i need suggestions on ship builds and tips to minimus

[vin50]

So from the start i've always had several problems with the game and i'd like them cleared up.

1: i always run out of most of my fuel just before i can get to orbit, how do i become more fuel efficient?

2: What are some good ship designs/builds? here is my current one but i run out of all of my fuel when im in an attempt to make an orbit around kerbin:

http://cloud-4.steampowered.com/ugc/612798735203417526/7B2F800C6EF62D31ECBE39C01160E5F04815CCE1/

http://cloud-4.steampowered.com/ugc/612798735203431333/679C9256D0459436C1F224D3BF1615DDA52F90BF/

im decent at landing ships and stuff (landed on the mun) but i'm really bad at fuel efficiency and building ships.

Edited May 7, 2014 by vin50

[SRV Ron]

I wonder what you are trying to do wrong in having to such a complex inefficient ship. Both of these 23.5 designs make orbit with the one using the three Kerbal pod being more efficient and stable. (The big windowed pod is aerodynamically unstable.) Both ships launch gradually starting their Gravity Turn at 5,000 meters and requiring a second orbital insertion burn after reaching an apogee of 100,000 meters.

Both these early Career Mode ships have orbited Mun and Minmus and returned safely.

[Pecan]

Start small. Much, much, smaller than that.

Get KER, MJ or VOID (mods) - they will show you vital statistics about your ship.

Vital statistic No.1: TWR. Thrust to Weight Ratio. If it's less than or equal to one the ship won't be able to lift itself off the pad. If it's 2 or more you'll be wasting fuel going up much too fast. In stock KSP an ideal launch TWR is 1.6 - 1.8.

Vital statistic No.2: DeltaV. If TWR is how fast you can accelerate this is how long you can accelerate for. Broadly, you need at least 4,500m/s deltaV to reach Kerbin orbit.

Design with mass, TWR & deltaV: If your TWR is too low a) remove stuff from the payload, add engines. The latter will probably reduce your deltaV.

If your deltaV is too low add fuel. This masses more so it decreases your TWR - go back to the line above. Repeat.

Fly a gravity turn to orbit: At launch go full-throttle (to terminal velocity ideally but don't worry about it if you are just starting) straight up to 10km. Turn to 45-degrees above the horizon (East is best) and switch to map mode. Watch the apoapsis marker on your orbit. When you apoapsis reaches 50km - if you aren't too rushed - pitch down to just above the horizon. When your apoapsis reaches 72-75km cut engines and create a manoeuvre node at apoapsis. Pull the prograde marker on the node (burning engines forward) until your projected orbit periapsis is over 70km as well. When you reach the node do the burn, then relax.

So - Mass, TWR, deltaV, gravity turn.

If you can get those 4 things in a row then you're in orbit :-)

Images 4 - 16 in this album will give you some smaller ideas than Ron's otherwise excellent ones.

Javascript is disabled. View full album

Edited May 7, 2014 by Pecan

[vin50]

thanks, i have 20 hours on this game and im still rather clueless xD

[EdFred]

I started out the same way. MOAR is GUD! Then realized I was waaaaaay over weight on things.

You're going to Minmus? Your final stage only needs to be a FL-T100 tank and a Rockomax 48-75

That provides around 1500dV - which is more than enough to deorbit Minumus, land, and even come all the way back to Kerbin.

[DoToH]

im decent at landing ships and stuff (landed on the mun) but i'm really bad at fuel efficiency and building ships.

Basically, if you have a ship capable of landing on the mun, the same ship should take you to Minmus (little more Dv to reach, but far less Dv to land on).

If you can't get to Minmus with the same ship that got you to Mun, maybe your transfer burn is not optimal. I suggest to match your inclination with Minmus orbit at LKO first and then make the transfer burn (if you are not doing it this way already). Plan your burns with nodes and compare transfer node Dv to any Dv map (like this map) to check if you are planning a good or bad transfer (in terms of Dv).

Edited May 7, 2014 by DoToH

[Pecan]

thanks, i have 20 hours on this game and im still rather clueless xD

We all were when we started. Getting into orbit at all is no mean feat.

Getting into orbit repeatedly and reliably is quite something.

Designing your own vehicle that you can do it with is a significant achievement.

Don't be discouraged

Incidentally - the album above is for one of the chapters of a long tutorial I (really) am writing. You may be interested to look at the others; earlier ones for where to start, later ones for inspiration (or not). http://ksppecan.imgur.com/, text not yet published. Ask if you want the ship files.

[vin50]

I downloaded KER but im confused by what you guys mean by twr and deltav. ker is very confusing and hasnt helped me at all aswell >_<

[FREEFALL1984]

my advice would be not to overfuel your upper stages, I used to end up with a huge lander which required immense amounts of fuel to reach an LKO and huge amounts of fuel to reach minmus SOI. Everything has a knock on effect.

Try and build from the top down, so whats the last thing your rocket needs to do?

1 - it needs to land on kerbin so add a command pod and a parachute,

2 - before that it needs to leave minmus SOI and drop to kerbins atmosphere, So add a decoupler (since there's no point landing an engine with your command pod) and add a small fuel tank and a small engine (a tiny engine will do but aim for a high ISP) you might also consider adding a couple of solar panels to this stage you should need less than 300m/s since you'll only be dropping your kerbin periapsis and most of the lifting work will be done by the lander.

3 - before this it needs to land on minmus and depart (many people do these things separately but I like to do them together) So you're gonna need a nice wide base and enough fuel to get from a (possibly ballistic) minmus orbit/trajectory, to a soft landing on the surface and then get most of the way to leaving minmus SOI. This will take a good chunk of Dv but the lander doesn't need to be very heavy so that Dv is easy to include, just 3 or 4 FL-T200s and 3 or 4 small engines should achieve it just attach them with radial decouplers so you can ditch the dead weight. Also remember to bring science, Expect this stage to take around 800m/s (that allows plenty of extra DV for targeted landings ect.

4 - before this you need to reach minmus and hopefully circularize, this takes about 1000Dv, and remember you're carrying a lander so you'll need a stage which can cover this, I recommend something like an FL-T800 and an LV45 (or if you dont mind the long burn times and LV909) engine. Watch out of you're using the LV909s though they don't produce electricity so you'll need a power supply or a bunch of batteries, and dont forget to turn off ASAS when your finished with it.

5 - You need to get from the KSC into orbit. This will take about 4500 - 4800m/s of DV but since its your first stage and you're a new player you can afford a bit of overkill, aim for about 5200m/s the extra fuel can be used to get you on the way to minmus. The initial lifter can be designed in many ways, either in several stages or in a single stage, but the ultimate goal remains the same, get the payload into orbit. With a good initial lifter you should be able to get into orbit easily, Also you can try and incorporate your lifter and your TLI phase into the same stage.

Now you can tweek some values, check your T/W on the main stage, if its too low, (less than 1.5) then consider removing some surplus fuel from one of the upper stages, this can be useful but if you're using fuel lines on your upper stages you could bog up your mission phasing by running low on lander fuel before landing for example, as long as your DV values remain as (or slightly more than) I've described you should be ok. If your T/W is too high, then consider removing some engines or limiting the thrust of the engines, but more importantly make sure you remain at terminal velocity during takeoff from kerbin, a T/W of 2 or more would be considered high but for your lander there is no such thing as too high.

A few things to remember, if your science isn't attached to your return phase (ie it will never land on kerbin) you will need to collect the science in EVA before jettisoning it, I prefer to do this on the surface of minmus since the gravity helps me maneuver. Adding boosters to the lower stages does help a little, but only if you dont exceed terminal velocity, if you have to throttle back so much that your LOX engines are hardly providing control (only on engines with gimbals) they your potentially going to have problems. Avoid them if possible. Finally learn how to get to minmus in theory before you launch. I've seen too many people wasting huge amounts of fuel by misunderstanding basic orbital mechanics.

[Pecan]

In the VAB, with KER main display shown, it should show you the mass, cost (not important), deltaV and TWR of each stage of your rocket as you build it. It is confusing though - I didn't have a clue what it was telling me when I first got it. As I said before, the important things in there are your TWR at launch (the bottom stage) and the total deltaV. It all starts to make sense when you see the figures changing as you build, rather than just showing a 'snapshot' of an existing vehicle.

Try this: start with a 1-man command pod. Stick a parachute on top of it (you never know, you might want to fly this thing!) and a decoupler beneath it. So far - no fuel, no engines. Pretty clearly this isn't going to space today and KER won't tell you anything useful.

Put a fuel tank beneath the decoupler. Put an engine under that. Which tank and which engine don't matter at the moment but now you have a rocket! On the bottom-right of the screen there should be two (or three) stages - pod, parachute and decoupler in the top one (the decoupler may be on its own in a middle stage, that's fine), engine in the bottom one. KER will now tell you how viable this rocket is ... look along the column headings for 'TWR' - if it's less than 1 (preferably 1.5) the engine isn't powerful enough to lift the rocket. If it's over 2 the engine's too powerful but at least you know it'll work ^^.

Try different engines to see how the TWR changes with more or less powerful ones. Try different size fuel tanks and look at how that affects, primarily, the mass of the rocket and therefore also the TWR. What you really want is the biggest fuel-tank you can get with an engine that can push it at 1.5+ TWR. Meanwhile ...

Alright, now I know what I'm talking about instead of just trying to remember it: A capsule, parachute, decoupler, tank and engine will give you three stages at bottom-right; parachute (stage 0, top, last), decoupler (1, middle) and engine (stage 2, bottom, first). KER shows cost, mass, ISP, thrust, deltaV, TWR and time. Cost and mass speak for themselves. The ISP is the efficiency of the engine but isn't immediately important. Similarly the thrust shows how hard the engine can push and isn't, immediately, important. DeltaV and TWR are important; TWR tells you how fast the engine can accelerate a vehicle of this mass. A more powerful engine can accelerate a lighter vehicle more quickly, so that's simple enough. The tricky one to understand is deltaV which is a matter of fuel-efficiency and how much fuel you have. A more efficient engine will generally be able to deliver higher deltaV but may not have enough sheer power to give a high enough TWR. Lower-efficiency engines may have the punch for a high TWR but burn the fuel so quickly that the deltaV is low. Read up on this when you have time but for now just know you want a TWR between 1.6 and 1.8 and deltaV at least 4,500m/s to get to orbit. Adjust the fuel tank and engine to see what figures you get.

One way to make a rocket (with the pod, parachute, decoupler above) that will get to orbit is to use an S3-14400 fuel tank with a 'mainsail' engine under it. It is not a good way, but it gives a TWR (according to KER) of 1.72 at launch and total deltaV of 5,361m/s; enough to orbit with a nice cushion for not getting the gravity turn perfect. KER also shows the time for this (single) stage as 2:35.4s, which just tells you that at full throttle the engine will burn all the fuel in just over 2 and a half minutes. In summary - this engine with this much fuel will push, starting at TWR 1.72, for 2 and a half minutes, accelerating the rocket from 0 to 5,361m/s (most of which will be spent climbing out of the gravity well).

More conventionally you may prefer to ditch the 'big bang' above. Instead stick a two FL-T800 fuel tanks (one above the other) under the pod's decoupler and add an LV-T30 engine. Rather smaller, TWR 1.95 and deltaV 4,515m/s. The deltaV's a bit of a pinch for orbiting but the TWR's a bit high so all you need is to add a touch more fuel (=more deltaV). An FL-T400 does it quite nicely.

It is usually impossible to get a sensible single-stage rocket like this, however. In any case for landing on Minmus or anywhere else you'll need landing legs - which wouldn't reach the ground here! Freefall's advice about 'designing backwards' is a good route and the basis for "Long Tom" shown in pictures 4 - 9 of the album I posted above. Note that Long Tom is only the 'payload' space vehicle, it still needs something to launch it!

Practice small, post again :-)

Edited May 7, 2014 by Pecan

[FREEFALL1984]

I downloaded KER but im confused by what you guys mean by twr and deltav. ker is very confusing and hasnt helped me at all aswell >_<

Delta V, or Dv, is the amount your ship can accelerate, since all maneuvers are basically acceleration its a better way to describe how much bang you get for your buck. Much better than fuel content, since the amount of fuel you have doesn't account for the weight of the vessel.

A good way to imagine DV is this, you have a ship in orbit with a DV of 1000m/s, and 500 units of fuel, if you add another 500 fuel, your DV will increase, if you then remove the 500 units of fuel your DV will drop to 1000 again, now you eject some weight from the vessel such as a lander or a few empty tanks, your DV will also increase even though the fuel qty is the same, this is because the vessel still holds the same amount of fuel but the net weight has reduced so you can accelerate a little easier. Its also worth considering that your original DV cannot be increased without either adding fuel or removing weight,

T/W or Thrust to Weight is how fast your ship can accelerate relative to a specific body. A T/W on kerbin of 1 would allow the ship to hold its own weight off the ground but not move up or down, a T/W of more than 1 would allow you to climb, a T/W of less than 1 would not allow you to move.

ie if your ship provides 1ton of thrust but weighs only 0.5tons, that ship would have a T/W of 2, which is thrust divided by weight,

Edited May 7, 2014 by FREEFALL1984

[Vanamonde]

A downloadable sandbox ship and written/illustrated walkthrough for reaching the moons is here. That ship is much larger than it needs to be, to give a learning pilot extra fuel and thrust to correct mistakes.

A much more efficient ship made for use in career is the third one in the first post of this thread. It uses on parts from tiers 0-3.

[DoToH]

I downloaded KER but im confused by what you guys mean by twr and deltav. ker is very confusing and hasnt helped me at all aswell >_<

TWR readings are intial for stage full of fuel and (max) for stage empty of fuel

As atmosphere has an effect on ISP (engine efficiency) you should click the "atmospheric stats" button to check if your initial stages (launcher) can get the ship to orbit (you need about 4500 Delta v to orbit Kerbin)

TWR is like engine power. Delta v is like rocket range.

1 - More mass -> less TWR and less Delta V

2 - More fuel -> more Delta v, but more mass also (and because of that, adding more and more fuel doesn't give you infinite source of Delta v)

3 - More engine trust -> more TWR (note that adding more engines of the same model for more TWR doesn't change Delta V but for new engine mass increasing total mass)

Hope this clarifies KER stats and some concepts

Edit to add: Allways have in mind that while firing engines and consuming fuel you are also decreasing mass and thus increasing TWR

Edited May 7, 2014 by DoToH

[EdFred]

1 - it needs to land on kerbin so add a command pod and a parachute,

Says who?

If you've got 200dV left and a TWR ratio of 3 you can suicide burn to the surface. How do I know that? I just returned from Eve sans parachutes. It's 5 units of fuel left in a FL-T200 with a lander can and a Rockmax 48-75.

MC: Wait....wait....wait....

Jeb: Now?

MC: Wait...wait...wait...

Jeb: Now?

MC: Wait...wait...OK full burn!

...

...

Jeb: Whoa, it worked!

(You can do it with 130 dV but your engine and tank explode on impact, the lander can and Jeb will survive)

[FREEFALL1984]

Says who?

If you've got 200dV left and a TWR ratio of 3 you can suicide burn to the surface. How do I know that? I just returned from Eve sans parachutes. It's 5 units of fuel left in a FL-T200 with a lander can and a Rockmax 48-75.

MC: Wait....wait....wait....

Jeb: Now?

MC: Wait...wait...wait...

Jeb: Now?

MC: Wait...wait...OK full burn!

...

...

Jeb: Whoa, it worked!

(You can do it with 130 dV but your engine and tank explode on impact, the lander can and Jeb will survive)

Haha yeah fair point,

[EdFred]

Haha yeah fair point,

And as with all things Kerbal, discovered on accident.

Hey, where's my chutes? Oh...um....well....I might be able to slow down enough with engines.

Chutes? We don't need no stinking chutes!

[DoToH]

Says who?

If you've got 200dV left and a TWR ratio of 3 you can suicide burn to the surface. How do I know that? I just returned from Eve sans parachutes. It's 5 units of fuel left in a FL-T200 with a lander can and a Rockmax 48-75.

MC: Wait....wait....wait....

Jeb: Now?

MC: Wait...wait...wait...

Jeb: Now?

MC: Wait...wait...OK full burn!

...

...

Jeb: Whoa, it worked!

(You can do it with 130 dV but your engine and tank explode on impact, the lander can and Jeb will survive)

EVA reentry and land on Jeb's head/helmet also works (said Jeb because he is mad enough to try).

Edited May 7, 2014 by DoToH

[cantab]

http://wiki.kerbalspaceprogram.com/wiki/Basic_maneuvers

Check the ascent to orbit guide there, and keep your speed around what it says, at least below 10 km. Trying to bean it up is inefficient and the error I made when I started out.

[Kasuha]

The Kerbal-X stock ship can get to Minmus and back to Kerbin. You may not make it all the way back on the first try, but it's also decent for learning how to do proper gravity turns.

[xcorps]

Have no fear Vin50. Here's some facts that will help you stay with it:

If you can get a rocket to lift off the pad, you will be able to build a ship to get to orbit.

If you can build a ship to get to orbit, you can build a ship to get to Mun.

If you can build a ship to get to Mun, you can build a ship to get to anywhere.

[vin50]

Thanks guys, i do believe i found my problem with fuel efficiency, i didn't know when to turn my ship and what direction. i forgot most of the basic maneuvers tutorial so i'm gonna reread that. Appreciate all this

[Tortoise]

Get KER so you can calculate for Delta-V and also your rocket is pretty extreme IMO.

Heres one of my rockets, I used it to get in an orbit around kerbin, then go to minmus to get in orbit around there for kethane scanning:

[SRV Ron]

Time to practice landing and returning my creation.

My lander Minotaur design.

Closeup details.

Flight used SRB set at 55% thrust which placed the rocket over 20,000 meters. Second stage placed into orbit and on the way to Minmus with a small additional and correction burn of the lander stage. Lander stage placed in low orbit and landed with the fuel you can see left.

Lift off and return burn needed little fuel still being used from the lander stage.

And return to Kerbal. Note how much fuel is still left in the lander plus what shows in the return stage donuts tanks.

When you reach low Minmus orbit, try a landing on the flat sea. On my first ever landing and return, I brought the ship in to 2500 meters before placing it totally vertical. Then it was fine tune to cancel all drift using partial thrust and SAS. Best to watch the altimeter rate meter since it is easy to yo yo the landing in Minmus low gravity. Easily got the drift to zero as I reduced the vertical drop to under 5 m/sec and down to 2 or three at touchdown. Takeoff is a short burn with starting a turn East, then map mode till apogee about 10,000 meters. Then, an orbital maneuver, then the burn retro to Minmus orbit to escape and drop towards Kerbal for an aerobraking landing. Tons of fuel left in the lander and none used in the assent stage.

The Minotaur is all stock except fot the decouplers which the stock ones will still work OK.