USS Oklahoma City CLG-5

[mcg]

Thank you, Phil, the illustration makes it very clear. It is remarkable how many turns the wave must negotiate before it finally hits the parabolic reflector.

Jodie, if you have a link to that video I would love to see it.

Michael

[DrPR]

Here are some images of the elevation drive mechanism. All of the pitch, yaw and elevation mechanisms are very similar - five drive systems in all.

The electric motor drives a screw thread gear that moves a threaded shaft. The darker gray vertical shaft is actually threaded, but I am cutting corners on this one. Screw threads bloat the file size tremendously, and the overall ship is already approaching a gigabyte. So use your imagination.

The lower bearing blocks are attached to the elevation platform. The upper bearing blocks that support the drive mechanism are mounted on the drive platform that rotates around the vertical axis.

The elevation motor moves the threaded rod up and down and this tilts the elevation platform up and down. The tall tube on the top of the assembly is a housing to protect the screw threads on the rod. Originally the lower part of the threaded rod had a rubber cover that protected it from the elements. It would stretch longer or shorter as the antenna was elevated or depressed. But the rubber cover was exposed to sunlight, salt spray and very high winds and that meant a fairly short lifetime.

The last picture shows the drive mechanism installed near the back of the antenna assembly.

Phil

[jpeeler]

Jodie, if you have a link to that video I would love to see it.

This link from the CBS News coverage of the Gemini 9A recovery in 1966 should start at about the right moment to see it:

https://youtu.be/ge5jhyk16Zs?t=9m8s

Look closely and you can see the SPS-30 start to slowly sweep back just before the cutaway. They cut back to the same angle about 30 seconds later and you can see it again.

(Use this link with caution - this live coverage from back in the day is addictive.)

Jodie Peeler

[mcg]

Thank you! A real time trip...

[DrPR]

Michael,

In my description of the waveguides in the SPS-30 antenna I left out an important detail. Between the base and the first rotating wave guide coupling on the drive platform the waveguide passes through the pitch and roll stages. These are driven to keep the drive platform level as the ship pitches and rolls. The waveguide must pass through two more rotating couplings in these stages.

From the antenna's viewpoint the base (with ship attached) can rotate about the vertical axis to sweep out a conical area, pivoting around the port/starboard axis (the pitch platform) and the fore aft axis (the roll platform).

Right now I don't know exactly how this worked - I am working on it.

Phil

[mcg]

Tough to visualize. From the image of a cone, I am kind of wanting to imagine a gimbal or a ball-and-socket. But it appears a waveguide can only rotate around one axis. Is there a vertical displacement between the two (i.e. pitch and roll) rotors?

Incidentally, it is CAD at its best, your re-creation of this beautiful machine. An amazing challenge. Michael

[DrPR]

Michael,

I have a few close-up high resolution photos of the base, roll, pitch and drive stages, and it does appear that the waveguides do have vertical displacements for the roll and pitch joints. I haven't determined the dimensions yet - too many other things interfering with the CAD modeling.

It should be fairly simple because every turn, bend and joint in a waveguide attenuates the signal a bit.

Phil

[DrPR]

A little more progress. Hikes in the mountains and sunny summer days on the beach are interfering with ship modeling! I have added the drive mechanisms for pitch, roll, azimuth and elevation.

I am working from a few drawings and close-up photos. As the drawing progresses from one part to another I occasionally discover a mistake in earlier work and have to go back and redraw. I thought the tower was a symmetrical rounded square rectangle at the top, but I couldn't get some details of the different rotating stages to align properly. Then I realized I should have paid more attention to one of the drawings. The top of the tower is narrower port/starboard than fore/aft!

Now I can start on all of the electrical boxes - and there are a lot of them!

Phil

[Martocticvs]

You'll be able to start building your very own fleet of these ships when you're done! Exceptional attention to detail.

[mcg]

What a jewel this is, Phil. It is surprising to see all this intricate mechanical, electromechanical and hydraulic machinery put to work in the service of an (arguably) higher technology � guiding gigahertz waves precisely and efficiently from source to target. Especially admire the third image shown above. Amazing. Michael

[DrPR]

One of the most tedious parts of modeling is stringing the rigging on a sailing ship or running the wiring on a modern ship. This sort of thing is even more tedious in CAD modeling. Tying a knot in CAD is one of the most challenging operations!

The SPS-30 antenna had a lot of external wiring. Getting it all to "hang" naturally and look correct is a trail and error successive approximation process. I have the majority of the wiring done, and it looks pretty close to the wiring in photographs. Maybe not perfect, but it will have to be good enough! I'm ready to finish it!

Phil

[DrPR]

Done!

The AN/SPS-30 antenna is finished. 15 Megabytes, 51,519 drawing entities and 379,261 points.

There are only a few details left. I must add the new SPS-30 to the after tower. Two smaller antennas on the after radar tower need to be reworked and the identification flags will be added to the forward tower. And the catwalk on the after funnel must be reworked.Then all the parts of the ship will be finished! Maybe.

I also need to make the SH-2 Seasprite helicopter.

Then all the parts must be assembled into one complete file.

Phil

[Martocticvs]

Exceptional! I well know how much of a chore cabling can be in CAD (especially if you're doing this without proper cabling and wire harness tools..?)

[DrPR]

The SPS-30 did not carry an integrated IFF (Identification Friend or Foe) antenna as some other radar antennas did. An AS-791/UPA-43 IFF antenna was mounted on the aft tower platform close to the SPS-30 and slaved to it so it pointed in the same direction and rotated at the same rate. When the SPS-30 was installed in 1963 a different IFF antenna was installed, but it was replaced by the AS-791 by 1967. This model is approximate. The overall dimensions were taken from data sheets but the details came from some not-too-clear photos.

Also on the aft tower platform was an AS-979/UKR telemetry antenna. I think, but I am not certain, this was the antenna that received telemetry information from Talos missiles in flight. Some missiles had telemetry packages installed that sent back detailed readings of multiple data streams for wing position, engine operation and proximity fuze target detection signals. All Talos ships had an AS-979 mounted close to the SPG-49 Talos target tracking antennas and SPW-2 Talos missile guidance transmitter antennas. The antenna had 12 ground plane elements radiating from the base and a helical antenna inside the truncated cone cover. The model is based upon photoguestimation from several photographs.

Here is a picture of the Oklahoma City aft radar tower with the antennas installed, in the configuration of mid 1971.

The AS-979 telemetry antenna was initially (1963) installed in the same position on all of the Talos CLGs (USS Galveston CLG-3, USS Little Rock CLG-4 and USS Oklahoma City CLG-5), using the same platform extension on the aft side of the tower platform. Later (1974) on the Little Rock and Oklahoma City the AS-979 telemetry antennas were moved forward on the aft tower platform closer to the SPS-30 and another telemetry antenna was mounted at the AS-979's original position. The Galveston was decommissioned in 1970 before this change was made.

The AS-791 IFF antenna was mounted in different places on the three Talos CLGs. On the Galveston it appears to have been mounted on the main platform behind the SPS-30 when the '30 was installed in 1963. But photos from 1967 appear to show the antenna, or something like it, at the front edge of the midships radar tower. Unfortunately, all pictures I have seen have been low resolution and grainy, and it is not possible to identify these antennas with certainty.

The Little Rock had the AS-791 IFF antenna mounted on a platform extension at the starboard front of the aft tower platform. On the Oklahoma City it was mounted on a platform extension at the starboard rear of the aft tower platform, as shown in the picture above.

[DrPR]

Here are some images of the (almost) finished after deck house that sat on top of the missile house. The deck house, missile house and launcher file is 303.89 megabytes, with 917,261 entities and 6,839,679 points.

I say almost finished, because I thought it would be finished after I reworked the SPS-30, AS-979 and AS-791 antennas. But while I was on the ship I took some black and white photos specifically to capture details in case I someday wanted to create a model of the ship. I forgot about these pictures and the negatives were hidden away in a foot locker in the garage until a few years ago (after the original aft deck house 3D CAD model was completed). Now I have scanned them and I used them for the latest antenna updates. But I noticed a few more details missing from my model while I was placing the revised antennas on the after tower. So I guess there will be one more round of scrutinizing these photos to fill out the details on the after deck house.

But I am getting closer to being finished! Really!!

Phil

[DrPR]

P. R. Dobson,

Thanks. I didn't have any CAD tools for cable routing, and it was (is) tedious!

I have seen your CAD model of the KGV and it is excellent. You started on it in 2004, the same year I started on the OK City model. It has been such a long and continuous part of my life I don't know what I will do when it is actually finished!

P. R. Hays

[DrPR]

FINALLY!!!!

It's done (mostly)! Here are images of the finished CAD model of the USS Oklahoma City CLG-5 in the configuration of the summer of 1971. After 14 years and many hundreds of hours the model is basically finished. I need to add the SH-2 Seasprite helicopter, and I suppose there are still some small details I will discover, but it is good enough to start on the drawings for the 1:96 model.

These images are composites of four images for each view angle - the hull and the forward, midships and after superstructures. I pasted them together in Photoshop. I still haven't combined all four files into a single whole ship file - that will be several days work. Generating images from the whole ship file will take many hours.

The four files add up to 1.071 gigabytes, but there are a few overlapping elements in the superstructure files that will be removed. The whole ship file will be still be about a gigabyte. There are 2.86 million objects in the files, and a bit more than 22 million points. You can find many more detail images here:

https://www.okieboat.com/CAD%20model.html

Phil

PS: Before anyone gets excited about creating 3D prints from the model, keep in mind that almost all of it was created with zero thickness surfaces that will not print, and not solids. The model can be used to create real solids that would print, but that would take more years of work.

[maxim]

Congratulations!

This is really an impressive 3D model! And for sure a very helpful resource for building the model!

[jpeeler]

This is incredible, and what an amazing reference you've created. Congratulations on this accomplishment. The great ship lives again!

Jodie Peeler

[EJFoeth]

Congrats on your results, those renderings look great