Helpful 1.0 observations

[A_name]

Radially placed parts do not have any occlusion enabled and will ALWAYS suffer maximum drag penalties for a given orientation into airstream. This means that placing something externally and moving it inside the hull via gizmos (clipping in other words) does not lower the drag experienced at all, and that part is still just asd subject to overheat as it was externally.

So, for example, on a rocket is shaped like this, parts attached radially below the fairing, which would seem to be be occluded by the fairing (if flying vertical), will still experience drag?

Occlusion works for parts in a straight line (attached to the nodes in front/rear). Only the front part suffers maximum drag/heat penalties, and every part behind it regardless of size/shape is occluded and only suffers minor drag when angled. I know this is most likely a bug/exploit, but its how the game curently works so nice to let people know.

So let's say I have a Mk2 Lander Can with an LV-909 engine and I use the flat surface under the can to attach some stuff, will that not be occluded because they're not attached to the lander can's rear node?

- - - Updated - - -

To perform an S-turn, you don't only need to bank--you have to pull on the stick while in that bank--it is this pitching (albeit sideways) that should cause the change in the vector.

Yes, thanks for clarifying. That's what I meant when I said banking. Still when pulling up (sideways) in .90 my planes would not turn until below 30km or so.

[rodion_herrera]

Yes, thanks for clarifying. That's what I meant when I said banking. Still when pulling up (sideways) in .90 my planes would not turn until below 30km or so.

You only do S-turns when there IS significant air in the Kerbin atmosphere. Any surface having lift properties (wings of course, and even capsules because lifting bodies are now supported) have to "bite" into air or whatever gas is in an atmosphere, to cause them to affect vector. When there's nothing to bite into, you won't be turning.

Edited April 29, 2015 by rodion_herrera

[FleshJeb]

The staging bar in the editor doesn't scroll far enough down to not block the exit button.

Do the Home and End keys not work any more? I haven't tried 1.0 yet.

[Gfurst]

Did anybody noticed pressing the X key also stops time-warp?

Makes sense but is kinda annoying. Search the cfg file and there is no binding.

[Starwhip]

Ahhhhhh, hahaha ha ha haaaa! To the MUN! Finally!

1) Right, you need to upgrade your launch pad ASAP. It's the only way to get beyond LKO in career mode.

2) Aerodynamics doesn't really matter with small things (The boosters in the pic above), but if you put a big flat disk on one side of your ship you're just asking to be flipped.

[LordFerret]

Do the Home and End keys not work any more? I haven't tried 1.0 yet.

Scroll works fine for me (put in 15 stages to test) ... as do the Home and End keys.

[GoSlash27]

Parts

I have a few data points for the Mammoth at Eve.

Altitude (m)     ISP (s)
30 000           313
20 000           309
10 000           293
 3 000           246
     0           193

Fired at sea level, the output was about 2500 kN.

Happy landings!

Starhawk,

Thanks for doing the work on this!

It's about where I expected it to be, so the Mammoth is also a viable Eve booster, possibly able to edge out the aerospike for max DV.

If my math holds true, these are the only 2 engines that don't outright suck on Eve. There will be others that can generate some thrust (at horrible Isps), but they're not competitive with these.

Thanks again!

-Slashy

[Amishacker]

I've found that MK2 bicouplers make excellent heat transfer bridges

a) They are fuel tanks that have respectable thermal mass (1800-3400)

They conduct heat via three connections, enabling them to source and sink heat rapidly

In early testing, this makes for a respectable backbone for flying wings and branching VTOLs

[Starhawk]

Thanks for doing the work on this!

No problem. After all, it's for science!

It's about where I expected it to be, so the Mammoth is also a viable Eve booster, possibly able to edge out the aerospike for max DV.

If my math holds true, these are the only 2 engines that don't outright suck on Eve. There will be others that can generate some thrust (at horrible Isps), but they're not competitive with these.

That ISP is a far cry from the 270 I saw for the Aerospike. What is it that makes the Mammoth still competitive?

Happy landings!

[GoSlash27]

No problem. After all, it's for science!

That ISP is a far cry from the 270 I saw for the Aerospike. What is it that makes the Mammoth still competitive?

Happy landings!

Starhawk,

I'll have to re-run the numbers, but basically the improved t/w of the Mammoth allowed it to lift more fuel and tankage for a given payload than the aerospike. The improvement in wet/ dry ratio allowed it to overcome it's disadvantage in Isp and deliver more DV total. The advantage amounted to 300 m/sec in extremis, and improving as the payload fraction increased.

Best,

-Slashy

[Starhawk]

basically the improved t/w of the Mammoth

Thanks Slashy, I figured it must be related to t/w.

I had been thinking about the Mainsail, but it's a little worse on ISP and a little worse on t/w as well, so I guess that one would be a no-go.

Happy landings!

[eddiew]

Recycling Rune's post for SSTO builders:

Turns out the key is to follow the Mach effects, without blowing up. Basically, the closer you are to Mach effect territory, the more air you will have for your engines and the higher their thrust will get (the effect is quite dramatic, actually). If you go too slow, they won't give you enough oomph, so pull down AoA again until you get mach effects and a decent acceleration, then go up basically as fast as you can. But, once you get close to the thermal barrier (about 1km/s at 20kms, less if lower) you have to pull up to go higher, faster and thus avoid burning up.

Most helpful thing I've read anywhere since 1.0, tbh

[Wanderfound]

It does seem that the visual flame effects actually mean something now; if you see red, pull up immediately if you want your Kerbals to live.

[Speckix]

Testing to get new email sent for registration

[GoSlash27]

Thanks Slashy, I figured it must be related to t/w.

I had been thinking about the Mainsail, but it's a little worse on ISP and a little worse on t/w as well, so I guess that one would be a no-go.

Happy landings!

According to my numbers the mainsail would be worse on all counts. But of course, my numbers are just numbers at this point....

Feel free to check stuff out to make sure. I could easily be mistaken.

*edit*

What I did was start with the Kerbin sea level Isp numbers and then project them to their cutoff points in the config files.

Interpolating at 5 Atm and multiplying by full-tilt thrust allows me to guesstimate the Eve sea level Isp and thrust, although these appear to be spline curves rather than linear functions.. The only 2 candidates I saw by that method was the aerospike and mammoth.

Best,

-Slashy

Edited April 29, 2015 by GoSlash27

[Gfurst]

It does seem that the visual flame effects actually mean something now; if you see red, pull up immediately if you want your Kerbals to live.

Yeah, the effects are quite tense now. With the camera wobble and sound effects puts you right on the edge of your seat. Only thing missing now is the breaking the sound barrier sound boom.

By the way, is it safe to say now that whenever you get the high pressure effect, that its going trans-sonic, and burning up is hypersonic or something?

[GoSlash27]

Recycling Rune's post for SSTO builders:

Most helpful thing I've read anywhere since 1.0, tbh

Yeah, somebody had asked me earlier how I'm following the terminal velocity and I forgot to answer.

I'm surfing the Mach effect and keeping my acceleration at 2*sin(pitch) as I go until I hit 1G acceleration at 30* pitch.

for rockets, if I'm getting heating effects, I'm not doing it right.

Best,

-Slashy

[Ulzgoroth]

1) Right, you need to upgrade your launch pad ASAP. It's the only way to get beyond LKO in career mode.

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.

[malkuth]

Recycling Rune's post for SSTO builders:

Most helpful thing I've read anywhere since 1.0, tbh

You could even cut it closer and not see the effect at all, if you have camera shake on your vessel does this strange little dance before effects hit. I also think they have some pre Mach effects.. Its hard to tell on that one though.

[NathanKell]

GoSlash27: be careful, floatcurves are not linear. to compute the value for a given time, you need to actually evaluate them as cubic beziers, not linearly interpolate.

http://forum.kerbalspaceprogram.com/threads/93332

[Wanderfound]

By the way, is it safe to say now that whenever you get the high pressure effect, that its going trans-sonic, and burning up is hypersonic or something?

No; what you're seeing are Mach effects (the white clouds) and shock heating (red flames). Both of them are a function of atmospheric density (and therefore altitude) as well as speed.

The exact boundary between supersonic and hypersonic is a bit subjective, but it's generally thought to be around the Mach 5 mark. At low altitude, you can BBQ your plane long before you ever get near hypersonic. Transonic refers to the speeds immediately around Mach 1.

Exactly how fast Mach 1 is is also a function of atmospheric density, but for Kerbin (and Earth) around 350m/s does as a rough approximation.

[OhioBob]

Starhawk,

Thanks for doing the work on this!

It's about where I expected it to be, so the Mammoth is also a viable Eve booster, possibly able to edge out the aerospike for max DV.

If my math holds true, these are the only 2 engines that don't outright suck on Eve. There will be others that can generate some thrust (at horrible Isps), but they're not competitive with these.

The LV-T30 Reliant looks like it might not be too bad.

(ETA) Never mind. I see now that the ISP does not scale linearly. The LV-T30 kind of sucks.

Edited April 30, 2015 by OhioBob

[Gfurst]

No; what you're seeing are Mach effects (the white clouds) and shock heating (red flames). Both of them are a function of atmospheric density (and therefore altitude) as well as speed.

The exact boundary between supersonic and hypersonic is a bit subjective, but it's generally thought to be around the Mach 5 mark. At low altitude, you can BBQ your plane long before you ever get near hypersonic. Transonic refers to the speeds immediately around Mach 1.

Exactly how fast Mach 1 is is also a function of atmospheric density, but for Kerbin (and Earth) around 350m/s does as a rough approximation.

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

Anyway, some of the test went through ok and I had minimal input on the ascent curve, resulting as mentioned before around the horizon at 35k with is pretty optimal, It actually saved up a lot of fuel, more or less 2500 dV used. and thats even getting 100k or more altitude, the result is that with 35k altitude aiming at the horizon you have very little drag and a very shallow ascent, the apoapsis half around the world, and the final orbit nearly done. Very neat!

observation number 2: We may be able to perform even more efficient ascents than 2700dV, in a ballistic rocket like vessel I've made it around 2500 only

[GoSlash27]

GoSlash27: be careful, floatcurves are not linear. to compute the value for a given time, you need to actually evaluate them as cubic beziers, not linearly interpolate.

http://forum.kerbalspaceprogram.com/threads/93332

NathanKell,

Thanks, I kinda figured that had to be the case since the Aerospike had noticeably better Isp than I expected.

Best,

-Slashy

[Starhawk]

Well, of course the Aerospike should have a completely different curve than the other engines depending on how realistic the modeling is. The equations for calculating ISP are intimately related to geometry, and the Aerospike uses a very different geometry than a traditional bell shaped rocket.

So I'm not surprised that the aerospike's ISP would change very differently with pressure than the other engines do.

Happy landings!