How to perfrom gravity turn correctly?

[Fried Corn]

Hello everyone!

Reading all these interesting questions about stuff I don't really understand I fell like a total dumb-ass for asking anything like this. But I am just clueless. I made for about 40 types of my "Orbital Watcher" ships (get it? It's a joke!) and I am just not able to left them to fly around my planet. Here is what's happening most of the time: I am creating ship for over 40 minutes, then correcting issues I made for over 20 minutes and if it doesn't explode on the lauching pad it will (probably) fly. So I decid to hit the spacebar and it's flying. In the worse scenarios my ship's too heavy for the rockets to lift it off, or I am not able to control the whole thing and it'll fall and explode. However if I make it over 10 kilometers I start to think. By this time I am used to have one more stage ready and the second one is still in action. I tried to do gravity turn at 10 kilometers, 11 (I saw it today) or even at 20. It ends either me flying out of the the Solar system or me crushing to the planet below. If I want to perfrom a maneuver I usually don't have enough fuel to do so. This is my closest try: https://twitter.com/MisterFriedCorn/status/437996988823379968/photo/1. I tried all my "lucky trinkets" I own and I decided to fly only with Jeb (he is funny and also, one of my lucky trinkets - even if we fly towards certain death he's laughing, lunetic. One does not simply stop loving him).

Can anyone help me? I understand this is very simply, but I am quite new to this game. Thank you for all help you can provide.

Bye.

[godefroi]

Try starting your gravity turn at ~7500m, and from there, gradually bring the nose down to the horizon. Once your apoapsis (Ap) hits whatever you want it to hit (I usually shoot for at least 75km to give me a margin of error), turn off your engines and coast until you get close to your Ap. Once you get close, point your nose directly at the horizon and turn your engines on full until your periapsis (Pe) is outside the atmosphere. Congratulations! You made orbit!

Don't feel bad if your first few (many) orbits are highly eccentric (oval instead of round). You'll get there. For bonus points, while you're coasting, set up a maneuver node for your circularization burn (straight prograde until the Pe is where you want it. That way, you have a target to follow.

[Kasuha]

Gravity turn is best performed from map view. When you pass ~10 km and start turning to the east, open the map view (M), bring up the navball (Del key on numpad or press that little gray arrow at the bottom of the screen) and continue steering your rocket from there. Watch your trajectory in light blue and especially your apoapsis. You don't want to get past it, you want to get it gradually to about 75 km, but not more.

Try this video:

[capi3101]

Stock game launch - the advice I give folks in general is straight up to 10,000, then turn to 45 degrees elevation along heading 090. Follow the nav ball once it comes around and watch your time to Apoapsis (for which you go flying in map mode). You want your time to Apoapsis to be between 35-55 seconds during the bulk of the ascent (i.e. before your speed gets much above 2000 m/s). If it goes under 35 seconds, return to 45 degrees elevation. If it goes over 55 seconds, burn along the horizon (zero elevation). Watch your gee meter (on the right hand side of the nav ball) as you ascend; you want it right at the top of the green zone - throttle back if you need to. Kill the burn when the Apoapsis is where you want it (or go a little higher if your altitude is still relatively low, <~50,000 m). Set up a maneuver node to circularize and begin burning when the time to the node is roughly half the total amount of time indicated for the burn.

[Noticeably FAT]

It sounds like your problem isn't with the gravity turn, but with circularization (or rather the lack of). The gravity turn isn't strictly speaking necessary, it's just the most efficient way to increase your horizontal velocity. A single big burn cannot get you into orbit. You need to stop burning once your apoapsis (highest point in your orbit) is where you want it (either watch the map view, or get a mod that indicates orbital information), then once you hit that point you need to burn again towards orbital prograde (the direction that will increase your orbital velocity) until your periapsis is as high as you want it.

[DrD]

There are some excellent videos for newbies on you tube. Search under Scott Manley Kerbal and you'll get what you need.

[Vanamonde]

If the rocket is breaking apart and THAT hard to steer, it's probably just too big. Can you post a picture of it?

[TheGeoninja]

At 10,000 metres I make a 45 degree turn heading at 90 degrees. If my ship ways a lot or it doesn't have very good thrust then my turn isn't as steep.

[Arran]

It sounds like your problem isn't with the gravity turn, but with circularization (or rather the lack of). The gravity turn isn't strictly speaking necessary, it's just the most efficient way to increase your horizontal velocity. A single big burn cannot get you into orbit. You need to stop burning once your apoapsis (highest point in your orbit) is where you want it (either watch the map view, or get a mod that indicates orbital information), then once you hit that point you need to burn again towards orbital prograde (the direction that will increase your orbital velocity) until your periapsis is as high as you want it.

Not entirely true, i get my ships lately into orbit in one continued burn (i started with this, when i learned NASA rockets, coudnt turn off their main engines, and thus for immersion sake, i wanted to do so as well)

How i do this, once i pass the 10.000 meter mark, i start to make a normal gravity turn to 45 degrees, and keep this going till i pass the 30.000 altitude, and then continue to follow the prograde marker on the navball, then when my AP gets around 45 seconds, i pull the throttle back, and lower my AoA lower to around -10/-15 degrees and keep adjusting my throttle to stay on the 45s distance of AP and sometimes my AoA angle by a few degrees as well, near the end my throttle is often allmost down to 5% (lowest setting of the throttle) And keep this up till my circulazation is done.

In KSP its maybe not the best way to do it, since we can reignite a mailsail whenever we like, but for immersions sake thinking a mailsail cannot be restarted, its the only way to do i think

[problemecium]

This advice will sound like BLASPHEMY to a lot of Kerballers, but here it is anyway, it might help you:

When you're past 15km or so, turn down the throttle while watching the G meter on the right of the navball. Try and keep it around 2 Gs. As you get higher and the rocket gets lighter, you'll be turning the throttle gradually lower and lower (while also pitching down gradually per the above posts). For one thing, this helps big squishy ships not implode on ascent as I have had happen. But in this case, the benefit I see is that you'll be able to carefully control how high your orbit goes and not waste fuel.

All you need to do with the Apoapsis is get it above 70km (technically anything above 69,100m or so will work) and try to have it a minute or two ahead of you (but not more than four or so), so that when you hit it you're going somewhere between 1800 and 2100 m/s. Of course that's just what I do and I'm kind of weird.

[Pds314]

When running without mods (Stock): pitch over at about 8+ km and 200-400 m/s slowly to about 60 degrees and then wait for your Apoapsis to reach 70 km.

When running with the FAR mod: Do like real spaceraft and start at below 1 km and constantly point prograde after that. You should end up with a periapsis long before you reach your Apoapsis.