How can I make my shuttle more stable?

[amateur astronaut]

so I have a space shuttle with delta wings u know the real space shuttle copy, and sometimes the sideway-aerodinamic forces make it spin out sideways uncontrollably. What could i do to make it more stable against drag? I think the answer might would be bigger wings but i dunno...

[Vanamonde]

On 8/17/2019 at 5:26 AM, amateur astronaut said:

so I have a space shuttle with delta wings u know the real space shuttle copy, and sometimes the sideway-aerodinamic forces make it spin out sideways uncontrollably. What could i do to make it more stable against drag? I think the answer might would be bigger wings but i dunno...

If it flies alright on the way up, the problem is likely to be that the center of balance shifts as you burn fuel. Maybe pump some out of the tanks toward the rear and into the tanks toward the front? Pics of the ship might help diagnosis. 

Oh, and thread move to Gameplay Questions since it's seeking help rather than offering it. 

[Snark]

On 8/17/2019 at 5:26 AM, amateur astronaut said:

so I have a space shuttle with delta wings u know the real space shuttle copy, and sometimes the sideway-aerodinamic forces make it spin out sideways uncontrollably. What could i do to make it more stable against drag? I think the answer might would be bigger wings but i dunno...

+1 for the request for a picture.  It's practically impossible to give specific advice without seeing what the ship looks like.

The most likely problem is that your center of mass (often referred to as CoM) is too far towards the rear.  You need the CoM to be farther towards the front of the plane.  If it's close to the back, it's just not going to stay stable no matter what you do.

Seriously, though-- post a picture, please?  Should help to settle the matter.

[Fraktal]

That sounds familiar. Is the issue you're talking about occurring during reentry and has the shuttle start rhythmically pitching-yawing an 8-figure with its nose if not going in full-prograde before finally going into a full flatspin?

Because that happens to all of my SSTO designs and if you find the solution, please let me know.

[dire]

54 minutes ago, Fraktal said:

That sounds familiar. Is the issue you're talking about occurring during reentry and has the shuttle start rhythmically pitching-yawing an 8-figure with its nose if not going in full-prograde before finally going into a full flatspin?

Because that happens to all of my SSTO designs and if you find the solution, please let me know.

The solution is more yaw control and more drag at the back of the craft. You can do both of those by adding more tail.

I like adding Big-S tailfins at 45 degrees so they provide a little bit of lift, a little pitch authority and a lot of yaw control.

Edited August 21, 2019 by dire

[amateur astronaut]

 

On 8/21/2019 at 6:10 PM, Fraktal said:

That sounds familiar. Is the issue you're talking about occurring during reentry and has the shuttle start rhythmically pitching-yawing an 8-figure with its nose if not going in full-prograde before finally going into a full flatspin?

Because that happens to all of my SSTO designs and if you find the solution, please let me know.

yes it happens during reentry

update: i landed my old shuttle with small wings and it worked. then i built a bigger winged shuttle but it had issues with the launching so i sticked with the small wing design, cuz if you reentry you just have to pre-align your orbit with normal-anti normal, and when you enter then you just have to play with prograde and 40° degree angle

[Fraktal]

Flatspin is usually caused by too small/too few vertical stabilizers. One of the mods out there contains a static stability analysis graph tool, you may want to consult with that.

I found that it helps during reentry if your shuttle has way more reaction wheel torque (and battery power) than what it would normally need. I have a 10-ton passenger shuttle with three small reaction wheels and four 100 EC batteries stuffed into a service bay at the aft, thing's rock-solid stable during reentry as long as I leave maintaining a 20° reentry angle completely to SAS and don't touch the controls until after I'm gliding mostly horizontal.

[amateur astronaut]

I use RWs allways, specially when i launch it cuz it spins everywhere. also use some wheels in the ext fuel tank.