[Make a working jet with the J-90 Turbofan as the base]

Okay.

 

Spoiler

It has a tail fin, a fuel tank and landing gear, as requested. No cockpit, but it does have a probe core so you can fly it unkerballed if you want. But why would you?

It actually flies quite well, both with and without SAS. Takeoff without SAS is a bit hairy, probably because I didn't bother fine tuning the landing gear. And landing on the runway is… risky. Which is to say, I haven't pulled off a successful landing myself yet. But I added some parachutes instead, as requested.

Mind you, even with the chutes, landing can be slightly scary.

But it was actually just a broken landing gear. You can replace those.

Craft file: https://kerbalx.com/vyznev/TurboFun

Imgur album with more screenshots: https://imgur.com/a/k1bYB05

[Get to Minmus as fast as possible without crashing]

1 hour ago, farmerben said:

The Kraken is a spinny shaky monster that strikes in deep space for no reason.  Even if the ship held steady at launch.

Could be many reasons, but I've had that sometimes happen with too many autostruts. For example, from an old mission:

Spoiler

"I originally tried just autostrutting the engines to the root part (which is the heat shield on the re-entry module), but that turned out to cause problems. And by problems, I mean...

...that everything was fine until I got to LKO and tried decoupling the second booster stage, at which point this happened...

...and then this...

...and then this...

...and finally this. Basically, a full-blown kraken attack. Oddly enough, after twisting itself out of shape, the whole thing kind of stabilized in its new configuration. But it was clear that it wasn't going to Tylo any time soon. So I got rid of the autostruts and replaced them with some appropriately placed real struts, and that fixed it."

IME, autostruts are really useful, but they're a bit like a strong spice, best used sparingly. I use them, but only on specific parts that I think will need them. And I particularly try to avoid having too many parts autostrutted to the same (typically root) part, since that seems to be a common trigger for weird physics glitches.

Of course, all this could also be completely irrelevant to whatever's messing up your vessel.

[Get to Minmus as fast as possible without crashing]

7 minutes ago, farmerben said:

Good job.  Does DLC have much higher thrust engines than stock?

I keep trying a kerbal chair with 6 asparagus, and the kraken keeps striking;(

I believe all the engines I used (Spark, Terrier, Mainsail and Vector) are stock. So is most of the rest of the ship. I did use the 5m diameter DLC fuel tanks in the first stage asparagus cluster, but I don't think replacing those with a bunch of smaller tanks would've made much if any difference.

Not sure what kind of kraken attacks you're experiencing, but if it's just the ship wobbling too much and shaking itself apart, may I recommend more struts? I have quite a few of them on my ship (many aren't visible since they're hidden between the asparagus cores and the side boosters) and I also have a bunch of parts autostrutted to either "root part" (which was supposed to be the probe core on the last stage, although I think I accidentally made the fuel tank under it the root at some point) or to "grandparent part" (handy on side boosters attached via radial decouplers).

My basic guidelines when applying struts are that: 1) every side booster should be attached (by strut or by decoupler) from at least two points, one at the top and one at the bottom, 2) side boosters on upper stages should be strutted to lower stages to support their weight, and 3) if you must have a bunch of small parts sandwiched between big fuel tanks in the core stack (which tends to make that section of the stack springy and bendy), either bypass them with struts or use rigid attachment to essentially fuse those small parts together.

[Get to Minmus as fast as possible without crashing]

@farmerben Here's the video: https://www.youtube.com/watch?v=FgKEVLOf0go (already edited into my earlier post)

[Get to Minmus as fast as possible without crashing]

2 hours ago, farmerben said:

I'd say VYZNEV must have been going faster than 9700m/s

Nope. I checked, and this was my highest speed during the run:

(It's relative to Minmus, since I flew most of the ascent with the navball in target mode, but that shouldn't matter much since the orbital velocity of Minmus around Kerbin is only 274 m/s, and it's at an almost exactly 90° angle to my flight path. Doing the math, sqrt(9506² + 274²) = 9510, so I shouldn't have been going faster than about 9510 m/s relative to Kerbin.)

I'm not sure why you're getting a slower time with a higher peak velocity. Maybe I'm just doing more efficient (= shorter) acceleration / deceleration burns? Mine are definitely not optimal, but I don't think I'm more than a couple of minutes off from the best my craft can do. And even that took quite a few retries to practice.

I do have a video of the entire flight, I just need to edit and upload it…

[Get to Minmus as fast as possible without crashing]

Same rocket as before, new flight, this time without premature staging. No mid-flight reloads this time, either. Time at landing 1:31:24. So close to 1:30…

(Don't ask me where the heck the F3 display pulls the "highest speed achieved" value out of. My actual peak velocity at the start of the coast phase was just a hair over 9,500 m/s.)

Edit: Here's the whole flight, sped up 4x:

 

[STTO (Single Tank To Orbit) Challenge]

Well, if you need a lot of thrust for cheap, the answer is surely to use SRBs, right? You just need to use enough of them.

More images in imgur album: https://imgur.com/a/u93vgAf

IIRC, a full S4-512 tank costs 51,200 kerbucks, so my score should be 442,632 – 51,200 = 391,432. I probably could've squeezed a little bit more off that by trimming off unnecessary parts (like do I really need that engine plate?), but meh, whatever.

Craft file: https://kerbalx.com/vyznev/Fuel-Lifter

BTW, one issue I noticed while building this craft was that the Clydesdale SRBs kept breaking off from the core on the launchpad. Apparently I'm not the only one who's noticed this issue. FWIW, my solution to the problem was: 1) struts, 2) autostruts, and 3) more struts.

[Get to Minmus as fast as possible without crashing]

Here's 1:37:10:

Spoiler

Here's the craft in the VAB:

And here it at Minmus, just starting the deceleration burn:

Also, for some reason I can't help but giggle at this image:

(Context: My landing burn wasn't ideal and I had to dodge a mountain ridge, leaving Val floating a few kilometers above Minmus once I got her horizontal velocity killed. And with Minmus's gravity it would've taken way too long to just float down, so…)

More screenshots and flight details on the imgur album: https://imgur.com/a/xul1flc

I actually kind of messed up this flight by dropping one of my booster stages while it was still half full, which probably cost me nearly 1000 m/s of total delta-v. With that mistake fixed and better flying in general, I think this rocket could probably do sub 1 hour 30.

Craft file here: https://kerbalx.com/vyznev/Minmus-Express

[Get to Minmus as fast as possible without crashing]

I might try this later. In the mean time, some random thoughts:

• It looks like most (all?) attempts so far have spent some time coasting under time warp. That's wasted time that could've been spent accelerating (and later decelerating), if one just had more delta-v. Over two hours seems long enough that nukes or even ions might be worth using for their high Isp (and consequently high achievable delta-v), even with their low TWR.
• At the kinds of velocities and accelerations involved, both Minmus and Kerbin gravity should be basically negligible. So is the orbital motion of Minmus, too. That means it should possible to approximate the ideal flight profile with some basic high school physics.

In particular, I believe an ideal flight profile (using stock KSP with no fancy autopilot / landing assist mods) should look roughly like this:

1. Time warp until Minmus is near its ascending / descending node.
2. Time warp further until Minmus is overhead from KSC.
3. Set Minmus as target and burn towards it until your remaining delta-v approximately equals your velocity relative to Minmus (with a bit of safety margin).
4. Turn around and coast (hopefully not too long) until your time to target is somewhere around half(!) your total remaining burn time.
5. Burn retrograde to slow down. Make sure not to miss the target.

(The "half your remaining burn time" estimate is assuming constant thrust and neglecting gravity. A proper suicide burn calculator should be able to give a more accurate estimate, or you could just quicksave and use trial and error to find the optimal start time for the deceleration burn.)

[Prove the puff engine is not useless]

Uh, this counts, right?

Because damn, this thing gets wobbly near the end of the landing. I guess it's my own fault, I should've included a reaction wheel. Or at least some RCS thrusters. But I wanted to show that this can be done with just one Puff engine and no other attitude control mechanisms. Which I guess I technically did.

In general, I went for minimalism with this design. There's the single Puff engine (rotated and offset so that its thrust vector points straight down and lines up with the center of mass), one monoprop tank (technically about 30% more fuel than needed for an optimal landing, but a bit of extra delta-v margin is always nice), one OKTO probe core (lightest possible, no built-in reaction wheels), six batteries (I guess I could've left one out; did you know that the small batteries are cheaper and lighter per unit of charge than any of the bigger ones?), two solar panels (again, technically one more than needed), one antenna and of course one seismometer.

[Bi-directional Flying Wing]

14 minutes ago, JadeOfMaar said:

If you tried them IRL then they would absolutely need to have some angle of incidence (non-zero static angle re: the forward direction of the plane during level flight) or they would produce no lift.

That's true in KSP too.* KSP plane builders just have to either manually tilt their wings by a tiny amount (which is awkward, since the rotate tool will only snap to multiples of 5°) or live with the fact that their plane must keep its nose pointed slightly above the horizon in order to maintain level flight (and the slight extra drag this produces, for most conventional plane designs).

*) Easy enough to test by putting some vertical wing panels on a rocket, launching it straight up (and holding surface prograde with SAS) with aero force visualization turned on, and observing that the wings indeed produce no lift in that case.

33 minutes ago, JadeOfMaar said:

Not all wings in KSP are flat. All the wing pieces that aren't the boards have some camber in them.

Do they, tho? I was under the impression that, while e.g. the "Big-S" wing parts indeed have variable thickness, they're still symmetric and thus have zero camber (and thus work equally well even if placed upside down).

I also suspect that, even though those wing models indeed look back-to-front asymmetric (both in thickness and in overall wing shape), the stock KSP aero model probably ignores that too. That shouldn't be too hard to test: just build a plane using those wings, with nothing else attached to them, then turn them backwards (while keeping the nominal center of lift at the same place, as shown in the SPH, which may require translating the wings forward or backward) and see if the plane still flies the same way.

[Bi-directional Flying Wing]

…anyway, I decided to try cheating a bit by moving the engines down and out (which of course would never work in real life, but in KSP connected parts don't have to touch and same-vessel collisions are optional ).

With that change, it does fly. Not well, mind you, but well enough to take off and stay in the air.

Spoiler

Trying to rotate the engines and change flight direction went about as well as I expected, though.

Spoiler

Mind you, that's probably in part because some of the control surfaces started acting the wrong way when I changed the control point. I think I remember having that issue with the CuBoid too, and IIRC I "solved" it there basically by having a completely separate set of control surfaces for sideways flight and locking the surfaces that were not in use based on the selected heading. That might be the way to go here, too.

[Bi-directional Flying Wing]

Anyway, that crazy airplane concept mentioned in your original post intrigued me enough that I wanted to try building a working replica of it on KSP and see how it flies.

Spoiler

To absolute nobody's surprise, it flies like excrements. Or rather it doesn't, because it can't even take off — the elevons don't have nearly enough pitch authority to counteract the massive downward pitch moment from the top-mounted engines, and its negligible yaw stability isn't enough to keep it going straight. And the wobbly rotation servo doesn't help with that, either. About all this thing's good for really is doing donuts on the runway.

Spoiler

I could maybe fix the yaw stability by adding some kind of deployable tail surfaces, like I used on the 8-way CuBoid plane I linked above, but I see no easy way to solve the pitch problem — at least not while leaving the result looking anything like the original concept design. (A bit ironically, turning the landing gear 90 degrees and taking off narrow-side-forward might actually work better, at least if I added some extra pitch control surfaces near the nose and the tail in that orientation, since that would put them further fore and aft of the center of mass.)

Alas, all this means that I didn't even get to test how switching direction mid-flight (near Mach 1!) would've worked. I suspect it would've also ended rather poorly, though.

Honestly, looking at the design, I have no idea how anyone ever thought this would fly in real life, and I suspect making it flyable in KSP isn't possible without massive cheating* either.  But who knows, maybe someone better than me can pull it off.

*) Like adding lots and lots of reaction wheels or abusing the aero model to make parts dragless, etc.

[Bi-directional Flying Wing]

Not sure if this old craft qualifies, since it's uncrewed. If it does, I believe it meets the "Reuse Me", "Look Ma, No Wheels" and "Double Trouble" extra goals.

[The All-Contract Challenge]

5 hours ago, Superfluous J said:

Another rules question. If we don't have a contract to return anything, are we still allowed to return home?

That's a good question. I can see at least three reasonable rulings:

1. If the contract doesn't tell you to return (or to "transmit or return science" or return samples or recover a part or a kerbal, etc.) then you may not return. Better send a probe or bring plenty of snacks.
2. Returning without being told to is allowed if you've already returned from all the locations (fly-by / orbit / surface of a given body) visited during the trip, as that means you'll get no new milestone for it.
3. Returning is always allowed. Kerbals want to get back home to their own bed.

I'm not sure which of these (other than option 3, obviously) my own playthrough actually qualifies for. I've tried to use probes for contracts that don't require returning, but looking back, I might've technically blown it with the very first progression contract, which IIRC strictly speaking only requires launching a vessel, not recovering it.

In any case, if you're not playing a strict "one contract, one flight" version of this challenge, I see no problem with grabbing a second contract to return from wherever your kerbals happen to be. That said, I would probably not allow just any repair contract as an excuse to return Bill home, since you could always hire another engineer instead.

(BTW, I already added one exception to my strict rules in my own playthrough: if the contract requires me to rendezvous and/or dock two vessels, then I'm allowed to launch two of them. While I'm pretty sure I could've finagled some way to complete that contract with just one launch, I felt that if I'm going to do what's basically a "re-enact Gemini 8" contract, then I should do it properly. )

[The All-Contract Challenge]

2 hours ago, vyznev said:

What annoys me a bit is that I could've unlocked another tier 4 node if I'd launched into a polar orbit and gotten that extra 32 science from EVA reports over the polar biomes. I even had the delta-v for it. But oh well, this should be good enough.

…which turned out to not matter anyway, since the very next contract I got was for "scientific data from space around Kerbin", so I just launched Bill into a polar orbit to get me those remaining EVA reports (and get some exp in the process).

In hindsight, I think the existence of this contract (which I'm not sure I've ever even seen before) presumably implies that the "scientific data from Kerbin" contract actually doesn't include space around Kerbin, which means I technically broke my own rules on the previous mission. But I still have the same total science (and funds and rep, more or less) as I would have if I'd done all the space science on this flight instead of the previous one, so I'm not going to worry about it. 

(I guess the way to really maximize the science gain would've been to do the "scientific data from Kerbin" mission with a plane and have it land in as many ground biomes as possible. Including all the KSC microbiomes, of course. But that would've been way too tedious, so I'm glad I didn't. )

[The All-Contract Challenge]

On 9/26/2022 at 3:42 PM, vyznev said:

I've been trying this challenge in "strict mode" — only one contract per mission* and one mission per contract, absolutely no science-gathering activities unless the contract asks for them, avoid milestones** unrelated to the current contract — and it's been surprisingly fun.

So, in my second "strict mode" run I decided to stall the "gather science from Kerbin" contract until I'd made it to orbit and unlocked the Science Jr. Was it worth it? I think so.

Before:

Spoiler

After:

Spoiler

What annoys me a bit is that I could've unlocked another tier 4 node if I'd launched into a polar orbit and gotten that extra 32 science from EVA reports over the polar biomes. I even had the delta-v for it. But oh well, this should be good enough.

Now, onwards to the Mun!

[The All-Contract Challenge]

I've been trying this challenge in "strict mode" — only one contract per mission* and one mission per contract, absolutely no science-gathering activities unless the contract asks for them, avoid milestones** unrelated to the current contract — and it's been surprisingly fun.

The one-contract-per-mission requirement forces you to play in a more "realistic" way, with lots of simple incremental missions and no grinding EVA reports etc. to maximize the science gain from each mission — unless, of course, it's an open ended "gather scientific data from" contract, in which case grind away.

One thing I did notice is that you should indeed prioritize upgrading Administration and enabling the strategies that convert reputation and money to science. It's probably not absolutely necessary, especially if you prioritize the "Kerbin World-Firsts" contract line, and indeed I left it rather late since I normally tend to ignore strategies entirely. But it's at least worth doing if you're going to take any rescue contracts, since otherwise those will give you lots of money and rep but basically no science at all.

It's also worth not completing the early "gather science from Kerbin" mission immediately but saving it until you've unlocked the thermometer and the barometer and maybe upgraded the Astronaut Center to allow in-flight EVA. It might even be worth waiting until you've reached orbit or at least escaped the atmosphere first before doing it, although you'd have to do those with fairly primitive rockets if you're putting all your early science into unlocking more instruments.

I'm not sure if I'll stick to the "only one contract per mission" rule for interplanetary missions, but I might. It might be a bit frustrating to launch lots of missions for each target body, but OTOH it keeps those missions simple. You have a contract for a Duna fly-by? Well, then slap a probe core on a simple rocket and do just that, don't start adding any science instruments or landers or anything else unnecessary to the craft.

No detailed mission report yet, since I'm thinking I might actually want to reboot my run. But I've currently done a Mun fly-by and a bunch of rescue missions in Kerbin orbit, and would probably do Mun orbit and science next if I don't restart.

*) Contracts that explicitly ask you to move a previously launched vessel excepted, of course. Also, I'll probably allow reusing previously launched craft with science instruments for repeat science gathering contracts if they're already in the right place for the contract.
**) At least the ones that you get contracts for, like reaching space or orbit or flying by / orbiting / landing on another body. I'm not counting altitude / distance / speed records or things like recovering a craft from a crewed mission, or anything else that doesn't have its own contract, and in general I'm not super strict about that stuff anyway. If doing the mission in the most straightforward way gets me a milestone, then that's fine. But I did decide to try to avoid things like gravity assists off bodies I haven't yet had contracts to fly by. Not enough delta-v to complete the mission without gravity assists? Just build a bigger rocket and try again!

[Head to Eve and back WITHOUT MANUVEUR NODES or a EVE transfer window]

37 minutes ago, MechBFP said:

The reason why I am asking is because the specific time window that is used changes the challenge anywhere from completely impossible to slightly harder than a normal eve trip.

Is there a time limit for mission duration? Because if not, surely you can just launch into an orbit that intersects Eve's and wait? You'll get an encounter sooner or later…

[A very dumb challenge]

Just a seat and some rockets, eh? OK, I think I can do that.

This fine craft contains 14 parts: one command seat and 13 solid fuel boosters. No command pods, fairings, nose cones, aero surfaces, reaction wheels, decouplers, LF/OX/monoprop tanks or structural parts were used. Staging is done using the "explosive staging" method, by using a pair of empty Flea boosters as ersatz decouplers that will blow up when the rocket above them fires, and stability is maintained by spinning the rocket up on ascent using the eight slightly tilted Mite boosters at the bottom of the first stage Clydesdale booster.

And yes, it can indeed escape the Kerbol system with plenty of delta-v to spare.

More screenshots and commentary on the imgur album: https://imgur.com/a/2Ca7Ky7

Ps. Craft file here, for anyone who wants to try it out: https://kerbalx.com/vyznev/Dumb-Rocket

[Safety First Space Program]

Nice challenge!

I decided to try starting in vanilla on hard mode and doing the initial science collection without using science rollers, because those things are dangerous! In hindsight, I'm not sure that was a good idea. It is doable… but not easy or fast.

Basically, without science rollers you can only get crew report and goo canister science from two mini-biomes (launchpad and runway). To get science (other than EVA reports) from other biomes you need both an engineer and a scientist: the engineer carries the science instruments to each biome and deploys them on the ground, the scientist runs the experiment and collects the data. (Alas, you can't do that with goo canisters, since they're too bulky to fit in a kerbal's inventory.)

So, after unlocking the first two research nodes (basic engineering and survivability) and getting the thermometer and the barometer, you still need 45 science to unlock the node that gives you the Stayputnik. And you can effectively only get 5 science per biome (EVA report = 1.4, termometer = 1.4, barometer = 2.2) so you need to visit nine different KSC biomes, not counting the ones you've already explored to get the 20 science for the first two nodes (that's probably launchpad, crawlerway, runway, shores and VAB). You can still get barometer science from those, of course, but even if you do that for all five, that's still only 11 science, i.e. equivalent to two unexplored biomes. That's basically a full tour of the KSC — on foot, with two kerbals that you can only move one at a time.

It gets slightly easier if you can also grab science from the building mini-biomes: "VAB Main Building", for example, is a distinct mini-biome from "VAB". But it seems that trying to deploy science instruments in those can be hazardous — I managed to attach a thermometer to the VAB wall, for example, but after going "click" it disappeared inside the wall and was nowhere to be found. Maybe dropping them on stairs might be safer…

(Also, it really helps early on if you break safety regulations a bit and take one EVA report while jumping to get that sweet "flying over Kerbin's shores" science. )

[Tylo Lowest twr Lander Challenge!]

On 8/17/2021 at 10:26 PM, EveMaster said:

I thought about that at first, too. But the time starts when the periapsis is at 0m. So unless you raise the periapsis up again into a proper orbit, that limits how long you can maintain the ultra low twr. Raising the periapses back above 0m once the descent has started should not be allowed in my opinion.

Even so, falling from high orbit takes a loooooooong time.

IMO, the simplest fix would be to just specify a reasonable maximum starting apoapsis altitude. Maybe 30 km? (And, yes, forbid raising periapsis above 0 m after timing has started.)

[Tylo Lowest twr Lander Challenge!]

11 minutes ago, AlpacaMall said:

Regarding rule 3: What counts as the “final stage” of a lander? For example:

* I have a large, high-TWR stage I eject a meter above the ground

* I lithobrake with a stage, but eject it before coming to a halt

I’m assuming that the first one is fine and the second one isn’t, but where’s the line between the two?

I can't speak for the OP, but I assume the intent of rule 3 is something like: "No destructive lithobraking. You can discard used stages and have them crash on the surface, but that must happen well away from your actual lander. The lander itself, or anything in contact with it, must not hit the ground hard enough to break any parts."

(Also, rule 4 puts additional constraints on both destructive and non-destructive lithobraking, and I assume it's also intended to apply to anything in contact with the lander at the moment of impact.)

Anyway, lithobraking on Tylo has been done already by @sturmhauke. (Not from full orbital velocity, though, which you'd kind of need to do if you wanted to aim for TWR ≈ 0. But TWR < 1 with lithobraking seems doable to me. Just not in this challenge.)

[D.A.T.T. : Direct Ascent To Tylo]

If you did add a "no gravity assists" rule, would that rule out braking at Jool periapsis? What about multiple passes through Tylo's SOI to slow down?

(I assume Laythe assists would definitely be ruled out.)

[Asymmetrical Aircraft Challenge]

40 minutes ago, camacju said:

Am I allowed to have a single small reaction wheel on a 35 ton plane? I'm planning to fly it to another planet/moon and I'm going to need some kind of attitude control while in vacuum.

A gimbaled engine can work for that. So will RCS, although the restriction on using each part only once is going to make RCS port placement a bit more of a challenge than usual.

Heck, technically you could even steer a craft using differential thrust from normal non-gimbaled rocket engines, although doing that in stock KSP without something like a kOS script to map steering inputs to engine throttle would be a huge pain.