Just 1 cm before throwing this game in a bin

[HebaruSan]

4 minutes ago, Ariggeldiggel said:

https://imgur.com/a/jKzDFHe

All the fins should be at the bottom. Otherwise they'll either not help or make the flipping worse.

Edited January 5, 2022 by HebaruSan

[Ariggeldiggel]

2 hours ago, king of nowhere said:

Try maybe with basic designs like this

I already landed on the mun several times. It's not about landing on that thing, it's about installing a mineral-, fuel- and ore station. If it was landing about the moon I would not build that big.

3 minutes ago, HebaruSan said:

All the fins should be at the bottom. Otherwise they'll either not help or make the flipping worse.

So like this?

https://imgur.com/a/ubQmQCP

 

If I put them further down the center of lift will be at the rockets feet

[HebaruSan]

9 minutes ago, Ariggeldiggel said:

So like this?

https://imgur.com/a/ubQmQCP

No, that's the middle. Those won't do anything.

9 minutes ago, Ariggeldiggel said:

If I put them further down the center of lift will be at the rockets feet

That's what you want, as far down from the center of mass as you can manage. That way they impart a counter-force when the rocket drifts off of prograde.

Edited January 5, 2022 by HebaruSan

[Ariggeldiggel]

5 minutes ago, HebaruSan said:

No, that's the middle. Those won't do anything.

That's what you want, as far down from the center of mass as you can manage. That way they impart a counter-force when the rocket drifts off of prograde.

Doesn't work. It flips like there's no tomorrow.  https://imgur.com/a/OdMjMqq

[HebaruSan]

6 minutes ago, Ariggeldiggel said:

Doesn't work. It flips like there's no tomorrow.  https://imgur.com/a/OdMjMqq

The center of mass is still pretty far back from all that draggy stuff up front (I'm not sure about the current state, but it at least used to be the case that the center of lift marker doesn't reflect drag, when it really needs to for a case like this). You can either move the center of mass upwards (those outer side tanks could be dragged upward pretty easily with the translate tool) or add more fins at the bottom (or both, depending on how bad the problem is).

It sounds like you may have been relying on some rules of thumb for planes; there are important differences between planes and rockets. A plane relies on lift to counteract gravity, so it wants to keep its center of lift near the center of mass, whereas a rocket mainly just flies straight into the airstream in a ballistic arc and relies on its engines' thrust to keep it moving. The farther a rocket's center of lift is from its center of mass, the more stably it will fly.

Edited January 5, 2022 by HebaruSan

[Ariggeldiggel]

1 minute ago, HebaruSan said:

It sounds like you may have been relying on some rules of thumb for planes; 

Well.. No.. The rule I followed was "Oh. Yes. That looks about right. Let's try it!" The last 70 hours this worked perfectly and all was fun. But this now is.. Well. Yeah.. Not at all.

[HebaruSan]

13 minutes ago, Ariggeldiggel said:

Well.. No.. The rule I followed was "Oh. Yes. That looks about right. Let's try it!" The last 70 hours this worked perfectly and all was fun. But this now is.. Well. Yeah.. Not at all.

The stuff you're doing now is harder than the stuff you did earlier, and once you master this newer stuff, you'll be able to go back and do the older stuff even better.

Another fun, slightly exploity trick is to manipulate the fuel drain priorities on those tanks so the bottom ones drain first and the top ones drain last. This has the effect of moving your center of mass upwards during flight, sometimes enough to help a flip-prone design.

Edited January 5, 2022 by HebaruSan

[Scarecrow71]

@Ariggeldiggel

I downloaded the craft file, and I was able to use it.  I ran a few tests on the craft, launching it and trying both manually and using MechJeb to get this thing into orbit.  And even MechJeb couldn't do it.  The simplest explanation here is that your lifting stage just doesn't have enough power to get this thing to orbit.

The craft starts with a TWR of 1.05 at liftoff, which is barely enough to get off the ground.  In fact, it took several seconds to get off the ground, which just burned fuel.  Both manual flying and using MJ, I started the gravity turn at 100 m/s, and this is where things really went wonky.  For myself, flying manually, I couldn't get this thing above 20km without it flipping.  I checked all the parts, and I checked the fuel drain, and all that.  It simply would not stop flipping.  So I added a fairing to the top of your craft, just above the reaction wheel you've got in the middle of this thing.  And then it couldn't fly because it was too heavy.  The fairing gave it aerodynamics, which it desperately needs, but it was just too heavy.  I let it run for a few seconds, and it eventually got off the ground...but wasted half the fuel in the first stage to do so.

After that happened, I removed the fairing and launched this thing with MechJeb's Ascent Guidance.  Again, TWR at launch is 1.05, and the gravity turn was started at 100 m/s.  Which, coincidentally, was at about 3500m.  You should reach 45 degrees somewhere in the neighborhood of 10km, but even MJ didn't hit that until about 19km.  And at 20 km, she started to turn over 45 degrees.  Which isn't all that bad, but with TWR was still under 2 at this point.  At 22.5km the first stage burned out and the boosters on the side ejected.  TWR dropped to 0.6, and for the rest of the flight it never got above 0.65.  She reached an Ap of 38501m, at which point she started to come back down to Kerbin.  Even with MJ flying, it would not get into orbit.

My first suggestion is to redesign the lifter stage and add some thrust/power there.  The craft simply does not have enough juice to get off the ground and get to orbit.  My second suggestion is to ask why you have a large reaction wheel in the middle of the craft?  Normally, reaction wheels (from what I've seen) go near the engines to use their thrust to help with turning.  I'm not saying where you have it is wrong, I'm just questioning why.

[king of nowhere]

2 hours ago, Ariggeldiggel said:

Well. This big stuff worked to get up there... It's not even the biggest object flowing around in my orbits. I already did everything with smaller rockets. I landed on the moon with a small rocket about 20 to 30 hours after buying the game. Now I just wanted to start building an infrastructure - Research stations and fuel stations around kerbit and mun as well as satellites. Kerbit already got a research and fuel station, kerbit and mun have each 2 satellites and the mun got a station that combines research and fuel. Only thing is missing is a mining spot on the mun aswell as a real mun base.

That's my kerbit research station for example:

https://imgur.com/a/HSeNWBY

That was a good sequence of coupling trainings. With some fails and so on it took me around 15 couple processes to build it together in space. After that I saw somebody on youtube who shot a whole station up in space and thought "Wanna do that to". After that the mun station was created that you can see above.

ok.

then you're not somebody who just started and is stumbling on the early roadblocks. you already figured out a lot of stuff, and you're trying to do very difficult stuff. What can I say, it's part of this game. It took me weeks to get my most ambitious projects to work.

29 minutes ago, Ariggeldiggel said:

Okay, now I'm really sad. I bit the bullet and built it way, way smaller. The end? It does the same. Flips to west, when I turn to east. No matter what I do......

https://imgur.com/a/jKzDFHe

I removed the spotlights, so it should work for you now: https://1drv.ms/u/s!AhlFszFINTbFcFvzXUTIexezecE?e=EBb7C7

I can't open the vehicle in the VAB, says it's incompatible with this version (1.12, unmodded).

But I can give some general pieces of advice:

1) as @Geonovast said, you can pull your payload instead of pushing it, and that's stable. I launched some unbelievable crap this way myself too.

2) when ships have big aerodinamic problems, you can avoid gravity turning, and just go straight up until the atmosphere is thin enough. If you flip anyway, slow down too; if you climb vertical and slowly, you'll never flip. Of course, this will suck a lot more deltaV, but I see you're not afraid of making a bigger rocket....

3) that spherical crew pod, that's extremely draggy. No idea why, it doesn't look bad, but it's worse than a flat tank. swap it for a normal Mk1, and it's likely to improve a lot

[Ariggeldiggel]

8 minutes ago, Scarecrow71 said:

@Ariggeldiggel

I downloaded the craft file, and I was able to use it.  I ran a few tests on the craft, launching it and trying both manually and using MechJeb to get this thing into orbit.  And even MechJeb couldn't do it.  The simplest explanation here is that your lifting stage just doesn't have enough power to get this thing to orbit.

The craft starts with a TWR of 1.05 at liftoff, which is barely enough to get off the ground.  In fact, it took several seconds to get off the ground, which just burned fuel.  Both manual flying and using MJ, I started the gravity turn at 100 m/s, and this is where things really went wonky.  For myself, flying manually, I couldn't get this thing above 20km without it flipping.  I checked all the parts, and I checked the fuel drain, and all that.  It simply would not stop flipping.  So I added a fairing to the top of your craft, just above the reaction wheel you've got in the middle of this thing.  And then it couldn't fly because it was too heavy.  The fairing gave it aerodynamics, which it desperately needs, but it was just too heavy.  I let it run for a few seconds, and it eventually got off the ground...but wasted half the fuel in the first stage to do so.

After that happened, I removed the fairing and launched this thing with MechJeb's Ascent Guidance.  Again, TWR at launch is 1.05, and the gravity turn was started at 100 m/s.  Which, coincidentally, was at about 3500m.  You should reach 45 degrees somewhere in the neighborhood of 10km, but even MJ didn't hit that until about 19km.  And at 20 km, she started to turn over 45 degrees.  Which isn't all that bad, but with TWR was still under 2 at this point.  At 22.5km the first stage burned out and the boosters on the side ejected.  TWR dropped to 0.6, and for the rest of the flight it never got above 0.65.  She reached an Ap of 38501m, at which point she started to come back down to Kerbin.  Even with MJ flying, it would not get into orbit.

My first suggestion is to redesign the lifter stage and add some thrust/power there.  The craft simply does not have enough juice to get off the ground and get to orbit.  My second suggestion is to ask why you have a large reaction wheel in the middle of the craft?  Normally, reaction wheels (from what I've seen) go near the engines to use their thrust to help with turning.  I'm not saying where you have it is wrong, I'm just questioning why.

Well, you surely can say if I've done something terribly wrong, I've no doubt I did mess up a ton of stuff. The position of the reaction weels.. To be honest? It's random. I just put them here and there to make sure it's distributed very evenly. Why? Because I thought it was best if the power of turning is distributed quite well. If that's wrong, it's wrong and I've to change it.
I chose a TWR between 1.00 and 1.10, because I thought "You need 1 to get off the ground, the rest is wasted power and is invested better in more Delta V by more fuel" Why? Because I always have a fuel problem. Usually I start the rocket and never turn it until I reach the apoapsis. So I give full throttle, wait for the apoapsis to get to 100km and set a maneuver for creating an orbit. After that I start throttle with focus on the maneuver node at T - throttletime/2. Three days ago I started to turn the rocket while starting to the 45°. How I do it? Completely intuitive and I guess completely wrong.

[king of nowhere]

4 minutes ago, Ariggeldiggel said:

Well, you surely can say if I've done something terribly wrong, I've no doubt I did mess up a ton of stuff. The position of the reaction weels.. To be honest? It's random. I just put them here and there to make sure it's distributed very evenly. Why? Because I thought it was best if the power of turning is distributed quite well. If that's wrong, it's wrong and I've to change it.
I chose a TWR between 1.00 and 1.10, because I thought "You need 1 to get off the ground, the rest is wasted power and is invested better in more Delta V by more fuel" Why? Because I always have a fuel problem. Usually I start the rocket and never turn it until I reach the apoapsis. So I give full throttle, wait for the apoapsis to get to 100km and set a maneuver for creating an orbit. After that I start throttle with focus on the maneuver node at T - throttletime/2. Three days ago I started to turn the rocket while starting to the 45°. How I do it? Completely intuitive and I guess completely wrong.

Ok, then we discovered the big problem. You are spending a lot more fuel than you should on your launches.

Ideally, you should have TWR between 1.5 and 2. The reason is, while you are firing your rockets and barely lifting, you are wasting a huge amount of fuel. You'll see your first stage already is half empty and you barely gained 50 m7s of speed. The more thrust at start, the better - the only practical problem is when the engine mass starts getting too much, or when you accelerate too much too early and it causes aerodinamic problems. In fact, you often put fast-burning boosters just to increase thrust in the first minute of flight. Even if you're launching slowly to reduce aerodinamic problems, you want to go fast at first. I am launching a big flat surface right now, and the best flight profile is to accelerate at full thrust (TWR 2) until the craft reaches 180 m/s, and only then throttle down and stabilize speed.

And - provided you're not having huge aerodinamic issues - you should turn early. You reach orbit by gaining lateral speed; all that vertical burn? that's wasted fuel. You can't help it, because you have to get out of the atmosphere, but the less you burn vertically, the better. On airless bodies, an efficient launch entails pointing just enough above the horizon that you don't smash into the nearest hills.

So, as others have said, at 10 km altitude you should be inclined by around 45 degrees. This also needs some thrust to work, or your rocket will just lay down.

On the downside, I just told you to launch at low speed and go straight up to reduce aerodinamic problems. If you were already doing that, then those problems are even worse than we thought. I'd be real curious to try your rocket, no idea why it doesn't work on my pc

[Ariggeldiggel]

28 minutes ago, king of nowhere said:

1) as @Geonovast said, you can pull your payload instead of pushing it, and that's stable. I launched some unbelievable crap this way myself too.

Well. I tried to pull it. Not-So-Fun-Fact: It flips: https://imgur.com/a/LJ0N0rr

 

[HebaruSan]

1 hour ago, Ariggeldiggel said:

I removed the spotlights, so it should work for you now: https://1drv.ms/u/s!AhlFszFINTbFcFvzXUTIexezecE?e=EBb7C7

This one got to orbit OK for me out of the box, but it was a very delicate, challenging launch. The thrust at launch is indeed quite low, but that's more of a minor inconvenience than a launch-wrecking problem. The real difficulty was the very low thrust after the side tanks are emptied and detached (the initial TWR of that stage is something like 0.3). To deal with that, I performed a very gradual gravity turn (tilt eastward just enough to notice the prograde marker moving slightly away from vertical, then straight up till at least 200 m/s or so, then lock prograde), which incidentally helps with flipping, then when the prograde marker started to drop too fast toward the horizon, I kept the nose pointing thirty-ish degrees above it until well outside the atmosphere (locking prograde again once the time-to-apoapsis stabilized at about 8s and started ticking back up). This managed to pull the prograde vector up just enough to give me time to get up to orbital speed.

Spoiler

That probably isn't too easy to follow if you haven't done something like that before, so I would recommend making the craft easier to launch instead of trying to replicate what I did with this one. My ideal launch profile is to tilt a degree or two eastward off the pad, lock prograde early, reach 45 degrees around 10km, cut thrust when the desired apoapsis is reached, then thrust again to circularize. Try to keep all your stages' initial TWR at or above 1.0 and you'll have an easier time.

[Ariggeldiggel]

11 minutes ago, HebaruSan said:

This one got to orbit OK for me out of the box, but it was a very delicate, challenging launch. The thrust at launch is indeed quite low, but that's more of a minor inconvenience than a launch-wrecking problem. The real difficulty was the very low thrust after the side tanks are emptied and detached (the initial TWR of that stage is something like 0.3). To deal with that, I performed a very gradual gravity turn (tilt eastward just enough to notice the prograde marker moving slightly away from vertical, then straight up till at least 200 m/s or so, then lock prograde), which incidentally helps with flipping, then when the prograde marker started to drop too fast toward the horizon, I kept the nose pointing thirty-ish degrees above it until well outside the atmosphere (locking prograde again once the time-to-apoapsis stabilized at about 8s and started ticking back up). This managed to pull the prograde vector up just enough to give me time to get up to orbital speed.

  Reveal hidden contents

That probably isn't too easy to follow if you haven't done something like that before, so I would recommend making the craft easier to launch instead of trying to replicate what I did with this one. My ideal launch profile is to tilt a degree or two eastward off the pad, lock prograde early, reach 45 degrees around 10km, cut thrust when the desired apoapsis is reached, then thrust again to circularize. Try to keep all your stages' initial TWR at or above 1.0 and you'll have an easier time.

Oh lord... I wish I was able to even come to the point where I decouple the tanks mate^^.. I only come to 4-5km height and that's it...

[HebaruSan]

9 minutes ago, Ariggeldiggel said:

Oh lord... I wish I was able to even come to the point where I decouple the tanks mate^^.. I only come to 4-5km height and that's it...

Sorry for the equivalent of the tech support "is it plugged in" question, but are you turning on SAS? This thing really shouldn't have any problems flying straight up for a few km.

[Ariggeldiggel]

Well. I finally know my problems thanks to you guys.

https://imgur.com/a/z8wnl2e

1. I went for a lower TWR, because of youtube videos where ppl told about "At least above 1 and between 1.10 and 1.20 is fine". Well. Not for these situations I guess. So problem 1: Higher TWR

2. I started to turn the rocket since I started playing the game. Before it was like: Straight up until apoapsis ~100km and then turn. Now I went: get 100m/s, turn (no matter how high I am) to 27,5°. Then after reaching 150m/s to 200m/s turn to 90°. Usually I was about 4-5km height there. That was waaay too early for that payload I guess.

9 minutes ago, HebaruSan said:

Sorry for the equivalent of the tech support "is it plugged in" question, but are you turning on SAS? This thing really shouldn't have any problems flying straight up for a few km.

Yes I turn it always on. But yeah, you're correct. Read 2) above

------------------------------------------------------------

This is, what I was doing:

Spoiler

 

You're allowed and invited to laugh^^

The result of watching some guides and thinking "Oh! That could be more efficient!" eventhough one was doing everything correct before and changing it caused the whole problem now...

Edited January 5, 2022 by Ariggeldiggel
fix a typo; making the text beautiful

[Ariggeldiggel]

And there we got to the mun with that damn thing! 
https://imgur.com/a/uxd9sLX

Thanks again everybody for your help and advices!

[Snark]

Just now, Ariggeldiggel said:

I went for a lower TWR, because of youtube videos where ppl told about "At least above 1 and between 1.10 and 1.20 is fine". Well. Not for these situations I guess. So problem 1: Higher TWR

Which TWR is "right" depends on a lot of factors, including how you like to fly and what sort of payload you have.

In general, you never want to go higher than 2.0, and usually no lower than about 1.2.  The optimal rocket design changes quite a lot based on the TWR.

If you have a very "draggy" payload (which most of your rockets look to be-- you've got a lot of flat surfaces, these are not very aerodynamic), then usually a lower TWR tends to work better, at least for the first several kilometers of ascent.  This is because a high TWR causes you to go too fast when you're still too low, so you're wasting all your fuel trying to shove a draggy thing through thick soupy atmosphere.  Taking off a bit more slowly, to keep drag down, may help.

(Normally, the solution people go for is to make their craft more aerodynamic and then raise the TWR, which is more fuel efficient.  But if you have an awkward payload that has to be draggy, you may have better luck starting off a bit slower.)

4 minutes ago, Ariggeldiggel said:

I started to turn the rocket since I started playing the game. Before it was like: Straight up until apoapsis ~100km and then turn. Now I went: get 100m/s, turn (no matter how high I am) to 27,5°. Then after reaching 150m/s to 200m/s turn to 90°. Usually I was about 4-5km height there. That was waaay too early for that payload I guess.

In general, the most efficient (and stable) ascent path is called a gravity turn (that's a good term to search the forums for, if you'd like to read about it).

The basic idea of a gravity turn is that you nudge the craft just a little bit eastward, practically right off the pad... and then you just set SAS to hold all the way up.  No steering needed, you're just going all the way, as your ship gradually and naturally pitches farther and farther eastward as it climbs.

Just how much of an initial "nudge" you should give it is the tricky part, of course.    There's no one right answer, because it depends on your TWR and how aerodynamic you are.  But there's a fairly straightforward way to find out:

1. Launch to the pad.
2. Take off!
3. Immediately upon lift-off, pitch a small amount eastwards.  (Just take a guess, as to how much.)
4. As soon as you do that, set SAS to hold
5. Don't do any further steering.  The only time your hands should touch the controls is to jettison empty stages when the time comes.
6. Take a note of what your trajectory is like when you reach an altitude of 10 kilometers.  Specifically,
   • how fast are you going?
   • what angle are you pitched at?
7. Ideally, you should probably be pitched roughly 45 degrees at that point, and traveling something like 300-400 m/s.
8. If (at 10 km) you are going too fast, or pointing too vertically:  This means you didn't pitch quite enough in step 3.  Revert to launch, and repeat, and pitch it a bit more this time.
9. If (at 10 km) you are going too slow, or pointing too horizontally:  This means you pitched too much in step 3.  Revert to launch, and repeat, and pitch it a bit less this time.
10. Keep repeating steps 2 through 7 until you're going about the right speed and angle when you're at 10 km.  At this point, you're in the pipe and probably going to space, as long as your fuel holds out. 

The above is only a very rough rule of thumb, but I've found that it works pretty well for most people most of the time, and at least is a pretty good starting point for flying your ship.

13 minutes ago, Ariggeldiggel said:

Before it was like: Straight up until apoapsis ~100km and then turn.

Really don't do that.  Very very fuel inefficient, and will waste scads of dV.

17 minutes ago, Ariggeldiggel said:

Now I went: get 100m/s, turn (no matter how high I am) to 27,5°. Then after reaching 150m/s to 200m/s turn to 90°. Usually I was about 4-5km height there. That was waaay too early for that payload I guess.

That's also very inefficient, and likely to cause control problems, as you have no doubt discovered. 

The moral of the story is:  You want your rocket to be traveling at all times.  Never point more than just a couple of degrees off while thrusting, if you can help it.

[Kerbart]

I haven't had as much fun in ages reading this thread. When I checked the pictures my fist incline was are those side boosters using... Mammoths?

Don't get me wrong, I'm not laughing at you. Creating monstrous rockets is part of the fun and, you, sir, do have a talent for that.

However, a lot can be learned from a "smaller is better" approach, and I emphasized the "learn" word there because I don't mean it as "your aim should be to build tiny rockets" (dream big! build big!) but more that your KSP engineering skills will improve quicker when focusing on smaller rockets first. It's perfectly feasible to go Mun and Minmus using only 1.25m tanks and engines, and just by trying to cut down the weight and part count of a rocket (and launching it again and again and again) you'll develop a better feeling for what good TWR's are, what aerodynamically works and what doesn't, where to place struts, and so on. And once you've mastered that, gradually work your way up to landing bigger and bigger craft on the moon.

And then post a picture of your successful mining/refining operation.

[Scarecrow71]

1 hour ago, Ariggeldiggel said:

Thanks again everybody for your help and advices!

You are more than welcome!  That is what we are all here for!

[Vanamonde]

KSP is not like most games and making several failed attempts before you work out a ship design is just normal even for the old pros. If you get discouraged, remember that it's not easy even for the professionals. 

 

[modus]

12 hours ago, Kerbart said:

I haven't had as much fun in ages reading this thread. When I checked the pictures my fist incline was are those side boosters using... Mammoths?

Don't get me wrong, I'm not laughing at you. Creating monstrous rockets is part of the fun and, you, sir, do have a talent for that.

However, a lot can be learned from a "smaller is better" approach, and I emphasized the "learn" word there because I don't mean it as "your aim should be to build tiny rockets" (dream big! build big!) but more that your KSP engineering skills will improve quicker when focusing on smaller rockets first. It's perfectly feasible to go Mun and Minmus using only 1.25m tanks and engines, and just by trying to cut down the weight and part count of a rocket (and launching it again and again and again) you'll develop a better feeling for what good TWR's are, what aerodynamically works and what doesn't, where to place struts, and so on. And once you've mastered that, gradually work your way up to landing bigger and bigger craft on the moon.

And then post a picture of your successful mining/refining operation.

Yeah this was fun to read

He did exactly what I (and many other I guess) did when I started playing. I used to assume: better means bigger.  "Moar boosters!", you know? Let's put the huuuugest engines on the huuugest fueltanks and strap some moar huuuge tanks to that. Poweeeeer!
I used to have the exact same problems, the flipping, the raging...

But when I look at my go to launcher(s) now, they aren't nearly as big as when I started. They are efficient and purposeful though.
And, when I really want to have some big monstrosity, I do multiple launches and assemble in orbit. That way you can discover a whole new set of frustrations: those wonderful fits of rage that go with learning how to rendez vous and dock. Good times!

 

[Ariggeldiggel]

Hey guys, 

many of you are talking about how big my rockets are - But how on earth should I get a mining machine up to mun without building big enough?^^ I tried to use smaller tanks and smaller engines, but there I get to 1500m/s DeltaV and around ~0.2 TWR . That will never ever get to orbit .

[Rylant]

1 hour ago, Ariggeldiggel said:

Hey guys, 

many of you are talking about how big my rockets are - But how on earth should I get a mining machine up to mun without building big enough?^^ I tried to use smaller tanks and smaller engines, but there I get to 1500m/s DeltaV and around ~0.2 TWR . That will never ever get to orbit .

One of the options is split the ship in pieces and launch it in multiple launches building it in orbit. 

One question. Are you playing in career or science mode? And if so, do you have the entire tech tree unlocked?

I know that I generally try to keep my launches ideally at 1.3 TWR at launch. If it's higher than that, I intentionally lower the thrust of the engines. I find a 1.3 TWR to be a bit of a sweet spot for control at launch. 

Rylant

[Kerbart]

1 hour ago, Ariggeldiggel said:

Hey guys, 

many of you are talking about how big my rockets are - But how on earth should I get a mining machine up to mun without building big enough?^^ I tried to use smaller tanks and smaller engines, but there I get to 1500m/s DeltaV and around ~0.2 TWR . That will never ever get to orbit .

Well, I’m not saying you can’t build big rockets, and surely large payloads require large rockets.  But… my recommendation, based on your disclosure that you just started the game some weeks ago, is don’t go there yet. Build up some experience in constructing rockets. Learn to build lean, and get skilled at putting things into orbit,maneuvering them, and landing them.

As your DV requirements to safely land on Mun shrink, so do your launch requirements (not to speak of what you need to get into orbit in the first place) . My advice to focus on getting the smallest craft possible to the surface of Mun and back will allow you to fail fast (a 30-part rocket takes less time to build than a 300 part), and learn quickly. Many missions will teach how much DV you really need. Finally, that refinery doesn’t have to be2.5m parts for starters either. The smaller parts are not as efficient, but neither is what you’re launching right now.

Build a lot. Learn a lot. You’ll end up with 1/2 (or less) of the rocket to put your refinery on the Mun.