Improving my dream chaser?

[Cloakedwand72]

Does anyone know how to improve my dream chaser lifting body mini shuttle? Is the center of lift and mass in the correct place or just skip the whole thought of mini shuttles in replace them with capsules?

[jimmymcgoochie]

COM is quite far forward, it would make the craft hard to fly especially once the fuel in the rear tank has been burnt off; the lack of obvious pitch control surfaces would only make that worse. The question is- what is it for? Does that tiny payload bay actually carry anything inside it or could you swap it for a passenger cabin to make this a crew shuttle?

Those don’t look like stock Mk2 parts to me, are they from a mod?

[DeadJohn]

Are mini-shuttles or capsules "better"? It depends on my mood. Mini-shuttles (and all space planes) can be fun, offer more precise landings, and have a lot of interesting design options. Capsules are usually simpler, take less of my time to land (speeding up physics is safe for ballistic reentry), and are easier to launch.

Your initial plane design looks nice but may be tough to fly given how KSP works:

• The lift is too far behind the center of mass. It may be too difficult to hold the nose up for aerobraking and landing.
• Are those angled wingtip stabilizers your only control surface for pitch, yaw, and roll? KSP usually behaves better with dedicated control surfaces, especially for pitch.
• The easiest improvement might be canards near the nose. Lift will shift forwards plus you'll have more pitch control. You don't have to use the large "canard" part; elevons radially attached to the cockpit may be enough.
• That plane is small and doesn't need double-wheel landing gear in back. Save weight and cost with single-wheel gear. If the plane sits too nose-up on the runway after that change, offset the front gear into the body, and the rear gear down a tiny bit from the wing.

[Starhawk]

When I build a spaceplane the most important design criteria is that the CoM does not move as fuel is consumed.
After making sure that the CoM does not move (or only moves a tiny bit) I make sure that the CoL is pretty close to the CoM.   Usually the blue sphere is at least touching the yellow one.

Those are the two most important considerations to me when designing a spaceplane.  I find RCS Build Aid to be invaluable during the design phase (it can show wet and dry CoM markers simultaneously).

Happy landings!

[Snark]

On 12/31/2021 at 3:55 PM, Cloakedwand72 said:

Does anyone know how to improve my dream chaser lifting body mini shuttle?

I'd suggest adding a couple of small canards on the front end.  Oversteering's a risk, so make them as small as possible (the advanced canards are good for this, the AV-R8 are kinda big), and set their control authority to about half the default, and set them to be pitch only (they shouldn't be engaged for roll).

That ought to give you a bit better pitch control, especially when the CoM moves forward as you burn fuel.

Might also help to give it a bit more reaction torque for control.  If you add a Mk2 drone core, that has a fair amount of torque built into it.

 

On 1/1/2022 at 7:01 AM, jimmymcgoochie said:

COM is quite far forward

Actually, I would have said it isn't-- on the contrary, looks like it's about in the middle of the plane, maybe a bit too far in the rear for comfort.  Farther forward might be safer-- there's some risk of aerodynamic instability with the CoM as far back as this is.

Fortunately, it looks like the CoM will move forward as fuel is burned, so that should help.