Sunday, August 20, 2017

Odd'l Rockets F-104 Fuel Tank Correction

When I posted the first prototype build of the Odd'l Rockets F-104 Starfighter, I heard about it!
Most comments were positive but a few let me know the wing fuel tanks were too small.
To be honest, I didn't have many dowels and grabbed what was handy. I bought larger dowels.

Above is the first prototype. It has quite a few stable test flights.

I cut off the fuel tanks and carved two larger ones. On the left is the size comparison.

The inset shows where the paint was scraped off to glue onto the wing.
Is this better? - hope so!
Compared to the OOP Centuri kit, this version is much closer to the truth.
Now . . . more test flights.

Estes Starship Nova #1371 Build, Part 18, Fluorescent Paint TIP

The new, wider fairing was glued onto the split engine tube.

CA glue was applied with a Q-tip. After drying the fairing was lightly sanded smooth with 400 grit.

The exposed end surfaces were blackened with a Sharpie.

These inside areas would be very hard to get to with a spray can after gluing onto the rocket body.

The housing are set in place and a light pencil line was traced around the housing. Go light with the pencil, you don't want to scar the balsa.

Masking tape was set down a little inside the pencil line.

It took quite a few coats of hand painted fluorescent paint to get a good coverage.
TIP: Only use fluorescent paint over an opaque white surface!

Here's the inside of the engine surface after about four coats of fluorescent orange. Paint, lightly sand the high spots and paint again.

Saturday, August 19, 2017

F-104 Intake Pattern Development, Part 2

The round intake tube segment was ironed flat. My iron was set on cotton with a little bit of steam.
Here's what I ended up with. The 1" long reference lengths were added so a picture can be copied to Corel Draw and traced at full size.

With the body tube segment ironed flat I was surprised at how thin body tube walls are. Spiral rolling Kraft paper into a tube substantially increases the strength.

Some test patterns were printed up and a few more intakes cut out. The fit was perfect!

Three more edits later I have a good template for the new kit!

Estes Starship Nova #1371 Build, Part 17, Engine Housing Fittling

The split housings were marked for the 3/8" overlap of the card stock fairings.

The engine housing sides were sanded to fit after setting the split tube on the wing and rudder.

Here's a good fit against the wing.

I cut out the curved housing fairing.
When it was formed and curved that crease (already in the kit supplied card stock) really shows.

GOTCHA: A test fit showed it was too short, just like the intake fairings.

Two more will be traced on 110 lb. stock a little longer than the kit supplied fairings.

Friday, August 18, 2017

F-104 Intake Pattern Development, Part 1

The upcoming F-104 Starfighter kit from Odd'l Rockets had some interesting kit design challenges. One is the intakes on each side of the body.
The old Centuri kit folded card stock rectangles. They didn't look like the round intakes on the real jet.

I wish I could say the intake shape was developed using some complex geometry. I took the easy way out - I guessed.

Some BT-20 tube was cut into half wedge shapes. This picture shows how many tries it took to get the best fit.

Final shaping is done by sanding the rough cut edges with 220 grit wrapped around the BT-50H body tube.

Okay, here's a good fit!
To make a paper cutting pattern I could just wrap a paper around this intake and trace, but I wanted something more accurate.
More in next post - 

Estes Starship Nova #1371 Build, Part 16, Fin Gluing and TIP

Glue on the rudder directly opposite the engine hook.

The "Q" piece works well to align the rudder on the body tube.

The instructions have you bevel the outside edge of the wing pieces after they are glued onto the boy tube.

TIP: You'll find it much easier to sand in the flat bevel into the wing edge before gluing it onto the body tube.

On the left is the 3/32" wide bevel.

On the right shows the approximate bevel angle of the fin against the sanding block.

Here's how the mode looks up to this point with the wings glued on.

The wing tips still have to be added.

Thursday, August 17, 2017

Estes Starship Nova #1371 Build, Part 15, Wing, Rudder Dowels and TIP

TIP: Recently I've been cutting off the corner tips on the parachutes. This allows the shroud line knot to be a little closer to the tape disk hole.

Three dowel lengths are cut - Two at 3" long and one at 4 1/2" long.

One end of each dowel is rounded.

TIP: You could simply glue the dowels on the outside edges of the rudder and wing extension piece. Sometimes I'll sanded a slight curve into the outside edges with some 220 grit wrapped around the dowel.

On the right is the is the sanded inside curve. It makes a better fit and a stronger glue joint.

Estes Starship Nova #1371 Build, Part 14, Engine Housing Caps

The inside of the end caps were "painted" with orange fluorescent acrylic paint. It took a few coats to get full coverage.

The outside was blackened using a permanent marker. The inside edges were also blackened.

The end caps are glued on, flush with the ends of the body tube halves.

Wednesday, August 16, 2017

Estes Starship Nova #1371 Build, Part 13, Engine Housings Paint

This is the engine halves after sanding down the interior seam fills. (Yep, I can hear you now - "Why fill the interior seams? Nobody will see them!)
The interiors were spray painted gloss white, then sanded.
TIP: To properly "glow" fluorescent paints require an opaque white undercoat.

I didn't use a spray paint this time. I found some fluorescent orange acrylic at Michael's crafts. It was a good match for the orange decals.

The first coat was brushed on. It seemed a little rough and showed the brush strokes. I lightly sanded with 400 grit.

The next two coats were applied using a fingertip.

That seemed to smooth it out. On the left is the finished interior orange.

On the right I scraped off the edge to glue on the end caps.

Tuesday, August 15, 2017

Estes Starship Nova #1371 Build, Part 12, Rear Engine Housings & TIP

A tube wrap is used to mark the BT-60 in half.

An aluminum angle was used to mark the tube and then used as a knife guide to cut the tube in half.

After the first side was cut I slipped my sanding block between the halves and sanded the cut edge straight.

The insides will be painted fluorescent orange. The tube seam was filled with CWF and sanded smooth.
The end caps were laser cut and a bit rough.
The centers were removed first.

TIP: Leave the caps on the card stock to lightly file the edges smooth. I used a fine diamond file. It's easier to file the edges smooth with the support of the outside card stock still in place.

I only filed in one direction. That left the side that will be facing out flat and square. There might be a little lip (right side) on the inside of the plate but it won't be seen.

Monday, August 14, 2017

Estes Starship Nova #1371 Build, Part 11, Intake End Form Gluing

The gluing area on the intake was scraped for better adhesion.
Notice to the left a scraped line for the ends of the intake form.

Slightly wider intake ends were traced and cut from 110 lb. stock.

A glue stick was used for most of the gluing onto the intake end. The bottom edges were glued down using wood glue.

To harden up the card stock, medium CA was wiped over the outside of the intake form.

After drying it was polished smooth with 400 grit sandpaper.

Here's the finished look with full closure of the ends against the body tube.

Sunday, August 13, 2017

Estes Starship Nova #1371 Build, Part 10, Intake End Forms

The intake forms were cut from the card stock sheet.
I cut curves with scissors and the straight lines with a knife and straight edge.

To smooth out the curve sand with some 400 grit.

I pre-curved the pieces with the back end of a Sharpie in the heel of my hand.

There was a crease in the card stock, you can see it right above the pen barrel.

GOTCHA! The pieces weren't long enough! When set at the center lines the edges don't reach the body tube. Both were cut right on the black border edges.

I'll have to trace two wider pieces on some 110 lb. card stock.

I found this interesting - The instruction sheet shows the same "U" piece in the same direction on the front and rear of the intake. The side view has it correct.
Not a big deal but it could confuse a builder.

Friday, August 11, 2017

Estes Starship Nova #1371 Build, Part 9, Low Intake Tube Fitting TIP

TIP: There is one great thing about having instructions sheets in different languages. Cut out your tube marking guides off the sheet you won't be using! This saves your English instruction sheets intact.

TIP: Glue the lower intake tube in place AFTER the engine mount is glued in. You won't be fighting the glue (that is quickly setting up) trying to get the engine hook centered with the lower intake position.
Glue the engine mount in first, wrap and mark with the fin guide in line with the hook, then glue on the intake.

GOTCHA: Well, another fin marking guide that didn't quite match up! Maybe this is why Carl at Semroc didn't include them in his kits.

I rotated the grey overlap area directly above the engine hook for a line to place the intake.

Here's a better view to show what I meant.
The center notch on the ring is directly above the engine hook line.