Estes Mini Bomarc Clone, Kit #TK-5, Part 14, Color Paint

Paint is pretty easy on this one.

Nose cone is brown, the main body is a light gray.

After these dry, the rear of the nacelle tube is painted silver.

I was concerned about the balsa grain fill on the nacelle nose cone. 

This turned out pretty well.

There is still a masking paper strip on the root edge (gluing surface) of the "P" support piece.

I

The main body assembly is an overall light gray.

The nacelles are ready to be masked for the silver. 

The main body still needs some sanding and another final gray coat.

Estes Mini Bomarc Clone, Kit #TK-5, Part 13, White Undercoats

I thought it would be difficult to get paint around the ramjet assemblies. The main body and nacelles will be painted separately.

I masked off two gluing lines for the root edges of the nacelle support "P" pieces. I shaded the mask strips with pencil to show up better in the photo.

On the right is the inside end of the body tube masked off.

The root edge of the "P" supports were masked off with a thin piece of tape. These were taped down to a scrap piece of cardboard.

The top and sides were spray painted gloss white. 

After that paint dried, 

The nacelle assembly was slid over a dowel and the underside sprayed.

This is the underside of the wing and body.

You can see how difficult it is to get paint coverage on the inside areas.

Estes Mini Bomarc Clone, Kit #TK-5, Part 12, Launch Lugs

The launch lugs are short, two LL-2AM at .37" long.

These were cut from scrap pieces and sanded to insure both were the same length.

Because these lugs are short - 

Hold on to the lug with the tweezers while applying two thin glue lines. While still holding with the tweezers, set the lug in place under the rudder and wing.

The rear lug is even with the low end of the tube.

The upper lug is tucked under the forward tip of the wing. 

I didn't apply glue fillets on the lugs. It's difficult to get a good fill in that tight corner with all the air bubbles that can form.

School Supplies? Rocket Building Stuff!

Save some money - School supplies can are cheaper now than any other time of the year.

This is the nozzle on a bottle of school glue. I wouldn't recommend the water soluble school glue for model rocket building. 

Replace the wide applicator nozzle on your wood glue bottle with this orange, fine point nozzle for more control of the glue flow. 

Unscrew the nozzle at the white collar, wash out any school glue and replace  the wood glue nozzle. It will fit the threads on the wood glue bottle.

I've used glue sticks for cardstock adapters and in carded rocketry.

Using a glue stick can give your more control on a cardstock adapter "glue tab".

Sharpies come in handy for black paint touchups, line details and Saturn V masking. Go to my Saturn V build for more details.

Estes Mini Bomarc Clone, Kit #TK-5, Part 11, Gluing On The Raceway

The upper picture is s a dry fit of the raceway checking the fit over the wing and stabilizer.

The inset picture shows the line of glue just down the centerline on the underside of the raceway. The side edges won't be making contact with the round tube. I also didn't want squeeze out of glue. Any gaps will be filled with a glue fillet.

I didn't initially cut the curve to fit over the low end of the raceway. 

Set the rudder over the back and trace over the raceway curve end with a pencil.

On the right is the rough cut.

After more forming with sandpaper rolled over a dowel, I got a good fit.

 

Follow up with some glue fillets to fill any gaps.

Estes Mini Bomarc Clone, Kit #TK-5, Part 10, Gluing On The Rudder & Wing

The fin lines are extended down the length of the body tube.

The rudder goes on first using the center lines down the tube and rudder.

ry fit the wing under the raceway and mark the position.

Glue the wing onto the body tube. While the glue is still  wet check the placement with a dry fit of the raceway. 

When all is fitting together, remove the raceway.

Let the wing and rudder glue joints dry with the assembly placed on a flat surface. This aligns the wing and rudder.

Estes Mini Bomarc Clone, Kit #TK-5, Part 9, Gluing Together The Nacelles

Draw a pencil line down the Nacelle tube.

Glue the P1 support pieces onto the line, even with the front end of the tube.

The picture on the right is a dry fit (no glue) of the nacelle nose cone.
 

Before gluing in the nose cone - the fit could be better. 

Slide in the nose cone, not quite against the body tube.

I folded up a piece of 400 grit and lightly ran it around the gap between the nose cone and body tube. This will clean up any rough shoulder and give a closer joint.

The print of the instructions marking guide wouldn't fit around the BT-20 tube.

I went to payloadbay.com and clicked on "tools".

Click on "fin wrap tool".

I entered a three fin BT-20, just to get the correct width of the tube diameter.

I dropped the scan into Corel Draw and blew up the original fin marking guide to the width of the payload bay image. The "Nacelle" and "Top" lines were extended onto the correct wrap diameter.
 

Estes Mini Bomarc Clone, Kit #TK-5, Part 8, Raceway Buildup

The stabilizer is even with the end of the body tube.

The raceway sits on top, 1" from the end.

These are still dry fittings, don't glue the raceway on yet.

The front of the raceway overhangs the front end of the body tube.

Cut it off even and sand flat.

With the raceway off the body, it's easier to form the ends.

With a sanding block, shape the side profiles first.

then round down the top.

Then round the sides.

Smooth things out with 400 grit over your fingers.

For a better fit over the round tube, I sanded a slight dip into the underside.

400 grit was wrapped around a BT-5 tube and the underside was sanded. Don't sand to a perfect fit, the raceway still needs to fit over the wing and stab.

I used a smaller tube than what it will be glued to. This can make for a better fit.

Estes Mini Bomarc Clone, Kit #TK-5, Part 7, Raceway Buildup

Step 7 in the instructions have you build up the raceway on the model, then sand the ends "to a point". This is when I steered away from the instructions. I couldn't see how you could sand and form the raceway ends after they were glued to the body.

I taped the pieces down to a countertop keeping all in line.

See the next #8 post to understand why. 

This is the rear R1 piece pressed in between the wing and rudder. Don't glue the ends to the wing and rudder yet.

Butt the forward R2 piece against the front of the wing, no glue.

Just the top of the raceway (the original kit included a rounded raceway top) is glued to the R1 and R2 pieces. Don't glue the top raceway piece to the wing and rudder, glue only to the R1 and R2 pieces underneath.

Do your best to line up the sides of the R1 and R2 even with the sides of the long upper raceway piece.

Estes Mini Bomarc Clone, Kit #TK-5, Part 6, Nose Weights

I needed two Estes NCW-1 nose cone weights. I found an single original lead weight in my spare parts drawer.

The older Estes catalogs say one lead washer weighs 0.12 oz. Two would weigh 0.24 oz.

Deep in the spare parts drawer was a few older Semroc NCW-1 weights. One weighs 0.15 oz. There is no center hole for the screw eye.

The Semroc weight is larger in diameter and won't slide into the BT-20 main body tube.

I used a wire cutter to reduce the diameter. 

The lead disk was rounded on some 220 grit sandpaper.

A diamond rat tail file started a hole for the screw eye.

After drilling and shaping, the disk now weighs 0.30 oz. I did some more sizing and got the two lead disks down to 0.25 oz.

The nose cone was from Balsa Machining Service (BMS).

BMS drills out their nose cones for a hardwood dowel. The screw eye is turned into a small hole in the dowel center. This attachment is much stronger than balsa alone.

The fit of the dowel was tight. I sanded the sides a bit, but it wasn't enough.

When pressed into the hole, the nose cone started to split! Some CA glue was run into the split and the gap filled.

Estes Mini Bomarc Clone, Kit #TK-5, Part 6, Downsizing A Parachute

The original Mini Bomarc kit had a 10" parachute. Estes makes a 9" chute, but I didn't want to spend the $4.49 price.

I have a lot of Odd'l Rockets parachutes. I'll cut a 10 chute from one of these.

Mark the center of the chute material. Then, simply mark 5" on either side of the center. Repeat for all six sides.

Make straight cuts, parallel to the 12" dashed lines above. 

Rotate the chute make the next five cut lines.

Here's the 10" chute with the plastic reinforcement rings in place.

The finished chute using #10 cotton embroidery thread for the shroud lines.

Estes Mini Bomarc Clone, Kit #TK-5, Part 5, CWF Sand & Filler Primer

The old Estes instructions don't mention it,

but I rounded the leading edges of the wing, stab and rudder.

I also rounded the leading edge of the nacelle support. You've got to be careful because of the balsa grain direction.

The balsa pieces were taped down to a piece of cardboard and shot with filler/primer.

Sanding follows.

On the left the nose cone is shown with the CWF applied.

I realized the nose cone was also used in the Estes Stinger (K-53) kit.

After sanding, the filler/primer was sprayed and sanded.

Here's the rudder and stabilizer after the filler/primer was sanded.

I tend to sand down more filler than others might.

The filler/primer soaks into the balsa a bit and still seals the surface if most is sanded off.

Estes Mini Bomarc Clone, Kit #TK-5, Part 4, Filling Nacelle Nose Cones

The small (BT-5 size) nacelle intake nose cones are difficult to fill. There are some inside angles that should be sharp and remain round.

On the left - the CWF has been brushed on.

On the right - the CWF has been sanded down and smoothed.

The secret? A good sanding block with 400 grit.

The sandpaper is only on the bottom surface, not rolled up on the sides. You can't sand into the corner of the intake cone at the top.

On the left - the nose cone balsa grain is filled. It a second round of CWF to build up the low areas.

Note the tubes seams have been filled with CWF and sanded.

 

I'd recommend filling all the balsa surfaces before gluing everything together.

It'll be difficult enough to get spray paint into the nooks and crannies.

A SHOT DOG Find and a Question

This design goes back to 2008, and entry in the old EMRR Odd Ball Design Contest.

A flying Hot Dog, or SHOT DOG.

Open bun, with empty condiment packages surrounding the balsa fins.

You can read about the ups and downs of the Shot Dog here - 
https://www.rocketreviews.com/scratch-shot-dog-by-hans-chris-michielssen.html 

I was looking at some 3D parts on Makerspace and came across a 3D printed Shot Dog by Scott Dee. Scott also drew up the 3D Centuri Skylab parts I was interested in.

Scott Dee (Mills)

https://www.thingiverse.com/thing:3272143

Scott's model looks to be a bit taller with four fins instead of three. This would make it more stable!

3D PRINT QUESTION: Anybody interested in printing the Centuri Skylab parts for me?

https://www.thingiverse.com/thing:2881947

Looking for all the 3D printed parts, as smooth as possible (no real ridges). Resin print preferred.

Send a price estimate to oddlrockets@bellsouth.net