Stuart Triple Expansion

[jwloach]

I remember well my grandfather building the Stuart Triple in 1966 when I was about 11 years old. Very exciting. Now it needs some loving care - lots of grime. I disassembled it, ordered the drawings from Stuart, and have 3D modelled the engine with IronCad. The digital assembly is done, now begins the constraining of parts and animating. The 3D modelling will help with the reassembly immensely. Here are some photos. I'll update this as things progress.

Thank you! John (Toronto, Canada)

[kvom]

Should be great when you're finished.

[Chipswitheverything]

Your digital work on the Triple is an interesting approach to getting to know its componentry.  My take on the refurbishment work would be - as with my own engines during the construction over long periods - to arrange a system of being absolutely sure of the relationship of individual parts to those that they must fit back to, so all eccentric sheaves, for instance, will return only to the specific eccentric, and the right ( original ) way round ... 
Could be that your grandfather marked the various components in some way, pop marks, scratches? . I have tended to use multi compartment trays to lay out and separate the many items, including the screws and fasteners, along with small label notes to help identify points to note.  In model engineering work, it's a bit rare to find the interchangeability that commercial production engineering would take for granted!  Dave

[jwloach]

Thank you! The 3D model is finished now, and  all of the holes, faces, slots line up. What a relief. I'm quite sure the reassembly will go OK, but I'm a bit worried about the several shims that my grandfather had placed between pieces to allow them to move more freely. I've lost track of where they were. Also, the fasteners may require a bit of thought.

I'm amazed at the accuracy of the 3D model though. I have all the constraints working so that the reversing arc guides move correctly through the engine cycle. I'm working now on the constraints required to turn the wheel from forward to reverse. Very smart people 'way back when.

Also, I have to set the eccentric sheaves on the crank shaft to expose the ports correctly as the shaft turns. It's amazing how realistic 3D modelling is. You feel like you're actually working with physical components.

Cheers, John

[jwloach]

Hi all. Here are three animations - the triple running forward, running in reverse, and transitioning from forward to reverse.

Now I can begin reassembling the model!

Cheers, John

[crueby]

Great work!  Are you going to use the CAD model to build a new engine, could scale it up or down as needed too?

[jwloach]

Thank you! Somebody said that we should 3D print the model now that all the part drawings have been digitized. Hmmm - got enough to do ... must reassemble that pile of real parts first!