Mainsail Replacement

[MadDoctor5813]

I'm playing Career mode currently, and really enjoying it. I'm pretty far up in the tech tree, and I'm on the node just before Mainsails, and I have also gone interplanetary. However, when I used to play Sandbox, I always used Mainsails for launch. I don't have those as of yet, and I've been using a tri-coupler with 3 LVT-30s on it. I placed them in a 6-way radial formation, and it works, but when I drop the radial boosters, the single stack left over has about .7 TWR (thanks, Kerbal Engineer) and it just starts losing speed. The craft I used had about 10,000 m/s dv, so it was fine, but still, I would like a better replacement. Is there even one, or am I just going to have to deal with it.

I don't have any pictures, as I am at school right now.

Edited November 22, 2013 by MadDoctor5813

[Taki117]

If you have the tail section (In aerodynamics) you could use that for a more aesthetically pleasing engine cluster (It will result in 7 engines per tank) and then use asparagus staging in 6x symetry.

[Kerbart]

A skipper with 6 radial Mk 55 engines doesn't give you that much less thrust for a little bit more weight but all in all it puts you in the same ballpark.

[Johnno]

Here's a tutorial I made. You can do similar with cubic struts/girders or similar.

Edit: More thrust than a mainsail, better ISP. Downside is more parts.

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[Ravenchant]

What they said. It's entirely possible to lift 50+ tons to orbit without Mainsails or the orange tanks. With Johno's technique, the engines may not always be able to attach, though (red hue). If that happens, build it in 1x symmetry, then copy the whole cone+engine in higher symmetries.

Happy launching

[capi3101]

You could also use Johnno's technique with parts clipping turned on (ALT-F12 to bring up the debug menu). Largely that's where the game thinks there are parts collisions - right up there at the top, where the tops of the engine units overlap one another. Parts clipping overcomes that annoying little problem.

Same method happens to work with Modular Girder Segments, BTW. Just attach them radially, then turn them flush against the sides of the tank and add your engines. Girders allow fuel crossfeed so you don't need fuel lines or anything. They happen to have the advantage of lower mass than tail connectors and they're available from the get-go; 25 Science to get to the -T45 is all you need before you can be shooting off massive payloads like in you're still in Sandbox mode. Probably the only down side is that they look like crap.

Four LV-T30s and a Skipper are another option; lower Isp, though. You can also get roughly the same thrust as a Mainsail with just six LV-T30s; Johnno's solution with eight provides moar thrust.

Edited November 22, 2013 by capi3101

[linkxsc]

Like what capi said, you can get the same effect with girders. They're actually really great at it.

After fudging a mission to minmus as part of a competition with a couple friends (who could get the most science points in their first mission with the most basic of parts.) And the subsequent contest to see who could get the most science from there in a second mission. That kind of setup became my workhorse to get a mun/minmus/gilly lander mission, and several others until I got mainsails and nuclear rockets.

[Turvok]

When I left home I was in the same boat as the original poster. I did manage to get a 60 ton payload. (pusher and lander) into orbit without mainsail. I could have used something like the pictures above but didn't know how to do it.

What I personally did was use 18 solid boosters to get the initial oomph. Plus a 6 way plus middle engine in esparagus stage. The last engine did get me out of the atmosphere. But I had to use my 2 nuclear engines on my pusher to have enough thrust to get it into orbit. Once I was in orbit I could transfer fuel back to pusher stage. (I put my nuclear on an action group to toggle them)

I tried transferring the fuel and tried a number of ways. But for shear amount of patience I ended up not transferring fuel and just letting the last remaining main engine help with my boost to Duna. Otherwise it was going to be a 4 or 5 min burn.

My final stage before pusher had a TWR of 0.86 I think. So I knew I was close.

Also want to point out that I couldn't go more then 5 degrees into my gravity turn until I was close to the 60 or 70 km range or I would just fall back to kerbin. It wasn't a great shop but it got me to Duna and back.

Edited November 22, 2013 by Turvok

[ScottyDoesKnow]

If you don't mind a massive part count, the tiny rockomax is one solution. http://forum.kerbalspaceprogram.com/threads/55575-Cheat-Rocket-60

Somebody further down in that thread posted another engine cluster solution as well.

[Sirrobert]

I always build my rockets in parts and dock them in orbit. Makes it much easier

[WafflesToo]

If you don't mind a massive part count, the tiny rockomax is one solution. http://forum.kerbalspaceprogram.com/threads/55575-Cheat-Rocket-60

Somebody further down in that thread posted another engine cluster solution as well.

I just got ninja'd

Was going to say "50 48-77's" but it looks like I was thinking too small.

[MadDoctor5813]

OK, thanks guys. This will really help my interplanetary quest. I'll try and mark this answered. The design with the cones reminds me of the Russian Proton rocket.

Edited November 22, 2013 by MadDoctor5813

[Taki117]

Here's a tutorial I made. You can do similar with cubic struts/girders or similar.

Edit: More thrust than a mainsail, better ISP. Downside is more parts.

Gallery

This is exactly what I was talking about!

[Skorpychan]

Smaller rockets and Skipper engines. Just harvest science until you get to mainsails.

I managed to get an Eve landing with just Skippers and a nuclear cruise engine. Worked surprisingly well, for a non-return probe.

[Ravenchant]

I managed to get an Eve landing with just Skippers and a nuclear cruise engine. Worked surprisingly well, for a non-return probe.

How big was the probe? Because that sounds like overkill

[Kasuha]

I designed this ship in Career mode after I unlocked skippers and I did not need any better ship till the end of the Career. I only added landing legs to the second asparagus stage (because the "lifter" stage was strong enough to do interplanetary transfer and most of braking) and added more solar panels and scientific instruments to the probe and finally made it a rover. It was good enough to visit the moon and then land on planet both on Duna and Eve.

On Gilly:

On Eve:

Edited November 24, 2013 by Kasuha