Estes USS Enterprise #1275, Part 29, The Tail Caps

GOTHCA! The tail cap liners (slip-in shoulder base) won't fit into the tail caps!

The diameter of the liner is the same diameter of the tail cap. Notice the sides of the liner taper towards the right side.

The instructions say to "sand the liners until they fit 1/4" into the tail caps. I sanded using 220 grit.

The picture to the right show how much of the edge was sanded off that first shoulder.

 

After sanding, one tail cap liner slid in.

The second liner required a cut slit in the side. No amount of sanding the tapered shoulder would allow a slip fit.

Estes USS Enterprise #1275, Part 19, The Radar Dish

A hole is made in the radar dish center to fit over the sharpened dowel.

Start the hole by spinning a blade tip in the center.

Enlarge the hole using a small rat tail diamond file. By using a file to open it up, you'll end up with a rounder hole.

Careful, it's easy to make the hole too big. File a little and check the fit. 

Glue the dish using liquid plastic cement.

The "ball" at the end of the dowel tip is a drop of white glue. You might have to build up the diameter of the ball using a few applications of glue.

Estes USS Enterprise #1275, Part 17, The Homing Beacon

The homing beacon is cut off the vacu-form sheet the same way the larger pieces were.

Ball point pen outline, then scoring the edge.

Break away the sides by cutting and cracking off angled wedges.

The sides are a little rough after the first cuts.

Sand the bottom flat until the edge starts to roll off.

The finished beacon wasn't perfectly round.

The instructions say to sand down the overlap seam 3/8" wide, 1/8" from the rear. The pencil marks show how wide that marking is - too long.

On the left, the overlap ridge is removed to fit the actual diameter of the beacon.

On the right, the fitted and glued on beacon.

Estes USS Enterprise #1275, Part 16, The Hull Pylon

The internal pylon assembly was set inside one side of the secondary hull. A pencil line was traced around the bulkhead.

Contact cement was applied on one side at the pencil bulkhead line and at the pylon doubler contact areas.

Repeat for the other side.

Before allowing the pieces to touch - carefully align. 

The pylon assembly was pressed in place.

Be sure to check that the slots line up at the back.

The secondary hull assembly.

Two small hairline cracks occurred on the forward end of the hull. The cracks formed where the plastic was the thinnest. 

I'll fix this in a later post.

Estes USS Enterprise #1275, Part 15, The Hull Pylon

The doublers are glued on each side of the hull pylon.

Do your best to center the doublers

 -

 

Here's how they lined up.

I lined up the doublers using the retainer ring recess at the top. That left the front and rear of the doublers short against the center piece.

Rounding the front and rear did clean up the short side pieces.

For a better fit against the motor mount tube, a curve was sanded into the top of the laminate pieces. Otherwise, there would be gaps on both sides when glued up.

The bulkhead piece was very loose around the back notch of the central pylon piece.

A cardstock strip shim was glued on the inside for a tighter fit.

Estes USS Enterprise #1275, Part 14, Secondary Hull Brace Slot Cutting

I put off cutting the brace slots in the secondary hull. I wanted to practice on cutting the tube slots first.

Draw a pencil line a bit smaller than the brace width. Square on the front, round on the back. 

Use the tip of the knife to make the square corners.

Note the blade is turned up to make the lower corner cut first. 

The long sides are cut.

Leave the rounded back end for last.



I used a round diamond file to extend the width and round the back.

Finish up with a flat file for the sides.

Here's a good friction fit of the brace in the slot.

Estes USS Enterprise #1275, Part 13, Pylon Brace Gluing

A quick update after my dog Dakota's first camping trip - 

She did great! Lots of new smells on the hiking trails. Met a few people and slept through the night on her dog bed from home. 

Didn't bark once - until she got home.

    

The instruction drawing shows the interior brace contacting the tube at the 3 and 9 o'clock positions.

My brace position ended up lower inside the tube.

You can see some glue reflection inside.

I used a glue bead on a Q-tip to reach inside and apply fillets.

The corner of a CD case was used to check the right angle of the pylon brace on the tube.

Estes USS Enterprise #1275, Part 12, Gluing The Support Ring

The contact cement capsules have dried out and aren't useable. I bought some new contact cement at Home Depot.

If you've never used contact cement before - 

You apply the glue to both parts and let it dry. When the dried glue touches the other glued part, it grabs and holds strong.

There is a good reason why it is called "contact" cement.

The support ring is centered in the bottom hull half and the perimeter is traced with pencil. Center and trace the ring on the upper and lower hull halves.

A ring of contact cement is brushed on the pencil line.

Contact cement is applied to the edge of the support ring and allowed to dry.

Center the ring inside the pencil line and press into the hull.

Here the lower edge of the support ring is set and glued in place.

Apply contact cement to the upper edge of the support ring and inside the pencil line in the upper half.

Fit, press and join the two hull halves together adhering the support ring in place. 

Held up to a light you can see the ring inside the round hull.

Run liquid plastic cement inside the overlapping joint.

Dip and push the brush into the seam as best as you can.

Estes USS Enterprise #1275, Part 11, Pylon Brace Fit

The pylon brace fit was very loose. 

No amount of glue fillets will fix this.

On the left: A strip of 110 lb. cardstock was slipped into the slot, folded over and glued to the face of the brace. 

On the right: Look close to see the white cardstock shims in place. The fit is much tighter. 

Another dry fit of the pylons. 

The braces are inside locking the pylons in position.

Centuri Skylab Build, #KB-4, Part 10, Panel Supports

This is one of the few kits where pre-cut (die-cut) balsa needs to be recut. It makes me wonder if the die-cut razor blocks was made too long. Or, maybe the extra length was needed for strength when doing that center punch?

From the instructions:

You are told to cut off 1/8" off each side of the die-cut panel supports. Then bevel the ends to a 45 degree angle.

 

Later on, there has to be a 1/8" space between the top of the panel support and the bottom edge of the wrap.

On the left is an early dry fit of the wrap and top of the panel support.

In the inset picture is the beveled top.

Centuri Skylab Build, #KB-4, Part 7, Fitting The "Super" Shroud

Mentioned in the previous post - 

Here's the smaller end showing the inside stepped shrouds.

This gives a better fit and adhesion area onto the smaller tube.

One of the previously made centering rings is glued into the doubled shroud. 

After the glue dries, the edge should be stiff enough to sand off, even with the face of the centering ring. 

The fit is good -

Even if the low end were a hair wider than the larger tube, the 3nd printed instrument wrap would cover any shroud lip.

In the next post:

Now that all the parts are almost ready, the actual build can start. 

Centuri Skylab Build, #KB-4, Part 6, Making A "Super" Shroud

Cardstock shrouds have always felt like the weakest part of a LPR build. You can make a stronger two layer "nested" or super shroud.

For a complete explanation of the technique, I wrote an article for the Apogee Peak Of Flight: CLICK HERE
 

Go to payloadbay.com and click on "Tools", then to "Transition Tool".

Enter your tube diameters and length of the transition.

I printed the transition on 110 lb. cardstock.

The unused lower half of the page is cut off and taped behind the printed transition. Two layers are cut out at the same time. 

Note the glue tab in the upper right, added it with a pencil line.

I don't pull the shroud under a straightedge or pull it over a table edge.

Form the shroud in the heel of your hand with a smooth dowel. Press the dowel in an arc matching the curve of the shroud. 

Your shroud should be formed until it can stand on its own.

I don't put glue on the outside glue tab,

the glue stick goes on the inside where the tab will touch.

This makes the glue area easier to handle and prevents any glue getting on the outside of the shroud.

Burnish the glue tab area over a dowel set on the inside.

Repeat with the second shroud.

Pick the best shroud to go on the outside.

 Apply glue to the outside of the central shroud and press the two together placing the seam joints on opposite sides. 

After drying you'll notice how much stronger a nested shroud is. It almost feels like sheet plastic.

Inside the smaller end  the tow shrouds are "stepped" making a better joint over the upper tube. 

Look at the bottom and you can see the inner shroud overhanging the outside shroud. This will be sanded off in the next post.

Centuri Skylab Build, #KB-4, Part 5, Making Centering Rings

The outside circle is cut with scissors.

The traced pencil line will be a bit large.

Stack the rings on the smaller tube and reduce the diameter with 220 grit on a block.

Again, sand and check the fit.

Here's a good fit in the 2" lower tube.

I used my rotary punch to make an engine  hook notch in the nozzle bell centering ring.

The inside wall of the 3D printed nozzle was thicker than the original kit vacu-formed part. The ring sat high, almost over the top.

The diameter was cut down with scissors.

After rounding the edge - 

The final fit of the nozzle ring is recessed.

Centuri Skylab Build, #KB-4, Part 4, D.I.Y. Centering Rings

TIP: One of the best centering ring materials is the left over mat board found at a frame shop. Ask the manager if they have any scraps, leftover pieces too small to be used in a frame.

If you're lucky they might give them to you for free! If not free, cheap anyway.

Trace around the diameter of the tubes. Trace the larger tube first, it's easier to center the smaller tube afterwards. 

It might take a few tries to get the smaller pencil ring centered.

With a new blade, cut the center out first. 

Cutting the center hole first is easier when you have more of the cardstock to hold onto.

That small circle in the center was on the mat board from an earlier build. I should have erased it for the picture.

Some 320 grit was rolled around my finger to enlarge the diameter..

Sand a bit, check the fit - repeat until you get a good friction fit.

When the hole is to size,

you might find a raised lip around the edge.

Leave the lip. It gives you a tighter fit and a wider gluing edge later on.