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Cunjo Carl

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About Cunjo Carl

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    Rocket Fancier

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  • Location
    Staring out the window
  • Interests
    Science. All of it!

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  1. Trina Ray (lead scientist of Cassini's Titan flybys) gives a first hand talk about a few of the fantastic findings of the Cassini-Huygens mission. She talks a lot about how people reacted to the data as it unfurled and slowly pieced together some rather amazing big pictures. It's lovely, figured I'd share!
  2. What kind of bearings does turbo machinery use? Like on a turbojet or a turboshaft. I heard somewhere they use plain bearings, but that sounds crazy. Thanks in advance!
  3. So good news for me, I have no idea for how long but my hands cleared up a bit, and the place I consult for is temporarily closed so I got to use some time to brush up on thermo and figure this out instead! It was surprisingly nice to just do something silly. Also good news for me, my instincts were on point and the engine would work roughly as claimed. Despite this, both I and others pointed out that it probably won't be a terribly popular engine cycle for lack of a proper niche. But at the bottom line the pressure boost numbers wind up looking tantalizingly usable, and the engine would
  4. Oof, I wish I could interact more. I'll be back in a week or two!
  5. If we warm up the He somewhere where the RP1 is flowing, the RP1 will never cool down that much because it has so much more thermal mass.
  6. Er, you shouldn't be able to get anything like Carnot efficiency by dumping a high pressure gas straight into a low pressure chamber! Consider the reverse process.
  7. Interesting. I didn't know that was standard! If you know of a reasonable choice of temperature for the heated He entering the prop tanks, please feel free to use it! I agree Helium is probably the most conceivably benign fluid to have hot. Edit: (with the temp of the He entering the turbine raising accordingly as well, I'd assume) Edit 2: If T1/T2 stays the same, I think physically we should get the same work per tank volume. So I guess further heating the helium doesn't matter too much except that it lowers our dry mass. No complaints there!
  8. The amount of Helium (mass-wise) should just be found from doing PV=nRT on the propellant tank pressures and temperatures, for a given O:F ratio. Let's rephrase the problem backwards as: for a 12bar propellant pressure at the turbopump outlet, how low can we make the prop tank pressure? For adiabatic isentropic expansion of Helium (monatomic), Work = mass*Cp*(T1-T2), or in context Work = mass*(5/2)*R*T1*(1-(P2/P1)^(2/5)) . I forgot how to do the VdP work for a turbopump though, and can't surf enough to find out It's true! But there will also be a much stronger negative feedbac
  9. Yep! I guess engineering-wise it's like a halfway point in complexity and performance between the pressure fed and expander/bleed cycles, which is how I approached it. It fills a niche no one asked for, but hey that's why it's new! For advantages, there's no need for a regenerator (so you can use a simple ablatively cooled chamber), no extreme temperatures or chemical conditions across the turbopump, no chance of saturation in the turbine, the He is inert so you can use leaky seals, and it can work with garden variety kerolox. Just futzing with numbers in my head, I'm thinking we'd get 0.
  10. Hey! I'm still with it . It's been a rough couple seasons, but I'm very slowly improving again. For long term health reasons I can't quite science like I used to. I've had an idea floating in the back of my head for months though, and I was hoping someone might help me run the numbers? The idea is to slightly boost the efficiency of a simple, cheap pressure fed kerolox engine like the Kestrel (or similarly with the Xombie) by using the Helium that's onboard anyways for pressurizing the prop tanks. The Helium Bleed Engine Cycle: * Start with high pressure Helium (60 - 200bar)
  11. @JonnyOThan Congrats on taking the record!! I look forward to watching your run.
  12. Well, sad news. I got a secondary infection of hand foot and mouth disease which has more or less taken my hands out of commission for a while now. I can't really browse or type, so I can't really interact in the forums any more. If I improve I'll be back! In the meanwhile, be well. Keep healthy! And if you can't fly safe, fly fast.

    1. Ultimate Steve

      Ultimate Steve

      Oof. I hope you get better soon, but better for real.

    2. Cunjo Carl
    3. xendelaar


      that's sad news indeed. i hope you get well soon! 

  13. I'll put my money on nanoparticles. They can behave like semisolids even when anhydrous, and there's lots of opportunities to make them on the Moon. Definitely looking forward to hearing more!
  14. Could someone please make one of these fireworks in KSP and post a video for me to watch? I'd love to see what people come up with! You can see a slow motion video of one taking off at 5:20. The ones in real life are more complex, but in KSP we can make something equivalent using only the tippe top effect. For extra challenge, maybe try making one with SRBs only. Part clipping is 100% ok, as are DLC and mods. Good luck, have fun, and thanks in advance!
  15. Fortunately the planets themselves can be left on rails, despite orbiting eachother (see the video as an example). A space ship trying to fly between the planets though is another story...
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