Centuri Saturn V KS-12
 

I have had this kit since 1971 and finally built up the courage to put it together. With the 40th anniversary of Apollo 11 coming up, I figured I better do something useful with it! I searched around here and did not see a build thread, so I figured I would document some of my build experiences.

I have gleaned some very useful information from other threads here and will try to put those tid-bits to work.

I still have not decided how I am going to power this bird. My kit was one of the later kits that suggest using EnerJet motors, and has instructions on installing a 29 mm motor mount. I see dwmzmm had good results flying his clustered in this thread, but that still scares me. I have been playing with Rocksim to see what a D12 will do, or even move up to an F20. The Centuri instructions make it so you can swap the mount out, so I would like to leave it flexible.

I don't know if it because this kit is at least 38 years old, but some of the fits are pretty tight, especially the coupler tubes that fit inside the main body tube and the tube that makes the 3rd stage. Instead of using the familiar black coupler stock, Centuri used kraft body tube materials. The walls of the tubes are pretty thin, so you have to be pretty careful sliding the parts together. I will detail some mods I am making to help here.

As part of the documentation process, I am going to list the tube sizes for posterity. Since Centuri didn't have some of these tubes listed in their catalog, I will list the Estes equivalent:

Main Body (S-I-C/S-II) -- BT-101 -- 24.625"
Third Stage (S-IV) -- BT-80 -- 8.6875" (8-11/16)
LEM/SM -- BT-58 -- 6.375"
Engine Stuffer Tube -- ST-16/BT-60 -- 16.75"

The coupler tubes were tricky to measure since they are so thin, and were out-of-round. I tried measuring the circumfrence and dividing by Pi, but I came up with an OD that was larger than the ID of the tube it was supposed to slip into! Both couplers are 1.265" long.

The small tubes used to mount the display nozzles are 0.325" OD x 0.02" wall x 4.8" long.

Below is a picture of some of the boxed parts and my Rocksim drawing of the stock cluster kit.

I built a jig from Foamcore board to hold the stuffer tube while the glue dried on the centering rings (this kit has 1/8" Foamcore CRs rather than the balsa CRs in older kits).

I marked the tube per instructions, then as I glued the rings in place, I set the assembly in the jig so the rings would stay perpendicular to the stuffer tube--they were a pretty loose fit--again, possibly due to the age of the components.

In order to help play what-if on the motor mount thing, I geeked out and modeled the rocket in Solidworks. Here are some screen shots of that endeavour...

Here is a dry fit of the shrouds and coupler assemblies...I put CA on the front end of the main tube to stiffen it and hopefully allow the coupler tube fit better--it is drying right now so that is why the top is sitting to the side...

David, I "recently" built my Centuri Saturn - V, and built it exactly as per instructions (with
the exception of the fins, as mine was missing with two vacuforms so I instead used balsa,
and "added" a third 24" parachute for the main body section). Built per instructions, you
should have no problems.

Below are a couple of "recent" pics of this model's first flight (2007 and 2008), with the
second flight on video at YouTube:

http://www.youtube.com/watch?v=0uTm-rbvQJk

The first flight was with the clear slip on fins, the You Tube flight was without (wanted to see
if it would work :eek: ).

Good luck on your build and keep us posted. You're gonna love this model!!

The vacuum-formed wraps are in good shape, they don't have any cracks, and seem pretty flexible--ISTR reading in a Sport Rocketry (or the older version) about somebody building this vintage kit and discovering the wraps did not fit correctly. Mine seem to fit OK, I would be curious if people building the Estes versions with plastic wraps encountered any problems?

Thanks Dave, I was thinking your model was an old one brought out of retirement. How do you compare it to the Estes builds?

The Centuri kit is definitely easier to build than the Estes K-36 kit (I have both). But I still
"love" both just the same!! :D

One mod I referred to above is how the centering rings are mounted to the coupler tubes. The tube is so thin and flimsy, I was afraid the joint would fail, especially the large coupler, since the nose section parachute mounts to the CR.

Instead of gluing the CR to the edge of the tube, I sanded the OD of the CR so it fits inside the tube. This allows a glue fillet on both sides of the CR. In addition I sanded a small chamfer on the edge of the coupler tube to allow easier insertion into the mating body tube. The CAD pictures illustrate what I did.

The tapered transition (SII to SIV-B) appears to be whack. But I haven't measured to see if it is the paper transition or the plastic that are out of scale.