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Helpful 1.0 observations

GoSlash27

By GoSlash27
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Wanderfound

Wanderfound

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Yeah yeah, I know but what I've meant is: If we start getting mach effects can we reliably say its passing the transsonic to supersonic barrier?

I'm not actually sure how closely tied the white effects in-game are to the speed. Do a test run and check when they occur? Preferably at varying altitudes?

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OhioBob

OhioBob

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Parts

Just performed a fuel cell test. Fuel cells do not need to be connected directly to a fuel tank. They work like RCS thrusters in that they can be placed anywhere and will draw liquid fuel/oxidizer from the available tanks through an implied piping system. They appear to draw LF/O from all tanks evenly, even across decouplers.

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Starwhip

Starwhip

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I was able to launch a drone Mun flyby without upgrading the launch pad, and it had enough excess fuel and batteries that it could have easily been used to orbit and radio back temperature readings.

For manned missions, you probably do need the upgraded launch pad.

True, but if all you've got is the Stayputnik drone control, you're not gonna have a good time. Though it should still be possible.

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Aethon

Aethon

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Sadly, staying around terminal velocity during ascent is a thing of the past (atmospheric efficiency used to be my favorite readout in KER). TV per altitude is so much higher with the new aero that you'll never catch up to it. Go for an on the pad TWR of around 1.70.

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A_name

A_name

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Has anyone figured out the new terminal velocities for various altitudes yet? Not sure how you'd go about finding them but I had the old one memorized and the sooner I can get started on the new one, the better.

I heard Kerbal Engineer has been updated to show this info (not sure if a specific field for this was added or if they just adjusted the Atmospheric Efficiency function to reflect new terminal velocities)

- - - Updated - - -

Sadly, staying around terminal velocity during ascent is a thing of the past (atmospheric efficiency used to be my favorite readout in KER). TV per altitude is so much higher with the new aero that you'll never catch up to it. Go for an on the pad TWR of around 1.70.

Other players have suggested much lower TWR's in the region of 1.2. Just a heads up.

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Gfurst

Gfurst

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I'm not actually sure how closely tied the white effects in-game are to the speed. Do a test run and check when they occur? Preferably at varying altitudes?

I did test, did you read the rest of the post? (Or maybe doing properly documented and controlled tests too)

Yeah yeah, I know but what I've meant is: If we start getting mach effects can we reliably say its passing the transsonic to supersonic barrier?

I did some test and it seems that no, with the debug info for heat and aero on watching some tests flight. It was a rather small probe with the stock resource scanning(wanted to test that) the 45 small engine and two SRB on the sides. TWR 2.1 dV of 6000

After launching and just letting the rocket do its turn on aero alone, at first the orcket quickly breaks the transonic barrier, giving some mach effects. these pass out and stabilizes at around 1.6~1.8 mach. Some of the test if I was going too shallow and too fast the front of the rocket, eg stock fairing, bit bigger sized due to Scan part, start to gain a LOT of temperature, this temp conducts to other parts, but the result is the fairing blowing up some of the time (without any of the mach or heat effects).

Which leads to observation number 1: Watchout fairings will overheat too, the visual indication was on the stage sequence

Well I was quite sleepy, so maybe the writing doesn't make a lot of sense.

Summarizing: the white a red effects seems to be high pressure and high heating due to excess velocity in a certain pressure altitude.

Reaching trans-sonic flight gave me some intense high-pressure effects, but after breaking it, going at around ~1.7 mach at higher altitude, the effects went away. But this was misleading, I was still going supersonic flight, high pressure, with increasing drag and lots of temperature gain at the rocket top, this caused my fairing to explode in a couple of the test, something forcing me to slow down.

So a rewrite of the observations := Be careful as supersonic effects are still happening even without the visual effects, high drag and overheating.

This also led me to wonder, as you climb altitude how does the speed of sound varies? I was believing that mach was high in higher atmosphere, but its actually the reverse isn't it? Sound travels faster in higher density medium. Can some clarify this?

Has anyone figured out the new terminal velocities for various altitudes yet? Not sure how you'd go about finding them but I had the old one memorized and the sooner I can get started on the new one, the better.

As mentioned above, Terminal velocity is not a constant. It depends a lot on aerodynamics and atmosphere pressure, it never was a good indicator to optimal velocities. Now the real issue is sonic speed, when going transsonic and higher a lot more of drag is created, specially in bad aero designs. However, I suspect going lower than trans-sonic isn't going to get you very far either. There probably is a mach speed sweet spot.

Also related, in the above test I did, I get a lot efficiency, around 2400~2600dV only, but its was pretty much like an ballistic missile, and had to fight the high heating effetcs.

- - - Updated - - -

Answering to my own question above:

This also led me to wonder, as you climb altitude how does the speed of sound varies? I was believing that mach was high in higher atmosphere, but its actually the reverse isn't it? Sound travels faster in higher density medium. Can some clarify this?

Wikipedia is our friend: http://en.wikipedia.org/wiki/Speed_of_sound#Altitude_variation_and_implications_for_atmospheric_acoustics and http://en.wikipedia.org/wiki/Speed_of_sound#Mach_number

Basically Mach speed depends on pressure, density, humidity, temperature and a bunch of other things. As the atmosphere lowers pressure so does density, so its a trade-off, humidity I don't believe matters on KSP, so the main factor for sound speed is temperature (as it also is for Earth). The temperature drops up to the lower atmosphere, so does mach speed, after that it actually has higher temperature gradient, so does mach speed increase. Considering the complexity of newer aero and thermo dynamics, I think it most surely holds up for KSP, but some testing would actually help.

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GoSlash27

GoSlash27

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Thanks for all the answers. I think one person in a 1.0 video said that staying close to terminal velocity, whatever it would be for the craft & altitude, would make it easier to control/ harder to lose control of. Any idea if that is acurate or not?

It works great for me. I don't need tailfins and my efficiency is good. Plus I'm not having any problems with overheating.

Best,

-Slashy

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malkuth

malkuth

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maybe its some sort of artifacts but I have a Station at about 78000. When I fly over the space center at night I can see the lights on. I could be crazy too.. But also seems like stuff is more noticeable, like Duna and Minmus from kerbin.

No mods.

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Gfurst

Gfurst

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Posted
Thanks for all the answers. I think one person in a 1.0 video said that staying close to terminal velocity, whatever it would be for the craft & altitude, would make it easier to control/ harder to lose control of. Any idea if that is acurate or not?

That makes sense, as the high pressure would make more likely to continue its own path, and not to much resistance as to keep things too wobbly. But more importantly, how can you tell terminal velocity for a given situation?

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WOODY01

WOODY01

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Something helpful for building landers:

The materials bay fits perfectly in the center of the 2.5M service compartment leaving enough room at the sides to add goo canisters, batteries, and other sciencey stuff.

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joebopie

joebopie

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bugs bugs and more bugs, and a game start the feels like a seriously un fun grind.

I think I will wait for a few more months before I bother with ksp again.

1.0 does not deserve to have that title. this version of the game feels far more buggy and unbalanced that a lot of other old versions.

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Starhawk

Starhawk

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Posted (edited)

Parts

Well, I have some new data for engine stats at Eve. Make of them what you will...

Altitude(m)    ISP(s)
             Aerospike    Mainsail     Mammoth
10 041        287.5        282.6        293.2
 3 065        232.7        221.1        246.9
 2 045        218.5        201.4        232.4
 1 043        203.0        177.5        215.0
     0        185.6        147.8        193.2

        Thrust at Eve Sea Level(kN)
               98.3        715.2       2454.0

I can't for the life of me understand the aerospike's stats compared to what I measured in 1.0. The ISP has taken a huge nerf, but the thrust is almost the same very low value I measured previously. Very weird.

I thought that the aerospike was supposed to be 'tuned' to be as efficient as possible at all atmospheric pressures (including vacuum), while bell-shaped engines were 'tuned' for their intended operating environment.

Happy landings!

edit: Looks like I got that ISP number for the aerospike wrong when I checked in 1.0. It wasn't 270. Probably 170. My mistake.

Edited by Starhawk
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vsully

vsully

Posted
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Ahh… I know this isn't related, but for the devs:

The website says that the pics on the site are of the latest version (1.0), but they are ancient, they're the same pics as there were back when the latest version was 0.24?

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Gfurst

Gfurst

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Posted
Not only does docking mode not lock out staging but docking mode no longer even puts your keyboard into docking mode. You need to use the H,N, and so on keys.

I too would like some clearance on this, having start using docking mode yet so I wouldn't know.

Hint hint: I went through all the keys mapping, setting some of my favorite tweaks, and for everykey you have to set in which mode they're valid. So its possible your keys didn't get assigned/update to the way mapping works.

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GoSlash27

GoSlash27

Posted
  • Author
Posted (edited)
Parts

Well, I have some new data for engine stats at Eve. Make of them what you will...

Altitude(m)    ISP(s)
             Aerospike    Mainsail     Mammoth
10 041        287.5        282.6        293.2
 3 065        232.7        221.1        246.9
 2 045        218.5        201.4        232.4
 1 043        203.0        177.5        215.0
     0        185.6        147.8        193.2

        Thrust at Eve Sea Level(kN)
               98.3        715.2       2454.0

I can't for the life of me understand the aerospike's stats compared to what I measured in 1.0. The ISP has taken a huge nerf, but the thrust is almost the same very low value I measured previously. Very weird.

I thought that the aerospike was supposed to be 'tuned' to be as efficient as possible at all atmospheric pressures (including vacuum), while bell-shaped engines were 'tuned' for their intended operating environment.

Happy landings!

edit: Looks like I got that ISP number for the aerospike wrong when I checked in 1.0. It wasn't 270. Probably 170. My mistake.

Starhawk,

You probably had it right the first time.

They went back and adjusted all of the engines between 1.00 and 1.02 and it ain't in the DevNotes.

Aerospike from 1.0:

MODULE
    {
        name = ModuleEngines
        thrustVectorTransformName = thrustTransform
        exhaustDamage = True
        ignitionThreshold = 0.1
        minThrust = 0
        maxThrust =[COLOR=#ff0000] [B]153.788[/B][/COLOR]
        heatProduction = 100
        fxOffset = 0, 0, 0.25
        EngineType = LiquidFuel
        PROPELLANT
        {
            name = LiquidFuel
            ratio = 0.9
            DrawGauge = True
        }
        PROPELLANT
        {
            name = Oxidizer
            ratio = 1.1
        }
        atmosphereCurve
        {
            key = 0[COLOR=#ff0000] [B]330[/B][/COLOR]
            key = 1 290
            key = 20 0.001
        }
    }
    MODULE

Aerospike from 1.02

MODULE
    {
        name = ModuleEngines
        thrustVectorTransformName = thrustTransform
        exhaustDamage = True
        ignitionThreshold = 0.1
        minThrust = 0
        maxThrust = [COLOR=#ff0000][B]180[/B][/COLOR]
        heatProduction = 110
        fxOffset = 0, 0, 0.25
        EngineType = LiquidFuel
        PROPELLANT
        {
            name = LiquidFuel
            ratio = 0.9
            DrawGauge = True
        }
        PROPELLANT
        {
            name = Oxidizer
            ratio = 1.1
        }
        atmosphereCurve
        {
            key = 0 [COLOR=#ff0000][B]340[/B][/COLOR]
            key = 1 290
            key = 20 0.001
        }
    }
    MODULE

Since the Isp vs pressure is a spline curve, I wouldn't be surprised if their tweak wrecked the Isp at 5 Atm.

Best,

-Slashy

Edited by GoSlash27
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Starhawk

Starhawk

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Posted
They went back and adjusted all of the engines between 1.00 and 1.02 and it ain't in the DevNotes.

Since the Isp vs pressure is a spline curve, I wouldn't be surprised if their tweak wrecked the Isp at 5 Atm.

I hear you Slashy. Thanks for the details.

At the moment, if you look at the TWR stats, it would appear that the Mammoth is the go to engine for Eve surface level ascents.

I still haven't tried an Eve ascent in 1.0.2. I keep thinking that 1.0.3 must be right around the corner and that will have even more changes I need to learn to account for. Honestly, at this point, all I want is a stable environment to learn to fly rockets and planes in.

Happy landings!

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