Can't get my Control Tower to the Mun!?

[SmashingKirby148]

Sorry guys, what was actually the problem was my Thrust to weight ratio. The aerospikes weren't powerful enough.

Edited June 4, 2015 by SmashingKirby148

[TheXRuler]

I seem to remeber someone having a similar issue, ended up being something screwy with KER or mechjeb (can't remember which one they were using). Did you add up how much your manouvre nodes cost you? I assume it's not some newbie mistake since you have already been to laythe etc.. I have found that KER is very weird when the root part is not in the last stage so maybe that'll help.

[SmashingKirby148]

I seem to remeber someone having a similar issue, ended up being something screwy with KER or mechjeb (can't remember which one they were using). Did you add up how much your manouvre nodes cost you? I assume it's not some newbie mistake since you have already been to laythe etc.. I have found that KER is very weird when the root part is not in the last stage so maybe that'll help.

Ok, I'll try that. (also, how do you know I've been to Laythe? Do you come from my Youtube Channel?)

[RAINCRAFTER]

I come from there. Don't know the answer to the question, but I know that you landed a rover on Laythe recently, and also good luck with getting this problem fixed and making the base episode.

[MarvinKitFox]

... I do everything as normal, take off, turn 45 degrees at 10,000m up....... Was it the Aerospikes?

No, it was your piloting skill.

The first part quoted indubitably proves you are piloting in the least efficient way you could find.

The second part shows that your design choices come from the same manual.

[Warzouz]

It's very strange you get 8750m/s and end 3000m/s in LKO. You should have at least 4000 m/s left (probably around 4300m/s).

[MathmoRichard]

No, it was your piloting skill.

The first part quoted indubitably proves you are piloting in the least efficient way you could find.

The second part shows that your design choices come from the same manual.

Harsh, nothing wrong with it if it was done gradually. If the turn was 0 to 45 in less than 10 seconds then maybe that's bad. But actually, it would only cost you a small percentage, we're looking at a 50% ∆v loss, and on the ascent it is at least that. If it's not a bug with KER then I think it must be a bug with the game.

Screenshots?

[Teilnehmer]

It's very strange you get 8750m/s and end 3000m/s in LKO. You should have at least 4000 m/s left (probably around 4300m/s).

Maybe, 8750 m/s is the value for vacuum?

[Warzouz]

Maybe but the ASL ISP rises very fast to vacuum value. It's not too significant except if you use very unefficient ASL engine (Poodle, terrier, LVN...).

I sent a rocket on orbit that said 2750 m/S for ASL dV.

[TheXRuler]

Though what marvin is saying might be part of the reason, it is indeed uneccesarily harsh.

A more realistic gravity turn might save you a ton of dV, also, not going quite so fast early on will reduce drag losses quite a bit.

What real rockets do is burn straight up for a very short amount of time, then more or less immediatley tilt over by ~3°-5°, depending on the TWR. Higher TWR=bigger angle.

Then, as you gain speed you tilt over ever further, so that you are going at ~60° relative to launch, 30° relative to the horizon, when you reach 40km at a speed of ~1500 m/s.

From then on you slowly tip further until you are going completely horizontal when your AP leaves the atmophere). Now this is still just a rough approximation, In the absolute best case you tilt at launch and the n follow the prograde marker until you have circularized, however this is very hard to do in KSP ^^

If my explanation did not help much I recommend getting Mechjeb, and watching the autopilot do an ascent, if you follow that profile it will be close enough.

[SmashingKirby148]

No, it was your piloting skill.

The first part quoted indubitably proves you are piloting in the least efficient way you could find.

The second part shows that your design choices come from the same manual.

Nope, did it again with Lvt-45s and I did it. T'was the aerospikes. Strange how they do that though.

- - - Updated - - -

Though what marvin is saying might be part of the reason, it is indeed uneccesarily harsh.

A more realistic gravity turn might save you a ton of dV, also, not going quite so fast early on will reduce drag losses quite a bit.

What real rockets do is burn straight up for a very short amount of time, then more or less immediatley tilt over by ~3°-5°, depending on the TWR. Higher TWR=bigger angle.

Then, as you gain speed you tilt over ever further, so that you are going at ~60° relative to launch, 30° relative to the horizon, when you reach 40km at a speed of ~1500 m/s.

From then on you slowly tip further until you are going completely horizontal when your AP leaves the atmophere). Now this is still just a rough approximation, In the absolute best case you tilt at launch and the n follow the prograde marker until you have circularized, however this is very hard to do in KSP ^^

If my explanation did not help much I recommend getting Mechjeb, and watching the autopilot do an ascent, if you follow that profile it will be close enough.

Yeah, I did that and it worked.