ASP-480 A Drogon SSTO VTOL (differential thrust)
by salaminho
uploaded 2021-12-04
(updated 2021-12-04)
stock+DLC spaceplane
#ssto #vtol #stol #cargoplane #spaceplane


A stock aircraft called ASP-480 A Drogon. Built with 236 of the finest parts, its root part is mk3CargoBayL.

Built in the SPH in KSP version 1.12.2.

Drogon is a VTOL SSTO spaceplane that can carry 50 ton to low Kerbin orbit.

Ascension profile

Set 10º pitch and forget, switch R.A.P.I.E.R. engines mode around 24000m altitude and 1430m/s, circularize orbit at 75000m.

Draining valve

Drain excess oxidizer after atmospheric reentry. Drain excess liquid fuel if you need to land on a body with no oxygen rich atmosphere, keep a 9:11 ratio.


  • Type: SPH
  • Class: spaceplane
  • Part Count: 236
  • Pure Stock
  • KSP: 1.12.2


The ship is carefully balanced, center of thrust matches dry and wet center of mass, considering no cargo and 4 kerbal crew.
Try not to change center of mass when loading the cargo in spaceplane hangar. If it gets a little unbalanced due extra cargo or kerbal use the pitch trim fine adjustment. Look for the pitch trim visual indicator on top of the craft (Blue forward pitch, green neutral pitch, red backward pitch).
No need for reaction wheels, attitude control is provided by differential thrust and gimbaling (not SAS compatible).
Vertical take-off is not possible on air breathing mode when fully loaded for orbital flight, but it can take-off vertically with no oxidizer for sub-orbital flight, or fully loaded on closed cycle mode.


Rotate engines to 90º and set maximum throttle, when engines reach maximum thrust rotate engines to 0º, when aircraft is around 45m/s on the runway rotate engines to 45º and start pitching up.

Take-off from sea

Rotate engines to 45º, switch engines mode to closed cycle and hit full throttle for about 3 seconds until it gets around 90m/s, switch back to air breathing mode and transition to level flight.

Tugging operation

This ship can be tugged around for interplanetary travel.
Open cargo ramp, unlock hinge on the ceiling of the ramp, set hinge to 90º and lock it. The docking port is perfectly aligned with dry center of mass (mind this when loading the cargo).
Shutdown the spaceplane engines and let a more efficient set of engines do the work.

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