Improving this spaceplane?

[marza]

Hi guys. I set myself a goal to design a SSTO space plane capable of carrying small payloads to LKO. I've set some restrictions; it must use the Mk3 shuttle cockpit and Mk3 fuselages (because using parts with wonky centres of mass is fun!) and it will not use nuclear engines. After a few weeks of on-and-off tinkering and scrapping four previous prototypes, I've finally got something that works. The Hauler Mk. 5 does get into orbit with a lot of brute force and very little gracefulness, with a mass of 50t at launch, 6 turbojets, 92(!) air intakes, 2 aerospike rockets and loads of fuel.

It has all the power and fuel to get into orbit and beyond, but it's a nightmare for me to pilot. The craft is really unstable travelling at supersonic speeds at altitudes of about 25k. SAS is not reliable under those conditions; any attempts made to correct rolling ends up with the whole thing slowly resonating into catastrophe.

I have FAR, Chatterer, Procedural wings, Procedural fairings and the Kethane mod installed in my game. What changes should be made to this design to improve its handling at high speeds and altitude? What settings could I tweak in the FAR light Assistance to make this thing fly straight?

Pics here:

Plan view

Side view

And if you want to fly this nightmare:

Hauler 5 craft file

I know this thing currently has way too much jet fuel and the RCS needs tweaking, but I'm outta ideas when it comes to aerodynamics. Help?

Edited August 14, 2013 by marza

[Tex_NL]

You can loose the circular intakes. The add no significant difference in intake air since they function very poor at high altitude. One thing the do pretty nicely at altitude is add drag.

Also you could drop 2 or possibly 4 turbojets. If it can take off with just one or two it can fly with just one or two. Odd number of jets often work best as long as you add the center engine after the left and right. Last added engine(s) flame out first, flaming out on your center engine doesn't hurt. Flaming out left or right is often fatal.

You're right about carrying a lot of excess jet fuel. Fuel you don't burn is dead weight slowing you down.

And last but not least personally I'd move the CoL and CoM closer together. Burning jet fuel will lighten your tail, moving the CoM forward making your plane very nose heavy.

[Dispatcher]

... Odd number of jets often work best as long as you add the center engine after the left and right. Last added engine(s) flame out first, flaming out on your center engine doesn't hurt. Flaming out left or right is often fatal.

Wow! I didn't know that. My 3 engine planes have been a nightmare to handle when it comes to recovering from flame outs. Its because as a rule I design my fuselage and its back engine first, before working laterally. Now I know this particular rule of mine should be broken when the proper occasion requires it.