Kerbal Space Program

I still need it to fix the tumbling. If only I could design a better multi-stage launch system.

I tried to put together a heavier lander and fix my tumble problem for my "Big Muny" series rockets, but it keeps shaking itself apart under 4,000 m.

Got the shakes? Less throttle and/or more struts.

I have plenty of struts on the lower stage, which falls away all at once. But there is only a single wide decoupler linking it with the upper stages, and no matter how many struts I put (I had 16 at once), it still shakes.

Guess throttling down is necessary.

Multiple Mainsails are notorious for destroying spacecraft

Probably. I tried a single mainsail with 8 smaller liquid engines around them (the non-thrust vectoring kind), but my rocket didn't have enough power to get off the pad. My 7-mainsail is the only thing that has worked so far, and only just barely.

This game is AMAZING, i bought it a week or so ago ;D I actually have some videos on my YouTube channel if anyones interested ;D

Anyone else looking forward to the next patch as much as me? Docking sounds awesome

cardgame said:

ASAS can be skipped too, but only if you're a masochist

Click to expand...

Not for me. Especially if you have a big stack with thrust vectored mainsails, skipping out on ASAS means the thrust vectoring ability is wasted when in SAS mode and without it a big stack is unstearable when you've already skipped the RCS's.

Antilogic said:

Probably. I tried a single mainsail with 8 smaller liquid engines around them (the non-thrust vectoring kind), but my rocket didn't have enough power to get off the pad. My 7-mainsail is the only thing that has worked so far, and only just barely.

Click to expand...

You have probably grossly over-engineered the thing. I'd start from scratch with a much smaller rocket. I have the same problem in that I always assume bigger is better, but if you work out the thrust/weight ratios, you actually end up with much less DeltaV from your lower stages than is optimal if you build a monster rocket.

Unfortunately, you can't use multiple mainsails easily with one stack (like the 5 F-5 engines at the bottom of a Saturn V) so you have to add more tanks to support more engines. But adding more tanks means you have to add more engines, which means more tanks and so on.

The reason my friend did so good last night is he only had one main stack surrounded by three booster stacks, each with a mainsail. But instead of adding like 9 tanks to each stack, (as I would) he just had 3 or 4. It got him into orbit and started his Munar injection burn. The lander had enough fuel for the rest. It was glorious - his stack did what my mega stack does only on a perfect launch with fuel to spare. (Also, make sure you are using fuel lines to connect the bottom of your side boosters to the main stack so that even though the main stack is firing with the boosters, upon separation it will still be fully fueled)

So go smaller - also, rip off successful Youtube videos if necessary.

For your tumbling problem, what kind of semmetry are you using? My main rocket has four boosters around a central core with mainsails. I tried adding more fuel to the lander by using triple symmetry to attach fuel tanks to it. It turns out mixing triple symmetry with quad symmetry is bad idea and it rolls and tumbles uncontrollably. Are you doing something like this?

One last thing, a rocket I ripped off Youtube has 8 smaller engines clustered around your mainsail and it works perfectly. Are you staging it so that the mainsail fires when the booster fire on the pad? They all need to go off at the same time or it won't get off the pad. Take the mainsail engine (and nothing else, not it's tanks and certainly not it's decoupler, just the engine) and put it in the same stage as the boosters, but don't change anything else. That way it will fire the whole time but when the booster separate, even if the mainsail is in the same stage as them, it won't fall off until it's own decoupler has been activated.

Neth said:

This game is AMAZING, i bought it a week or so ago ;D I actually have some videos on my YouTube channel if anyones interested ;D

Anyone else looking forward to the next patch as much as me? Docking sounds awesome

Click to expand...

I endorse this post.

hobbsyoyo said:

You have probably grossly over-engineered the thing. I'd start from scratch with a much smaller rocket. I have the same problem in that I always assume bigger is better, but if you work out the thrust/weight ratios, you actually end up with much less DeltaV from your lower stages than is optimal if you build a monster rocket.

Unfortunately, you can't use multiple mainsails easily with one stack (like the 5 F-5 engines at the bottom of a Saturn V) so you have to add more tanks to support more engines. But adding more tanks means you have to add more engines, which means more tanks and so on.

The reason my friend did so good last night is he only had one main stack surrounded by three booster stacks, each with a mainsail. But instead of adding like 9 tanks to each stack, (as I would) he just had 3 or 4. It got him into orbit and started his Munar injection burn. The lander had enough fuel for the rest. It was glorious - his stack did what my mega stack does only on a perfect launch with fuel to spare. (Also, make sure you are using fuel lines to connect the bottom of your side boosters to the main stack so that even though the main stack is firing with the boosters, upon separation it will still be fully fueled)

So go smaller - also, rip off successful Youtube videos if necessary.

For your tumbling problem, what kind of semmetry are you using? My main rocket has four boosters around a central core with mainsails. I tried adding more fuel to the lander by using triple symmetry to attach fuel tanks to it. It turns out mixing triple symmetry with quad symmetry is bad idea and it rolls and tumbles uncontrollably. Are you doing something like this?

One last thing, a rocket I ripped off Youtube has 8 smaller engines clustered around your mainsail and it works perfectly. Are you staging it so that the mainsail fires when the booster fire on the pad? They all need to go off at the same time or it won't get off the pad. Take the mainsail engine (and nothing else, not it's tanks and certainly not it's decoupler, just the engine) and put it in the same stage as the boosters, but don't change anything else. That way it will fire the whole time but when the booster separate, even if the mainsail is in the same stage as them, it won't fall off until it's own decoupler has been activated.

Click to expand...

Trust me, you haven't seen over-engineered (I'm not quite as bad as the Insane Rockets Division guy, but have done a few like that for laughs). My old launch system was pretty good for getting to the Mun and back--7 mainsails, 4 large fuel tanks for each, plenty of lashing to hold it in place for the vertical lift. One smaller 2-tank mainsail for maneuvering to near-orbit. I stop at near-orbital with that because I want the stuff to burn up in the atmosphere and not leave permanent space-junk. Then my lander goes to the Mun, drops off its extra fuel tanks there on the descent, and returns in mini-form to Kerbal. By dropping my excess fuel tanks on vertical descent, I can kind-of gauge the distance to the ground I'm landing on since we don't have sensors yet (i.e. I drop the empty tanks, and I see them explode about 1.5 km beneath me; since I am at 2.6 km height and falling, I know the ground is around 1.1 km for planning purposes).

The small lander I have is pretty efficient besides the fact that it ultimately has a 1,600 L tank and a poodle to return on. There's not much else that can be cut and still maintain lander functionality, and I don't really want to go down to a 400 L tank because I'm fuel-inefficient enough on the return flight as-is. I think my problem might be that I don't know the most fuel-efficient route to return to Kerbal from the Mun (or anywhere else I land on)--I use the 90° routes because they seem to be the most fuel-efficient, but I haven't rigorously tested this yet, just going based off old physics knowledge and some gut-reckoning. I'm also getting much more efficient at Munar landings and I'm not "hopping" as much, which saves fuel for the return trip.

My tried-and-true lander system has triple symmetry and the boosters are on a hex, so stuff lines up pretty well. I put on appropriate nose cones so I hope the drag is reduced.

Regarding the new system, yes, I've gotten creative and made sure my staging works right (it's essential to do that if you have a lander with detachable gear and fuel tanks like mine does). The new launch system I had did mix symmetry, which may have been a problem. Originally, I thought the problem with that system was how heavy the lander was relative to the boosters (the lander had a 4,400 L fuel supply in the core and 3,000 L strapped on explosive bolts--excessive, I know, but I was planning to use this for multiple moon hops before returning home to Kerbal).

Side questions: does using normal SAS work with the large engines if you use a transition cone to connect them? Do nose cones actually reduce drag?

Antilogic said:

Side questions: does using normal SAS work with the large engines if you use a transition cone to connect them? Do nose cones actually reduce drag?

Click to expand...

SAS doesn't control thrust vectoring, only ASAS does. ASAS will work as long as it is on and the engines are firing regardless of transition cones and SAS will create torque on the rocket if it's on regardless of transition cones.

I'm not sure if nose cones reduce drag or not. Many parts have weight and drag values (struts, RCS thrusters) but the physics engine doesn't utilize them. So despite what they say on their labels, parts like struts have no weight or drag. I don't know if nose cones fall under this or not.

I am avoiding using as many of the accesory parts as possible. When .18 comes out, they are ditching all the old engines and tanks and replacing them entirely. I assume they will do the same with many of the parts. So I avoid them because I don't want to integrate a part that may prove crucial to a design that may not be available in the future. Can't avoid using the current engines and tanks though.

Then why do so many people stack so many SAS on top of each and every rocket? I thought it controlled thrust vectoring too.

I'm just going to switch back to my old system and drop this new thing right now. The super-heavy lander may look cool but I don't have the chops to get it into space.

Antilogic said:

Then why do so many people stack so many SAS on top of each and every rocket? I thought it controlled thrust vectoring too.

I'm just going to switch back to my old system and drop this new thing right now. The super-heavy lander may look cool but I don't have the chops to get it into space.

Click to expand...

They probably do it to add extra torque to be able to control it without RCS units. Or they just have such a heavy rocket that they need that torque to be controllable at all between burns. Thrust vectoring only helps when the engine is actually on. But yeah ASAS controls it, not SAS. Also, SAS is cummulative while ASAS is not. So if you add more SAS units, you get greater torque. But one ASAS until will controll all of the control surfaces, adding more does nothing but add weight.

I made it to Minus with my friends design. It takes the same amount of fuel as a Mun landing. The really tricky parts are matching the inclination and landing. The inclination matching wasn't so bad once I youtubed it and saw how it is done. However, the tiny gravity on Minmus makes landing a chore as it is really hard to not overdo things. Also, there is a glitch I encountered where it overstated my velocity. Even when I was on the ground, it was saying I was going 9 m/s, but I had no way of knowing this until I touched down.

Consequently I spent a lot of time overcorrecting because I could never zero out my velocity. Argh. Plus, not knowing how high up you are sucks. I tried Antilogic's trick of dumping the side fuel tanks to use for range finding, but I dropped them too early and they exploded and were too far off course to be of use even if they had survived.

Anywho, proof:



Off to Duna next, though I may use the debug menu to get infinite fuel on that one. I haven't managed to design a Duna capable rocket yet.

If only I got my inclinations right last night, I would have a similar screenshot, but with a half-tank of fuel. Instead, I seriously missed Minmus on two attempts and wasted time on my heavy lander.

EDIT: The tanks don't have to survive for my range-finding trick to work. I hover over the Escape button and watch the distance between the tanks and my ship. When I see the tanks explode, I hit it to pause the game. Then, I do the math since I know at what distance they exploded and the distance to sea-level.

I was able to land on Minmus and return with the same rocket that got me to the Mun. It was also able to make it to Duna orbit, but didn't have enough fuel to return. I'll probably skip on trying interplanetary missions until .18 comes out and I can make my interplanetary mothership.

You really only ever need one Mainsail.

Can you show us your super heavy lander?

I think mine is roughly 20 tons

I wish there was a simple indicator showing your orbital inclination (unless it's somewhere on the HUD and I just don't see it). Because having to guess and make a ton of tiny corrections is really grating.

MechJeb has that info available if you so desire. Not necessary to use the mechanics and autopilot if you just want the orbital information.

cardgame said:

You really only ever need one Mainsail.

Can you show us your super heavy lander?

I think mine is roughly 20 tons

Spoiler :

Click to expand...

Nice ship. How do you get away with just one Mainsail?

MoreEpicThanYou said:

I was able to land on Minmus and return with the same rocket that got me to the Mun. It was also able to make it to Duna orbit, but didn't have enough fuel to return. I'll probably skip on trying interplanetary missions until .18 comes out and I can make my interplanetary mothership.

Click to expand...

Yeah my Mun lander can make it to Minmus easily. It's the same fuel. Or are you talking about both in one trip? I actually think I could do this too once I get better at piloting and waste less fuel. Hell, I could probably do it right now...the fuel requirements too/from Minmus once in Kerbin orbit are very small.

cardgame said:

MechJeb has that info available if you so desire. Not necessary to use the mechanics and autopilot if you just want the orbital information.

Click to expand...

Is Mechjab easy to use?

Also, what do you suggest for a Duna capable lander using stock parts?

One Mainsail, a boatload of SRBS and an array of radial 1m engines and tanks, a decently sized second stage, etc.

I can maintain a stable launch system pretty well with just a single mainsail and 2m tanks, and one ring of 1m tanks or SRBs. I can't get multiple layers to work right, though. Do you attach the second ring to the first exclusively, or to the 2m core rocket somehow?