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skendzie

How do I get more delta v without expanding outwards?

Question

I don't understand how you can make rockets tall enough to go to the mun withouth having a lot of booster rockets on the side. Every time I try make something with over 10k delta-v I hit the ceiling of the VAB and am forced to go outwards instead of up. I have KW Rocket pack btw.

Thank!

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in short, easialy you really can't. also 10k is more than enough for a complete trip to the mun, mimnus, and back. maybe you aren't flying correct.

post the .craft file and I'll take a look at the design.

Edited by leax256

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10K DELTA-V FOR A MUN ROCKET?

That's enough for a duna return AND THEN go to the mun.

But anyways, strip unnecessary weight, and if you need more space that desperately you can assemble in orbit.

Mun return from low kerbin orbit is about 1.5 km/s. Landing, allow for an extra 500ish

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Dude, 10K delta v is enough to leave the SOLAR SYSTEM. (Well, maybe not quite, but you can sure get close)

Nah, you just need to improve your efficiency, you need to start with a large section to get you at least most of the way out of the atmosphere, with 3.5K-4K Delta V, 800 Delta V is enough to get to mun, 500 is enough to land, and less Delta V to get back. So in total you only need around 5.5K delta V for a mun mission.

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Yeah...it takes about 860m/s Dv to get to the Mun from LKO. 10K is overkill to just go to the Mun.

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I have all the delta v maps so I know how much I need. I guess I was just reading too much on the real Saturn V and its first stage was like, 12k delta V. I know the scale is about 10 times smaller as well, I dunno. Just curious how to maximize.

Also, I don't use MechJeb and am doing everything manual. I'm not perfect at it yet so I need some error room. Guess I was trying to overkill it haha. Orbital maneuvers and docking manually have been accomplished. I'm pretty efficient with that. Just trying to get a hold of aerobraking and slingshotting and whatnot.

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I have all the delta v maps so I know how much I need. I guess I was just reading too much on the real Saturn V and its first stage was like, 12k delta V. I know the scale is about 10 times smaller as well, I dunno. Just curious how to maximize.

Also, I don't use MechJeb and am doing everything manual. I'm not perfect at it yet so I need some error room. Guess I was trying to overkill it haha. Orbital maneuvers and docking manually have been accomplished. I'm pretty efficient with that. Just trying to get a hold of aerobraking and slingshotting and whatnot.

I'm fairly certain the first stage of the saturn V didn't have 12k delta-v, since it only takes 9.4k or so to get into LEO..

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Use two side boosters (I recommend KW rocketry's SRBs), a long-burning first stage, then secondary stage to get to LKO. After that, you need about 900 delta V to get to the Mun. A couple hundred more to circularize, then boom! You are at the mun! I must emphasize that (depending on the payload) that you will not need more than two side boosters at any time to get to the Mun. I NEVER use more than two boosters, make it to the Mun with delta V to spare.

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I feel stupid, because I don't completely understand the concept of Delta-V and how to efficiently construct my rockets and other things to plan for. Anyone have a "KSP Delta-V for Dummies" guide or something that can open up the synapses in my brain to let me understand the mathematics behind this stuff?

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First, unlike real world KSP rocket engines has low trust for weight, mainsails has 25 real world engines something like 70, this force you lift a lot of engines, the asparagus design let you drop engines as you go. However with KW rockets it's no problem building an Saturn 5 copy. Start with an large 5 meter tank and the 5 meter engine, default 3.5 meter engine and small tank, next an 3rd stage with an poodle or an fiting KW engine, large gray tank. lander with lander can, medium 2.5 meter tank and an fitting engine, poodle is overkill here. simlar engine and medium gray tank under the command module. Strut this good and you are off to go. 3rd stage should take you to orbit with enough fuel to reach Mun or Minmus.

Downside is that you could replace this with an orange tank with an grey tank under and mainsail, four similar boosters in asparagus.

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I feel stupid, because I don't completely understand the concept of Delta-V and how to efficiently construct my rockets and other things to plan for. Anyone have a "KSP Delta-V for Dummies" guide or something that can open up the synapses in my brain to let me understand the mathematics behind this stuff?

Well, you could get Kerbal Engineer Redux and look at the output data. That's generally pretty revealing. But if you'd rather not, here's a quick primer on the Rocket Equation, in layman's terms.

1. Rockets need thrust to lift off. How much thrust depends on the weight they are lifting. How much weight they are lifting depends on gravity. Ergo your thrust-to-weight ratio depends on what gravity looks like from where you're at when you fire.

2. How long your rockets can fire before they run out of fuel is expressed in specific impulse, or I(sp)/ISP. The higher your ISP, the more bang for your buck you get. The trade-off is generally that high ISP comes at the cost of low thrust.

3. When not on the surface of a planet or moon, unless you plan to land, its gravity level is not important for the thrust-to-weight ratio. You can have a TWR of 0.01 and still technically be able to increase your velocity. It will just take MUCH longer if TWR is very low.

The summation of all this is: you don't need big heavy engines once you get off the surface. In fact, you're better off with more efficient engines like the LV-909 or LV-N. Only when you're planning to do a powered landing (or ascent) and are dealing with high gravity (Kerbin, Eve, Tylo, Laythe, and to a lesser extent, Moho) do you really need to worry about your TWR.

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Don't worry, I had no idea it existed till a few days ago. Now I know how to calculate it haha. Delta (triangle is the symbol which is a symbol for change) V (velocity). So it's just your change in velocity, or to simplify it farther, your rockets range. Everything in the Kerbal solar system has a delta v range calculation. You just need to find out what it is :)

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I don't understand how you can make rockets tall enough to go to the mun withouth having a lot of booster rockets on the side. Every time I try make something with over 10k delta-v I hit the ceiling of the VAB and am forced to go outwards instead of up. I have KW Rocket pack btw.

Thank!

10km/s dV rocket without any radial expansions?

Challenge accepted.

KSP%20-%20No%20radials.png

KSP%20-%20Hurrah%20Mun.png

KSP%20-%20Going%20home%202.png

I'm pretty sure that fits in the VAB stock, though as I have Deadbeef's tools I'm not certain of it.

EDIT:

Also, the nuke stage is completely unnecessary for a Mun land&return and in fact makes the rocket considerably wobblier, but you did ask for 10km/s+. :D

Edited by foamyesque

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10km/s dV rocket without any radial expansions?

Challenge accepted.

I'm pretty sure that fits in the VAB stock, though as I have Deadbeef's tools I'm not certain of it.

Very impressive :D

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Look at his equations carefully, he's calculating delta-V in feet/s not m/s.

Yes I know, those silly Americans.

Argh, what the heck. I'm American and I still hate it. Anyway, even after converting, it's about 12,000 m/s for the first three stages which were meant to send it to the moon. Heck of a lot of delta v :o

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silly kerbals on the Muuuuun.

RIGHT! now everybody else happy with my little plan of blasting off to the Mun a bit?!?!

Edited by wbcundiff

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I feel stupid, because I don't completely understand the concept of Delta-V and how to efficiently construct my rockets and other things to plan for. Anyone have a "KSP Delta-V for Dummies" guide or something that can open up the synapses in my brain to let me understand the mathematics behind this stuff?

In layman's terms, delta v is how much total oomph your rocket can exert, regardless of speed or direction. Therefore it is a dimensionless unit, unlike acceleration, which has a vector associated with it. Dv is different from your thrust, which would be a measure of your instantaneous oomph, rather than your total oomph. You can have high thrust and low Dv, like with the gas guzzling Mainsail engines, or low thrust and high Dv like with the ion and nuclear engines.

Your rocket has a potential of Dv stored inside it, based on how much fuel you have and how efficient the engines you've chosen are. Doing certain things like getting to orbit or transferring to another body require a certain amount of Dv to do, and if your rocket has insufficient Dv left in the tanks, you'll fall short and run out of fuel before you can complete the maneuver.

You can find your rocket's Dv totals manually, which involves an obscene amount of math, or you could let Kerbal Engineer or MechJeb do it for you. The KSP wiki has useful Dv numbers for various situations that you can use for reference.

Good luck!

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Surprised no one has mentioned engine clusters. It would be far more effective, but I guess it can also be considered to be "radially" attached, and some consider it an exploit.

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In layman's terms, delta v is how much total oomph your rocket can exert, regardless of speed or direction. Therefore it is a dimensionless unit, unlike acceleration, which has a vector associated with it. Dv is different from your thrust, which would be a measure of your instantaneous oomph, rather than your total oomph. You can have high thrust and low Dv, like with the gas guzzling Mainsail engines, or low thrust and high Dv like with the ion and nuclear engines.

...

(emphasis mine)

Miostly correct, just one terminology issue.

Delta v capacity is a scalar, possessing magnitude but not direction. It has dimensions of LT-1 (length divided by time). Strictly speaking, the values should be quoted with units associated, because of the issues with multiple units systems, as highlighted by this thread...

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I feel stupid, because I don't completely understand the concept of Delta-V and how to efficiently construct my rockets and other things to plan for. Anyone have a "KSP Delta-V for Dummies" guide or something that can open up the synapses in my brain to let me understand the mathematics behind this stuff?

Have you tried google or wikipedia? http://en.wikipedia.org/wiki/Delta-v

Delta means change, V stands for velocity. Hence, Delta-V = change in velocity. If someone says an operation will take 800 DV, they mean you'll have to change your velocity by 800 m/s to accomplish it.

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Yes, with 10k dV I could probably brute force it out to Duna (no gravity assists, I usually use Mun as a cheap way to escape Kerbin)

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On 5/3/2013 at 10:44 AM, itsme86 said:

Delta means change, V stands for velocity. Hence, Delta-V = change in velocity. If someone says an operation will take 800 DV, they mean you'll have to change your velocity by 800 m/s to accomplish it.

^ This. Likewise, knowing the full and empty mass of a rocket as well as the exhaust velocity of it's engine, you can calculate the change in velocity ("DV") it will achieve. These two understandings of DV go hand in hand in rocket science.

 The simplest concept is above; "Delta means change, V stands for velocity. Hence, Delta-V = change in velocity". This is why it drives me nuts to see DV discussed without citing the units.

Best,
-Slashy

 

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On 2013-05-03 at 3:07 AM, Temstar said:

Look at his equations carefully, he's calculating delta-V in feet/s not m/s.

Mars Climate Orbiter Syndrome strikes again!

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Just crafted a simple 3-stage rocket that gets my comm-sat payloads to Duna, and I've still got a whole bunch of leftover Delta-V. So if I was feeling really frugal, I could probably strip some of the fuel tanks I've got on the upper stage but I like having the extra margin for error. It's all about efficient flying my man. 

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