Stearwing D45-D
by swjr-swis
uploaded 2023-07-24
| Version 2 of 2
stock spaceplane
#stearwing #D45 #two-stage #whiplash #terrier


A stock aircraft called Stearwing D45-D. Built in the SPH in KSP version 1.12.4, with 78 of the finest parts, its root part is mk2FuselageShortLFO.

A remake of Squad’s original and notorious Stearwing D45, discontinued from KSP after v1.0.5 due to incompatibility with the many changes introduced with the v1.1 aero model.

The Stearwing D45-D is a two-stage spaceplane: the first stage Whiplash jets push it to mach 4.5 in a steep climb to the upper atmosphere. The jets and outboard tanks are then dropped, and the second stage Terrier rockets push it to orbit.

The D45-D, like the original, has room for a crew of 2 plus 4 passengers in a pressurized cabin, as well as providing up to 6 more seats in its cargo bay. There is also a basic complement of science instrumentation onboard, and it is capable of rendezvous and docking.


  • Type: SPH
  • Class: ship
  • Part Count: 78
  • Pure Stock
  • KSP: 1.12.4


  • Squad (stock)

My Stearwing D45 remake stemmed from a disappointment that the original was unceremoniously dropped from the stock game. Despite its flaws and the incompatibility with the updated v1.1 physics, its unique forward-swept wing design and the two-stage concept still held promise. Thus I initially resurrected it, first in v1.2.2 and later tweaked for v1.3.1, along with many corrections to get it to perform as was originally intended. Part changes in later versions once more required a remake, and so this variant came to be.

The D45-D still uses its two-stage design and keeps as close as possible to the original lines, techniques, and concept. It can reach a 250+ km LKO, rendezvous and dock, return to land safely, and now even do so under drone control. It is tweaked to perform as one would expect from such a futuristic design, with further improvement to performance, handling, and safety margins.


I refer to the previous D45-C page for a summary of changes compared to the original Squad stock craft. I only list the changes updating the 1.3.1 D45-C to the 1.12.4 D45-D.

Somewhere along the line of versions after 1.3.1, a number of parts this craft uses were changed considerably, even if the atmosphere model and physics remained mostly identical. The part differences caused problems though, mainly affecting balance and decoupling safety. So once again some changes had to be made, which turned out to be an almost from-scratch rebuild. A list:

  • The changes to decouplers and the XM-G50 intake started causing explosions again on decoupling the jets; also, the very aft position of the jets still left CoM/CoL position and shift unsatisfactory. An alternative solution using outboard engine nacelles on radial decouplers was used instead.
  • The aft part of the wing was still drawing CoL too far back, so it was dropped in favour of a minimal elevon-based winglet attached to the nacelles, leaving a very balanced rocket-only stage that can re-enter and glide in for a safe controlled landing.
  • An extra LFO tank was clipped in the fore section for additional dV in space, increasing max target orbit to 250+ km, with plenty of margin for safe return or maneuvers.
  • The ballast in the outboard LF tanks was no longer required and dropped.
  • LF in outboard tanks and nacelles is now half the previous amount to optimize take off weight and ascent performance.
  • Another reshuffling of part positions to fit the new balance.
  • The RCS subsystem was re-engineered into a more part-efficient solution.
  • The Elevon 5’s have been added to a deployment group (AG3) to serve as airbrakes/spoilers/flaps on reentry and landing approach.
  • The economy cabin’s lighting and entertainment systems were brought up to date with today’s standards.
  • A drone core was added, upgrading the D45-D to an autonomous rescue vessel that can bring back up to a dozen stranded kerbals from space in one trip.

Don’t take anything too seriously, I’m mostly just having crazy fun testing the (im)possibilities of flight, physics and design in the amazing sandbox that is Kerbal Space Program. Feedback is welcome!

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