wasml

[WIP][1.0.5] Aerostats v0.0.2.1 (3/7/16)

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Non aerostat album parts: landing gear is stock and fans are from RoverDude's Exploration pack.

 

 

 

 


WARNING – early WIP.

 

 

 


Ever since I started playing KSP I've wanted to play with airships. I found Hooligans airships and had fun with those and then Procedural airships. While I really liked both of those mods I wanted to go in a bit different direction with this. I also wanted to learn how to make mods so....

 

 


Currently I have models for rigid aerostats (think Hindenburg) and non-rigid aerostats (think Goodyear blimp – technically semi rigid for the newest one). These consist of three centers and three end caps. Gondola parts include a cockpit that has some extra info display functionality for aerostats, a crew compartment and a gondola tail. Three hydrogen cylinders, one fin with a control surface, a probe core if you want the extra aerostat display info without the gondola and finally a tweakscale MM patch. I'm new to 3D modeling so the models are rather basic.

 

 


Operation wise you have a lift cell and the lift cell contains a balloonet or a balloon within a balloon. The balloonet allows you to vary the lift gas volume so you can maintain a set altitude – the bigger the balloonet is inflated, the less room for lift gas, the lower the altitude you stabilize at . Gas cells (lift cells and balloonets) can rupture if subject to too much pressure. If a gas cell is ruptured it doesn't pop like a balloon but will start leaking gas. To prevent disaster the gas cells have an emergency relief valve that will vent gas at a set pressure and while it should prevent a rupture in most circumstances, it won't save you if you ascend too fast.

 

 


To control the craft right click on envelopes to control each envelope individually:

 

 

  • Cell Main/Cell Balloonet to select the part of the envelope to control - lift cell or balloonet.
    • Step +/- to change the amount to change
      • Lift +/- to change the selected (lift or balloonet) fill by amount.
        • Dump to manually dump gas
           

 


Or on a areostat controller (cockpit or probe core) part for info/control of all envelopes:

 

  • Pressure Hold on/off to automatically try to keep pressure at 500 Pa
    • Venting on/off to allow over pressure venting - also called ERV or Emergency Relief Valve.

      When you stabilize at your desired altitude turn pressure hold off.
       

 


Working

 

 

  • Lift calc's – parts will fly.
  • Cells will randomly spring a leak if over pressure(1500 Pa for now) - probability increases with time over pressure and how far over pressure.
     

 

 


Not working

 


  • Under pressurized non rigid aerostats work just as well as when properly pressurized.

 


To Do List

 

 


  • Add hatches to the gondola parts (you can't EVA at this point).
  • Add a GUI
    • Move over burdened right click menu to GUI.
    • Auto trim function. (or /- trim)
    • Auto altitude function.
    • Auto pressure function – for non-rigids.
    • Graphical status for each lift cell.
       

    • Add configuration window.

    • Allow change of lift gasses – currently Hydrogen only.

  • Add hot air, and heated gas options.
     

  • Part scaling - needs to independently scale length and diameter so part count can be reduced.
  • More envelopes, gondola parts, better models, better textures.
  • Balance the pieces.
     

 

 

Required mods:

 

 

  • Community Resource Pack.
     

 

 

Recommended mods:

 

 


At this point I haven't played with this enough to be able to recommend any mods to go with this but AirPark looks very promising and KAS should be perfect for anchoring to towers or the ground. There is only one size of envelope so TweakScale (MM cfg included) is needed if you want bigger envelopes.

 

 

 


Download

 

 


And a final warning – progress is going to be slow.

 

 

 


License CC BY-SA

 

 

Edited by wasml
Update

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does this work with FAR? cause i have a vessel with 3889 or so kilonewtons of lift, and the vessel wieght is like, 9 or 5 tons? idk, but it should lift off on kerbin, right? and it aint.

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OMG that idea is epic! I've always dreamt of that kind of mod, but I was too lasy to make my own zeppelin mod...Your work is already better than what I would have done!

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@123nick Nothing special for FAR though I would think it should work. As far as the weights - From Wikipedia "One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared" so you would need local gravity * X Kilo-newtons of lift to hover X tons of craft. And thanks! this may have just pointed me to a possible problem that was patched over with a kludge. Also thinking I should display this as Kg lift - so when "weight = Kg lift" your hovering.

Edit: OK - looking at the code - it's messed up but when lift = mass you should be about neutral buoyancy.

@Quabbo Thanks! Oddly enough I went and purchased a rocket simulator and one of my first ideas was a blimp mod?!?

Edited by wasml

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From the procedural Airships mod, which seems to be dead (the source is available) he recommends airpark http://forum.kerbalspaceprogram.com/index.php?/topic/123669-104-airpark/ which I think would be a no brainer for this mod.

Ignore, can see you already checked the mod out

Edited by selfish_meme

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On 1/2/2016 at 0:10 AM, wasml said:

(think Goodyear blimp – technically semi rigid if I understand correctly).

This depends on which Goodyear blimp you refer to. The newest ship is indeed a semi-rigid, as it's actually a Zeppelin NT model. Previous Goodyear ships were proper blimps, meaning fully non-rigid, requiring gas pressure to maintain the envelope shape. Semi-rigid means it has some structural elements inside the envelope, but it still relies on gas pressure to maintain most of the shape. Rigid airships (as one might guess) have a fully rigid structure inside the "hull" that maintains the shape, with gas-bags inside to provide lift.

Really looking forward to seeing where this goes. I've always been a huge airship nut. 

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Tried playing around with this last night. Couldn't get the right buoyancy balance, but I didn't try all that hard as I had another mission to think about. 

I did notice though that the game ran extremely slow and choppy when I placed one of your gondolas. I tried with the little unmanned one and the regular cockpit one (away from my computer now or I'd give part names) and both would drag the game down, in the hangar at least. 

Not a problem with the hulls. Built the first test with the Stayputnik core and it worked fine (except for the fact that I have no idea how to use this mod yet). 

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kananesgi - Thanks for the feedback. Both the cockpit and unmanned part have extra functionality, a central control point so you (eventually) won't have to mess with the envelopes individually, sounds like it's in this code. I'll take a look at it this weekend and see if I can spot what's going on.

At this early stage I'm afraid the controls aren't particularly intuitive. The right click on the envelope has the following controls:

Cell        this controls which cell - the lift gas cell or the balloonet is being controlled.

Step+     Increases the amount that will be added on each "Lift+/-" click

Step-      Decreases the amount that will be added on each "Lift+/-" click

Lift+       Add gas to the selected cell

Lift-       Removes gas from the selected cell

Edit: Gave this a quick check on my system and couldn't see any difference with or without the gondola parts either in the editor or on the runway. I'm wondering if it's a conflict with another mod - are you running other mods? If so which ones?

Edited by wasml
spelling/ update

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Progress update:

Progress continues at a slow pace. Have rewrote a few times - think I have something workable now.

When in flight the control section displays buoyancy correctly - can balance a craft to hover a meter off the runway with only a couple of mm/s vertical when buoyancy reads zero. When in the editor the buoyancy is off by a considerable amount. The calls to get the atmospheric density in the editor are different than in flight and return a different value causing the calculations to be off. In flight I'm using part.atmDensity which works well but is not available in the editor. So in the editor I'm locating the spawn point and using selectedBody.GetPressure(spawn.alt) and selectedBody.GetTemperature(spawn.alt) to feed selectedBody.GetDensity(P, T) - the two methods disagree by approximately 10%. If anybody knows of a better way....

Have a "Hold Volume" that has passed the initial test - should hold the craft at altitude and keep the pressure at a set point. Pressure target hard coded to 500 Pascal for now.

Working on a "Set Altitude" function, some crude internals and some slightly improved models.

Aiming to update not too long after 1.1 when I should have a few more things working.

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I'll get something up today or tomorrow - have some improvements nearly ready and if I can work a few more bugs out I'll post a 0.0.2.

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@MatttheCzar Added an interim version to SpaceDock. A few of the initial issues have been fixed and some new issues added :) 

To control the craft right click on envelopes to control each envelope individually:

  • Cell Main/Cell Balloonet to select the part of the envelope to control - lift cell or balloonet.

  • Step +/- to change the amount of gas to add/subtract

  • Lift +/- to add/subtract the selected amount of gas.

  • Dump to manually dump gas

Or on an areostat controller (cockpit or probe core) part for info/control of all envelopes:

  • Pressure Hold on/off to automatically try to keep pressure at 500 Pa

  • Venting on/off to allow over pressure venting.

When you stabilize at your desired altitude turn pressure hold off.

Max pressure currently had coded to 1500 Pa - above that and the envelope may spring a leak.

The right click info displays in the editor should be taken with a grain of salt - Buoyancy is close but the others... not so close.

PS: forgot to mention - the cockpit has a door on one side that due to a messed up texture shows as a window - will fix on next release.

Edited by wasml

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Got a hot air balloon going - the burner is an upside down engine with negligible thrust that heats the envelope above it. Uses the ideal gas equation and Archimedes principle to compute lift. Still needs balancing - have to figure out what a reasonable vent rate is. Also need to figure out how to show the Kerbal in the basket.

http://imgur.com/Q73Cebb

http://imgur.com/z76lxpD

 

Edited by wasml
Attempt to insert picture

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Can't get it working, have hydrogen tanks but I'm unable to fill the main cell or the balloonet. Nothing happens. Any suggestions?

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@novahike999 Controls aren't very intuitive at the moment - hope to add a GUI after 1.1 releases. Did you see the my March 7th post - described the controls. If you did it may be the step is low - bump it up a few times and then hit Lift + see if that helps. If not a craft file and log would help. Edit: Another thought - pump needs a bit of electric charge to function.

@Lemcal Kerman What engine did I use? Currently using RoverDudes ducted fan from his Exploration pack.

And a bug - if you turn on Pressure Hold you may not be able to remove gas from the envelope - even if you turn Pressure hold back off. Have a fix for this and will include in the 1.1 release.

Edited by wasml
additional info

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