The value of gravity turns--a dramatic example

[Loren Pechtel]

I just made it into space with a TWR of .07 in the third stage!  I miscalculated a bit, I was intending to do the ascent burn entirely on chemical rockets and switch to the nukes for the circularization burn and beyond.  I didn't include quite enough oomph in the chemical stages, though and the second one fell off as I left the atmosphere--apoapsis just under 100km (target was 200km as MechJeb would fly it into Kerbin during the ejection burn otherwise), periapsis still over 150km underground and 340m/s short of what I needed.  This wasn't quite a normal ascent, I sent it up a lot steeper than normal because it's carrying a drag monster.

I hit the first apoapsis with the periapsis still 50km in the rock and fell back 13km before the periapsis was safe and another 7 before heading up again.

[Grounder]

You are a better man than me.  I would've given up and reverted to the launchpad. However, you are probably committed with a harder difficulty setting.

[Loren Pechtel]

3 hours ago, Grounder said:

You are a better man than me.  I would've given up and reverted to the launchpad. However, you are probably committed with a harder difficulty setting.

I wouldn't play without revert enabled, too many things can go stupidly wrong.  I just let it fly to see what would happen and it made it to space.

[Blaarkies]

20 hours ago, Loren Pechtel said:

I wouldn't play without revert enabled, too many things can go stupidly wrong.  I just let it fly to see what would happen and it made it to space.

If it wasn't for game bugs, then no reverting would actually be fun (it is nerve wrecking).
But having parts go poof, spazzing out for no reason, spacplanes rolling left because of an open anntenae inside the closed cargo bay...thats what revert and F5 is for

Edit: Remember it is ok to point 20degrees up from prograde, the losses are less than we think:
-cos(20')=94% of thrust still happens in the prograde direction
-cos(30')=87% of thrust still happens in the prograde direction

Going further than that induces greater losses though, but if you can keep your craft out of the atmosphere at that price(6% efficiency) with super efficient engines like nukes...you still win.

Just remember to be consistent. Rather point 20degrees off prograde for 3 minutes, than to point 40degrees off prograde for 1minute(the 40' burn is going to be more risky and less efficient)

This pointing upwards thing is what real rockets(at least the last stage of them) do to get into orbit as well. They don't have enough TWR to finish the orbit insertion burn before they reach Ap, they have to constantly raise the Ap to stay up there longer, to gain orbital speed.
We in KSP often have too much TWR to finish that long before reaching Ap

Edited April 11, 2017 by Blaarkies

[Loren Pechtel]

3 hours ago, Blaarkies said:

If it wasn't for game bugs, then no reverting would actually be fun (it is nerve wrecking).
But having parts go poof, spazzing out for no reason, spacplanes rolling left because of an open anntenae inside the closed cargo bay...thats what revert and F5 is for

Edit: Remember it is ok to point 20degrees up from prograde, the losses are less than we think:
-cos(20')=94% of thrust still happens in the prograde direction
-cos(30')=87% of thrust still happens in the prograde direction

Going further than that induces greater losses though, but if you can keep your craft out of the atmosphere at that price(6% efficiency) with super efficient engines like nukes...you still win.

Just remember to be consistent. Rather point 20degrees off prograde for 3 minutes, than to point 40degrees off prograde for 1minute(the 40' burn is going to be more risky and less efficient)

This pointing upwards thing is what real rockets(at least the last stage of them) do to get into orbit as well. They don't have enough TWR to finish the orbit insertion burn before they reach Ap, they have to constantly raise the Ap to stay up there longer, to gain orbital speed.
We in KSP often have too much TWR to finish that long before reaching Ap

It's not just things like parts going poof, but that we don't have engineers modelling things like separatrons.  I consider reverting such mistakes as something the engineers should have done before flight.