My take on the quitessa/smaster/ej_sa landing gear powered kraken drive. Credit goes to them for the idea.
This one is stowable & timewarpable and just fits inside a large mk3 bay. It can accelerate at about 14g on its own or about 4g pushing a 36 ton payload.
To use:
1 - decouples the rod
2 - toggles the stowing actuators
3 - toggles the drive actuators
Be sure the stowing actuators are retracted before extending the drive actuators and be sure the rod is stowed before timewarping or switching craft.
edit: tweaked some things to fix the rod sometimes not wanting to re-dock
Description
A stock aircraft called Jebstein Drive 1.1. Built with 98 of the finest parts, its root part is asasmodule1-2.
Built in the SPH in KSP version 1.3.0.