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Atmospheric Lifting vs Hydrogen

Discussion in 'General' started by AirplaneFood, Apr 3, 2019.

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This last post in this thread was made more than 31 days old.
  1. AirplaneFood Apprentice Engineer

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    Basically, I'm attempting to add planetary landing capability to a space-only cargo ship. I want to know which form of thrust would be better for the purpose. Hydrogen thrusters weigh less and have more thrust, but you have to take into account the weight of the Hydrogen Tanks, Conveyor system, H2 Generators, and the ice. Atmospheric thrusters weigh quite a bit more and have less thrust, but can be used on their own.

    All of this is probably pointless anyway, cause when I filled just 5% of its cargo containers with steel plates, 100 large atmospheric thrusters couldn't lift the thing, but still curious which one is better overall.


    ~AirplaneFood aka Admiral Yu
     
  2. Ronin1973 Master Engineer

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    It depends how and where you are operating. If you need to get up and down off a planet, to and from a fixed point every time, atmospheric thrusters are pretty moot. If you're exploring a planet, you'll want them. The way the atmospheric mechanic works there's a "dead-zone" in the upper atmosphere where the pull of gravity is still pretty strong, atmospheric thrusters are too weak and so are ion thrusters. In the dead zone, you use hydrogen thrusters in order to break free of gravity. Depending on your build, you can even get away without using hydrogen. But it takes a lot of careful mass-thrust management.
     
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  3. mojomann71 Senior Engineer

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    If your goal is to mainly to have a space only ship that occasionally goes to the planet surface, then your best bet if you are wanting to limit mass (weight) is to use the Hydrogen thrusters. Since it seems you are trying to keep mass down I would not use a combo of Ion and Hydrogen, just go Hydrogen all the way, just will have to deal with Hydro tanks :(

    You could always grab a mod that has smaller size and mass hydrogen tanks as well. Not sure how you feel about using mods though or if you are on a server that even allows mods if you are doing multi-player.
     
  4. AirplaneFood Apprentice Engineer

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    I suppose I could just make a new cargo ship designed for planets, but I feel like it would make my current one rather pointless... or perhaps not, since it would have much less capacity. I don't think there is any elegant way to get 400 full containers to the surface.
     
  5. Roxette Senior Engineer

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    If it's a one-way trip, all you need is parachutes.
     
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  6. AirplaneFood Apprentice Engineer

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    I forgot those existed. Its not a one way trip, but they can still be used to get down, then after all the cargo is taken out it would likely be able to lift itself again. Still, that doesn't seem very realistic...

    On a side note, its always annoyed me that cargo containers are fixed to the ship. It would be more fun to actually offload the containers instead of just the materials.
     
  7. mojomann71 Senior Engineer

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    @AirplaneFood - That is how manned space travel first went. (And still today) Rocket up in space plummet down to earth with parachutes. :)
     
    • Agree Agree x 1
  8. Spaceman Spiff Senior Engineer

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    You'll need hydrogen thrusters to ascend to space; atmospheric thrusters will help get you partway there and correspondingly reduce overall hydrogen consumption. On the other hand, I have proven that you can build an ion thruster-only spacecraft that is capable of descending to and ascending from a planet's gravity well (I've built both a large and a small version as proof-of-concept test articles), and they still work today (I just checked).

    I'm curious about your lift issue though. Are you sure you converted your build to a ship before you tried to lift? Sometimes I forget and nothing happens. It just blasts away without moving because it thinks it's a station.
     
  9. AirplaneFood Apprentice Engineer

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    Its definitely a ship. I only play with 5x inertial dampeners, so it will hover until I try to ascend, at which point it will do the opposite. She is a massive freighter, but surprisingly, it doesn't take that many thrusters to get her off the ground. Until you fill her containers up, and suddenly not even 400 thrusters work. Its like all the cargo weighs more than the ship itself, that can't be right lol
     
  10. Stardriver907 Senior Engineer

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    Well, I have some old ships that were designed and built before the game had planets. I have one ship in particular that I swore I would never take to a planet because it was a spacecraft. It is also, unfortunately, a cargo ship, and not using it to go to planets meant I needed ta have a ship that was only for going to planets, and that was just too many ships.

    So I had to add atmospheric thrust, which allowed the ship the capability to operate in atmosphere. Later I added hydrogen thrust because you can't leave the planet without them. Only other solution is insanely powerful modded engines.
     
  11. Spaceman Spiff Senior Engineer

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    If you've set advanced settings to 10X cargo capacity and you fill the cargo containers, the mass increases really quickly.
    --- Automerge ---
    I disagree. You can still build an ion-only spacecraft that will fly to/from a planet. (See my earlier post.)
     
  12. AirplaneFood Apprentice Engineer

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    I use 1x cargo. I thought if you set it higher it would lower item weight to compensate. Guess not anymore? Geez, I can't even imagine how its possible to lift off if you have it on 10x.
     
  13. Spaceman Spiff Senior Engineer

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    How about power? A lot of times people don't provide enough power. Atmospheric thrusters are power pigs. If you're power meter is redlining, then your thrusters will work at a reduced efficiency and correspondingly reduced thrust. I've had that happen a bunch of times. I always provide enough power so that my ships don't exceed about 80% of the necessary power to fly; this accounts for thrust override when the inertial dampeners kick in and the thrusters are trying to stop my ship.

    Sorry for all the guessing.
     
  14. AirplaneFood Apprentice Engineer

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    Plenty of power too :) Its just super heavy, and has no right to be anywhere near a planet. If anyone has some examples of cargo ships that can still take off from a 1g planet at full load, that would be nice. Bonus points if its actually a useful amount of cargo.
     
  15. Spaceman Spiff Senior Engineer

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  16. Roxette Senior Engineer

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    I accidentally built a shelf...

    [​IMG]
     
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  17. CalenLoki Trainee Engineer

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    I know I already posted it in like 10 different places, but it seems relevant to the topic:

    https://docs.google.com/spreadsheets/d/1H9Pl5GNfTnZkmc9NocqctnfHNNbJGX7K0MSJpJTLm7E/edit?usp=sharing

    Unless I miscalculated something, h2 thrusters are way more mass efficient than ions in space, and atmos in atmospehere.
    But only for large grid, as small grid tank is really overweight.
    And that assuming you store energy in batteries. If you power it with reactor, atmos and ions win in terms of energy storage per kg.
     
  18. Spaceman Spiff Senior Engineer

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    Well of course you did!
     
  19. AirplaneFood Apprentice Engineer

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    I did some testing when I woke up.

    1. This is Creative, 2. This is all large ship blocks & 3. This is 1x inventory

    So I made 12 large containers and filled them with steel plates, 140,625 per container. In total this weighed (with a pass.seat) 7,298,995.00 Kg

    I then added two Hyperion 3 Reactors for a total of 1,890,905.00 Kg

    It took a total of 70! Large Atmospheric Thrusters to be able to ascend, and it took 130!! of them to achieve what I would consider an acceptable amount of stopping power. That is roughly 6 and 11 Large Atmo thrusters per container respectively. That is quite frankly ridiculous and imo unrealistic, I do not believe it would take anywhere near that many yumbo yet engines to lift a single container in real life. Containers should not become so much heavier when full that it takes 11 futuristic yumbo yet engines to lift just *one*

    Further, when I tested 12 large containers that were EmPtY, it took just two* large atmo to lift it and the two reactors, and those 2 atmo also provided acceptable stopping power.

    My conclusion is that cargo itself is waaaay too heavy. Not sure if a mod exist that lowers the weight of items in containers/in general, as I haven't looked, but that would be my first choice as the amount of thrust provided otherwise is fine.
     
  20. CalenLoki Trainee Engineer

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    @AirplaneFood
    Atmospheric thrusters in game, together with batteries to power them, have from 11:1 to 17:1 thrust to weight ratio. As comparison real life F-22 engines with afterburner have 9:1.

    Cargo containers have cargo volume exactly the same as the space they take. I agree it's a bit too much, as realistically some space should be wasted for external walls, internal conveyors, space wasted in-between non-flat objects and internal machinery that distributes and stacks cargo.

    Steel plate have density slightly lower than real life (maybe accounting for mentioned wasted space?)

    So the most unrealistic part is our expectations to transport base worth of materials with an flying minivan.

    And to be honest I like it that way. Planets challenge engineers a lot more than space.
     
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  21. Kalantris Trainee Engineer

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    My error most of the time was putting too much storage on all my ships and then watching them fly like a mockingbird without cargo and plummet like a brick as soon as they got to maybe 25% capacity. It's quite easy to create a ship that's able to increase its mass ten times if filled with cargo. A single large container on a small grid is all you can reliably fly back and forth with a ship that still looks more like a ship than a thruster. And it's quite realistic, I mean lifting 7,300 tons off the ground without any fudge-factors like antigravity or whatever quantum else the author sees fit to make things work is quite a challenge. Then putting those 7,300 tons outside earth's gravity range is another "small" step you have to take.
     
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  22. AirplaneFood Apprentice Engineer

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    bah, planets suck anyway. I'll just deny material shipments to anyone located on a planet :p
     
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  23. Kalantris Trainee Engineer

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    Couldn't you perhaps connect cargo containers to your atmospherically challenged ship via connectors and/or mergeblocks, position yourself above the client's base and drop it on a couple dozen parachutes with a bit of side thrust? The extra cost of parachutes and a connector is pretty negligable compared to a couple thousand tonnes of hydrogen you need to produce to create enough lift for that cow to go to space ;).
     
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  24. AirplaneFood Apprentice Engineer

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    I've tried something similar before, but I can never get connectors and merge blocks to work together without summoning Clang. I really wish there was just a conveyor merge block. I don't even know of a mod like that.

    Edit: You know, I could use Advanced Rotors and just detach the head. Then again, rotors aren't much better in terms of clanginess
     
  25. Kalantris Trainee Engineer

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    You could also put an armor block between them and then manually grind it once in position. That sounds pretty much Clangproof.
     
  26. Malware Master Engineer

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    No, merge blocks aren't docking blocks and the clang you experience is a result of the fact that blocks are moved from one grid to another and the smallest grid destroyed. They're intended mainly for permanent merges, a repair tool. What we need is a way to dock ships with airtightness without using merge blocks. And fix whatever other issue or problem people are having in that regard which prevents them from using connector type systems over merge blocks. Gimme a docking collar.
     
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  27. mojomann71 Senior Engineer

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    1,661
    Sometimes we do get too caught up in "realistic" in the game. We have to remember it is a game, for fun and slight challenges.
    If it were totally realistic builds would take days months or even years (based on some of the larger builds that are out there).
    If it were that realistic fun value would probably drop big time for many many players.
    Sometimes it is best to be like ok if this were real this wouldnt be possible, but in this "world" I am in it is possible so lets go with it. :)

    (if I am incoherent sorry haven't had my dose of caffeine yet! :) )
     
  28. Spaceman Spiff Senior Engineer

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  29. Cyber Cheese Apprentice Engineer

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    140,000 steel plate is equivalent in weight to 933 heavy armor blocks (minus the lighter metal grids), enough to make a 12x12x12 hollow cube, which is about 30 cubic meters in volume. I think it makes sense for the game to require 6 jumbo jet engines to hover with a steel structure that is 10 stories tall. (In real life, we do not use a VTOL turbine engine to move cargo, we use winged craft--which are not an option in SE--or rockets.)

    To answer your original question, for something this size I would definitely use hydrogen. Otherwise you will need an ungodly number of motors, and probably won't be able to exit atmosphere again without finnesse.
     
    Last edited: Apr 4, 2019
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  30. Darkheyr Trainee Engineer

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    A singe large grid large container filled with ore masses roughly 1140 tonnes. Many thingsare heavier. 1140 tonnes, as a frame of reference, is about 4 times the empty weight and two times the max takeoff weight of an Airbus 380.
    Its actual usable payload once you deduct fuel is only somewhere around 80 or 90 tons. So much for realism - SE craft are overperforming.

    That said, for heavy lifting an Ion/Atmo combo is hogwash. Small grid is a bit better, but even there thrust to mass is fairly miserable in comparison to large grid hydrogen thrusters.

    I use these two orbital haulers, both designed two lift 1 LGLC filled with ore, on a ~300 tonne frame powered with hydrogen:
    - https://steamcommunity.com/sharedfiles/filedetails/?id=1374758354
    - https://steamcommunity.com/sharedfiles/filedetails/?id=1620718613

    For lighter stuff I have two ~60 tonne ion/atmo small grids carrying a SGLC and some people each:
    - https://steamcommunity.com/sharedfiles/filedetails/?id=1622343858
    - https://steamcommunity.com/sharedfiles/filedetails/?id=1372619112

    I've only updated the Hunchback for the new update, but you get the general idea. As for lifting 400 containers...

    Don't. Thats 456'000 tonnes of ore alone, meaning you need 4'560'000 KN of thrust or 634 large hydrogen thrusters just to safely hover. Or over 700 large atmos. I dont remember their exact new fuel / power consumption offhand, but itll be somewhere around one full hydro tank or battery per second.

    I cant fathom a reason for why you'd go for all that trouble though. 400 containers is really excessive and just about never needed
     
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