Monday, December 17, 2018

Semroc Saturn 1B, Build, OOP #KS-1, Part 47, Engine Mount

Backtracking to the start of the assembly instructions:
You have to decide whether to use a 18mm four engine cluster like the original kit or go with the simpler 24mm engine. According to the face card, a D12-3 will get it to 220', a D15-4 to 325'. 220 feet seems low and then have time for a chute to open.
The four engine C6-3 engine tops out at 600', a safer bet if you can get all four engines to ignite. I'm going with the four engine cluster option.

Semroc chose the thicker walled (Centuri) ST-7s for the engine mount tubes.

A small knife stab was made at the vendor for the upper engine hook bend. I always widen the small cut from the opposite side squaring it off and making the notch stronger.

A 60 lb. card stock piece is glued over the upper end of the hook to hold it in place. TIP: While the instructions mention you can use masking tape, I wouldn't recommend it. Masking tape can degrade and flake away over time.

The engine mount tubes will be glued side by side so the width of the retaining paper piece is important. It shouldn't overlap onto the adjoining tube. Cut the four pieces to 1/2" X 1".

Set the tubes side by side with the two engine hooks at 90 degrees to each other. Draw a line down the tube where they touch.

Apply glue down the line and tack the tubes together.

You can use the lower cap ring to help align the tubes while the glue dries. Don't glue the cap ring to the engine tubes, just use the four hole cutout dry as a guide to hold the alignment.

Build time this post: 0 hour, 30 minutes
Total build time so far: 42 hours, 00 minutes

Sunday, December 16, 2018

Semroc Saturn 1B, Build, OOP #KS-1, Part 46, Capsule Coupler

A black fish paper coupler is glued to the back of the capsule assembly.
TIP: Coupler edges are typically cut at a slight angle. For a stronger glue joint, sand one side of the coupler flat.
TIP: The other side can be rounded for smoother insertion and less chance of peeling the inside edge of the BT-70 tube below it.

I use very little glue to initially tack the coupler in place. If it ends up off center that little bit of glue is easier to cut and reglue the coupler.

Test fit the coupler in the BT-70 tube to be sure it is centered. After you are happy with the coupler positioning, then you can apply a glue fillet on the inside joint.

Build time this post: 0 hour, 15 minutes
Total build time so far: 41 hours, 30 minutes

Semroc Saturn 1B, Build, OOP #KS-1, Part 45, Capsule Details

The seven lines were cut from some adhesive backed paper from an Avery CD label.
Using self-adhesive strips is just cleaner and easier, no glue.

Here's a dry fit of the tower.

Look below and you can see the subtle tape on the seven lines and the hatch cover. It's not a lot of detail but I think it's better than the old hand drawn print of what was under the protective cover.

Under the the escape rocket, four small circles were scraped exposing the balsa under the paint.

On the left - 
Four white glue drops were set on the tower tops. The glue drops are consistent in size. When the escape rocket is pressed in place the glue will squeeze out around the tower side struts making automatic fillets.

Build time this post: 0 hour, 45 minutes
Total build time so far: 41 hours, 15 minutes

Saturday, December 15, 2018

Saturn 1B Designations

The Saturn 1B had changed a bit in it's history.
I'm basing my build on the AS-205 Apollo 7 version.
This one had the most detail and still kept the alternating black and white H-1 engines in the low end.
The earlier AS-201 and AS-202 missions had the white service module, like the Estes kit. The Apogee kit is based on the Apollo 7, AS-205.

Friday, December 14, 2018

Semroc Saturn 1B, Build, OOP #KS-1, Part 44, Capsule Details

You knew I'd get back to the capsule and tower sooner or later - 

The instructions have you use the tower assembly jig to mark the capsule top for the tower leg ends. If you use the assembly jig, punch out the center hole. The tabs should be trimmed and the open circle lightly sanded so you don't scar up the balsa.
The instructions say to use a scrap dowel to make indentations at the tower leg locations. I didn't have any scrap dowels left after the tower build!

I ended up pressing the tower ends into the balsa top. Make sure your tower is straight before making the impressions.
I went back and made the dents deeper and the edges cleaner.

I wanted to add some details to the capsule cover.
Page 282 of Alway's Rocket of the World has an overhead drawing.
There are seven lines running evenly out from the center.

The Alway drawing was blown up and the lines extended outside the BT-70 diameter.

Set the capsule assembly over the blown-up drawing and pencil mark the seven divisions.
This picture shows some of the "test" tape lines.
More in the next post - 

Build time this post: 0 hour, 30 minutes
Total build time so far: 40 hours, 30 minutes

Estes Mini Mean Machine Coming Soon -

This seems to be Estes' month for re-issue rockets.
A mini engine Mini Mean Machine is coming soon.
Here's the link: CLICK HERE
Where's the nose cone in that parts picture?

This one reflects the new blue and white decor of the large version.
On YORF, TBZEP said it best: "Looks like the original Mini Mean Machine had an affair with Blue Bird Zero."

The Mini Mean Machine is BT-20 based and 39" long!
When this model was first talked about, I built my own version called the Spaced Needle using 18mm engines.
I went back and forth with the idea of a center separation but decided to go with a nose cone blow and small parachute.
I should have made the model with a break in the center. Being so long, the model was hard to transport. Returning from the club launch, the body tube was bent when cargo shifted around in the back of the car.

I hope to build it again, it turned out well. There are some long lines of black decals alternating with chrome Monokote trim.

Thursday, December 13, 2018

Semroc Saturn 1B, Build, OOP #KS-1, Part 43, Service Module Paint Pattern

One great thing about modeling the Apollo 7, SA-205 rocket is the detail on the Service Module. The detail wrap can be cut from aluminum Trim Monokote and wrapped around the tube.

Here's the drawing from page 284 of Peter Alway's Rockets of the World.

It was enlarged to fit the circumference of the BT-70 and re-drawn.

Here's a test wrap, a simple print onto 20 lb. paper.
It's a great fit with a very small overlap seam.

If you would like a copy of the wrap email me at:
and ask for the Service Module Wrap PDF

Along with the service module wrap, I'll send the previous escape tower decals and upcoming capsule detail template.

Build time this post: 1 hour, 30 minutes
Total build time so far: 40 hours, 00 minutes