Sunday, August 1, 2021

Estes DARC-1, #7307 Build Part 10, Recovery Compartment


The Part "N" sides are glued onto the center "O" piece.
Look close and you can see how the glue was applied on the teeth, just on the sides that will make contact.

You can go light with the glue and add a fillet for strength after it dries.




Here's the "P" piece template to set the side angles.
While holding the template in place - 
You can add more glue to the center joint on either side of the P piece. After it dries, remove the P piece and complete the fillets.

This assembly makes a parachute compartment. The chute is held in place during boost by the shorter, central fin.



Glue the two cardstock Q pieces on either side of the balsa R piece.

This makes a ejection bulkhead to go inside of the back end of the ST-19 tube.
 

Saturday, July 31, 2021

Estes DARC-1, #7307 Build Part 9, Interior Slide Tube Gluing & Lug Trim


CA glue (or Fabri-Tac glue) is set around the sides of the centering ring and front of the the body tube edge.

Line up the launch lug with the hole. The assembly is slid all the way forward into the shroud body making contact with the inside body walls. 





The outside joints of the the launch lug are hit with medium CA glue.





The lug might look a little rough - see the next pictures to clean it up.

Using a new single edge razor blade, the launch lug is trimmed off matching the angle of the shroud body. It's best to cut the lug off a shade long and shave it down to the shroud body. 

Note how the rough cut lug isn't a clean oval - yet. 

Use a sharpened dowel to push out and raise the the thin skin on the lug wall.
Apply some CA glue with a Q-tip to harden it. Sand smooth.
Repeat if needed until you get a smooth rounded edge at the top and bottom. 

Those pencil marks on the shrouds are where the low seam areas were filled with medium CA and sanded smooth.


Here's a final fit and smoothing of the lug in the hole.

Notice the lug wall at the bottom near the knife point. The lug wall looks wide because it was cut and smoothed at an angle.

If you take your time, you can end up with very little joint filling.

Friday, July 30, 2021

Estes DARC-1, #7307 Build Part 8, Removing The Back of the Aero Shroud



The back end of the aero shroud is cut off around the raised step.
Trace around the raised half circle with a pencil.
This plastic at the "hump" is thick, I'd recommend using a thin razor saw to cut through it.
The rounded plastic wall near the fin slots is much thinner. Cut through this round side carefully with a sharp knife. Mark with a pencil and cut with a few light passes. 
Be Careful - Your blade could go through the plastic when you don't expect it. Don't let it get away from you -  
Cut these curves first, then work on the flats connecting the cuts.





This picture shows the thick plastic at the top half round.
The outside plastic towards the fin slots is thin by comparison.

Thursday, July 29, 2021

NARAM 62, Manufacturer's Forum Videos

The NARAM 62 Manufacturer's Forum videos are on YouTube.

Estes: CLICK HERE
Erockets: CLICK HERE
Peter Alway: CLICK HERE
Aerotech/Quest: CLICK HERE
ARA Press: CLICK HERE

Of special interest to me were the new Estes Blue Origin. 
Estes hinted at a future Fly or Display Space X model.

Estes DARC-1, #7307 Build Part 7, More Lug Hole Fitting


With the engine mount glued up, it still won't slide through.
On the right, I've marked the top (outside) that needs to be tapered. The (bottom) inside surface also needs tapering, a mirror of the upper taper but inside.

I finally got the lug to slide in but for the best fit the centering ring might need some contouring.

In the left side picture, there are three pencil boxes marked with pencil. I made the marks wide so it would be easier to see in this blog pic.
The centering ring is making good contact against the inside body wall at the pencil marks. The ring sides were sanded where the contact points were. 
With the high spots sanded down, wider areas of the centering ring made better contact with the inside walls of the plastic shroud.

The picture on the right shows the final upper taper to fit the angled lug. The pencil arc shows the outside taper. There is a "mirrored" taper arc inside the shroud on the low end of the hole.

Inside view: Here's the better fit of the centering ring.

Outside view: The lug slide is clean and straight with no tension or distortion.

Years back I built a Mars Lander kit. It was never flown because the long through the body launch lug was crooked. The finished model wouldn't slide down a launch rod. 
Be sure this lug is straight and won't bind when slid down a rod.

Wednesday, July 28, 2021

Estes DARC-1, #7307 Build Part 6, Cutting The Launch Lug Slot

This could be the most difficult part of the build. The plastic at the nose of the body is thick! Be prepared to take some extra time to get a good fit of the launch lug.
 

On the left - the raised "nub" for the launch lug to pass through.
I've already drawn around the sides with a sharp pencil.

A knife score is started around the raised area thinking it would leave a hole when cut off.


The plastic is thick. There was no hole when the raised plastic nub is cut off.

I built two kits. On the right is the first try at cutting through the plastic wall with a knife. 
On the second build I tried two different ways to drill into the plastic. These holes at either end were joined with more knife cuts.

Starting by spinning a knife tip or a very small hand-turned drill bit. A small hole was spin drilled to make an opening for a rat tail diamond file. The file kept the ends round as the holes were enlarged.
In the left side picture - the long launch lug is seen peeking through the lug hole. More plastic has to be removed for it to pass through.

The rat tail file is used again at approximately the same angle that the lug will be when slid in with the interior mount. At this angle, the file will remove tapered plastic from the outside top and the inside bottom around the hole.

I've drawn up a PDF that better shows the inside and outside plastic wall taper recesses to be shaped. The PDF is available to Patreon supporters. 
Email me at oddlrockets@bellsouth.net and ask for the Darc-1 PDF.
I recommend this PDF pattern for this build.

Tuesday, July 27, 2021

Estes DARC-1, #7307 Build Part 5, Interior Mount


The laser cuts left some browning on the edges of the centering ring. Most of this can be removed with a white eraser. 

Use a white eraser, a pink (pencil end) eraser can leave a pink color.




The shorter body tube (Part J) was a tight fit in the ring. The hold down tics were shaved down with a half round diamond file.

The launch lug fit was also tight. A sharpened dowel widened the hole a bit.


With the L spacer piece glued on there was a slight space between it and the launch lug.

FIX: A rectangle piece was cut from the leftover cardstock and glued to the top of the "L" spacer support to fill in. Keep the leftover cardstock pieces for quick fixes like this.



One of the shock cords is knotted and slipped through the slit in the centering ring.