Need help, im improving my transfer stage with lv-n!

[TheScareCake!]

Greetings. Im doing interplanetary journey to joolian moons. I love to use lv-n nuke engines for the transfer stage. Usually, i use two nuke engines and one orange tank, but it doesnt have much dv.

How can i improve it? Thanks in advance.

I will give reputation for good answers.

[Dave Kerbin]

You'd really need to show or explain what kind of payload you are carrying. Delta-v is a function of ISP, fuel to burn and mass. By itself an orange tank and 2 LV-Ns has over 12,000 m/s of delta-v which is a lot. That delta-v is reduced as you add additional dead weight.

[TheScareCake!]

Im never carrying more than 50 tons of payload.

And, as we know that lv-n engines will burn up if you will attach them directly to jumbo orange tank so i like to attach two longest 1,25m fuel tanks on its sides and then put two lv-n on both. I still dont understand how some people manage to do the jool-5 challenge...

[Red Iron Crown]

There are only four ways to increase the amount of delta-V a ship has:

1. Higher Isp

2. Less payload/dry mass.

3. More fuel.

4. Staging.

You've covered point 1 already by using LV-Ns, and I'll assume that point 2 is already handled (though paring anything unnecessary from your payload will certainly yield dV gains).

Point 3 is about increasing the proportion of your ship's mass that is fuel (mass ratio). More fuel is more dV, though the dV gains diminish the more you add.

Point 4 is about shedding dry mass. Losing the mass of empty tanks has a similar effect to reducing your payload. Rather than one big fuel tank, consider breaking it up into several smaller tanks with decouplers and fuel lines. As the tanks empty, stage them away. If you combine this approach with Point 3, make sure the tanks you add can be dropped when empty.

Have fun in the Jool system, it has some of the best views in the game (I love watching Jool rise from orbit).

[GoSlash27]

ScareCake,

In addition to the above, you could consider reducing your payload, splitting it among multiple transfer vehicles, and eliminating one of the LV-Ns.

Especially the "reduce payload" part. Designing your surface payload and launch vehicle to be as mass- efficient as possible reduces your lander's mass. Reducing your lander's mass has a dramatic effect on your payload mass. Little changes at the far end of a mission have a dramatic effect on earlier stages.

Although honestly... 12,000 m/sec DV is more than plenty enough. Rather than looking for ways to increase your DV, why not look for ways to use your existing DV more efficiently?

Best,

-Slashy

Edited July 31, 2014 by GoSlash27

[Dave Kerbin]

With a 50 ton payload you have a little over 3000 m/s using just the orange tank. That would get you to Jool though getting into orbit of anything but Laythe would require a lot of skill.

A couple of things:

Are you reaching Jool orbit at all? You should have around 800L of liquid fuel left once you reach Jool orbit. If you can't reach Jool with just the orange tank then you may need to examine how you are getting there. Do a search for Launch Windows and Hohmann Transfers.

Reducing your payload would help a lot.

If you must you can add additional drop tanks with radial decouplers and fuel lines.