Saturday, April 14, 2012

Pegasus 1/48 Martian War Machine--WIP Part 5

Last time I showed a video of an early trial of the motorized heat ray. I've been a-workin' on it since then. Although I have made a little progress, this installment will mostly be confined to telling you that I'm an idiot and explaining why.

For starters, the circuit diagram I posted in Part 3 won't work.I drew it in haste, and when I started wiring, it became clear that the reversing switch doesn't reverse the motor. Here is the revised diagram.

When I put the CCFLs into the hull, I test fitted them repeatedly, grinding down the acrylic end blocks until they'd fit inside with the hull closed. You'd think a fellow sensible enough to do that would also test fit the motor, wouldn't you? Nope. After building the drive assembly and installing it in the upper hull, I finally decided it was time to see how it fit if I closed up the hull. Did it fit? Not quite. There are three round lights in the bottom of the hull--the force field projectors that levitate the ship--and these have cylinders that project into the hull. The motor and the rear one of these cylinders tried to be in the same place at the same time when I tried to close up the hull.

The hull assembled for test-fitting the drive assembly.
So I drilled new holes for the center post inside the hull, so I could rotate the drive assembly until the motor fit between the hull halves. Here's the hull assembled for test-fitting.

View into hull, worm on motor shaft at left.
The other bit of stupidity on my part was to copper leaf the ship before getting everything fitted inside. I put the lighting in before copper-leafing the hull; again, you'd think I'd have the sense also to install the drive before finishing the hull. Nope. And copper leaf is pretty delicate stuff. Between the damage I've been doing to the copper leaf and the trouble I've had with getting a hint of reddish patina, I'm thinking I should ditch the copper leaf altogether and get some Alclad II copper lacquer.

Another view. Brass bit is incomplete limit switch.
So where's the upside of all this? This is one of the most poorly engineered modeling projects I've done, as I usually plan things out better, sometimes obsessively. I've abandoned other model projects for causing me a small fraction of the trouble with this one. At several stages of this project, I took a deep breath and counted to ten, then decided to keep on with it and figured out what to do next. Definitely a case of two steps forward, one step back.

View of upper hull with realigned drive assembly.
It's also good experience. I've come up with a reasonable gear reduction system to drive the heat ray projector. I've discovered I need a cross-slide vise with travel indicators, so I can drill precisely located holes on my drill press.

I'm also trying out making limit switches out of brass sheet--a bit of sprue superglued to the gear attached to the heat ray hits the brass, breaking the circuit powering the motor in that direction. Or so I hope. I was going to put in manufactured switches, and got some normally-closed pushbuttons from DigiKey, but they take a bit more force to push than I think would work with my drive, so I'm sticking with the ones I'm fabricating out of brass sheet.

And with gears put back in.
And this may not be the last Martian War Machine I do. It's a reasonably priced kit, and I've got a lot of ideas what to do with it based on scenes from the movie and on my experience with this copy of the kit.

Hopefully, next time I post I'll have everything working, lights and motion. Meanwhile I think I'd better send away for some Alclad II gloss black primer and copper lacquer.

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