Downscale Carded A.S.P. Part 7, Trim and Finish

Cut out the nose cone decor piece off the 24 lb. sheet.
Glue it to the plastic nose cone using a glue stick.
(Yes, a glue stick will hold it on.)

The finished model came out pretty good. I'll have to make another with the spinnerons on the correct side. I know it should be fluorescent red/orange but this is as close as an inkjet printer will get.

You can see the spinnerons off the trailing edge of the fins.





Here's a better view of the nose cone and red decor piece.
The only paint is the silver nose cone tip.

A streamer and shock cord were installed.
It'll fly with a 1/2A3-4t or A3-4t engine.

Downscale Carded A.S.P. Part 6, Fin and Lug Gluing

Using white glue, glue the fins on even with the back end of the body tube.

Simply match the fin color to the facing body tube color.

White glue dries clear, don't use yellow glue on the outside surfaces of printed carded models!

The fillets were smoothed with finger then a Q-tip.




The 1 1/4" long x 1/8" diameter launch lug was covered with the orange skin square from the 24 lb. printed sheet.

Rub on a thin coat of glue stick and roll the skin around the lug.








Glue the lug at the base of a red/orange fin side.

Downscale Carded A.S.P. Part 5, Body Tube Wrap

The body wrap skin is wide on the left side.
The pencil mark in the picture shows the extended side.

Cut it to just the outside of the ink where the pencil mark is.
This slight extension of the left side is the first side you glue down and ends up as the underlap.

Make a straight pencil line down the 9" long BT-5 tube.

Apply glue stick to the underside of the entire body skin.

Start the wrap down the line and even with the tube ends.

By the time you get to the end of the wrap the glue might be too dry to adhere to the tube.
Apply more glue and close up the end seam.
The top still needed a little more glue applied under the skin with a knife tip.







Sand the ends even with some 400 girt on a sanding block.

Downscale Carded A.S.P. Part 4, Fin Fold and Skin Gluing

The through cut was made on the other side. The other side of the fin (shown here) is oversize to insure there is color coverage when the fin is cut out.

Here's the (larger printed area) back side of the fin. You can see how the cut is inside the ink bleed area.
Cut the root edge first.

Turn over the fin to cut the trailing edge.
Cut lightly only through the top skin and card stock center, leaving the spin tab still attached on the other side.
This is not as hard as it sounds.
Start the cut using a straightedge. Finish with light cuts.
You'll feel when the center layer is being cut off.

Apply a glue fillet on the spinneron edge.

Downscale Carded A.S.P. Part 3, Fin Fold and Skin Gluing

NOTE: Your printed fins and location of the spin tabs won't be the same as pictured below.
This is the first build before corrections were made to the PDF. Your model fin color and spin tab position will be correct. The following posts can still be used to make the model.

Cut and separate the fins.
Leave a 1/4" wide border around all sides.
For now, notice only the spinneron side trailing edge is cut out on the ink border.





After making the embossed leading edge from the last post -
Lightly fold down the embossed leading edge line.


Burnish the fold flat and sharp with the back end of a Sharpie or other smooth, round dowel.






Apply glue stick to both inner sides of the fin skin.

Don't apply any glue to the tab in the area shown.







Set the skins over the cereal cardboard straight edge cut earlier.

Be sure the skin fold leading edge is all the way down onto the cardboard edge.

Place the fins in a heavy book to dry.

Downscale Carded A.S.P. Part 2, Fin Prep

NOTE: Your printed fins and location of the spin tabs won't be the same as pictured below. This is the first build before corrections were made to the PDF. Your model fin color and spin tab position will be correct. The following posts can still be used to help make the model.

Patreon members can email me at:
oddlrockets@bellsouth.net and ask for the A.S.P. PDF.

The fins are three-ply.
The outside skins are printed on 110 lb. cardstock.
The interior layer is cereal box cardboard.
The outer print skin will "butterfly" fold over and glue to the card stock interior.

Sand the glossy print side of the cereal box sheet for better glue adhesion.

The inside leading edge has to be straight.
Cut a straight line with a sharp blade and straight edge.

Lightly sand the edge round for an easier fold of the outside skin.

These fins are different, they have a spin tab (spinneron) on the left side of all four fins.
Pre-cut just the tab trailing edge before cutting out the whole fin or folding the leading edge.
Cut only the fin tab trailing edge side for now.




Use a dull butter knife, no serrations on the tip (or the rounded back side of a single edge razor blade - put a few layers of masking tape over the sharp edge now facing up) to emboss a fold down the "fold line".
TIP: Don't cut into or through card stock to make a fold line.
Try making a long shallow embossed "trough". Practice on some scrap to get it right.

Downscale Carded A.S.P. Part 1, Background

I've always wanted to build the A.S.P or
Atmospheric Sounding Projectile
since the first time I saw the Estes Plan #37.

Check out the instructions at JimZs - CLICK HERE

Estes did come out with an ASP kit years later but it didn't have this paint pattern.






I drew up a carded BT-5 based version.
No painting, except for the silver tip of the nose cone.
The body tube and fins get printed wraps.

This was a tough design to get correct!
You couldn't simply draw a fin, copy and flip it over.
From left to right, the first and third fins are the same. Fins two and four are opposites.















On the left is the first set I drew up. These were wrong.
By the time I was ready to glue the fins on, I realized my mistake. The red and black sides didn't match up with the body tube patterns.
Checking Peter Alway's book, Rockets Of The World, I noticed the spinnerons (spin tabs) were also on the wrong side.
On the right are the corrected fins.

ASP Engine Adapter 13/18 Part 3

The coupler assembly is glued on the center of the BT-5 motor mount tube.

The third ring is glued flush with the forward end of the BT-5 tube. (not shown)

You have to cut out a piece of the fourth, low ring to allow the engine hook movement.
Make one cut and set it over the engine hook to mark the second cut.

Glue the slotted ring flush with the low end of the BT-5 tube.

TIP: The ends of the notched ring won't want to stay down.
Set the ring into a BT-20 tube to hold the centering ring ends down while they dry.





The completed mount.

This A.S.P. mount is much more substantial than the three ring mounts you've seen before.

ASP Engine Adapter 13/18 Part 2

Press the peeled rings into place using a flat surface. I'm using the flat side of my sanding block.
Using a flat surface like this guarantees the ends are flush.

TIP: You should take down the raised "burrs" along the inside of the centering rings.
This makes fitting the BT-5 tube much easier,

Any round surface can be rolled over the raised edges. I'll use a dowel or back end of my X-Acto knife handle.

With the engine hook set into the slit, the dried coupler assembly is slid over the BT-5 tube 
The rear 5/20 ring slides over the engine hook.
The fit was tight, you can see the BT-5 tube being pressed in a bit.

Mark the lower centering ring for a shallow notch.

TIP: Cut your notch on the opposite side of the interior wrap seam.

Centering rings are rarely glued very well. If you were to cut the notch on the seam (or side of the wrap seam) the wrap nearest the seam could come off.

ASP Engine Adapter 13/18 Part 1

A build blog about an engine mount?
The Aerospace Specialty Products (A.S.P.) 13/18 Engine Adapter is different enough to justify it.

Lots of parts - For such a small adapter (13mm to 18mm)
Four centering rings and a central long coupler will make one strong mount.

Enlarge the picture and you can see the cross section drawing better.

In the center of the BT-5 motor mount tube is the coupler and two of the 5/20 rings.

This goes over the engine hook holding it in line.  

To start, you have to peel some outside layers off two of the 5/20 rings.

Peel off enough to friction fit into the brown coupler.

To show how much of the ring is taken off, here's two rings.
Before on the left and peeled to size on the right.