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Physics/Aerodynamics/Engines

ISP continues to fall off with pressure as pressure increases above one atmo. The Terrier hits zero ISP at about 3000 m on Eve.

Happy landings!

Awesome! I was hoping that would be the case.

So double bonus points and 5 internet for the first sea-level Eve return in 1.0 :P

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Engines: Your thrust will go down with your ISP, so that Terrier which can produce 60 kN in space, will only get you ~15 kN on the pad. Pay attention to the Max Thrust ASL vs. Max Thrust Vac. And going by what Starhawk just said, it wouldn't produce any thrust below 3000m at Eve.

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From what I've seen, you need to be VERY careful when deploying parachutes, upon re-entry, as well as how your ship is positioned. I've had... small crafts wrench themselves apart because they were falling too fast and were upside-down WHEN I deployed the chutes.

Also, seems heatshields somehow make your crafts fall FASTER (I couldn't deploy my chutes because it was falling at 200 m/s in the LOWER atmosphere AT THE OCEAN... I lost Val, man... I! LOST! VAL! ;.;).

Edited by Dire_Squid
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Don't be afraid to pop the chutes at 25k in the middle of a firestorm. They will pretty immediately slow you down without burning off. This has saved me a couple of times now.

~34k seems to be the re-entry sweet spot now. It will take a few orbits to lower the apoapsis, but you can go "engines first" re-entry safely without a heat shield.

The circular bays are a great spot to stick the Octo probe core and batteries so your rescue and science vessels can do their job without going *foom*.

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Testing with the Ravenspear Mk1, monitoring the standard canard connected to a Mk1 cockpit (small objects that stick out into the airsteam heat up the most)

10m altitude

710m/s => rapid climb to 700K, continues to slowly climb in a manageable fashion (1400K after 10 minutes, no sign of stabilising)

715m/s => rapid climb to 1000K, continuous climb is noticeably faster than @710m/s

5km altitude

655m/s => rapid climb to 750K, continuous steady climb... (reduced atmospheric density reduces conduction faster than shock heating?)

670m/s => rapid climb to 1000K

15km altitude

700m/s => rapid rise to 800K, doesn't really slow down like it does lower down though

20km altitude

700m/s => rapid rise to 650K, really starting to slow down past 800K

820m/s => 1450K

Ran out of lift past 20km and the high AoA to maintain altitude meant I was losing speed pretty quick

tl;dr

Stay under 700m/s until somewhere between 15 and 20km if you want to keep canards or other small sticky out surfaces.

NOTE:

The fact temperature doesn't seem capable of stabilising without decreasing speed for short periods is concerning me

Edited by Crzyrndm
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The order of explodybits was provided during the KSPTV stream yesterday, I believe it was KasperVid who laid it out - batteries, then panels, then.... This also means you can use batteries as "canary" parts. If your batteries start popping, slow down!

That's a cool tip... thanks!

- - - Updated - - -

Physics/Aerodynamics/Engines

ISP continues to fall off with pressure as pressure increases above one atmo. The Terrier hits zero ISP at about 3000 m on Eve.

Happy landings!

Zero ISP seems like a bug. It stopped producing thrust entirely? Shouldn't happen...

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Zero ISP seems like a bug. It stopped producing thrust entirely? Shouldn't happen...

Nope, that's real life. It means that the atmospheric pressure is higher than chamber pressure on the engine. So, the engine sucks fuel, but won't run.

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My observations after about 20 minutes of building and flying a custom jet:

OMG! The controls are touchy! I swapped out my elevators for a pair with about half the lift and that helped a lot. I also adjusted my COM much farther forward of my COL than I would have in 0.90... and I finally got it to be stable without doing backflips on takeoff.

Also, when flying slow (less than 80m/s) and you think you just found another infiniglide, you drop straight down like a rock and crash. Kudos to the devs for creating a realistic stall, but be warned: it is very unforgiving!

"Even tiny planes with only two engines can reach OMGWTFBBQ speeds at extremely low altitude, when such planes could barely reach 250m/s before." - RedDwarfIV

BBQ speed? LOL Yeah, that just about sums it up! :) Won't be long before modders will be creating new mods to bust the windows out of the administration building on a flyby... (hint, hint)

Mods you may not need now: FAR, Deadly Reentry, Stage Recovery(?), Scan Sat, Karbonite...

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First impressions... everything is very explody and people who use spaceplanes for everything are going to be highly disappointed at their cockpits going boom at about 1200m/s in the upper atmosphere. Rockets4lyfe.

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There appears to be a balance point after you've done your orbital burn for spaceplanes where you can have your lift continue to raise Apo beyond your drag point. Seems to knock off ~65k for a 1 lift : 1 ton craft.

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Can second the fragile batteries. I had a transfer stage with nuke and did a munar transfer burn. 3/4 of the way through the whole thing is glowing dull red and my four radial batteries mounted near the engine explode. :confused: Need to try that heat-sink wing strategy.

In my tests, batteries were very good at absorbing heat, but bad at radiating. If they are mounted near the engine, they will absorb the heat quickly and overheat and explode, since they have only 1000 degrees heat tolerance.

Edit: One last test I ran yesterday before bed is suggesting you can also insulate parts of your craft. The nuke with the spacer (the lower fuel tank was empty, and is there just to attach the fuel line) worked well at first, and you can see on the left, the main fuel tank barely heated up after the burn. The engine was however really really hot, and the system continued to equalize for a very long time(about 3-4 times as long as my conventional radiators) and topped of at 760, which is still 100 degrees less than the control. I think this system could be used if the heat radiators are not an option for some reason, but will not withstand long burns, as the nuke will simply get too hot and explode.

nuke2_zps4adeeln0.jpg~original

Edited by Torham234
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Testing with the Ravenspear Mk1, monitoring the standard canard connected to a Mk1 cockpit (small objects that stick out into the airsteam heat up the most)...

So the sudden spike in heating between 710 and 715m/s is caused by passing through Mach 2. The rate of increase of thermal energy (flux) before Mach 2 is maybe 10 per m/s of speed increase, above it instantly jumps up to hundreds if not thousands

Edited by Crzyrndm
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Jets perform like jets now. That means thrust varies with atmopsheric density and current mach number. The basic jet will taper off past Mach 1, the Turboramjet (note name change) peaks around Mach 3 but can still provide thrust past Mach 4, and the RAPIER (in air breathing mode) peaks around Mach 4.

Anything about their Isp? Why is there nothing about jet engines in the changelog...

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ISP for jets seems to be based on LF only (finally). No variance with pressure, turboram is 8k, basic is ~20k IIRC

Sounds good. Isp should vary with speed, and those numbers are about 4x stronger than reality

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Aerodynamics:

It looks like wing loadings should be much higher than before for best results in spaceplanes; somewhere in the neighborhood of .25. Engines run out of steam in a hurry above 20 km and you'll run into thermal problems at mach 3-4. You really just need enough wing to fly level at that altitude/ speed range.

Flaps can be used to make it behave a little better around the runway.

Best,

-Slashy

Edited by GoSlash27
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Aero / Part occlusion:

When putting stuff into cargo bays and you want to "pull" them out (no node attached on one side) be aware that any engine still inside will not work because of part occlusion. This made my ideas for "launch tubes" completely obsolete. Same thing with interstage fairings btw.

Edit: Landing gear appears to be a lot wobblier than in 0.90, especially the "old" gear. When it's not placed very carefully it whacks out the plane.

Edited by ShadowZone
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The edge of Jool's atmosphere has moved out to ~200km from 138.2 km.

I wonder if some folks are going to find ships currently harvesting resources at the old edge are going to find their ships in a "surprise reentry" situation?

In passing, the new atmosphere limits and the new aero model means the online aerobraking calculator at http://alterbaron.github.io/ksp_aerocalc/ is currently out date.

My tip is to those who are working with ships designed under 0.9 and now trying to do aerocapture around Jool. Expect the thermal issues to be significant; without heat shields only grazing encounters with the atmosphere are survivable. It seems that that first encounter can yield an orbit, but expect a long orbital period on the first pass.

I found the number of passes needed to achieve a low orbit to be higher than I had patience for. I ended up using the cheat to ignore heat limits. I think that's a good option for those wanting to stay with 0.9-style aerobraking gameplay.

(I'm very thankful for that addition: means I can finish up with my 0.9 ships before moving on to new 1.0 designs.)

Elliptical orbits are still doable with unshielded ships, possibly even in one or two passes depending on the ship and target orbit.

Edited by Camacan
Clarify that it is aerobraking to low orbit that most challenges ships without shields coming into Jool.
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I spent about 30 minutes this morning in 1.0 and built this, which can do 1300m/s at 22000 - 24000m, but only with the Mk1 pod on the nose since it has an extra 400K of heat tolerance. What I learned: the old adage of building the smallest possible aircraft for speed is no longer true. The tapering thrust curve now gives you a reason to throw a bunch of engines on an aircraft if you gottagofast.

Also: precoolers are your friends. Regular intakes explode third in the list of explodybits (first are batteries, second are solar panels). But precoolers keep on keeping on.

http://i.imgur.com/hjuFGxB.png

Building small aint possible, im sorry but what do u call this thing:

Javascript is disabled. View full album

Its literally the smallest craft ive managed to SSTO, and the best part is that is gets 6K dV once in orbit, ions+massless batteries FTW!

But you are correct that the age of super micro fighters is all but done, especialy since there is nothing smaller then a MK-2 bay for storing ordinance, the little service container thing is just useless in the 1.25m variant as you cant even fit a single weapon in there, let alone the 2-6 i usually arm on fighters. Small designs are still doable, but one pain in the arse to actually pull off and get into orbit (my design actually abuses massless batteries+clippd ions since ions work inside hulls still), so i wouldnt call this a 100% legit craft.

Also, the drag occlusion works kinda odd, sometimes clipped stuff occludes, and sometimes you end up having the stuff thats clearly occluded adding to drag, so that requires some messing around to get perfect (occlusion seems limited to in line connected by nodes).

Finally about overheating, RAM intakes all the way, not only do they look super badass, but they have 2100 max heat, vs the 1900 of the circulars, not to mention better performance at higher alt. Ive found that airbrakes (or for smaller vessels clever use of flaps) is the best way to bypass any reentry issues, even when going interplanetary speeds or some very steep angles, and if you manage to slow below 1500 before hitting 20km you wont even have reentry effects at all and just glide in (ofc interplanetary is another thing, dont expect this kinda low speed). Also, ive found heat shield+in line intake is a very valid option, as you can cover the nose that always fries 1st with heat shield, and not worry bout intakes as much.

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