Designs for a Heavy (7-10 man) Space shuttle?

[Carter938]

Hello. I recently docked a habitation module to my space station with room for 20 Kerbals. I intend to crew it with 7 to 14 Kerbals. So, I thought that rather than launch a series of small SSTOs and rockets, I would build a large space-shuttle like Spaceplane with room for 6 or more Kerbals to minimize the number of missions the drop off crew. The Spaceplane is launched from on top of a vertical rocket but comes back down by landing on the runway like a real spaceplane. I have had success with much smaller 1 and 3 man spaceplanes in doing this. However, while I can launch and perform orbital manuvers with this "Jumbo" shuttle rather well, I cannot land it. Every time I renter the atmosphere, no matter how shallow my trajectory is, my spaceplane always and inevitably points downwards. I will post a picture to show what it looks like. What do I need to do to stop this and land my shuttle safely on the runway and how? More lift? More thrust? Less weight?

Edited October 9, 2013 by Carter938

[boomerdog2000]

So it sounds like you burned all the fuel in the back and your center of mass shifted too far forward.

You could try adding canards near the nose or maybe adding more weight in the back.

[Starglider]

If you don't want to do canards, you can move your wings forward (imo canards are better though). Also, if you have any fuel mass left, shift it aft before entering atmo. You have to make sure your center of lift is in front of your center of mass, and that is complicated by how your fuel drains out of your plane.

[boomerdog2000]

Given the setup from the pics the larger rockomax should drain first, it's just that hitchhiker and command pod are heavy.

[lammatt]

if you dont mind playing with mods,

try B9, they have tons of planes oriented parts

you can basically build a plane with 20+ crew easily. (well... i huge plane doesnt fly as easily as it could be tho')

try to shift your center of lift closer to the center of mass so that your plane can be more maneuverable.

[SofusRud]

add a bunch of reaction wheels. Use them to they'll help you overcome the instabilities of your craft. Of course, depending on the required number, you might want to add boosters to your launcher. That's how I'd anyway

[bsalis]

So it sounds like you burned all the fuel in the back and your center of mass shifted too far forward.

Yep, that. Try to keep the wet and dry center of mass (CoM) close together. Try moving the hitchhiker container further back in the stack.

[boomerdog2000]

add a bunch of reaction wheels. Use them to they'll help you overcome the instabilities of your craft. Of course, depending on the required number, you might want to add boosters to your launcher. That's how I'd anyway

This may help but depending on where they are added they could just contribute to the CoM problem.

[Carter938]

I will attempt the weight shift first. If that does not work I will use canards. However, I thought the fuel tank and engine were heavier than just a hitchhiker and command pod. Correct me if I am incorrect though.

[boomerdog2000]

On their own they probably are but it doesn't take much to shift your CoM around to mess with your flight characteristics.

[Carter938]

I tried everything but eventually realised it was futile. I redid the design into a NASA Space Shuttle clone (though it launched like the one above) and it works better, at the cost of crew space. I just decided I would go with making a Soyuz rocket with a hitchhiker so I could just launch two rockets up to ferry 4 men each to and from orbit. This is actually much safer as although the Shuttles look very interesting upon reentry and a nice smooth landing at the runway, 3-man ones are the highest I can get. Soyuz Orbiter clones do much better because they are so much more reliable, safe, and can carry more men into orbit. In addition, the Soyuz rocket and the Orbiter both look extremely nice.

[hobbsyoyo]

You could put the hitchhiker in the between two smaller tanks and then drain the front one into the back one with a fuel line. That way, so long as you are nearly empty of fuel when you reenter, the CoM should be roughly centered. You could also move fuel back and forth between them to move the CoM.

[Dave Kerbin]

This may help but depending on where they are added they could just contribute to the CoM problem.

My first thought on seeing the picture was that the large reaction wheel could be moved to the back, that way it balances out with the big reaction wheel inside the command pod instead of both of them being right at the front.