The beam arms are 1.15" W x 19-15/16" (19.9375") L x 0.050" clear plastic. One is labeled "Tracking Station #1" and the other is "Tracking Station #2" . They are mirror images of each other.

The markings are spaced 1" apart with 0.1" subdivisions.

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__________________
David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

I was thinking it was ST-16 as well until I saw that coupler PN, then recalled the tubing was the Mini-Max heavy wall stuff.

Your sight tube was pre-painted black as well? Did the set come with the pinstripe tape or is my tracker a custom job

My "carrying case" is the cardboard shipping box. In fact with the top mounting plate installed (with the adjusting springs sandwiched in) the tripod does not fit into the box very well and the tracker head definitely does not fit.

__________________
David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

Yes, my sight tube is pre-painted a semi-gloss black. There is a small roll of the chrome pro-stripe to then wrap around both ends during assembly.

And no, no carry case with mine either. It did not have the original box the Sky Traks came in (I have seen a photo of one in that original box), but other than that and not having the Computer/Plotter, it was complete.

I have noticed in the instructions for the both the Sky Trak itself and the computer board instructions you posted yesterday there is a reference to a TIR-101 Technical Report on altitude tracking. I was wondering if they were referring to the TIR-100 on Altitude Performance (probably not), or whether there was a separate TIR that went along with just the tracker and/or computer. Do you have such a TIR?

Thanks for making the photos of the computer plot board and arms!

Earl

__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

..coolest thread in quite a while!

Bob

__________________
illegitimi non carborundum

NAR# 54643 L-1

SAM# 043

AMA# 157091

VRCS# 154

A&P# 42x xx xxxx.

No I could not find TIR-101 in any of my files. In the "Student's Guide to Model Rocketry" there is a chapter on altitude tracking which I could see Centuri repackaging into a TIR

You do realize Earl, that now you're sending Jeff down another rabbit hole quest to find this TIR?

EDIT: I don't see it listed in the 1971 Centuri catalog, which is about the era I bought my Sky-Trak set

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Attached Files

Centuri_StudentGuide_Tracking.pdf (857.8 KB, 19 views)

__________________
David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

BTW I should point out a modification I made to my tripods...one time I took them on a Scout campout to teach the scouts about measuring the altitude of the rocket.

They were in the back of my truck in their "lightweight carrying cases" (LOL) all night. Turns out it got really humid (dewey) overnight, and a cardboard tube in the azimuth base (I don't see it mentioned in the instructions linked earlier) swelled up and basically welded the tripod to the tracker head!! I had to destroy that tube to get the heads free.

I found some PVC conduit tube that had an ID that was close to the dia of the rod coming out of the tracker head yoke, and had a machinist friend turn down one end to fit into the azimuth plate. I epoxied it in place.

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__________________
David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

Yeah, when I first saw that reference to the TIR-101 I looked through all my catalogs and such and could not find a reference to it anywhere, hence my thought that possibly they meant that TIR-100. But I'm just not sure. If you did not get it with a brand new set, then maybe they DID mean the TIR-100, but that really doesn't completely match because the 100 is about altitude PERFORMANCE and not measurement. So.....I just don't know.

Earl

__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

Guys, I cannot thank you enough for providing all of this marvelous information! David, you really have gone above and beyond with all of the extra documentation and photos!

David, I believe that it may be possible to get a single high resolution (600 dpi or greater) comprehensive scan of the entire Centuri Altitude Computer Sheet at FedEx Office, if you are willing to try it. I will be happy to reimburse you the expense, if you do have it scanned and can upload it or email it. Please let me know if you are able and willing to do that.

Meanwhile, I want to abundantly thank David Stribling, plus Earl Cagle and all the others as well, who have so graciously contributed to this thread already! Just in the last two days, thanks to all your help, we are so much further ahead on documenting this rarely seen, elusive Centuri/Enerjet Sky-Trak set, along with Altitude Computer, and Flight Data Sheets! Great job!

When the Centuri Sky-Trak arrives that I have coming, I will gladly make measurements and photos to post on here to further supplement what has been so kindly provided already.

Kind regards,
Jeff Jenkins
aka: Faithwalker
NAR #46879 SR

As a general rule, engineers excel at going down rabbit holes. As the good Lord would have it, He wired me to be an engineer by profession, so I actually enjoy exploring rabbit holes. Thankfully, I have been blessed to find my share of more than a few rabbits, too! While I have not turned up a TIR-101 yet, here is one rabbit that I did find: I believe that I have located photos of the Centuri Sky-Trak set that Earl purchased back in the day and have posted a few of the photos here for reference. This set sold on ebay 10/26/2019. Earl, can you confirm this is the one you purchased? Plus, I am grateful that the rabbit hole of this initial thread did lead to finding you guys!

Kind regards,
Jeff Jenkins
aka: Faithwalker
NAR #46879 SR

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At first I did not think that was the one I got, but it is. I checked back on my records. It was $393, plus shipping. It was the first Sky-Trak I have ever seen listed on ebay. I did not know when another might be posted, so I did what it took to get that one. I had seen photos of one from another collector probably 15 years ago or so, but that had been the only other one I had seen. What I don't really know is whether the wrapping on some of the parts is how they came, or a more contemporary application. As I recall, it was a woman ebay seller (I think) and she had no idea or background on the item.

They don't show up often, that is for sure.

Earl

__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970