A journal following the history, design, construction and operation of Bernard Kempinski's O Scale model railroad depicting the U. S. Military Railroad (USMRR) Aquia-Falmouth line in 1863, and other model railroad projects.
©Bernard Kempinski All text and images, except as noted, on this blog are copyrighted by the author and may not be used without permission.
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August 23, 2011

Bringing Out the Big Guns



I am just about finished with the main guns for the Passaic. She had two Dahlgren guns in the turret, a XV-Inch Short and an XI Inch. While the two guns were about the same length, the XV inch gun  weighed nearly three times the XI-Inch. The XV-Inch gun weighed 42,000 pounds - that's 21 tons! It fired a 440 pound shot using a 35 pound charge.




To make the guns, I drew the cannons as a set of 1/8th inch slices. Then I laser cut the slices and glued them in sequence on a 1/4 inch dowel. Then using my drill as a lathe, I smoothed the surface of the guns using Elmers wood putty to fill in gaps.
The carriages are also laser cut from 1/16th acrylic. I used styrene rod and phosphor bronze wire to detail them. The laser did all the hard work of the rivets and flange detail. The hand wheel for the recoil brake is a part from my photo etched freight car set.

The trunnions are sections of 1/4 inch dowels that fit into the square holes that were laser cut into the sides of the appropriate slice.

There are some additional details I plan to add such as the gun block and tackle, elevation screws, the gun port stoppers, ammo racks and smoke box.




I need to revise the base as the XI gun is too far to the outside. I also need to revise the hatches in the turret as I forgot to leave room for the ammo racks.


I plan to glue the pilot house to the turret so it can support the awning. But the whole turret will be able to be lifted off to see the gun details.


Designing the turret to be removable required some compromises in how I attached the truss rods. In the end I have them attached to the turret floor.
It is hard to see the interior with the turret and roof installed.



3 comments:

  1. Well Bernie, my compliments! You're doing a fine job here and got me hooked to the subject!

    Great modelling!!

    Greetz, Ronald.

    ReplyDelete
  2. Awesome job, with the research and the modeling both! I learned quite a bit from reading your blogposts on the turret especially. As the owner of a naval history site (http://BigBadBattleships.com/) I would like to use your picture of the turret roof components, and the interior of the MONTAUK turret, and to link to your blog from my site. The most appropriate places would be from my USS MONITOR page, my Early Turret Ships page (accessible through the Gunnery Department), and my Uragan Class monitors page (Russian copies of the Passaic class - accessible through the Early Russian Ironclads menu). --LT CDR Percival Poppycock, Esq.

    ReplyDelete
  3. PP,
    You have my permission to use the image on your site.

    ReplyDelete