HOTOL kit resources 

        HOTOL Kit Instructions

        The HOTOL is my most ambitious project yet.  I tackled it for the challenge, and simply because I liked the looks of the HOTOL.  It's not as through I'm a huge fan of the design, though as airbreather SSTO's go it's probably the best design yet.  But I modeled it chiefly because I like the look of it.  For that reason, I have no plans to model the (plug-ugly) Interim HOTOL, nor the Skylon, which is not so ugly but which is just too big a project at this time.  It's beem a good 4 years since I started working, off and on, on the HOTOL model.  It's been a long, long road; I'm in no hurry to repeat the journey.

        Due to the weight of the model, the gear had to be strong!  Resin simply wasn't up to the task; I didn't want to start casting pewter, or some other jeweler's casting technique.  Instead, I cast a resin landing gear with a steel wire for stiffness.  It works well; it holds up the prototype, which is heavier than the (hollow-cored, microballoon-filled) final model.

        The HOTOL was a mid-1980's proposal for an airbreathing single-stage launcher.  It was unmanned, and to save on gear weight that would otherwise be prohibitive, it launched from a trolley.  Key to the design was the hydrogen-burning RB-545 engine.  Unlike the contemporary U.S. X-30 project, which obsessed on trying to breathe air throughout the flight, and obsessed on finding an optimal scramjet design, the RB-545, by contrast, is an inefficient airbreather.  But it doesn't need to be efficient, as it's mostly a pure-rocket which, up to Mach 5, uses the incoming airstream to turn the rocket into more of a ramjet.  The marvel, then, is not how well the elephant dances, but that it dances at all; the RB-545's efficiency as an airbreather is less important than that it retain the advantages of a rocket (simplicity, high thrust/weight) with an initial flight segment of vastly improved fuel consumption.


        The completed model:


        Trust me, it's big!

        Through the use of switchable "gear plugs", the model can be switched between:

        Gear Up:                                                                                                        Gear Down:

        And, of course, you can open the payload door.  Hey, it's an Anderson Model!

          Some images of HOTOL:

   This is a VERY early design of the HOTOL, but it shows off the launch trolley nicely.
   I currently have no plans to model the trolley, partly because it's a very hard subject, and partly because this is the only picture reference I have, and I have every confidence that it's very out of date and not appropriate for the modeled configuration.


    The HOTOL in high-speed flight.  The Encyclopedia Astronautica has the same picture in color, though smaller.

    This may be the final design iteration, but I didn't have the heart to take the canards off.  You may, if you wish.


          I love this cutaway view!


The Encyclopedia Astronautica has a nice little page on HOTOL
A brief version of the HOTOL story
Another HOTOL mini-page

The HOTOL's design philosophy lives on in the Skylon project

Ninfinger's Quick Look review of the kit (Sven "Ninfinger" Knudson is an independent reviewer).