Bring 10-15t Payload in low orbit

[T3E]

Hey guys,

I have build the first part of my space station and I would like to bring her up in an orbit around 400km.

My main problems are the engines of the first stage:

If I put 1 Mainsail (+ 1 x Jumbo Tank) + few solid fuel boosters, I dont have enough dV to reach the orbit with my other stages.

When I put more than 1 Mainsail, lets say 3 (each with a jumbo tank) I am way to fast (results in being really unstable) and also I have to throttle down to avoid overheating. And I heard of the "rule" that if you have to throttle down, I should take smaller engines.

But this exactly leads me to my next problem: Smaller Engine than Mainsail? There is in my opinion a huge gap between Mainsails and all the other engines. I saw crafts with multiple small engines at one jumbo tank, but I fail to trick the game to make it happen.

Googling for designed rockets is usually results in super sized rockets with minimum double stacked jumbo tanks for payloads arund 50ts. Way too much for me at the moment!

So if someone could give me a simple idea about the engines I should use, I would be really grateful

Another thing, my navball kinda "flipped". I have now West on my right hand, anyone know how to flip it back?

Cheers.

p.s.

if I missed a thread where someone else had a similar problem, I am also grateful if you could just redirect me

p.p.s:

How to zoom in/out in the building hall? I could provide with pictures of payload/rockets i made.

[Dictator Dan]

Mainsails coupled to orange tanks tend to overheat, you can put a smaller buffer tank between them to act as a heat sink, or just run at lower power. Dont forget to strut tanks together, otherwise you get some serious wobble.

Try radial mounted tanks, asparagus staged, as it will allow you to shed dead weight as you climb.

<- video for asparagus staging, brief view it looks to do a good job explaining it.

To mount several smaller engines to a large tank, put the cubic strut at the bottom on the tank, near the edge, just have it selected to place 4, symmetrically, and then you can place smaller engines on them. Alternatively, you can put the long tappered nosecone-ish piece from the jet parts on the side of a tank. You can fit 6 of those on one orange tank.

To zoom the camera out or in inside the VAB, use the + and - keys.

Hope this helps, or at least makes sense, Im pretty tired. If I remember Ill check back on this later, and see if I can give it a better pass.

[tavert]

LV-T30's are probably your best all-around bet for lifting things from Kerbin, with a few LV-T45's and fins for control. Have a look at the smallest of these http://forum.kerbalspaceprogram.com/showthread.php/24787-0-19-1-Zenith-rocket-family and search for various tutorials on Asparagus staging to learn how to use fuel lines and staging for best efficiency.

You can cluster engines under large-diameter tanks using the small cubic octagonal strut piece in symmetry mode, or (heavier but easier) using bicouplers or tricouplers.

You probably rotated your capsule or probe core part. Pick it up and rotate it back 180 degrees with Q or E. Default keys for zoom is + and - on the numpad. Mouse wheel either zooms or translates up and down, I play on a laptop so not sure which.

[EndlessWaves]

My main problems are the engines of the first stage:

If I put 1 Mainsail (+ 1 x Jumbo Tank) + few solid fuel boosters, I dont have enough dV to reach the orbit with my other stages.

Yup, your first stage is the problem alright. You don't want to be using parts anywhere near that large to lift 10-15t, otherwise you're wasting most of your fuel lifting itself.

For 10-15t you want to be using 200L and 400L tanks, maybe a few 800L one for a first stage if you don't want to use jets. Keep the total weight under 100 tons.

[T3E]

Hey guys, thanks for the replies.

I am little bit familiar with the asparagus system,even tho it didnt helped me out.

The nosethingy things from aerodynamics work well, but I dont see how I can attach more tanks outside to use the asparagus system as well.

And about the cubic octagonal strut pieces, dear god, HOW?

The Link about the Zenith rockets is quite good, but I need to manage it with the cubes to copy some of the design.

If I attack them as far outside as possible, the engines get "green" but attaching doesnt work tho. Do I need to use multiple cubes?

I wish I would be more a builder than a pilot

Update:

I managed so far to attach more engines, but struggle hard now when I release the attached tanks, they crush pretty much always in the engines.

The whole mission slowly gets really complicated.

http://i.imgur.com/zxzSSiR.png

Edited May 19, 2013 by T3E

[DaRocketCat]

There is indeed a huge gap that is filled by the KSPX mod.

[Blackbird]

I managed so far to attach more engines, but struggle hard now when I release the attached tanks, they crush pretty much always in the engines.

The whole mission slowly gets really complicated.

http://i.imgur.com/zxzSSiR.png

Try to spin your craft before releasing the outer tanks so they get "thrown" away from your craft due to the rotational forces or whatever they are called

[Rhomphaia]

Hey guys, thanks for the replies.

I managed so far to attach more engines, but struggle hard now when I release the attached tanks, they crush pretty much always in the engines.

The whole mission slowly gets really complicated.

http://i.imgur.com/zxzSSiR.png

MOAR BOOSTERS!!

...in this case sepratrons, attach a couple of them to your boosters set to fire when the decoupler does so they push the spent stage away from the remaining engines. try also to angle them so that there exhuast doesn't hit the engines on the active stages as this can cause explosive overheating.

[Pursuedtank]

Looking at that picture you almost certainly don't have enough fuel to get into orbit. You need around 4500 m/s of delta V. You can get away with slightly less but you should aim for 4500 m/s for some wiggle room.

[Actzoltan]

This is how i handle asparagus stageing

To explain what your seeing here:

My Main stack has 4 rockomax200-32 fuel tanks attached to a radial stack decoupler.

The 4 rockomax x200-32 have decouplers on top and bottom with identical tanks attached.

All tanks except the main, and bottom fuel stack feed into the 1st 4 rockomax 200-32 tanks by girders and fuel lines attached to the girders.

The 1st 4 rockomax tanks feed into the main tank and the bottom 4 fuel tanks.

The 4 bottom fuel stacks connected to the first 4 tanks have 2 girders which sandwich a decoupler the fuel lines connect to the ouside girder.

when that decoupler is triggered the fuel line is cut.

The bottom 4 fuel stacks have engines under them connected to tri couplers.

[T3E]

Try to spin your craft before releasing the outer tanks so they get "thrown" away from your craft due to the rotational forces or whatever they are called

Try to spin your craft before releasing the outer tanks so they get "thrown" away from your craft due to the rotational forces or whatever they are called

Thanks a lot! I managed tho in this case (i centered the engines more of the maintank) but this will help me from now on in 90% of the cases where I have the named problem

Looking at that picture you almost certainly don't have enough fuel to get into orbit. You need around 4500 m/s of delta V. You can get away with slightly less but you should aim for 4500 m/s for some wiggle room.

Indeed. I increased the fuel and changed some engines. Even tho at the end I managed it with little less than 4500.( I really think I am more the Pilot type )

This is how i handle asparagus stageing

To explain what your seeing here:

My Main stack has 4 rockomax200-32 fuel tanks attached to a radial stack decoupler.

The 4 rockomax x200-32 have decouplers on top and bottom with identical tanks attached.

All tanks except the main, and bottom fuel stack feed into the 1st 4 rockomax 200-32 tanks by girders and fuel lines attached to the girders.

The 1st 4 rockomax tanks feed into the main tank and the bottom 4 fuel tanks.

The 4 bottom fuel stacks connected to the first 4 tanks have 2 girders which sandwich a decoupler the fuel lines connect to the ouside girder.

when that decoupler is triggered the fuel line is cut.

The bottom 4 fuel stacks have engines under them connected to tri couplers.

Gratitude for the explanation, but all in all I think that this design is a little overkill for my "small" payload (i know you guys usually have a payload of 50t and more).Even tho I appreciate the further asparagus explanation. Especially with the up/down fuel ducts (never thought of this myself )

At the very end I managed today. (could have been earlier if the gf wouldnt give me a hard time, damn women, delaying science since mankind).

So thanks everyone for the input This community just never fails you