Space Shuttle building issues

[Rodyle]

Hi there guys,

I've been watching some videos and became interested in building a functional space shuttle. However, I have been having some issues with it.

1: properly lining up CoM/CoT. This has so far been a huge issue for me. Because I'm trying to build in a cargo bay, I'm trying to keep the CoM around the middle of that, so I don't get screwed over when using different cargos. However, getting the centre of thrust properly lined up is hard. Furthermore: It's even harder to get a good line through the CoM and CoT so that the external fuel tank's CoM lines up with these two. I think this is an issue of getting the CoM far enough backwards. Maybe I should not have any liquid fuel on the shuttle?

2: Having decent aerodynamic properties on the shuttle. My tests so far have shown these to be horrible. Even after dumping all liquid fuel, it has huge difficulties getting the nose up. Could this be an issue of having the CoM too far ahead of the CoL?

Thanks in advance!

[Geschosskopf]

1. Yup, any time you build something highly asymmetric, you're going to run into all sorts of CoM/CoL/CoT issues. This is the big challenge of doing lopsided shuttles in KSP, especially because there's not really any good way to adjust the rig of the thing between and during flights like could be done with the real things. There are several ways of dealing with this:

A. Acquire infinite patience and just keep redesigning and tweaking until you get something that works.

B. Give up and instead build the shuttle as symmetrically as possible, like by putting the glider part on top of the boosters instead of on the side (which is what many folks do).

C. Get one of the various shuttle mod packs where the creator has already done all this hard work, so that if you put his parts together per the directions, everything will work fine at least if you stay within the design parameters.

2. The real Space Shuttle had the aerodynamic properties of a brick but at least it was a controllable brick. So if you're not able to pull the nose up, it's probably due to something like you said, CoM too far ahead of CoL.

An issue with shuttles is that if you put enough wing on them so that they fly/glide more like airplanes than bricks, then you'll have a lot of trouble launching them vertically. Big wings means big lift at high speeds and this will all be pulling to 1 side during ascent. This can easily pull the shuttle off the booster or, if you strut it enough to prevent that, make the whole assembly tumble uncontrollably.

Because of both this problem and all the asymmetrical force problems noted above, it's often a lot easier (though still far from trivial) in KSP to just make a big spaceplane than it is to make a functional shuttle.

[Itoum]

I dont know if it will help but look at mine its flying like a boss and gliding like a champ loll !!! Look at the end i took pictures of my CoM/CoL with and without the external fuel tank, I'm using fuel tank on the shuttle as well. For the cargo ive realize that when in the cargo bay its better to place it at the back so ur CoM go back at liftup. http://imgur.com/a/hesKL#0

There is a Shuttle Challeenge too u migth want to look at it for idea http://forum.kerbalspaceprogram.com/threads/79273-Kerbal-Shuttle-Challenge

[RocketPilot573]

You can look at the link in my sig if you want to see my shuttle.

I found that tweaking the thrust of your engines is wayyy more reliable than trying to rotate them. Since even if you turn them 20 degrees, the stock engines still have such a tiny gimbal range that you'll still lose control no matter what you do.

[Rodyle]

Thanks for the help. I'll just go ahead and keep on trying, since I've done enough with space planes already and I kind of like the challenge. Keep ragequiting when KSP stops working, though... ' I don't know what I do, but I seem to be causing either memory leaks or faulty pointer references quite often.

Edited June 27, 2014 by Rodyle