Estes Mini Arcas, #2441, Part 6, Fin Supports?

Here's one reason why this kit has an "Advanced" skill level.

These fin supports were tough to shape when the original Arcas was a larger BT-55 size.

Check out the original K-26 kit instructions: CLICK HERE

"Sand a 14 degree angle after cutting the support in two?"

What makes it even harder - forming the smaller supports out of balsa!

The laser cut balsa supports are only 3/4" long by 1/16" thick. 

I made a special trip to an actual hobby store to find some strip basswood. I'll be cutting these out by hand. Basswood doesn't have grain pores to fill like balsa wood does.

The picture on the right shows an attempt at forming the first support. I can't imagine trying to shape and fill seven more of these from balsa!

Estes Mini Arcas, #2441, Part 5, Tail Cone Fix

Next time you make a tail cone, try placing the glue inside the end, opposite the glue tab.

I decided to make a double layer "super shroud". This makes a much stronger piece.

For more detail, I wrote an article for the Apogee Peak Of Flight newsletter: CLICK HERE

Notice the lower step inside the cone in the right side pic.

Glue one cone inside other.

Let dry with a coupler inside (don't glue the coupler in) to maintain the round shape.

After all is dry,

Cut off the upper overhang using the ridge as a guide for a razor blade.

Sand the upper side square using a sanding block with 400 grit.

Estes Mini Arcas, #2441, Part 4, Tail Cone Fix - Gotcha!

After forming too many shrouds printed from the scanned kit tail cone,

I thought I'd try the provided kit shroud.

GOTCHA: The kit shroud fit like my scanned cardstock ones did - 

It fits the BT-5 but was small on the BT-20 top end.

So - off to payloadbay.com and their transitions tool.

Four more were printed and cut out.

Notice the picture on the left - 

Run a fingertip over the curved sides, you'll feel some very subtle raised areas. With 400 grit, sand and round them down. This removes the high spots and makes a better fit at the base of the BT-20.

Four cardstock tail cones were formed with a clean dowel in the heel of my left hand. Check the last post picture.

Estes Mini Arcas, #2441, Part 3, Tail Cone Problems

Cut the flat sides with a ruler and sharp knife. 

Cut the curves with scissors.

I make a smooth curve by rolling a dowel in an arc pressed against the soft heel of your hand. 

It take very little glue to join the ends.

With the printed edge lines lined up, I held the shroud closed using smooth faced tweezers.

 

Here's where I ran into problems.

The bottom fits the BT-5, but the wider end doesn't match the diameter of the BT-20!

I made another tail cone with a slightly wider top. 

It was still too small!

These two shown above aren't the kit supplied tail cone. The kit shroud was scanned and some extras were printed up on 110 lb. stock. There doesn't seem to be any difference in size between the kit shroud and what I printed. I was saving the kit tail cone for a final try. It's a bit thicker and has a smooth side.

Estes Shark #1111, Build, Follow-up

Well, yesterday's post (shown below) ended up being posted on the wrong date, last week! Don't know how that happened. You can specify what days you want things to be posted. I must have hit "Set Date and Time" button and not the "Automatic" publish button.    

I got my BNC-50AR balsa nose cone from erockets.biz

The upper pic was the Alpha style "placeholder".

The lower picture shows the new, bare balsa cone.

How the rocket looked before:

Here's the build with the correct shape, original nose cone.

Sometimes a little change makes a much better design.

Estes Mini Arcas, #2441, Part 2, Tail Cone

Any rocket kit that has a tail cone only includes one cardstock shroud. If you've ever formed a cardstock shroud, you know the fit might be iffy. 

I won't be taking any chances with a single shroud.

I drew a 1" reference line above the printed kit shroud. The tail cone was scanned, the 1"reference span was double checked in Corel Draw. The shrouds were printed on 110 lb. cardstock.

Will I really need eight tail cones? No.

But, I can make a few and use the best fitting shroud.

Estes Mini Arcas, #2441, Part 1, Parts

Here's a newer one from Estes.

A larger BT-55 Arcas kit was produced by Estes from 1972-1973.

This "mini" motor version is BT-20 based with streamer recovery.

Parts are of good quality.

The streamer is 2" x 24" chrome Mylar.

To see the instructions: CLICK HERE

The balsa sheet is 1/16" thick.

The small laser cut pieces are the fin supports. They are tiny!

Only one cardstock shroud is supplied. 

More on that later -