Monday, January 20, 2020

Fin Tracings TIP


From Stanton Ewert on the Estes Model Rocket Facebook page: 
"*Tip of the day: Our Good buddy, James Helman in TX. taught us to keep all the face-cards from our Estes kits. It just dawned on me this morning to trace an out-line of the fin patterns on the reverse side in case one needs to make a repair, or re-build/copy; now; why didn't I think of this sooner - I got a LOT of face cards to go back & revisit to add this idea to them."

This is a great idea, a lot easier than scanning, editing and filing.
I tend to keep the face cards and instructions in the flat kit bag after a build is complete. Tracing the fins on the blank back of the face card would make for an easy repair or fin replacement later on.

Next time you are on the Estes Model Rocket or Model Rocket Fanatic Facebook pages, check out Stanton's hand painted models. Beautiful work - He must have a very steady hand!

Semroc (Centuri) Excalibur KV-43 Build, Part 6, Shock Cord Feed


Feed the Kevlar line out the top of the lower tube.

I mark the Kevlar below the top lip of the tube.
If the ejection were to happen too early or too late you could end up with a Zipper. A Zipper is a tear down the body when the Kevlar extends beyond the top tube end.

Here's the steps to feed the Kevlar out the back to tie on the elastic shock cord . . .


TIP: Make a grab wire out of a coat hanger. The top loop hook should be small enough to fit past the engine block in the engine mount.

The picture on the right shows the hook pulling the Kevlar out the bottom of the rocket.



With the line out the back, look for the mark made earlier. The black mark should be the top of the loop in the overhand knot.






While the Kevlar is still out the back end of the rocket, the elastic shock cord it tied on.

Feed both lines back (again) through the front end. The picture at the right shows the tie with the Kevlar line below the top lip of the body tube.

Sunday, January 19, 2020

Semroc (Centuri) Excalibur KV-43 Build, Part 5, Fin Gluing


The engine mount was glued in first. As I mentioned before, there is not much clearance between the ST-8 and ST-7 motor mount tube.

TIP: By gluing the engine mount in before gluing on the fins, I can then mark the tube and center the engine hook between two fins.






Here's the small upper fins on the ST-7 tube.

Look close to see the filler primer filling the remainder of the lower tube seam. In the higher seam you can see some beige CWF filler.





I didn't think the engine mount upper ring glue joint was strong. With the tubes so close together, I dropped in some glue to fill a bit of the void at the rear. After it dried the glue shrunk and wasn't as visible.

Saturday, January 18, 2020

Semroc (Centuri) Excalibur KV-43 Build, Part 4, Filler Primer

The fins were sprayed with filler/primer before gluing onto the body tubes.

On the left is one of the larger, lower fins after sanding down the filler/primer. The remaining gray filler shows how uneven the surface is.
On the right is the small upper fins, before and after sanding to surface.


The balsa nose cone and adapter were rough!
I did have to build up the shoulder edges by brushing CWF filler over the edge and quickly turning it against the body tube edge. This picture shows the raised edge bead after it was pulled out and away from the tube edge forming.






I used a sanding block to get the sides of the adapter flat. Apparently the adapter sides were a little rounded, I sanded through to the raw balsa!
This required another round of filler and sanding. The pencil marks outline areas needing attention.
The body tube seams were first filled with CWF and sanded to surface.

Here's the two sections after spraying with Duplicolor Filler/Primer. This will fill any seam that remains.

I shot the model in two sections. Tall models are difficult to spray evenly. It's easier to hit them in shorter sections.

Friday, January 17, 2020

Semroc (Centuri) Excalibur KV-43 Build, Part 3, Engine Mount


The engine mount tube had a small "stab" cut meant for the upper bend of the engine hook.
I extended the left side of the slot with my knife using the flat back side to square it off.
I didn't want to punch the engine hook through the stab slot and tear up the tube.



The Kevlar line gets a loop knot and is set under the upper bend of the engine hook.
TIP: There is very little space between the engine mount tube and the outside lower tube. Tie the knot so it will end up over the top of the engine tube when the mount is inserted. If the knot were tied closer to the top of the hook, you might end up with a bulge showing through the outside tube.




The fit of rings over the engine hook is too tight.

Cut a shallow notch on the inside of the rings (inset picture) so they can slide over the engine hook.



The finished engine mount fit was too tight in the ST-8 tube.



The centering rings were sanded down with 220 grit on a block. It took some sanding to get a good slip fit.

Thursday, January 16, 2020

Semroc (Centuri) Excalibur KV-43 Build, Part 2, Fin Prep




The fins were removed from the card stock sheet using a hobby knife.
The ash left from the laser cutting darkens up the edges.
Trust me on this -
Wipe off the burnt ash from the edges before proceeding. Remove most of the ash with a paper towel.

Sand off the remaining ash and hold-down tics with a sanding block and 400 grit.
If the burnt edges were left on, it would be difficult to cover the dark edges with spray paint.
The instructions say to use CA glue to "seal" the edges and prevent de-lamination. TIP: NEVER use CA glue on a root edge prior to using wood glue to attach to the body tube. CA will seal the card stock (or wood) fin. The wood glue can't absorb through super glues.

I applied a bead of white glue to the outside edges, none on the root edge. The glue was rounded with a fingertip. This rounds the leading, outside and trailing edges a bit.

After this dries, sand and smooth the round bead with 400 grit sandpaper.

Run your finger over the edge. If you feel any roughness, sand again until smooth.

Wednesday, January 15, 2020

New 2020 Estes Catalog Is Online!




From Y.O.R.F., Swillie found it first!
The 2020 Estes catalog is online: CLICK HERE

I'll let you explore and find the new items on your own.
My big takeaway - A C5-3 engine is recommended for the Leo Space Train and other large 18mm powered models. The C5-3 is listed in Engines (Page 70) as a "Super C".

TRIVIA: The "Super C" engine name is taken from the original engines made for Centuri: CLICK HERE