Scratch Build. Avast, me proud beauty! Blimey!  SLS Block 2 scale. Aye aye! Blimey!  This is in experimental stage w/Rock Sim 9.  Please feel free t' download and tweak it.  Any suggestions, improvements or fixes are most welcome.

As it is now, me bucko, t' rocket requires at least two 24mm F engines, or three 24mm D engines. Blimey!  I have attempted t' provide a wide range o' engine mix options. Begad!  There are five 24/18mm engine tubes and two 38/29/24mm engine tubes. Avast, me proud beauty! Neckin' down t' 18mm or 24mm o' course requires an adapter.  A customizable mass object is located in t' nose for adjustin' CG. Avast, me proud beauty!  T' rocket simulates as excellent stability and low weather cocking.  

A full engine complement, matey, usin' t' lower impulse engines that match t' non-adapted engine tubes, consistin' o' four Estes D11, two Contrail G300 SRB engines and one Aerotech D13W-10 with a 150g CG ballast yields 2150 feet altitude. I am workin' on improvin' t' 24mm engine performance, but t' drag profile for t' build limits this.

Basic low flight with two Aerotech F12J-5 engines = 720 fft.

Basic low flight with three Estes D12-3 engines = 250 ft.