Sign in to follow this  
Kyrt Malthorn

1.0.5 Buoyancy! What sinks?

Recommended Posts

Exactly, although the drag model acts more like the 0.90 souposphere than as a drag model like in the air. Essentially water is modeled as very thick atmosphere now.

That's what the 1.0.x atmo works like anyway, this is just exaggerated. It seems to effectively be upsidedown flight with a different "gravity" pulling you to sea level ( well ok, that's what bouyancy does ) but highly compressed, so diving ( which is the analog of climbing in air ) slows you down *massively*. Likewise climbing very slightly will make you gain speed rapidly.

Share this post


Link to post
Share on other sites

I can confirm that wings work as if in extremely dense air when under water. My craft for the deep diver challenge will stall out at ~110m/s in flight at sea level, but wil pull a ~5G turn no problem at 60m/s under water. This "underwater flying" is normally known as dynamic diving among submariners.

I can also confirm that it is possible to do what submariners know as static diving, that is you use ballast to change the buoyancy of your craft so that it becomes neutrally buoyant at the desired depth. I accomplished this with some large tanks almost enough to dive, then added a few radial tanks. By jettisoning one of the small tanks I could then transfer small amounts to the empty tank and jettison only small amounts at a time until I was neutrally buoyant, floating dead in the middle of the water. After that I transferred between the small tanks to trim out the craft so it would float level with no control input or speed.

  • Like 3

Share this post


Link to post
Share on other sites

Wow. That is super cool.

Nathan Kell also mentioned that water drag scales somehow. At high speed (eg when your craft enters the water) drag is higher then at low speed. This simulates the highly turbulent flow at low speed. It also makes sure that craft come to a complete stop after a water landing.

Share this post


Link to post
Share on other sites
I can also confirm that it is possible to do what submariners know as static diving, that is you use ballast to change the buoyancy of your craft so that it becomes neutrally buoyant at the desired depth. I accomplished this with some large tanks almost enough to dive, then added a few radial tanks. By jettisoning one of the small tanks I could then transfer small amounts to the empty tank and jettison only small amounts at a time until I was neutrally buoyant, floating dead in the middle of the water.

Too bad you can't weigh down Kerbals on EVA though. They're able to swim under water, but there is no way to make them go down, only up or move horizontally. The moment you stop swimming you will start to float to the surface.

For now I'm keeping my Kerbals on a leash (I mean, KAS tether) when they EVA on the ocean floor.

Wow. That is super cool.

Nathan Kell also mentioned that water drag scales somehow. At high speed (eg when your craft enters the water) drag is higher then at low speed. This simulates the highly turbulent flow at low speed. It also makes sure that craft come to a complete stop after a water landing.

It appears so, that also explains why you can't make a proper high-speed dive *into* the water (even with a highly aerodynamic craft) but it's perfectly possible to breach out of the water at 40-50m/s and transition to a stable flight almost instantly.

Share this post


Link to post
Share on other sites

Call me crazy, but I never expected *this* to stay afloat:

V6XTOTD.png?1

All of those ore tanks are full to the brim. So what do I need to make this drop down like a brick?

Share this post


Link to post
Share on other sites
Call me crazy, but I never expected *this* to stay afloat:

http://i.imgur.com/V6XTOTD.png?1

All of those ore tanks are full to the brim. So what do I need to make this drop down like a brick?

Well, the answer is simple moar ore tanks. Really cool build by the way. approximatley same volume of ore tanks as you have other stuff.

  • Like 1

Share this post


Link to post
Share on other sites

MK3 tanks produce insane amounts of lift (or buoyancy?). 4 large ones (with 8 adapter rounding off edges) managed to keep my 800 ton aircraft carrier afloat and stable enough for 80m/s at 4x time acceleration.

Share this post


Link to post
Share on other sites

To give a satisfactory answer to this thread I have created this craft to test as many parts as possible:

https://www.dropbox.com/s/ev9zhar8yqmcn7n/MS%20Buoyancy%20buster.craft?dl=0

So far:

All commandpods and probe cores float except OKTO2, which barely sinks.

All decouplers sink except from: Small hardpoint, Structural pylon, TR-18D (1.25m stack separator) and TR-38-D.

All dockingports float.

All adapters float.

All structural steel parts sink, except octogonal strut.

All airintakes float.

Engines is a bit of a mixed bag, but generally the bigger engines float and the smaller ones sink.

These float: All 2.5m+ engines, all SRBs, Whiplash, Panther, Goliath.

These sink: Wheesley, Juno ,Vector, Dart, Spark, Reliant, Dawn, Swivel, RAPIER.

edit:

smallest heat shield sinks, the rest float.

inline batteries float.

crew containers float.

science bays float.

refineries float.

survey scanner floats.

science lab floats.

materials bay floats.

claw floats.

RTG sinks.

Edited by neistridlar
  • Like 2

Share this post


Link to post
Share on other sites

I really want to build an underwater base now. Giant ore tanks holding everything down... It'd be hard to dock parts together though. I suppose you could just have a bunch of modules close together, but then transporting Kerbals between modules would be next to impossible.

Share this post


Link to post
Share on other sites
I really want to build an underwater base now. Giant ore tanks holding everything down... It'd be hard to dock parts together though. I suppose you could just have a bunch of modules close together, but then transporting Kerbals between modules would be next to impossible.

You could build a neutrally buoyant craft to transport the kerbals between the modules. When not in use it will just sit still in the water. As you use fuel though the craft will become lighter, so you need a fuel depot, or you can fill the ore tanks from the other base parts. To make it neutrally buoyant, just make it almost sink, and ad a "Mohawk" of radial ore tanks top and bottom. The one on the bottom will act as a keel to keep it upright. Then you start jettisoning ore from the top ones and transfer between them until you are floating dead and level in the water.

Share this post


Link to post
Share on other sites
All of those ore tanks are full to the brim. So what do I need to make this drop down like a brick?

Fuel tends to be lighter than water, especially sea water. The bathyscaphe Trieste used a large tank filled with gasoline as a floating device (because the gasoline wouldn't be compressed under pressure like air would). The design worked, as it was the first vessel to make it to the bottom of the Mariana Trench.

EDIT: Never mind, I didn't see you used ore tanks. Yeah, that's silly.

Share this post


Link to post
Share on other sites

Well, I made something that floated, however it was the wreckage I was in after trying to land a plane at the old KSC on the island......hit the runway, exploded and I skimmed across the water where I came to a floating stop :)

(Didnt like planes until today when I used my PS3 controller to fly......much better)

Share this post


Link to post
Share on other sites
Full ore tanks and structural parts like girders and beams seem to be the key to making things sink. I've had some promising results with ore tanks, a bunch of large ones for main ballast and then some smaller ones for fine-tuning (the dump ore function is all-or-nothing on each tank).

Pic because it's fun :)

https://dl.dropboxusercontent.com/u/61004449/KSP/1.0.5/screenshot2.png

That's an amazing submarine. How long did it take to design that?

I tried making a sea car with ore tanks and it floats upside down, I tried making a heavier, bigger one and it blows up on the runway. :D

I built a whale as well. It travels at a maximum speed of 0.4m/s and it can only travel with its mouth open. It also can't steer.

Share this post


Link to post
Share on other sites
That's an amazing submarine. How long did it take to design that?

The sub itself, about twenty minutes. The rover wheel arrangement to get it to the water and cleanly jettison without blowing anything up, about an hour.

  • Like 1

Share this post


Link to post
Share on other sites
You could build a neutrally buoyant craft to transport the kerbals between the modules. When not in use it will just sit still in the water. As you use fuel though the craft will become lighter, so you need a fuel depot, or you can fill the ore tanks from the other base parts. To make it neutrally buoyant, just make it almost sink, and ad a "Mohawk" of radial ore tanks top and bottom. The one on the bottom will act as a keel to keep it upright. Then you start jettisoning ore from the top ones and transfer between them until you are floating dead and level in the water.

That's a pretty good idea. I'll try some different options when I get home today. If all else fails, I could just drop then entire base as one module.

I'm gonna need to build a reliable way to get the parts into the same spot in the ocean... Oh, this is going to take a while.

Share this post


Link to post
Share on other sites

IIRC, KerbinSide mod has a seaplane base or two. Perhaps this could be used to launch ocean vessels directly into the water. Also, you can use it to put bases wherever you want, so that the spawn point is closer to your build site.

Share this post


Link to post
Share on other sites

Okay so on the topic of buoyancy, am I the only one who's suddenly finding water MORE deadly than it was before, at least in some regimes?

Landing seaplanes horizontally is nice, but when I splash down a large rocket, the buoyancy force pushes the bottom up so hard that the whole thing fractures and the pieces go exploding everywhere.

Share this post


Link to post
Share on other sites

Okay, pause on the whole water base thing. It's just going to be really tedious. Bouyancy overpowers Kerbals on ladders, forcing them up, so using that as transport isn't an option. I don't think I have the patience for such a thing.

And I'm really bad at base building. My only attempt at a "base" was several Minmus craft landed within a few hundred meters of each other. I had a lander, a communications module which tipped over and I couldn't put back up, and a little RCS hovercraft to do science with, as well as its fuel tank it could dock to. RCS craft ran out of fuel a few kilometers from the base, and the two scientists on board had to walk back. Then I think I tipped over the fuel tank at one point, and gave up on the whole endeavor.

Share this post


Link to post
Share on other sites
[quote name='Choctofliatrio']I suppose you could just have a bunch of modules close together, but then transporting Kerbals between modules would be next to impossible.[/QUOTE]

A slightly rescaled version of the newly hollowed-out Mk.1 structural fuselage could come in handy.

[img]http://i.imgur.com/uZkSrtdl.png[/img]

[code]
PART
{
name = kerbalTransitTube
module = Part
author = little square dot
rescaleFactor = 1
PhysicsSignificance = -1

node_stack_top = 0, 2.3438, 0, 0, 1, 0, 1
node_stack_bottom = 0, -2.3438, 0, 0, -1, 0, 1

buoyancy = 0.1 //<-IT SINKS

TechRequired = generalConstruction
entryCost = 2500
cost = 250
category = Structural
subcategory = 0
title = Kerbal Transit Tube
manufacturer = The Department of Placing Things on Other Things
description = A hollow transit tube.
attachRules = 1,0,1,1,0,0,0
mass = 0.25
dragModelType = default
maximum_drag = 0.1
minimum_drag = 0.15
angularDrag = 1
crashTolerance = 15
breakingForce = 100
breakingTorque = 100
maxTemp = 2000
fuelCrossFeed = False
bulkheadProfiles = size1

MODEL
{
model = Squad/Parts/Structural/mk1Parts/StructuralHollow
scale = 1.25, 2.5, 1.25
}

}
[/code]


**edit: I'm sure you could also make ballast tanks by adding an ore generator to a ore tank .cfg. I haven't actually tried though, so don't take my word for it. Edited by little square dot

Share this post


Link to post
Share on other sites

Somebody should do a full exploration of the ocean floor, there may be an undiscovered Easter Egg.

Share this post


Link to post
Share on other sites
40 minutes ago, SR said:

Somebody should do a full exploration of the ocean floor, there may be an undiscovered Easter Egg.

if you dive deeper then -1000 Meter (if i recall correct) you sub just disappears , even if the ground floor is deeper. So at the moment i doubt it there is an easter egg under water somewhere. Would be found also quite fast with scansat :D

Share this post


Link to post
Share on other sites
On 11/10/2015 at 9:06 AM, Stoney3K said:

Does "flying" into the water at a substantial speed (20-40m/s) also cause a craft to dive under or will it just slam against the water like it used to?

If the reverse-flight principle works with that, we could be looking at some really interesting dive-bombing aircraft.

I've been experimenting with sea planes, and with a shallow enough angle I've been able to safely land a cargo plane at 100 m/s. I've also literally stalled my plane about 30m above the surface and hit the water at about 40m/s and survived, so water is definitely more forgiving than it used to be. I've also tried diving from the air and it doesn't seem to work. The aircraft just gets pushed back up to the surface before getting more than the cockpit underwater, but once on the surface you can dive to your hearts content. I think I remember someone talking about how the games new buoyancy isn't static and so diving from the air causes the buoyancy numbers to go up and then settle. 

Share this post


Link to post
Share on other sites
4 hours ago, Ringkeeper said:

if you dive deeper then -1000 Meter (if i recall correct) you sub just disappears , even if the ground floor is deeper. So at the moment i doubt it there is an easter egg under water somewhere. Would be found also quite fast with scansat :D

I used Roverdude's Submarine mod to go explore the seafloor smiley south of KSC. (it is there. Kerbal Maps lets you see it fine) I think my sub descended into the left "eye" but the sub was fine. Its the terrain that mysteriously disappears, not the vessel. However the physics work fine so I actually managed to plant a flag down there.

This does also mean that a properly weighted rover could explore the depths as freely as one pleased. 

Personally though, I think this bug makes submarinal exploration a whole lot more interesting. KAS/KIS would definitely make things easier (particularly laying buoys around bases and whatnot so you aren't as likely to crash).

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this