LKO Tanker

[rdrdrdrd]

Once docking rolls around I will be creating fuel Depots and Shipyards (lots of nodes to dock to) orbiting Kerbin, for interplanetary missions abd such. One shipyard and one depot in LKO and one space colony in KSO, space planes will ferry fuel and modules to the depots and from there low powered ion or nuclear rockets will take fuel and modules to the space colony, and from there to a mun orbiting colony/yard.

The challenge, create a fully reusable space plane that can ferry a load of 3 MKII hulls with end caps (II to I adapters plus a nose cone on one end and a docking port on the other) or a 2X4 extra planetary infrastructure module to a 200Km orbit.

[SunJumper]

Planes are re-usable if you can land them. Otherwise, it doesn\'t matter what they look like...

[Kreuzung]

He said fully reusable. No space-shuttle-ish things.

[Sean Mirrsen]

Where would one get a docking port and how much does it weigh?

I\'ve got a design that can haul the described fuel pod into a 200km orbit, sans docking port.

(assuming you meant Mk2 hulls, not Mk3 ones)

I have some lag issues with the design though (as evidenced by the altimeter bugging out in the last shot), so I couldn\'t try to land it. It still has some two and half tons of fuel left to deorbit, and an appreciable amount of kerosene for a powered glide home, so it should be able to return safely. I\'ll try to simplify the construction a little in hopes of removing whatever causes the horrible lag, so I can try a proper mission with it.

[Kreuzung]

Docking port is probably from ExPI, like the 2x4m station he mentioned too.

[dylan1234]

Docking port is probably from ExPI, like the 2x4m station he mentioned too.

It could be from novasilisko BACE pack or kosmos space station parts

[rdrdrdrd]

Yes the docking port is just from the ExPI pack, however having a blank 1m end is fully acceptable, weight is negligible.

How did you get the plane to not spiral out of control with the weight on the bottom? thats the problem I\'ve had, good job though (crazy looking plane there lol), did you use fuel from the cargo tanks to power the plane?

[Sean Mirrsen]

No, I haven\'t used any fuel from the cargo pod, what would be the point?

The plane is made up in such a weird manner that the slanted form of the fuselage creates downward force that counteracts the balance shift from having the engines below CoM. All engines also have vectored thrust, and set up so that they barely have enough control to pitch the plane down with the pod attached, and just enough to pitch it up without the pod. It\'s mostly based off my normal Albatruss design, which is already proven to work as an SSTO craft, though here there are extensive modifications to the drive system.

I\'m currently fighting the wonky physics engine of KSP to make my revised design not fall apart on the runway. And there\'s still the lagg. I\'m trying to see if there\'s any underlying cause to it other than the sheer number of parts.

And if you think that\'s a crazy looking plane, just look at my first SSTO design attempt:

I kinda like it though. Probably could redesign it so it can actually reach orbit this time.

[Joshmo]

Where would one get a docking port and how much does it weigh?

I\'ve got a design that can haul the described fuel pod into a 200km orbit, sans docking port.

(assuming you meant Mk2 hulls, not Mk3 ones)

I have some lag issues with the design though (as evidenced by the altimeter bugging out in the last shot), so I couldn\'t try to land it. It still has some two and half tons of fuel left to deorbit, and an appreciable amount of kerosene for a powered glide home, so it should be able to return safely. I\'ll try to simplify the construction a little in hopes of removing whatever causes the horrible lag, so I can try a proper mission with it.

That freakin thing is beautiful.

[Candre]

I kinda like it though. Probably could redesign it so it can actually reach orbit this time.

I don\'t think sideways wings generate lift. Try removing the offending parts.

[Dobrodav]

Not sure that my craft is fully fit in conditions, but think that it can be easily modified.

Fully reusable SSTO 'Bobs Carrier'

That modification of 'Bobs' can deliver up to 20 tons of payload on circular orbits up to 400 km.

Was designed to deliver 2 long range probes on LKO.

It have 5 rcs tanks, witch numbers can be raised to 10 (or more, if payload mass reduced), if extensive maneuvers expected. Also payload can be placed on nose section (where is RCS tanks located) in witch case it actually controls better. Nosecon is good place for docking node. There is also 2 more good spots for payload/nodes just before most upper and lower fuel tanks.

Its initial mass is 111.23 tons and about 42 tons empty after landing on runaway.

Control rating at full mass - acceptable, rotating for lift off is done, just after slipping from the end of runaway, or by raising gear at 100 m\s. On orbit with payload - heavy with RCS off (unbalanced due to a mass distribution). On orbit without payload - good. During reenter - stable. Gliding\landing - good.

Here is a report of test delivery fly on 240km orbit.

http://imgur.com/a/aVE2W#0

Craft file in attachment.

[SunJumper]

Kreuzung, what I mean is, if you add a ton of parachutes, you can have any design you want so long as it meets delta-v requirements (and doesn\'t destroy itself instantly...). I think you can add parachutes to the side of things...

[rdrdrdrd]

Wow thats pretty cool, thanks guys

[Sean Mirrsen]

What annoys me the most is that most of my designs end up being so heavy that they are undone by the most annoying bug ever.

I can\'t even test and tune it properly like this!

[Dobrodav]

What annoys me the most is that most of my designs end up being so heavy that they are undone by the most annoying bug ever.

Hm, looks like rear gears go through the ground. Try to change angle at wich they are rotated. Mostly that bug occurs when gears are not 90 degrease to the surface.

[Sean Mirrsen]

Hm, looks like rear gears go through the ground. Try to change angle at wich they are rotated. Mostly that bug occurs when gears are not 90 degrease to the surface.

Nah, they are perfectly perpendicular at design time, it\'s just that the craft itself spawns with them already sunk into the runway. I\'ve mostly fixed that right now, but I broke the balancing of the space-mode flight. This tanker can do anything! It can take off, it can land, its decoupled capsule has (surprisingly impressive) glide capability and thruster sets for orbital maneuvering!

But it can\'t actually make orbit, because it keeps trying to make like a centrifuge once it leaves the atmosphere. *sigh*

I need me some kind of way to pre-rotate stock vectored engines.

[Dobrodav]

Well, they want to illuminate phantom forces in 0,16 version. Maybe you should just wait a little for this. Or inspect your craft for parts intersections.

[Sean Mirrsen]

No, it\'s purely misaligned thrust. Right now the biggest problem I\'m facing is one single problem that Harv and co don\'t seem particularly inclined to fix. It\'s the physics lagspike freakout at launch. It\'s currently a gamble every time I make a small change to the design. It may keep working just as well, start working better, or fall apart immediately upon appearing on the runway. It remains consistent until I change something in a way that somehow makes the whole thing work again. Usually it involves adding landing gear. The most ludicrous case being just recently, where the change was simply moving two engine pods about half a meter forward and rotating the tricoupler with engines attached to them. This was the difference between a craft that easily took off with zero glitches and just failed to establish orbit due to a minimal thrust misalignment, and a craft that snapped in half immediately upon appearing.

[that1guy]

so if I am reading this right, no boosters?

[Dobrodav]

Yep, no detachable parts in propulsion system. Maybe only in payload delivery system,- to put the payload at already established orbit.

[Sean Mirrsen]

Welp, Albatruss MkIV-Experimental 6 successfully completed its mission, at least up to putting the fuel pod in orbit.

Accelerating off the runway:

Achieving egress angle:

Rocket engines ignited:

200k apoapsis orbit achieved with six full tanks to spare (plus 100kg fuel in mostly empty tanks):

200k periapsis orbit achieved shortly afterward:

Payload detached:

Return to atmosphere:

However, a monumental f*ckup with piloting resulted in complete loss of the craft. The main body exploded seconds after the capsule detached, and the already-deployed parachutes were destroyed, making the capsule splash down hard and disintegrate.

I\'ll report later when I actually have a successful mission and return.

edit: I suppose I can attach the craft too. Mods used: ExPI pack for the docking module, Multiversal Mechatronics Fixed Camera (by accident, left mostly in places I can\'t reach at design time. Will try to rid the craft file of them manually, but for now they\'ll be prerequisite. Be advised, about four cameras are somewhere on the landing gear.)

Piloting notes: To take off, turn on ASAS and accelerate at full thrust until the end of the runway. At the very end of the runway, momentarily turn ASAS off and pull up hard. The trickiest part is not to let the tail hit the ground, catch the angle with ASAS again. Once you\'re sure the craft is rising, pull up landing gear and resume flight. Rise vertically, beginning to level off at about 30-35k. You may encounter a few points where ASAS alone won\'t be enough to maintain course, use RCS to boost control at those times. Once you have a 200km apoapsis, cut throttle and coast until there, then burn prograde till you have a 200km periapsis. Release payload, burn retro till your orbit touches atmosphere (there should be enough fuel to aim wherever). Can\'t quite tell you what to do on return or landing, but try to keep ASAS on until you\'re low enough to maneuver for landing. Watch the LFE\'s, they hang fairly low. The wheels on the swallowtail should help prevent smashing them up, but it\'s a hair\'s breadth thing. There aren\'t any landing chutes either. So be extra careful.

edit2: updated design to MkIV-X7, with removed extra cameras (still requires the plugin though) and fixed oversight with fuel lines for turbojets.

[Dobrodav]

Well, that bird is quite pleasant looking. Cool work at design, Sean.

I tried craft named 'Morning Star' posted somewhere at 'K prize' theme, and i was surprised how well it behave even without any ASAS attached. It was designed by its creator for long duration missions (i.e. to land on the moon and back). So it have some good potential to be redesigned as LKO tanker. Think will try to redesign it.

[Sean Mirrsen]

Well, that bird is quite pleasant looking. Cool work at design, Sean.

I tried craft named 'Morning Star' posted somewhere at 'K prize' theme, and i was surprised how well it behave even without any ASAS attached. It was designed by its creator for long duration missions (i.e. to land on the moon and back). So it have some good potential to be redesigned as LKO tanker. Think will try to redesign it.

The thing that I like best about KSP is that, unlike games like Spore or any 4X strategy with ship design options, it actually rewards good design. The design process is as much about visual design as it is about choosing the best components for the ship, the parts matter not only because what parts you choose, but also how you choose to place them.

If/when Squad is ever 'done' with KSP, I believe their next project should be a procedurally-generated open-universe sandbox game, a-la Elite or the X series. But with exactly the same ship design principles as in KSP.

And as far as modifying existing SSTO craft, I think the biggest challenge is making the craft behave well enough with and without the payload. Unless you mount the payload directly in front or behind the craft (not entirely feasible for spaceplanes, though not impossible), you will have issues with mass distribution. My craft sort of skips the issue by placing the payload close the thrust vector of the rockets, but most spaceplanes not purpose-built for this are going to have trouble.

While I am here, I\'m sort of wondering. There\'s quite enough extra fuel on this craft after all the orbital shenanigans, and I don\'t really need the rockets in atmosphere... what are the parameters for KSO? With some luck, I might be able to reach that.

[Dobrodav]

Yes, detachable payload is a pain.

But in the line of thinking about the craft exactly as a tanker, we might to count just delivered fuel quantities (in non detachable tanks), relaying on some fuel pump system, that will empty them through docking port. That kind of design is much more easy to accomplish. Thats actually an reusable space-plane with docking port and reach RCS power, able to reach and operate on orbit with significant amount of unused fuel.

About KSO - http://kerbalspaceprogram.com/forum/index.php?topic=14339.0

[Sean Mirrsen]

In-progress mission report:

Alrighty, got orbit transfer to KSO set up with four and a half fuel tanks left total. Assuming, generously, two full tanks each for both the burn to KSO velocity and the retro burn to return, I still have a little wiggle room left. Whee!!!

Manual orbital insertion is hard as... hooves. If I were using MechJeb, I\'d be in Mun orbit by now. I guess a ±50km KSO will have to do.

Releasing payload (I do love these kind of shots for some reason):

Burn for home complete:

..and with two-something tanks of fuel left for maneuvering! Huzzah!

I kept snapshots of every major stage here, so that no accident will foil my plans this time. I\'ll try to line up a good landing and report then. I did forget to add those braking chutes, too...