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Is it ever desirable to start a mission with engines at half throttle?


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What does overbuilt mean?
More TWR than is needed.

^^ This. You've added MOAR BOOSTERS than are needed.

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but I thought with the new atmosphere effects, and stuff like drag.. it was considered more effective to start at about 1/2 throttle? even going lower at times to avoid massive drag slowing you down and basically wasting fuel? until you reach about 20k or so, then bump it up to full or nearly? at least with the early tech rockets?
It varies by rocket and starting TWR. In some cases, especially with smaller rockets, you may actually have to throttle down to maintain a good TWR during the ascent. I generally tweak thrust in the VAB instead of throttling because actual rocket engines rarely have throttle capability and we have such a small engine selection.
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Going for realism? Starting at 100% throttle is a good way to make the engine go CATO aka. boom!

Recently, Copenhagen Suborbitals found that the ideal pre-stage throttle setting for their tiny BPM-2 engine similar to the LV-1R Spider, is not 50%, but 42%!

Link to article (in Danish): http://ing.dk/blog/42-175851

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It varies by rocket and starting TWR. In some cases, especially with smaller rockets, you may actually have to throttle down to maintain a good TWR during the ascent. I generally tweak thrust in the VAB instead of throttling because actual rocket engines rarely have throttle capability and we have such a small engine selection.

hmm. that makes sense. i'll try to remember that when I start doing bigger rockets. I'm just now hitting the max of the starting launch pad.

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When I have SRB's and a gimballing engine attached to a rocket, I usually set the throttle to no more than 1/3 or even 1/6 power. Purely for steering.

Then, when the SRB's are jettisoned, it's 2/3 to full power (yeah! (love flames!)).

Edited by T-Bouw
Ninjad
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hmm. that makes sense. i'll try to remember that when I start doing bigger rockets. I'm just now hitting the max of the starting launch pad.
You'll find a way that works best for you. I've just played so much Realism Overhaul/Real Solar System that I'm used to engines that don't throttle at all, so managing TWR with solid rocket motor burn times, or simply making the rocket bigger, is a large part of making a launch vehicle. I just pre-tweak instead of throttling.

Well, unless we're talking Angara A5. Then I throttle. Anyway...

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The more senior forum users will confirm; this comes up ever pretty frequently. And most will also agree 50% is pretty dumb. If you don't know to press spacebar to trigger your first stage you clearly don't know the controls at all. More useful would be a proper set of tutorials that teach people such basic skills.

To reset the throttle to a more sensible 0% (or whatever % you desire): http://forum.kerbalspaceprogram.com/threads/92076

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If im using first stage SRB's half or 1/4 throttle may be used just to make sure I have some control.

Yup, if you've got SRBs and the main engine going at once, having rather less than 100% throttle is usually necessary. Because SRBs are relatively cheap, I tend to use them a lot, so I frequently find the default 50% pretty close to what I need.

Also, I make a lot of "general aviation" and extreme STOL aircraft. These things typically fly best at 50% throttle.

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Yup, if you've got SRBs and the main engine going at once, having rather less than 100% throttle is usually necessary. Because SRBs are relatively cheap, I tend to use them a lot, so I frequently find the default 50% pretty close to what I need.

Also, I make a lot of "general aviation" and extreme STOL aircraft. These things typically fly best at 50% throttle.

Pretty much exactly what I do. Main column has liquid engines that run at 25-50% during take-off with SRB's. The SRB's give it the lift, while the Liquid engine acts as a means of control. Once I'm higher in the atmosphere and have shed the SRB's, then the thrust on the Liquid engine stack gets increased to 75% - 100%.

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I can see from some of the more experienced users that max throttle is not optimal in a lot of situations, but especially in the early game, when any rocket struggles to make orbit, anything less than max is a failed mission.

I think it would be ideal to default to max, but also have a tweakable value on the engine for default throttle setting. That way you can optimize without relying on your memory.

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After the release of 1.0, I was having trouble with rockets flipping after second stage ignition. I found that the rocket needed a few moments to stabilise after separation, so I took to keeping the throttle at 50%, and then throttling up after it stabilised. Since then I've switched from the LV30 to the LV45, which has enough gimble to hold the rocket on course. Henceforth, I stage at 100% now.

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It's more trouble that it's worth to have throttle default to zero, but a settings option would be nice.

I predict sal_valager does not use a flight stick. It is not more trouble than it is worth, having it at 50% when your throttle analog is at 0 destroys missions. It is beyond annoying, as far as I'm concerned it is a bug. I can not play hard mode all because of this, hard mode might as well not be an option in the game for me. It is broken, period.

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You mean from the pad? That does seem weird.

But in mid flight it makes more sense.

(im a noob)

Iv discovered that if the output from my Liquid engine is too strong after my Solid boosters are done, that sudden change in thrust and torque can initiate... a spin (or tumble, or some other vomit inducing reaction). But If I start with 1/2 throttle and then gently apply the power I can keep the rocket under better control. This of course only applied when Im launching Bob or Bill into orbit. No SAS... and I suck at steering at the moment.

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That's just it though, it wasn't :)

It's easy for experienced players to press Z or X though.

Not to say I'm an experienced player, but I know all about the Z and X keys and it's still not at all easy. Remembering to press Z after realizing that your rocket isn't doing what you expected is often waay too late to save Jeb.

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The 50% throttle decision makes little sense. It people are confused that their rocket didn't do anything when they hit space bar, then, maybe, they should learn the controls.

How did they even know to press space bar?

Lol! The first time I played I had no idea about spacebar, T or Z. I couldn't launch until I looked up the keyboard commands.

I recommend the demo to a few friends. Folks on the slower end of the curve gave up before they could figure out how to launch. System requirements should include the fact that you need < half of a brain to play. Lol!

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It is not more trouble than it is worth, having it at 50% when your throttle analog is at 0 destroys missions. It is beyond annoying, as far as I'm concerned it is a bug. I can not play hard mode all because of this, hard mode might as well not be an option in the game for me. It is broken, period.

You do know that with a HOTAS setup, all you need to do is wiggle the throttle before launch and the game will register it's positioning correctly?

What is wrong with all of you people? Is it really that hard to add the line "verify throttle setting" to your current pre-launch checklist? Or are you so impatient to launch your rocket you don't bother to do anything but hit spacebar and hope for the best? It takes 1 second of your time to check your throttle position.

Currently my pre-launch checklist looks something like this:

1. Check staging diagram, adjust as needed.

2. Verify abort procedure.

3. Verify resource levels and amounts.

4. Review mission objectives.

5. Check science experiment function.

6. Activate SAS.

7. Check throttle setting. <--

8. Review intended flight path.

3. 2. 1. LAUNCH!

As far as I'm concerned the throttle setting debate is a non-issue, but Squad should put something in the main menu options to change the 'default' throttle setting just to shut everyone up.

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In real life the Delta IV heavy core goes to partial thrust mode soon after lift off, and then ramps up to full again at booster sep. It also looks like it's made by Rockomax. :D

Edited by Fleb
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