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Wanderfound

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    Space planes break the tech tree

    in KSP1 Suggestions & Development Discussion

    Posted · Edited by Wanderfound

    There are mods around that allow you to re-order the tech tree, but yeah: the stock tree is neither realistic nor particularly fun. Ladders, wheels, fins and landing legs should not be advanced technology.

    If it were up to me, I'd re-order the tech tree with all of the basic stone-age stuff (ladders, fuel hoses, struts, basic aircraft parts, the ability to change what fuel you put in a tank, etc) right at the start, but with a lot more variety and depth in the science and space station parts.

    You should never get to a point where you've "done all the science".

    How cheap are low-tech(panther) spaceplanes?

    in KSP1 Gameplay Questions and Tutorials

    Posted

    6 hours ago, Abastro said:

    Hi,

    I recently started hard career with every parts reused except for heatshields, separators and fairing.

    I want to do it as cheap as I can, so I want to know if Panther-based spaceplane is cheaper than reusable TSTO.

    Basically these are what I want to know:

    1. Cost per crew

    2. Cost per ton of payload (does it beat 400/t easily?)

    Demonstration:

    That's an old FAR design, but it should be possible to make something similar work in stock.

    They're never going to be as efficient or sleek as a Whiplash or RAPIER ship, but they can be made usable. I'll see if I can throw together a Mk2 demonstrator this evening.

    How do I SSTO?

    in KSP1 Gameplay Questions and Tutorials

    Posted · Edited by Wanderfound

    Reinforcing...less is more.

    Less engine, less fuselage, less intake, less wing [1], minimal ancillary gadgetry.

    However...it's as much about the flying as the building. The best SSTO will fail if you fly it wrong, while even a bad one can often be coaxed into orbit if flown just right. The key is that you have to crank as much speed and altitude as you can from the jets before beginning the rocketry; you're aiming to get as close to 1,500m/s and 30,000m as possible before you light the fireworks.

    Start small; the bigger they are, the harder they are to get right. But if you build something that's basically just a cockpit, some wings and fins, one RAPIER, an intake, an FL/T-800 LFO tank plus around 400 units of LF (for the open-cycle jet phase), it should go to space without too much trouble.

    PYSO9VG.jpg

    For the "how much wing" question, see:

    For basic tricks (you may already know these, but just in case):

    1) Minimise distance between CoM and dCoM (AKA CoM with empty fuel tanks). You don't want the plane shifting its balance point mid-flight.

    2) CoL close behind CoM. How close is a judgement call; the closer it is, the more agile the plane; the further it is, the more stable the plane.

    3) You want enough wing to keep your takeoff speed below 100m/s, and enough engine to hit that speed before the end of the runway. Anything more is a luxury.

    4) In a tricycle setup, the rear landing gear should be just behind CoM. If it's a lightweight Mk1, you can get away with mounting gear on the wings. Anything heavier and you want to stick to fuselage mounting to reduce flex.

    5) Drag is king. Don't mount anything on the surface of your ship if you can stick it in a cargo/service bay instead. If it's a Mk2 or Mk3, build in enough wing incidence so that you can keep the nose on prograde during the speed run; a few degrees is usually sufficient.

    6) You need sufficient control authority to move the plane in three axes: roll, pitch and yaw. In each case, the further the control surface is from the CoM, the more power it will have. It's all about leverage.

    7) One shock cone or intercooler will feed three RAPIERs. One ram air intake will feed two. Etc.

    8) Make it look like a plausibly realistic plane. You can make freaky SF ships once you get good, but to begin with, you've got more chance of success if you copy the basic airframe of a real plane. They're shaped the way they are for a reason.

     

    [1] This is a matter of preference, see the linked post above for detail.

    1.0.2 Can anyone get a Mk3 SSTO spaceplane in orbit?

    in KSP1 Discussion

    Posted · Edited by Wanderfound

    24 minutes ago, TDplay said:

    Many crafts of mine do get off the runway, get into a promising horizontal takeoff, then they dive down, even if I hold 'S'.

    That suggests that you're lacking sufficient pitch control. Elevators and canards, as far from CoM as possible for maximum leverage. Keep the overall CoL fairly close behind CoM/dCoM.

    OTOH, if you can hold the nose up but the plane descends anyway, then you may have a need for more wing or more engine. Or more delicate flying; with overweight marginal stuff, if you hold the nose too high during the early climb you'll generate so much drag that you can't accelerate. Get off the runway, lift the nose just enough to maintain level flight, build up a little bit of speed (i.e. 150-200m/s), then climb.

     

    24 minutes ago, TDplay said:

    Can that lift MKS Tundra 2.5m modules, I need an SSTO to lift new parts to my station, it desperately needs my advanced Life Support module, and I'd rather not waste rockets.

    If it can fit in the bay (one standard long Mk3), it can lift it. The six-engine version can manage up to sixty tons, the eight-engine version eighty tons. You're unlikely to find a sensible payload that fits and weighs much more than forty, though; I had to pack the bay with ore tanks for the eighty ton test.

    You can get a craft file for a six-engine version at https://kerbalx.com/Wanderfound/Kerbotruck-Compact-Lander 

    1.0.2 Can anyone get a Mk3 SSTO spaceplane in orbit?

    in KSP1 Discussion

    Posted · Edited by Wanderfound

    20 minutes ago, TDplay said:

    The issue is, my SSTOs only get enough lift if it's a lifting body. I can get OPT J and K into orbit, but not the significantly smaller Mk3. The only exception is Mk1.

    Notice the lack of large wings on my examples?

    Wing incidence matters a great deal; you want to set it so that the plane can climb while keeping the nose prograde, to minimise fuselage drag. And, as with the smaller planes, keep the weight down; no more engines than you need, don't carry too much ancillary junk (and hide it in a cargo bay if you do; drag is a killer).

    If you can lift off at a reasonable speed (about 120m/s at the top end; lighter ships should manage it at 70m/s) and maintain altitude while accelerating, then you've probably got enough engine and wing.

    As demonstrations, here's my standard Mk3 taking the cruisy route to orbit:

    ...and here's a lightly modified version of the same ship with the cargo capacity stretched to the limit.

     

    Overall theme: you probably don't need as much wing, engine or intake as you think. And, if you're willing to take a bit of time on the initial climb, almost anything that you can get off the runway can eventually get up to speed and altitude.

    1.0.2 Can anyone get a Mk3 SSTO spaceplane in orbit?

    in KSP1 Discussion

    Posted · Edited by Wanderfound

    21 hours ago, TDplay said:

    Really? I tried simply scaling up my Mk2 designs, they won't even take off!

    Drag minimisation and heat tolerance matter a lot for Mk3 builds; you'll be spending a longer time accelerating in the thick air, so the heat has time to build. The less drag, the shorter that time will be.

    You can do some things once you get it right, though:

    WEXmRsJ.jpg

     

    W4pt324.jpg

     

    xN69GCe.jpg

     

    fpRgKpE.jpg

     

    15 hours ago, AeroGav said:

    BRAAAIINNZZZ  !      Zombie thread warning !

    This is fascinating though, how far we've come since then.    Has the community just got better at designing spaceplanes,  or is this the cumulative effect of small buffs, patch after patch?

    It's a zombie, but it's interesting enough; may as well let it lurch. :)

    Vernor Engines taking over for MonoProp Thruster Blocks

    in KSP1 Gameplay Questions and Tutorials

    Posted · Edited by Wanderfound

    6 hours ago, AeroGav said:

    Similarly for Duna, they only need to support half the weight of the craft at most, the wings can do the rest in the thin atmosphere and keep a survivable landing speed.  Provided it has a low landing speed to begin with ofc - but it's easy enough get a spaceplane landing at 30 m/s empty on Kerbin

    My high-wing-loading planes tend to stall and fall out of the sky at about 300m/s on Duna. So, my standard landing approach tends to go like this:

    3gSkwVX.jpg

    Get as low as you can while keeping it at about Mach 1, then gradually shift the load from the wings to the Vernors as the plane begins to stall. Just before touchdown, flare hard while firing the Vernors, using them as retrorockets. Pop the drag chutes just as you touch down.

    Ph4IheU.jpg I can't remember if I hit the chutes early on that landing or if that's a bounce, but the screenshot is from immediately after chute deployment. The yaw is because one chute opened a millisecond faster; easily compensated for with steering.

    Note that the speed has gone from 280m/s at 75m altitude to 70m/s in only eight seconds.

    oY97jzM.jpg

    It's a high-adrenalin landing method, but it works. :)

    Drill-O-Matic burns while aerobraking

    in KSP1 Gameplay Questions and Tutorials

    Posted

    1 hour ago, Urses said:

    Thus was mostly because off the drills looked like they are behind the Schild but where clipping Inside.

    Similar issues with cargo bays. If you've got drills too close to the edges of the bay, it'll count them as unshielded (generating massive drag) even though they appear to be entirely inside.

    I suspect that the collision mesh is slightly misaligned on both sizes of drill.

    Vernor Engines taking over for MonoProp Thruster Blocks

    in KSP1 Gameplay Questions and Tutorials

    Posted · Edited by Wanderfound

    I only use Vernors for low-g VTOL. Descend on the main engines, then flip horizontal and fire up the Vernors at the last moment.

    W4pt324.jpg

    They're generally much too overpowered for docking use; monoprop RCS works better for that. For control during launch...well, that's what gimbal and fins are for.

    On a ship like the one in the picture, I'd have the Vernors set to an action group so I can deactivate them while docking.

     

    Good tips for Jool 5

    in KSP1 Gameplay Questions and Tutorials

    Posted · Edited by Wanderfound

    Depends on how you plan to do it.

    Jool 5 has low-g vacuum, high-g vacuum, high-g oxygen and a potential extreme aerobrake on the Jool capture.

    First call is: are you landing one vessel on all five, or is it going to be a mothership plus specialised landers deal?

    For the first option, you just want an ISRU equipped SSTO that will hold five Kerbals. Not too hard to do in either Mk2 or Mk3 form.

    For the second...go as crazy as you like. Compact or huge, either will work. Just make sure you've got either a big heatshield or enough gas for the Jool capture, and try to take advantage of gravity assists from the moons. Get it right and you can capture very cheaply.

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