Real spaceship?

[Thunderbird]

Hello,

i have a slight (read explosive) problem.... Im trying to build a real 'space ship' with Ion engines for in-space maneuvering, essentially i want to be able to get anywhere, no matter how far it is. Im also at work and cant provide screenies,sorry :-)

The problem is not in the deep space/lander stage itself,but in how the hell am i going to get something so incredibly huge and bulky in space ;D

I built a standard RCS/SAS/small liquid engine landing (or emergency) stage, and already found a problem there. Heavy decouplers,no matter how awesome they are, will not hold hull segments,so i had to attach (large) boosters on them in a 6-star configuration (very weighty stuff already), because the spaceplane fuselage couldnt seem to act like a solid hull and fell apart. I had to use 2 heavy decouplers to get the boosters far enough from each other for the next stage.

The next stage was attached by hollow decouplers with 30 ejection strenght and retro-boosters, contained only a SAS module (i had to put something there) and then a adapter with 4 slots of the same size. These held the ion engine tank and the engine itself,with solar panels. The same 'ion drive module' belonging to this stage was also attached to the bottom of the lander stage engine. This gave me 28 ion thrusters, which was supposed to be enough to get anywhere really fast.

There i ran into a problem... this contraption was,surprisingly enough,almost stable without having to use too much duct tape, but is surprisingly heavy and HUGE.

There are no inverted 4-to-1 adapters to the 1-to-4 like i used to attach the ion engines,or i could not find any,i had no way of strapping on big enough ascent stage(s?) to get the crazy machine off ground. The thing i 'did' try however was attaching 6 incredibly huge (3-part) cone-shaped fuel tanks to the outer ion engines (im not sure how they are called atm,4-meters diameter on the bottom of the last one i think) and slapped on the biggest freaking engine ever (1100 thrust per one), and hoped for the best. When it DID work im pretty sure the lightly sideways push wasnt good for the parts either.....

By now i think you have an idea what kind of a abomination it was... I used fairly large amounts of duct tape and wire to stabilize the fuel tanks and the separate stages, and i did actually manage to get it off the ground stabilized (cant duplicate it for some reason ), but the tanks tend to break off from each other or snap off, and if i put too much extra weight on it or put struts in wrong places, the whole thing buckles and explodes in a huge ball of death.

So... my question would be i guess... do you have any idea how to make a stable ion drive spaceship and get it into space? A different shape than a star maybe, or where can i get parts to put the whole thing together better? The 4-1 adapter would allow me to put it together more sturdily i think,or atleast attach a proper fuel tank instead of the cone one...

I always seem to have structural problems of the weirdest kind :\'(

edit: i also tried attaching a Project Firelark instead of the first stage to test it,but that didnt even light off for some reason (tested it separately and it worked)

[Zeroignite]

Screenshots would be helpful. My visualization skills aren\'t good enough to understand the problem.

[derhp]

Yeah screenies really would help. The only thing I can think of would be to reconfigure your spaceship a bit. If you used some of the C7 flight parts you\'d be able to achieve a hollywood spaceship look, with wing mounted egines and that sort of guff. Here is the C& spaceplane thread http://kerbalspaceprogram.com/forum/index.php?topic=2421.0

In regards to getting it into orbit to begin with, regardless of what format you use, I think the kerbal adage of MOAR BOOSTERS should work. A mixture of liquid fuel booster and SRB\'s should get the thing moving to the heavens no worries. You\'ll need a deltaV of around 3300m/s to lift your craft to an altitude where the the Ion engines can overcome gravity.

[Thunderbird]

Well,i got home,redone the ship like 3 times over,and ended up with this.... i have tons of inherent control problems on this design apparently,and i cant control it because i have like 1 FPS with that goddamn thing....

I THINK it can reach low orbit,or atleast get high enough for the Ions to estabilish it.... the smaller boosters are a temporary slap-on because i didnt know what to do...

I used Tiberion`s slightly modified XC-40 (C-7 parts) Albatross as the 'return stage' (dont ask,i need lifting capability anyway) - Thanks Tiberius - i think that kind of contributes to the control problems because the XC-40 sure could be more stable... but not the main problem i guess

The whole thing is built on top of a sixpack of Firelark Project boosters (maybe temporarily,no idea), next stage are the Ions, after detaching Ions you end up with a fairly huge tank of liquid fuel tipped off with a Omnipotent Bertha drive block, the Ion blocks contain a Liquid Fuel Aerospike Engine - 1 each.... Stargazer actually is capable of achieving orbit on this stage (80% thrust or you burn out the Bertha),all lower stages are there to lift the overweight Ion drive sections...

The idea was to LAND with this monstrosity somewhere after detaching the Ion drive section, but thats somewhere in the land of dreams right now... i was thinking parachutes and low thrust, but meh. If i could do this it could probably visit 2 planets and return on the XC-40 stage alone... or use it for braking if i accelerate crazily enough somehow....

Please take a look on it, i completely lack experience to balance anything that is more complex than a 'standard' 3-stage rocket... and this has 11-13 stages,depending on configuration...

I use a lot of mods,sorry apart from the already mentioned there are the fine tunned stabilizers also found on the XC-40 (small blue,big red,etc)

Any help in stabilizing the damn thing,or improving the design in general,will be appreciated.... you can tell i like HUGE ships which can last long and go anywhere... i`d strap solar panels on it to be entirely self-sufficient too, but Ion fuel tanks wont take them and theyre heavy.... its still a prototype anyway ;D

[derhp]

I see what you\'re trying to do. Only advice I would give is try to reduce your weight up top, that big winged thing is a bit superfluous for a craft that is going to be spending it\'s time in orbit. I\'d also use an ASAS unit and a whole mess of RCS tanks and nozzles to keep her flying true. I\'m at work atm, and don\'t have KSP here, so please accept this MS paint of what i\'d do.

[Zeroignite]

Wings on top of a rocket stack are a really bad idea. For a stable rocket, your Center of Mass needs to be in front of the Center of Pressure. Basically, once you get up to speed, the wings are gonna act like a gigantic sail and flip you over backwards.

[Thunderbird]

Ahhhhhh ok its the wings then... When i tried to fly it,it was barely pilotable, since i have the fps problem... I guess that means i will have to build a lander stage afterall, i wass afraid of that :-)

Will try when i get back from work... Anyone tried to fly it btw?

Awesome pic tho derhp :-D

[Thunderbird]

Wings on top of a rocket stack are a really bad idea. For a stable rocket, your Center of Mass needs to be in front of the Center of Pressure. Basically, once you get up to speed, the wings are gonna act like a gigantic sail and flip you over backwards.

stupid idea here, you think i can just compensate that by adding m0ar wingy bits to the back? say slap them on the Firelarks and then drop them since it wont matter outside atmosphere anyway?

I wanted a semi-glider design for the return stage,but i really suck at designing space planes, and swapping that for a different one would mean starting over :\'( Thing is the rectangular wingy bits between XC-40 the separate fuselages have a lift factor of 1 (long wings have 1.6 i think?) and i think i would have to remove them too....

comment: not sure if lift factor is the actual value to look for here or if just the wing total surface area counts

[Zeroignite]

stupid idea here, you think i can just compensate that by adding m0ar wingy bits to the back? say slap them on the Firelarks and then drop them since it wont matter outside atmosphere anyway?

Possibly, but it\'ll be rather hard. You need a ton more wings on the back to overcome the drag on the front, which will be pretty difficult considering you\'re using the bus-sized wings. Downsizing is probably a good idea at least. You\'ll also need control surfaces on the lander if you want it to not fly like a brick, which will try to break your rocket in half during boost when any control input is applied. Struts, (tuned) ASAS, and experimentation will probably be your friends.

[Thunderbird]

Screenshot0 - earlier version,you can see the beginning of wobbling just as i dropped boosters

Screenshot1 - latest incarnation of the Stargazer, craft file included, with my own design Sparrow shuttle on top (only tested flight), seems to be stable enough but i suck at atmospheric flight.

What was happening,i think,was that the craft was beefy and short, and its ion engines were heavy and improperly stabilized... they were waving around just a tiny bit during flight, and the moment i hit stratosphere and the air stopped offering proper stabilization, it tilted the craft just a tiny bit, which tilted the whole 30k units of thrust just a teeeeny bit to the side... unfortunately this whirling effect was steadily and slowly increasing, especially when i dropped the empty SRBs

New design is,as you can see, even bigger,has a additional 7x nuclear engine stage on a 5k fuel tank for 2nd stage ascent before the actual ion drive,and the Firelarks have oversized stabilizer rings on them,and no freaking boosters.... still keeps Jeb plenty happy tho 8) I should also note that Stargazer Mk3 has a ridiculous amount of SRS packs and fuel (didnt feel like downsizing it again) and the Sparrow has quite a few of them too,with the central fuselage actually made out of SRS fuel tanks... i might get around to redoing it later but it works,so meh... on the Mk.2 i was experimenting with using the Sparrow as a stabilizer, didnt quite work...

I only tested it to the edge of atmosphere (which showed around 1 minute and actually took me like 10 with the massive game slowdown i get) and flight was stable with SAS,didnt bother using thrusters...

Then i got bored and decided to test retro-thruster fitted Firelarks if it has enough power to tilt them away from me while still under power.... nope, i used 8 or 9 and only managed to get them to rake across the entire hull,rip off the ion drives and then cook the huge middle fuel tank. Atleast the explosion was nice but i stripped them off before saving the ship

Someone please do me a favor and test the ship

Also,if you guys have an idea how to safely eject Firelarks at full power without dying,im listening =P

[Zeroignite]

I still don\'t know what the 'firelarks' you\'re talking about are, but trying to jettison still-burning SRBs is something you just generally try to avoid. It usually makes a mess.

[Thunderbird]

I still don\'t know what the 'firelarks' you\'re talking about are, but trying to jettison still-burning SRBs is something you just generally try to avoid. It usually makes a mess.

Its the MOAB

http://kerbalspaceprogram.com/forum/index.php?topic=2750.0

if you try to use it and still do maneuvers,even correction ones,do yourself a favor and strut the engine to the fuel tank