Kerbodyne SSTO Division: Omnibus Thread

[eddiew]

Those wing strakes don't blow up? I pulled all of mine off when they were the first thing that overheated. They're so small that they have no thermal mass.

I think it'll depend what they're attached to... in this case, a MK3 hull has a lot of heatsink potential.

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(BTW, just as a reflection on the relative realism and difficulty of stock aero: I landed this by flying directly above the runway at 500m, putting it into a 100m/s vertical dive, pulling out of that about 20m off the deck before gently settling down without a bump and easily braking to a stop)

Lol, yep, that's what I ran into last night as well. A tad more wing and I reckon it might simply pancake down at survivable landing speeds. Seriously tempted to try for a large-wing-area plane that can't be crashed as long as you stay horizontal Not sure what it'll do to the ascent though, the drag might make it impractical.

Side note; anyone else having problems getting spaceplanes to fly straight? However I build them, they all want to veer off by fractions of a degree, and by the time I'm in orbit that's magnified up to a 10-15 degree inclination :/ nuStock doesn't seem to include any concept of keeping the wings level...

Edited May 1, 2015 by eddiew

[Somtaaw]

Those wing strakes don't blow up? I pulled all of mine off when they were the first thing that overheated. They're so small that they have no thermal mass.

I don't think they blow up. On the other hand I'm having trouble getting more than 2km up because I initially designed the Mk3 Hi-Speed Station Slinger as a collaboration with a friend who was going to design a rocket for it to attach to, for maximum orbital delivery speeds, and keeping my fuel for orbital maneuvering. He backed out, so now I have to adjust my plane to try and make it an SSTO, and just make use of my massive LKO fueling station.

On the other hand, I've hyper-editted the Mk3 HISS into orbit and messed around with it coming from top down and the strakes don't burn up. I need to do some subtle tuning to it and I just can't do subtle well. I'll try and polish it as much as I can, before I post the .craft for Wander or someone else to do final tweaking.

[eddiew]

Challenge for you if you fancy it, Wanderfound, (and anyone else who's interested of course!); what's the lowest tech SSTO you can make that will launch a scanning satellite under nuStock? I need something cool that I can access early in my 1.0 career game to stop me being tempted by an easy life of rocketry

I've currently got this at 30.7T loaded, turbos and LV-45s only - but it's not exactly pretty and it has little margin for error. I'm also not actually sure if you get those swept wings by the time you have turbojets because all I've done so far is mess around in sandbox The satellite has 2k delta-v and the basic scanner, which turns out to require 1.5 cargo bays.

Ascent profile was a standard 'chase the mach effects' affair, getting just past 800m/s on the turbojets at 21km.

I feel sure there must be better things out there!

[SHiftER2O]

Challenge for you if you fancy it, Wanderfound, (and anyone else who's interested of course!); what's the lowest tech SSTO you can make that will launch a scanning satellite under nuStock? I need something cool that I can access early in my 1.0 career game to stop me being tempted by an easy life of rocketry

I've currently got this at 30.7T loaded, turbos and LV-45s only - but it's not exactly pretty and it has little margin for error. I'm also not actually sure if you get those swept wings by the time you have turbojets because all I've done so far is mess around in sandbox The satellite has 2k delta-v and the basic scanner, which turns out to require 1.5 cargo bays.

http://i.imgur.com/wiCreHq.jpg

Ascent profile was a standard 'chase the mach effects' affair, getting just past 800m/s on the turbojets at 21km.

http://i.imgur.com/CfnOB2u.jpg

I feel sure there must be better things out there!

You, sir, are a natural!

[Wanderfound]

Challenge for you if you fancy it, Wanderfound, (and anyone else who's interested of course!); what's the lowest tech SSTO you can make that will launch a scanning satellite under nuStock? I need something cool that I can access early in my 1.0 career game to stop me being tempted by an easy life of rocketry

Anyone put together a list yet of which tech is in which node of the revised tree? My career game isn't up to turbojets yet, and I'd hate to make a low-tech demonstrator with one forgotten high-tech part in the middle of it...

There's at least one set of swept wings early in the tech tree:

[Wanderfound]

BTW, Squad seem to have finally fixed parachutes. Mild deceleration on pre-deployment, gradual application of the G's on full deployment. All good.

Am I right in thinking that it's now possible to keep them attached while on the ground for drag chutes?

[Red Iron Crown]

Am I right in thinking that it's now possible to keep them attached while on the ground for drag chutes?

Yes! Excellent feature for aircraft builders.

[eddiew]

Don't know if you guys are interested, but I've kicked off a discussion about rapiers on the support forum: http://forum.kerbalspaceprogram.com/threads/118686-Rapiers-seem-too-weak

I took the same airframe up, once with 3x rapiers, and once with 2x turbos and an LV-T45, and both got to orbit with about the same fuel left. It seems wrong to me that rapiers aren't actually an improvement over turbos and rockets...

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You, sir, are a natural!

I think I got lucky... and did right to stay with turbojets. Rapiers appear to be broken right now, which is probably why so many people are having problems with SSTOs in general - I suspect that the majority of players don't even consider a turbo/rocket build, they just jump straight to the hybrid engines.

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Anyone put together a list yet of which tech is in which node of the revised tree? My career game isn't up to turbojets yet, and I'd hate to make a low-tech demonstrator with one forgotten high-tech part in the middle of it...

Not that I've found, and I may have actually done just this Ram intakes and turbojets are in the same node, according to the wiki; not sure about pre-coolers or swept wings, but given that there are bigger wings later, I won't be surprised if they're in there too - or at least, accessible to a tier 2 research facility.

[Wanderfound]

The big advantage of RAPIERs was always that they allowed you to carry one more jet (e.g. three RAPIERs vs two Turbos plus a rocket) and that they permit single-engine designs. I think of RAPIERs as a low-efficiency turbojet that compensates by being able to double as a low-efficiency rocket.

I'm not at all bothered by a good turbo/rocket design being able to match the RAPIERs; I'd be much more concerned if it was set up so that Turbojets were totally inferior to RAPIERs. All RAPIERs all the time is dull; variety is good.

Having that extra jet becomes more valuable in FAR, due to the more realistic takeoff runs. And for career KSP, the RAPIERs are now at the very end of the tech tree anyway...

[eddiew]

And for career KSP, the RAPIERs are now at the very end of the tech tree anyway...

That's why they should be good though :/ And the extra jet, while historically useful, doesn't seem to matter under nuStock - unless you're carrying rapiers... Maybe nuFAR will make them behave much better, but for a stock experience, rapiers are currently coming up short IMO. Certainly I think that lack of low-mid range power is what's causing so many people such a lot of grief. I'm finding it much easier to build a turbo/rocket design than a rapier design, and yet turbos clearly have a lower peak altitude, which will make most people start with rapiers (assuming that a lot of people play around in sandbox to figure out designs).

[Wanderfound]

Tried some RAPIER/Turbo/RAPIER builds? If the different engines have flat spots at different speeds, they may cover for each other nicely.

[eddiew]

Tried some RAPIER/Turbo/RAPIER builds? If the different engines have flat spots at different speeds, they may cover for each other nicely.

I did actually, and the result was monstrous power and an almost-dangerous 950m/s at 20km. Soon as you get rapiers over 400m/s they suddenly start producing more power, which makes more speed, which makes more power; the problem is that initial curve is just really bad. You need something else to get them off the line; hence I'm inclined to strap some little SRBs onto my plane and fire them when it caps out.

Turbo/rapier is probably ok if you have a plane with room for 4 jets, but when you want to downscale that to 2 jets and a nerva for some long range action, you get stuck because twin rapiers can't push that size of plane on their own. It may be intentional, I guess we'll see if anything comes of my post in support. Maybe the devs wanted to put an end to SST-Laythe... but I feel like they've also put an end to SSTO-refuel-anywhere useful as well

[UnusualAttitude]

Hi guys, I had a bash at the NuFAR dev build this evening in KSP 1.0.2... I'm pleased to report this happened on my first attempt, despite lacking luxuries such as a CoL indicator in the SPH (well, it was there, but it spent most of the time sulking under the floor:D).

Twin RAPIER and LV909 to 100km LKO with nearly a 1km of dV left in the 909. With the default FAR settings with regards to area rule, it didn't seem to be particularly punishing and it felt like going supersonic was actually easier than stock 1.0.

Also skipping off the upper atmosphere on re-entry is now a thing again; I hadn't experienced that since previous versions of FAR and NEAR.

And one more essential thing: frame rates were good even on my old Mac, and that is something I haven't experienced in a long while!

UA.

Edited May 2, 2015 by UnusualAttitude

[eddiew]

Hi guys, I had a bash at the NuFAR dev build this evening in KSP 1.0.2... I'm pleased to report this happened on my first attempt, despite lacking luxuries such as a CoL indicator in the SPH (well, it was there, but it spent most of the time sulking under the floor:D).

It is beautiful!

Meanwhile in nuStock, I have been re-educated...

if it means you can keep a very low AoA and therefore get the best thrust out of your engines. Flightplan for this plane was get to 12km asap, then aim horizontal until 400m/s, then pull up. And it was that easy.

Wing drag in nuStock? Not as significant as we were (I was?) led to believe.

Edited May 2, 2015 by eddiew

[Alias72]

It is beautiful!

Meanwhile in nuStock, I have been re-educated...

http://i.imgur.com/59tpoWp.jpg

if it means you can keep a very low AoA and therefore get the best thrust out of your engines. Flightplan for this plane was get to 12km asap, then aim horizontal until 400m/s, then pull up. And it was that easy.

Wing drag in nuStock? Not as significant as we were (I was?) led to believe.

They increased Body drag but wing drag was slightly lowered. More wing area is actually better so long as you get a benefit out of it (like reducing AoA)

[Wanderfound]

Kerbodyne Triske. Turbos and RAPIERs, singing in harmony.

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Craft file at https://www.dropbox.com/s/ga8orb9xrpxgk21/Kerbodyne%20Triske.craft?dl=0

[eddiew]

They increased Body drag but wing drag was slightly lowered. More wing area is actually better so long as you get a benefit out of it (like reducing AoA)

I thought it was wing lift and drag were both increased - meaning you'd want and need less :/ Unless the upshot of both numbers was that l/d per square metre went down, which could well be the case.

Kerbodyne Triske. Turbos and RAPIERs, singing in harmony.

Heh, they do go very well together if you only need an orbital lifter And yeah, tiny tails are in now. Seeing some builds that don't even bother with a yaw rudder...

Edited May 3, 2015 by eddiew

[Wanderfound]

It's a pain to do without having RCS Build Aid working, but I'm thinking that there'll be good possibilities in vertically stacked turbo/RAPIER and turbo/nuke combos.

[blowfish]

It's a pain to do without having RCS Build Aid working

RCS build aid seems to be functional modulo a couple of minor bugs.

[Wanderfound]

RCS build aid seems to be functional modulo a couple of minor bugs.

Toolbar buttons to open it don't even show up when I install it. I'm sure it'll be sorted shortly.

[eddiew]

Hi guys, I had a bash at the NuFAR dev build this evening in KSP 1.0.2... I'm pleased to report this happened on my first attempt, despite lacking luxuries such as a CoL indicator in the SPH (well, it was there, but it spent most of the time sulking under the floor:D).

Just tried this out myself; the CoL actually works for me, and my bi-rapier plane that couldn't is now a bi-rapier plane that could! It is however the most horrible, slippery, hard to control monster that has ever been spawned, and clearly I need to just start from scratch with nuFAR.

*edit*

Back to nuStock... because I wanted to try a silly idea.

Respectable payload to LKO, 1 full size cargo bay available for payload (and 1.5 bays used for dubious clipping) Thrust is very nearly balanced around the nerva by the time it reaches space, nothing a hold-prograde can't deal with, and you're not going to be doing much besides de-orbit anyway

Also discovered that you can adjust the thrust limiter of air and rocket mode separately, so the top engine is set to 70% in closed-cycle, and gives a reasonable balance during ascent. Good piloting dumps you at 80x80 with 550m/s left in the tank, with the cargo still in place. Optionally carry a fuel tank instead to give enough for a free return around Mun - not that you'll have any need for that by the time you have rapiers and nervas...

Edited May 3, 2015 by eddiew

[eddiew]

...the case for sticking with nuStock is growing...

This does rather demo the pointlessness of worrying about descent characteristics in 1.0.2 nuStock though. I forgot the air brakes, had to slow down by pitch control and chutes, and had no expectation at all of being able to land this critter on the runway; then it did. With a bit of a bump I grant you, but it hit the target. There's just no concept of stall, and hardly any momentum other than the way you're currently pointing. If you get nose-down above your target at 5km, you can pretty much steer anywhere you want to go and flare at the last minute to control your velocity. If anything, the chutes hindered me here, since they didn't allow the nose to rise enough to avoid breaking the forward intakes. Not sure it's an atmosphere so much as an oxygenated ocean.

Edited May 6, 2015 by eddiew

[UnusualAttitude]

That's... crustaceous! However, if you want your Munships back Eddie, I believe it will be possible in NuFAR, unless Ferram seriously nerfs the engines.

You just have to make your ships thin...!

I had to throttle back this 40-plus tonne ship in a 40 degree climb to stop it overspeeding. That's with two RAPIERS and a nuke, for 2 kms of dV left in orbit. And I still had nearly three tonnes of unnecessary oxidizer on board when I got there, having overestimated the requirements for the RAPIERS. Wow. And this is just the beginning, there is lots of room left to the top; and with all sorts of part clipping possible, encouraged even by the aerodynamics model, I have the balance of freedom of design and realism I was hoping for in KSP at last.

Edited May 5, 2015 by UnusualAttitude

[eddiew]

...with all sorts of part clipping possible, encouraged even by the aerodynamics model, I have the balance of freedom of design and realism I was hoping for in KSP at last.

Ooohuuuhuuu... I think I just had a crisis. I really like the idea that aesthetics has an actual effect on your aerodynamics. The concept that it's not just looks, but a benefit - or a hindrance - is... interesting. There's a lot of people are gonna consider that hella cheaty, but ultimately it's up to the individual ship builder to decide how far is too far.

I guess it depends whether Scuttler still flies in nuFAR xD I imagine it's problem will be that the wide arms will give it a lot of drag up front and tend to spin it round - but we'll see

[Wanderfound]

I'd expect Scuttler's main problems to be structural failures on the wings holding the "claws" (think about where the lift/drag forces are hitting when you pull up), and roll instability due to the huge proportion of mass out on the wingtips. It can probably be tuned to fly, but it might not be possible to make it a sensible thing to fly.