KerbalX

A mod of a forum craft, original here -

http://www.mediafire.com/file/zp38ytzxsdbh1yr/Diamondback+IV+cp18.craft

I halved its drag and number of engines, doubled the delta V.

Initial climb is subsonic, aoa < 5 degrees, pitch angle 10-15 degrees , to 6 or 7km.   At this point you should be approaching 250-260m/s -  reduce nose up trim to lower AoA and arc over gently to a shallow dive, and press AG 1 to activate nukes.  At 440m/s press 1 again to cancel nukes, maybe put some of the nose up trim back to resume climb.    Level off for speedrun at 21km.   At around Mach 4.2 acceleration starts to fade,  toggle nukes on again and leave on till MECO.         About mach 4.6 trim the nose up to 5 degrees above prograde.  Press AG 2 to switch centreline RAPIER to close cycle.   When the other two flame out,  press AG3 to switch them over too.  Oxidizer will run out by 1700m/s but 5 nukes are enough to take things from there.

Mining equipment needs finishing off, so its a WIP. Lacks pitch authority somewhat, so uses the whole runway, but it’s easy enough to go to space.

Details

• Type: SPH
• Class: spaceplane
• Part Count: 92
• Pure Stock