New to the game, lotsa problems. (craft design, steering etc..)

[Dewm]

So I've built quite a few ships, gotten a few into good orbits... but I'm trying to build a refueling center and get different modules into orbit etc. Here is a picture of my design:

(maybe I'm doing something wrong)

So I lifted off, got to about 11,000 meters and turn so I was dead on the 90 degree mark, stayed on that course until I hit around 19,000 meters. So I killed the engine (because I can't look at my orbit map and steer at the same time, and this thing was all over the place) So I looked at the orbit map, decided I wasn't high enough yet. Went back into normal view.. and I was spinning out of control and falling.

This happens to 90% of my stuff. what am I doing wrong? I've watched a ton of videos by scott mansley and others, and they seem to lift into space with ease, and don't really have to steer or do anything to get into orbit..

Once I'm in space I can steer and set courses just fine.. but getting out of that darn atmosphere is frustrating.

Anyways, some advice and or help would be great.

Thanks!

Edited July 29, 2013 by Dewm

[Vanamonde]

Long, thin rockets are inherently less stable. As you burn fuel in the lower stage, the center of mass shifts toward the top, and then you're trying to shove the thing around like balancing a broom in the palm of your hand. Try side-mounting the boosters around the payload instead of stacking the stages one on top of the other.

[annallia]

If it is wobbly add more struts, might not be pretty but it will help. (looks to me like it might be)

That said I have a few thoughts.

1 You need an SAS module unless its tucked in there and I just cant see it.

2 Without copying your design and testing it I cannot say for sure but you look under powered once you drop the side rockets.

3 I was having a fuel concern but you may have enough to make orbit, I would however swap out your rocket in the middle for a nuke engine (not the first stage one the one right below the fins).

4. I have personally never had success with designs like this and instead go for more of a square design. In other words 2 more rockets on each side to balance thrust all the way around the rocket.

5) Its tall and skinny, its going to be hard to maneuver If you can work it out to put your (assuming station piece?) mounted sideways do it.

[Rhyunix]

I can balance a broom in my hand.......

[Awaras]

Also, you CAN steer the rocket from the map view. Just click on the small tab on the bottom of the screen and the navball will pop up.

[Vanamonde]

I can balance a broom in my hand...

So can I, but isn't easier and the broom more stable if you're holding it in the middle?

[rodion]

Also, you CAN steer the rocket from the map view. Just click on the small tab on the bottom of the screen and the navball will pop up.

That's right, although with some of my worst rocket payloads with knife-edge steering I do find that even the small delay between switching and opening the tab can result in fatal loss of control.

[dlmarti]

Remove the two fuel lines, have only one fuel line from each of the external tanks.

There is a bug is 0.21 which causes this type of arrangement to screw up.

[SRV Ron]

Some changes I would recommend on your design. Ditch the fins. They won't work properly in the upper atmosphere. Are you using an LV-45 in the center stage? You only need one fuel line not two. Mount the vertical decoupler high up and brace the bottom. You look underpowered for the payload weight you are launching. You might need to add a second or third set of boosters to the center core for a total of four or six to get the added thrust for the launch phase. It should get you up to 20,000 plus before they run out of fuel with enough momentum to get to orbital height. Mount the upper set of thrusters higher up so they are in balance with the lower ones on the payload. Is there an SAS on the payload stage and a control module? Batteries to keep things powered when your engines are in shutdown?

Regardless of which view you are in, you steer using the Navball. You can bring it up in map mode to see what your ship is doing.

Don't use the nuke engine recommended, it is too heavy and far more underpowered then an LV-45.

[Dewm]

Some changes I would recommend on your design. Ditch the fins. They won't work properly in the upper atmosphere. Are you using an LV-45 in the center stage? You only need one fuel line not two. Mount the vertical decoupler high up and brace the bottom. You look underpowered for the payload weight you are launching. You might need to add a second or third set of boosters to the center core for a total of four or six to get the added thrust for the launch phase. It should get you up to 20,000 plus before they run out of fuel with enough momentum to get to orbital height. Mount the upper set of thrusters higher up so they are in balance with the lower ones on the payload. Is there an SAS on the payload stage and a control module? Batteries to keep things powered when your engines are in shutdown?

Regardless of which view you are in, you steer using the Navball. You can bring it up in map mode to see what your ship is doing.

Don't use the nuke engine recommended, it is too heavy and far more underpowered then an LV-45.

Thanks for the advice everyone.

I do have a SAS module in there, and a remote control module.

I do know that I can steer via the nav-ball in map mode.. but because my attention is on my course and setting new waypoints etc.. if the craft is really touchy and/or wanting to drift I have problems paying attention to everything.

Side note: Question about the nuke engine, it says it uses liquid fuel? I've noticed most ship in youtube videos use these engines once they are out in space.. whats the advantage to them?

So I think from what I read.... Short and fat is better then tall and skinny?

Thanks!

[SRV Ron]

Side note: Question about the nuke engine, it says it uses liquid fuel? I've noticed most ship in youtube videos use these engines once they are out in space.. whats the advantage to them?

Thanks!

Your design should be flyable. Many of my long range designs are similar in length and remain quite stable if brace stitched together.

The nuke is twice as efficient using fuel then any other engine except for an ion engine. Unfortunately, it is only slightly more powerful then the LV-909 at 4.5 times the mass. It only has an advantage for interplanetary probes of extreme distance where the fuel saved on long burns will be more then offset by the additional mass of the engine. Otherwise, use the LV-909 where it will take less overall boosters to launch into orbit or you can offset the lower efficiency with an additional 1.75 tons of fuel.

Ion engines are light and extremely efficient. However, they have tiny thrust with burn times measuring in hours for interplanetary maneuvers. They also require huge amounts of electricity.

Edited July 29, 2013 by SRV Ron

[annallia]

Thanks for the advice everyone.

I do have a SAS module in there, and a remote control module.

I do know that I can steer via the nav-ball in map mode.. but because my attention is on my course and setting new waypoints etc.. if the craft is really touchy and/or wanting to drift I have problems paying attention to everything.

Side note: Question about the nuke engine, it says it uses liquid fuel? I've noticed most ship in youtube videos use these engines once they are out in space.. whats the advantage to them?

So I think from what I read.... Short and fat is better then tall and skinny?

Thanks!

Nuke engine is liquid fuel, once you hit vacuum they become incredibly fuel efficient. They are a little under powered however.

[Dewm]

Your design should be flyable. Many of my long range designs are similar in length and remain quite stable if brace stitched together.

The nuke is twice as efficient using fuel then any other engine except for an ion engine. Unfortunately, it is only slightly more powerful then the LV-909 at 4.5 times the mass. It only has an advantage for interplanetary probes of extreme distance where the fuel saved on long burns will be more then offset by the additional mass of the engine. Otherwise, use the LV-909 where it will take less overall boosters to launch into orbit or you can offset the lower efficiency with an additional 1.75 tons of fuel.

Ion engines are light and extremely efficient. However, they have tiny thrust with burn times measuring in hours for interplanetary maneuvers. They also require huge amounts of electricity.

Thanks for the info..

Yeah unless I'm doing something horribly wrong its not flyable.

Everything goes great until about the 10k meter mark then i drop the side fuel tanks, it gets fairly unstable but still flyable.. and then around the 20k meter mark it starts drifting and no matter what I do I can't course correct.

:/

[Mr Shifty]

Everything goes great until about the 10k meter mark then i drop the side fuel tanks, it gets fairly unstable but still flyable.. and then around the 20k meter mark it starts drifting and no matter what I do I can't course correct.

Consider adding RCS thrusters near the top and bottom of the central section. (Try to space them the same distance from your center of mass.) When you start to lose control, turn on RCS, which should help provide pitch and yaw stability. SAS will use the RCS to maintain course as well.

[Dewm]

Thanks everyone for the help!

I ended up shortening it quite a bit and getting "fatter" fuel tanks

and now I have 2 sections in orbit!