a student will easily have a CFD package brute force through the problem overnight and be done.

My father, upon taking over his promotor's office in Warsaw Institute of Technology, found among other things a book in Russian that described analytical, symbolic methods allowing "good enough" approximated results for many airfoil/wing design tasks that are now exclusively done through CFD.

As described, in 30 minutes with pen & paper you had maybe a more coarse, but valid and in desired precision result that takes overnight run in ANSYS CFX.

Re: The Entire History of Soviet Rocket Engines

#35

Post by p_l »

rwmj wrote: post #25

The famous problem with the N1 was plumbing all of those engines to the fuel tanks without leaks. But SpaceX uses a similar design (lots of small engines) - how have they solved the plumbing problem?

Control systems and manufacturing and simulation were already mentioned, but a more critical issue is that N1, due to various design issues, had no way to do static tests that other rockets went through, meaning many issues were found when the rockets underwent Rapid Unplanned Disassembly in flight or on pad.

SpaceX built a much smaller, simpler rocket - and had a way to do the testing before flying.

Re: The Entire History of Soviet Rocket Engines

#36

Post by p_l »

tibbydudeza wrote: post #15
yborg wrote: post #12

Earlier quoted context omitted.

One of the perks of being in a Tu-22 unit in the 1960s was having access to the large supply of 40% ethanol used for the cockpit air-conditioning system.

The Mig-25 Foxbat also used alcohol for cooling - those PVO (Soviet Air Defence) units stationed in the cold could keep themselves warm.

Many airplane radar systems used alcohol in evaporative cooling system, "dipping into stores" was apparently a common problem.

Re: The Entire History of Soviet Rocket Engines

#37

Post by handrous »

HPsquared wrote: post #21
jacquesm wrote: post #14

Earlier quoted context omitted.

This is true, and one of the reasons why I feel that we have come too far too fast in the hardware department, the degree to which Moore's law has enabled sloppy and wasteful programming should not be underestimated.

Is there any kind of index of software inefficiency? Something like "number of operations required by the software stack to display a sentence on screen", with a trend over time.

Input latency's one potential convenient proxy for this, once you adjust for display latency. "How long does it take the computer to do pretty much the most basic operation an interactive computer system performs?"

Considering an IBM 8088 did way better on that than modern computers, with like 1/5,000 of the processing power (figure ass-pulled but probably not far off), indicates to me that the trend is really damn bad.

Re: The Entire History of Soviet Rocket Engines

#38

Post by handrous »

KMag wrote: post #4
cameldrv wrote: post #3

Earlier quoted context omitted.

YouTube is absolutely amazing for kids if it’s curated properly (admittedly perhaps not that easy). There’s a huge amount of content like this that is aimed at adults, but can be roughly understood by a 5-6 year old.

I'd love some way to expose an allow-list-restricted subset of YouTube to my 7 y.o. nephew. A couple of days ago, he noticed that his twisty balloons get cold when they deflate, which opened up a huge learning opportunity for adiabatic compression/expansion, Sterling cryocoolers, etc. YouTube search is broken on Grandpa's smart TV and as soon as Grandpa handed him the tablet to do a YouTube search, he was off watchin…

An allow-list feature would get me to let my kids on Youtube (despite the ads—it'd be really convenient to be able to just use the site/apps) rather than YouTube-dl-ing the videos. Even just a channel allow-list would be huge, but also being able to allow individual videos would be nice, too.

Of course, parents have been asking for this instead of the shitty "YouTube kids" garbage for... ever? Basically? So clearly Google just doesn't want to do it, for whatever reason. Probably doesn't let them extract as much money from advertising to kids, somehow.

Re: The Entire History of Soviet Rocket Engines

#39

Post by bewaretheirs »

MichaelMoser123 wrote: post #9

https://www.gazeta.ru/science/2021/08/27_a_13919672.shtml Here is an article in Russian about the effects of sanctions on RD-180 engines (these were powering the Atlas rockets run by ULA). it mentions a few interesting details: Energomash is loosing a third of its income, they will likely have to close down production of that engine, and that they won't be able to resume production of the engine in the future. This m…

The most critical piece of technology in an oxygen-rich staged combustion engine like the RD-180 is reportedly the metallurgy for an oxidizer-rich preburner.

But the required metallurgy is no longer exclusive to Russian engineers -- SpaceX's Raptor (which is a full-flow staged combustion engine) has an oxidizer-rich preburner on the oxidizer side of the engine.

Re: The Entire History of Soviet Rocket Engines

#40

Post by jacquesm »

handrous wrote: post #37
HPsquared wrote: post #21

Earlier quoted context omitted.

Is there any kind of index of software inefficiency? Something like "number of operations required by the software stack to display a sentence on screen", with a trend over time.

Input latency's one potential convenient proxy for this, once you adjust for display latency. "How long does it take the computer to do pretty much the most basic operation an interactive computer system performs?" Considering an IBM 8088 did way better on that than modern computers, with like 1/5,000 of the processing power (figure ass-pulled but probably not far off), indicates to me that the trend is really damn b…

That is a good one! And pretty easy to measure as well.
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