circular orbit problem with empty fuselage

[antipro]

hi, I'm testing this ship in order to land on Dres:
https://www.dropbox.com/s/iy8wbxpf8jhmg4q/Screenshot 2020-04-04 12.51.41.png?dl=0

I have a problem when I burn to orbit it, like if I had started engine too late:
https://www.dropbox.com/s/rzs7c52gh1ndk2r/Screenshot 2020-04-04 12.46.36.png?dl=0
https://www.dropbox.com/s/vec3t39x9sqbwrq/Screenshot 2020-04-04 12.48.01.png?dl=0

Not sure but I think it's because I didn't decouple those mk1 liquid fuel fuselage with the legs attached when they was empty. is it possible? or maybe is another thing?
The plan is of course to detach them as soon as I left Dres surface.

 

Edited April 4, 2020 by antipro

[Superfluous J]

What exactly is the problem?  That your orbit doesn't match the maneuver node?

How long was that burn? Nukes tend to have long burns and long burns tend to be inaccurate. I think that's all that's going on here.

[antipro]

11 hours ago, Superfluous J said:

What exactly is the problem?  That your orbit doesn't match the maneuver node?

yes

11 hours ago, Superfluous J said:

How long was that burn?

3m44s

 

[Superfluous J]

1 hour ago, antipro said:

yes

3m44s

 

4 minutes is a long time when you're coming in from interplanetary and trying to hit a burn perfectly.

However now that I'm rethinking this, the burn planner probably did think you were going to drop those tanks and have higher TWR. So it probably though the burn would take less than 3m44s. or it thought it would take 3m44s and it actually ended up taking you 4m or more.

[antipro]

44 minutes ago, Superfluous J said:

the burn planner probably did think you were going to drop those tanks and have higher TWR.

yes, it's what I though. by the way, I've now started the burn 18s before the correct time and even if not perfectly, the orbit now matches the maneuver node.
anyway it was a bit hard to determine the exact moment to start the engine.
thanks