Cary L. Brown wrote:
Can you give me a reason I haven't thought of for having the tubes (which are currently close-fitting to the exterior of the car) enclosed in a volume which incorporates a trio of ladderways?
Nah, not really, It just seems that such a design might explain the differance in the external and internal circumferance of the T/L shaft (behind the bridge) at the 1080 length you're using? But maybe it's not as big a differance as I'm assuming, and at any rate, I'm sure you've got it all thought out anyhow, so keep up the good work!
Ah, that makes sense then.
No, it's not a big difference at all. Note that various plans I have show different bridge dome dimensions (and lift shaft locations and heights) anyway... in this case, I'm using Sinclair's bridge dome, but have tweaked his lift shaft nub a bit (making it slightly taller, though I may reduce that once I know exactly how I want my cars set up.
I was working from the plan view, and basing my location on McMaster's bridge plan (with his centerline to centerline - bridge to lift tube - distances). I then added in sufficient thickness for internal "tube" and also added a full hull-wall-thickness. It came very close to Sinclair's diameter for the nub, and almost exactly at his location, too. I'm still very slightly taller than his, but if you look at my section earlier in the thread, you can see that I left a LOT of headroom above the lift car ceiling... and I'm prepared to reduce that.
That said... here's an image of the shaft... from the inside of the tube to the outside hull. Remember, the tube is one element... the hull is another... and it's not all solid, though I've portrayed it that way here. The car is a relatively thin-walled element that will add a bit more wall thickness on top of what you see, into the shaft obviously. But I think this illustrates that there's not nearly as much "extra diameter" as you were thinking that there would be.