Estes Shark #1111, Build, Part 8, Engine Mount & Fin Gluing

Set the engine mount and Kevlar line alongside the lower, longer tube.

The BT-20 engine tube is even with the bottom of the BT-50 main body.

This gives you an idea how long the Kevlar line should be, a little shorter than the top of the BT-50.

Tie a overhand loop knot (shown on the right) for the elastic shock cord attachment.

I used epoxy to glue the mount in, allowing me some positioning time.

Here's the BT-50 tube with the filler/primer scraped off where the fins will be glued. The scraping is a little shorter than the length of the leading edge.

The low fins are glued even with the end of the body tube.

On the forward fins and thrusters, I used a wrap of masking tape as an low alignment line at the corner of the trailing edges.

Estes Shark #1111, Build, Part 7, Fin Grain Fill

I first cut the thrusters from balsa -

Then I realized the would be a pain to fill and sand being so small. I cut a second set out of basswood.

Two step fill process:

1. The fins, tunnel. thrusters and launch lug got a brushed coat of CWF, then fine sanding with 400 grit.

2. After sanding down all the CWF, all were stuck down to some cardboard for a shot of filler/primer. 

The body tube seams and nose cone got the same two step fill.

Estes Shark #1111, Build, Part 6, Fins & Decals

The original kit fins were die cut. I don't know why the guidance thrusters weren't cut. Maybe they were too small?

The way they are set on the sheet, it would be difficult to cut all four with an even height. On my redraw (below) they are cut from a long strip.

Note the forward fins were cut with the grain running parallel to the trailing edge, not the leading edge. In my pattern draw below, the fins are rotated for the correct grain direction.

Even as cut with the wrong grain direction, the forward fins aren't subject to any real stress.

The USAF red, white and blue fin decal uses the same design (or close to) the Interceptor fins.

This decal and fin pattern is available as a PDF (home decal prints) only for Patreon subscribers. 

Email me at: oddlrockets@bellsouth.net 

and ask for the Shark PDF.

I added thruster decal dots. The instructions say "Ink in black thruster nozzles". I made them oval decals that go on the lower face of the thrusters.

Estes Shark #1111, Build, Part 5, Raceway or Tunnel

On the Shark, the raceway is cut to 6.25" long. On the Stiletto kit, the raceway tunnel was 7 3/4" long. I'll cut mine to 6.25" out of basswood.

The Shark instructions showed a long rectangle, rounded on both ends. The upper edges stay square.

You might find it easier to judge the end shape by viewing the underside as you sand. The picture on the right shows the underside.

 

After the side ends are shaped,

The tips are tapered. 

On the right is the finished tunnel.

Estes Shark #1111, Build, Part 4, D.I.Y. Nose Block (Coupler)

The coupler was cut to 1 1/4" long. The original kit nose block was 1" long. I feel better having a longer, more stable sliding joint.

I decided to make the coupler bulkhead wall out of 3/32" basswood.

The BT-50 coupler was set down onto the basswood and the interior diameter traced with a sharp pencil.

Two circles were cut out.

The sides were sanded to a circle.

Both were glued cross grained.

A inside reinforcement bar was cut and glued to the top face.

A pilot hole was carefully drilled before the screw eye was turned into the basswood. 

The bulkhead was glued into the coupler, recessed to allow for a glue fillet.

More glue was applied inside from the top using a Q-tip.

Estes Shark #1111, Build, Part 3, Engine Mount

The 20/50 rings were notched for the engine hook and Kevlar line.

The lower ring is on the left. I highlighted the notch with pencil.

The upper ring is on the right. Note the Kevlar notch directly opposite the engine hook  notch.

The instructions would have you position the upper ring above the top bend of the engine hook. I position the upper ring lower, over the top of the hook end making a stronger mount.

The Kevlar line is set directly opposite the engine hook.

The loose end of the Kevlar line is pressed into the upper ring glue fillet.

1/16" diameter heat shrink tubing is slid down the Kevlar and rests against the top of the ring.

Hit the heat shrink tube with a heat gun, shrinking it around the Kevlar.

Estes Shark #1111, Build, Part 2, Parts

The parts: This will be a spare parts build.

I re-drew the water slide decals. The original #1111 kit had stickers.

3/32" thick balsa

12" parachute, shroud lines will be replaced with #10 embroidery thread

I used heavy walled BT-50s, a 9.5" and 4" lengths

The original nose block (coupler) was 1" long. I'll make it a bit longer at 1.25"

Elastic shock cord, heat shrink tubing to protect the Kevlar line

A standard 20/50 engine mount, engine hook not shown

The nose cone is a "place holder" until I can get the proper BNC-50AR balsa cone.

Laminated kraft sticks (tongue depressors) were to be used for the tunnel and guidance thrusters. I ended up cutting those from 3/32" basswood.