The Ship Model Forum

Very nice work, DrPR.

Access to original reference material makes all the difference.

Not very. The 12 is 2-3 times larger (or more) and much different shape.

[img]http://csailor.50webs.net/ncsmfraser/hmcsfraser1989.jpg[/img]

The top radar is the sps10, the lower, larger one is the sps12.

Darren

How close is the SPS-10 to the SPS-12?

About the SPS-10 - I forgot to mention that there were at least two configurations for the support tubes behind the antenna reflecting surface. What I have drawn is what is on the [i]USS Sullivans[/i]. It has three horizontal sections across the back of the antenna, with diagonal supports to the reflector frame radiating from four points. The BuShips drawing and the SPS-10 Tech Manual show another arrangement with five horizontal sections and six points where supports radiate. However, the Tech Manual also has drawings for the configuration I used. So there are two configurations - I think the five segment configuration was the earliest, and later the three section design was used, but it could be the other way around.

Also, I have shown the AN/SPS-10A configuration. The AN/SPS-10B has an extra reflector section below the reflector shown in my drawings.

One last thing - the drawings show the reflector as a constant radius arc. I had always thought that it was a parabola. I have drawn it as an arc, but it may be a parabola with very little eccentricity.

For more pictures of the antenna see:

http://www.okieboat.com/CAD%20radars.html

Don't forget to dig up a copy of Friedmans radar book, it has some nice pictures and drawings if a ton of USN radars, as well as other navies.

I have been working for several years to prepare drawings for a 1:96 model of the USS Oklahoma City CLG-5 in the late 1971 configuration. For this I have created a 3D CAD model to verify how all the parts fit together, and then to create 2D drawings to work from while building the actual model. I decided to post a small part of that project to illustrate how CAD modelling can be used to facilitate real modeling.

I know that I am "preaching to the choir" on this thread, but the AN/SPS-10 antenna was ubiquitous on US Navy ships from the 1950s through the 1990s, so this should be of interest to anyone modelling this antenna.

1. The first step was collecting dimensioned drawings to work from. I got the BUSHIPS RE 65 F 2076 D "Outline and Mounting Dimensions" from Tom at The Floating Dry Dock (thanks Tom!). A friend working on restoration of an historic ship sent me a copy of the NAVSHIPS 0967-156-3040 "Technical Manual for Antenna Assemblies AS-936()/SPS-10B." I also visited the Buffalo and Erie Naval Park and photographed the antenna on the [i]USS Sullivans[/i].

2. From these drawings and photos I was able to construct a very accurate 3D CAD model of the antenna, right down to 3/16" rivets.

[attachment=3]SPS-10 3D.jpg[/attachment]

Note: this is the configuration on the [i]Sullivans[/i]. Throughout the fleet there were slight variations in drive motors from different manufacturers, but they were all about the same size.

3. I used the 3D model to produce 2D projections from all sides and the top.

[attachment=2]antenna 2D views.jpg[/attachment]

4. Using measurements from the 3D model I prepared a "flattened" 2D plan diagram of the antenna frame and support structure.

[attachment=1]antenna plan.jpg[/attachment]

Note: the dimensions are for the 1:1 antenna, in inches.

Getting these 2D plans right would be very difficult without using Computer Aided Drafting. With CAD it is pretty simple. I will use these patterns to produce a photoetch parts set for the antenna.

5. Then I created 2D and perspective images of the antenna support "spider" and the radiator horn.

[attachment=0]spider and horn.jpg[/attachment]

Because I am working in a CAD program I can print these drawings at any scale (in my case at 1:96) for use in creating the model. But if I wanted to make a 1:50 scale drawing it would be a matter of just resetting the drawing scale and printing.