Wrong maneuver time

[ANDAKIN]

Hello, when i want to ad a maneuver, the time that i need to burn is completely different, than it is in reality. Any help please?

[Chibbity]

In what way? More or, less?

Are you sure your navball is in the right mode? (Surface/orbital/target)

Did you stage between planning it and executing it? Are you using a different engine than the one that was active when you made it?

[ANDAKIN]

I start to burn. Than when my apoapsis is about 60 000 i try to set orbit. (that is 2nd stage of my ship) than i create a maneuver and it shows me 0 sec. When i start to burn it shows me for about 5 hours... and when i stop again, it shows 0 again.
Or sometimes happens, that it shows me 5 seconds. But i have no chance to make this big maneuver in 5 seconds :(

[RoofCat]

don't make maneuvers within atmosphere. Just fly in map mode and check how your Ap changes with burn - both altitude and time left. You need it above 70km (72km or so is great choice). When you are close to Ap, Pe on the other side should start to rise above planetary surface closer to 2200m/s. Try to keep Ap close changing thrust while Pe grows to the same altitude - just before you reach Ap spot or right after. It's a practice thing and rather easy.

Then maneuver nodes often show wrong burn time. Because you have decoupled stage and what not. Just burn for ~1 sec with low thrust right before reaching node to let game recalculate your engine power and thus burn time. It still won't be accurate, as burning your fuel your ship will also get lighter and acceleration will increase, thus your real burn will be roughly 10% shorter with rocket engines. With some diet engines (nukes, xenon) that difference rather won't be that big. And due to waste on orbital curvature burning at bad angles your burn time may even increase slightly on those.

[Chibbity]

60km is still in the atmo, you need to be at 70km+

Also, no reason to make a maneuver node while launching to Kerbin orbit. Just burn towards the horizon.

Try to keep time till Ap(You can check this in map view) between 5 and 30 seconds. Nose up to increase time, nose down to decrease. Once Pe is 70km your in a safe orbit.

[Astronaut]

I'm confused, but:


Here's how manuever nodes work:

You plot a manuever.
The estimated burn time can be N/A, some absurd glitch like 8d 2h 56m 34s, or just an estimate. This is not always accurate, but you want to split your REASONABLE burn time in half. For example, 4m burn time. Divided by 2 gives you 2m. You take this and start burning 2m before the actual manuever node, like stated in the tutorials.