General Tips and Tricks

[RangerDanger75]

Part of the description of the 'How to' forum is 'General Tips, Tricks.' So I thought it would be necessary to have a thread where people could share the smaller things they have learned about KSP, orbital mechanics, rocketry, etc. Stuff that may not warrant creating a whole new thread, but still deserves to be said. So go ahead and share the small pieces of advice that you have picked up on the way.

Corollary: Small questions that you don\'t feel need an entire thread devoted to them could be asked here as well

I\'ll start:

• 
  [li]When performing orbital plane changes, remember to continuously move the nose of the ship so you\'re perfectly aligned between the green velocity vector indicators[/li]
  [li]When performing prograde and retrograde burns, if you rotate your ship so the horizon line on the NavBall is vertical, you won\'t get as much vertical drift in the ship\'s orientation[/li]
  

[Volt]

• 
  [li]Spaceplanes with a large wing surface area/lots of wings glide surprisingly well, even if they\'re not designed or shaped for it. This may have changed with 0.11 and the stall model.[/li]
  [li]Decouplers put a small amount of \'forward\' velocity on the command stack, and a small amount of \'backward\' deceleration on the decoupled section. It\'s a negligible difference, but worth considering when doing things such as LKO satellite deployment.[/li]
  

[nivvydaskrl]

• 
  [li]The more fuel you have, the more fuel is needed to lift it. Doubling your fuel doesn\'t double your total available moving power (called delta-v).
  [/li]
  [li]There\'s a maximum amount of delta-v achievable per stage, period. Increasing the number of fuel tanks past a certain point does nothing unless you use decouplers to shed dead weight.
  [/li]
  [li]Once you get into orbit, you don\'t need a lot of fuel to change your orbit and go places. Once you\'re safely in orbit, a single fuel tank should be able to take you to escape velocity, to the Mun, or wherever else you\'d like to go. I\'ve set up an orbit with a maximum altitude of 1 light second, and accomplished re-entry with nothing but RCS thrusters.
  [/li]
  [li]Modifying your orbit\'s maximum altitude is done when you\'re at your orbit\'s minimum altitude. Modifying your orbit\'s minimum altitude is done when you\'re at your orbit\'s maximum altitude. Not only is this the most efficient way to do it, it\'s also the most controllable.
  [/li]
  [li]The greater the different between your maximum and minimum altitudes, the less fuel it takes to modify either one. When in a circular orbit, it takes a lot of fuel to start raising your maximum altitude -- however, as you keep raising it, it raises faster and faster, until you\'re using small RCS bursts to change your peak altitude by millions of meters.
  [/li]
  [li]SAS is only truly useful when you need it to keep from crashing a large rocket just after liftoff. Once you\'ve made orbit, SAS is certainly convenient if you have plenty of fuel available; however, if you\'re trying to do anything extreme or your energy budget is tight, it\'s best to shed your SAS early or leave them off the rocket entirely. Remember -- everything you lift to orbit requires a large amount of fuel to get it there, and putting on more fuel means you need even more fuel, which might mean more engines, which might mean even more fuel.
  [/li]
  [li]Gravity and drag are your two greatest enemies. Beating gravity means blasting off as fast as possible and spending as little time as possible going straight up. Beating drag means going as slow as possible and spending as much time as possible going straight up. There\'s a delicate balance between the two, or instead you can...
  [/li]
  [li]...use more boosters. I\'m serious on this one; booster rockets which are decoupled as soon as they\'re spent have very little in the way of downsides, but help you cut through gravity and the atmosphere quicker so you have more fuel left when you get to the other side. However, carrying extra boosters is a weight penalty, so boosters are best used once at liftoff to cut through as much atmosphere as possible in those first 25 seconds, before easing back to play the gravity/drag balance game.
  [/li]
  [li]Efficiency is important. In real life it\'s because of cost. In KSP it\'s because of lag. You can\'t fly something you can\'t control, and you can\'t control anything at 2 FPS. If your rocket is too big, think about your goals and think about where your inefficiencies are in your design. Build towards the goal, and try to cut it as close as possible.
  [/li]
  

[Ivan Ivanovich]

Building on top of the previous posting:

• 
  [li]Try to put as much thrust into the first stage (the 'takeoff' stage) as possible. Any rocket you lift into orbit that doesn\'t fire right from the start is dead weight until it fires. Usually, it\'s useless to carry boosters on upper stages, since they are dead weight until they start to burn. 6 boosters in first stage are better than 3 in first and 3 in second.[/li]
  [li]SAS will try to keep your rocket pointed in the direction it is going when SAS is turned on. EVEN AGAINST YOU. If you want to start banking, turn SAS off first or it will try to compensate your maneuvers. Also, SAS tends to be slow, if your rocket sways slowly, SAS can well aggravate the problem rather than solve it.[/li]
  [li]The taller your rocket is, the harder it is to bank and pitch. Also, tall, thin rockets are prone to slow oscillation. Even breaking in the middle from hard maneuvers isn\'t unheard of. Think of a javelin being thrown. Ever seen it at the olympics? This is your rocket wobbling like crazy. Put a thruster in the back and it\'s sure to break off.[/li]
  [li]The 'sweet spot' of stacking stock liquid fuel tanks on stock liquid engines is about 3-4 for first stage. More tanks means just more weight to be lifted, you climb slower and burn more fuel to achieve the same. Essentially, adding more tanks means you get less, not more out of them.[/li]
  [li]A good stock rocket consists of: Capsule, coupler, 1 liquid tank, liquid engine, coupler, tri-coupler, 3x4 liquid fuel tanks, 3xliquid fuel engines, 2xboosters on each of the three \'legs\', firing together with the 3 liquid engines[/li]
  [li]If your designs sways and wobbles, use struts. The three liquid 'legs' mentioned above should be strutted. At the bottom, for maximum impact. Watch for movement on your rocket, if your boosters 'cave' in towards your rocket, strut them.[/li]
  

[jgjiscool]

1. The RCS system is effective when used correctly...

2. The RCS system works similar to the SAS module (use the advanced SAS in one stage) and so you need to turn it off to realign the ship.

3. Move all of the RCS fuel tanks into separate stages or it may drain only one tank (BUG).

4. Although G-force does not have an effect at the moment, IT MAY EVENTUALLY KILL! Start practising to keep the Gs off the counter so that you don\'t have to learn when a new version comes out.

5. Sometimes the big rockets aren\'t always best. A long rocket can produce flexing in the centre if you use directional aids so build in scale: If you\'re rocket is long, build outwards somewhat aswell. If you\'re building wide, spread it by adding some length to the rocket.

[spite48]

Great comments.

Learn to use the navball. Learn what the symbols mean, and steer using the navball rather than the viewscreen. Works way better, especially when you land on the dark side of the mun.

[Omnivore]

This first one is, well common sense to most, but just to be thorough:

• 
  [li]Reducing payload mass is the single biggest improvement you can make in a rocket design.[/li]
  [li]The capsule usually doesn\'t need a decoupler under it as the parachute can slow down additional mass enough that the lower parts act as a crumple zone for your pod.[/li]
  [li]Your top stage is usually pretty easy to fly by itself so move RCS fuel tanks, any (A)SAS modules, and any winglets further down the stack if possible.
  [/li]

[Alchemist]

Your top stage is usually pretty easy to fly by itself so move RCS fuel tanks, any (A)SAS modules, and any winglets further down the stack if possible.

Or make the the top stage 100% RCS powered - despite lower fuel specific impulse it wins on smaller stages because 8RCS pods are 5 times lighter than 1 LFE (and sometimes you can fly with only 4 or even 2 RCS - you\'ll just lose some maneuverability if you do so). Just take lower thrust in account

For ascent in the dense atmosphere (at least below 15-20 km) the optimal speed is when drag consumes 50% of your thrust (and most of thrust left counters gravity), so when you reached this speed you need TWR only about 2-2,5.

• 
  [li]If your liquid engines produce more, thrust back a bit until you get higher. Or consider reducing number (and weight) of the engines[/li]
  [li]If your liquid engines\' TWR at liftoff if about 2 or less add some boosters to reach optimal speed fast enough (takeoff could be best done at TWR=3-4)[/li]
  [li]If your main ascent engines give you TWR=1,5 or less even after 25 seconds (SRB separation) consider adding more engines. Or reducing weight.[/li]
  

When you got to orbit, you don\'t need much thrust. So you would newer need more than 1 liquid engine in the orbital ship (unless your ship includes something like Munar lander) and reducing orbital ship\'s weight can be efficient even at cost of fuel.

[jgjiscool]

SAS modules produce a better torque distribution off center of the rocket. I.e. Just below a tricoupler or on top of radially coupled boosters.

Don\'t use shock plates as landing gear if you are new! They bounce and snap back because of... things. Wheels or RCS are the way to go.

Got a problem with breaking your rocket? Use the struts! If you plan to use many of C7\'s mini fel tanks, the disclaimer mentions the unstackability of the tanks, but this problem can be overcome with 3 struts!

[NonWonderDog]

Some tips from Jeb:

• 
  [li]Struts are almost as good as more boosters, since they allow you to mount more boosters.[/li]
  [li]If you have so many boosters that the rocket collapses on the pad, use struts to reinforce the joints in the main stack. You should be able to stabilize it enough to add more boosters.[/li]
  [li]If you drag your rocket sideways off of the circle in the VAB, you can start with your rocket suspended in the air next to the pad. If you can start the engines before the rocket hits the ground, you can launch with MANY more boosters than would otherwise fit. You can even get some 800 ton Munar landing practice this way:
  

[/li]
[li]Orbital transfer maneuvers are at theoretical maximum efficiency when done at periapsis or apoapsis with infinite thrust. The more boosters you have, the closer you are to infinite thrust. At some point, it\'s more efficient to carry more boosters and pay the weight penalty at launch than it is to perform your orbital transfer maneuvers with a small engine:

(You could always raise your orbit a little at a time, thrusting only at periapsis over several orbits. But who has time for that?)
[/li]
[li]When traveling to the Mun, get into Kerbin orbit and fire your boosters at it as soon as you see the Mun poke over the Kerbin horizon. Aim for a elliptical orbit with an apoapsis just further than Mun\'s orbital radius. If done right, you will insert directly and efficiently into a low Munar orbit. The more efficient your insertion into Munar orbit, the more boosters you can use to land on the Mun.

[/li]

[Samonite]

• 
  [li]Using a SAS-module during landing may reduce the amount of fuel used by liquid engines a lot, and make it much easier to land because you don\'t have to concentrate about the rocket tipping over.
  [/li]
  [li]When flying to the mun the apoapsis shouldn\'t be the same as the distance to the mun because that would make the mun coming very fast directly towards you!
  Instead try to make the apoapsis a bit lower or higher than the distance to the moon. (the higher apoapsis seems to be optimal but I haven\'t confirmed that yet)[/li]
  

[PeriapsisPrograde]

For Mun landings

• 
  [li]Do it the way Apollo did it. Burn retrograde opposite of your landing site until periapsis is ~10km, then gun the thrusters retrograde right at periapsis passage. A slow, continuous burn for a quarter orbit will leave you dropping out of the sky. We don\'t want that.[/li]
  [li]Also like apollo, use Hohmann transfers to the Mun. Look them up; they aren\'t too complicated.[/li]
  

[RedRockets]

Are using the 'Shotball' Liquid Boosters considered cheating?