Build thread: Plasma Dart

[Raptor 2]

GETTING STARTED

In a change from my usual sequence, I'll be starting with the front of the rocket first. I decided to split the rocket between the two front transitions; it seemed a bit risky but would make the build a bit more interesting, and give me a payload section up front for an altimeter. So I will first construct the entire payload section.

Step one is the front transition. Because it's relatively unprotected up there, I decided to do my own version of a super-shroud, using a technique I've used a couple of times with success.

First, the basic transition is made from 110 lb card stock, my new go-to. I made this one with the tab in the back, to keep the surface smooth.
View attachment 426909
Next I added the second layer. I cut another shroud, and then remove a piece from the end roughly the size of the tab I used to connect the original. Then glue in the second piece:
View attachment 426910
Its hard to get it perfect but I did a decent job here. This approach leave exactly two layers around the entire shroud, with no extra thickness where the connecting tab is to create an unsightly bulge. The inner piece does not quite go to the front of the outer piece, else it won't fit on the body tube.

I always set my cardstock shrouds on an appropriately sized body tube and centering ring to dry, to maintain perfect roundness. That's a lite ply 5570 centering ring, with the edge beveled so that it just fit inside the end of the shroud.
View attachment 426911
When it is completely dry, the excess inner shroud is trimmed off and the edge is sanded flat.

Nice work!

 

[Raptor 2]

Cannot concentrate on work here while the air elemental is throwing a tantrum outside, so I'll post a small update.

The centering ring was glued flush to the end of the tube, and then the shroud was glued on top of it, pushed down as much as reasonable to get it flush with the ring. Glue was applied only to the ring, not to the body. That is a lesson I learned in a previous build.
View attachment 426970
The small side of this shroud turned out o be just a wee bit large, leaving a gap or two around its circumference.
View attachment 426971
A small amount of TBII was rubbed around the joint to seal it up. Looks good.
View attachment 426972
I am not particular good at filling and smoothing the joint between the small end of the shroud and the body tube. This time I did it mostly with thinned CWF, followed with a wipe of thin CA. The thin CA was also applied to the entire shroud at this point to harden it up and (after sanding) provide a nice smooth surface for painting. The shroud seam was filled a bit as well.
View attachment 426973
Came out good and very solid.

Oh, the piece of body tube was completely covered in thinned CWF for seam filling, as is my standard practice now. Continues to work well.

TBII ? CWF. ? Wood filler

 

[Raptor 2]

PAYLOAD SECTION, PART 2

Because the payload section is BT60 and the plasma core is BT55, I need to adapt down. A small insert goes in the end:
View attachment 427528
And then the end is block-sanded as flat and flush and smooth as I could make it, which is to say *extremely* so.
View attachment 427529
Pic shows a light coating of thin CA as well (sanded smooth of course).

I had exactly 2" of BT55 nose block left over from the Skywriter, which seemed to me just about the exact correct length. I inserted a dowel and an eyelet in the nose block, and then pushed the whole thing in half way:
View attachment 427530
I also gave the block a wipe of thin CA, just to give it a bit of hardness and durability. Dunno if it really helps or not.

The whole assembly looks good, and it rock-solid.

Again nice work and attention to detail

 

[neil_w]

TBII ? CWF. ? Wood filler

Titebond II, Carpenter’s Wood Filler

 

[Raptor 2]

Duh I knew that but my age is showing...thanks for the refresher. I have not had much success with CWF for filling spirals in tubes. When I sand them in comes out of the groove. I’m now using Rustoleum Filler And Primer and mask off close to the spiral grooves.

 

[jqavins]

Are you diluting the CWF? I don't have much experience with it myself, but most people dilute it just a little with water. The say to peanut butter consistency, but I would call it that out of the tube, so maybe warm peanut butter?

 

[Raptor 2]

I did dilute it just a bit but it came out of the groove in little chunks. I then tried Apogee’s method with filler primer spray but mask off most of the tube leaving just a very narrow strip exposed on the spiral groove. Worked like a charm.

 

[jqavins]

Worked like a charm.

Well, that's what matters, isn't it?

On a previous weird project, for reasons that don't matter here, I made my own filler by mixing sanding dust from a cardboard tube with Elmers School Glue. I wonder if that has a germ of a valuable idea, filler made from glue, so that once it's forced into a space it's really not coming out.

 

[neil_w]

I did dilute it just a bit but it came out of the groove in little chunks.

For whatever reason, I haven't had much problem with the CWF coming out of the grooves. The subsequent coat of filler/primer takes care of most of that anyway. Once in a while I get a bit of spiral peeking through here or there, but it doesn't bother me.

I then tried Apogee’s method with filler primer spray but mask off most of the tube leaving just a very narrow strip exposed on the spiral groove. Worked like a charm.

I must confess that I don't quite get the theory behind "masking off everything but the spiral". That seems like a bunch of unnecessary work, especially if you mask the secondary spiral as well as the primary. And also the rest of the body tube would benefit from the filler/primer spray, so why cover it with masking. And then when it comes to sanding, I find it *much* easier to just sand the whole body tube rather than try to be particular in sanding just around the spirals.

But as Joe says, if it works for you that's all that matters.

 

[BABAR]

maybe someone has already asked, but what's with the Pangolin Avatar? (Of course, since I don't even HAVE an Avatar, maybe I shouldn't be the one asking!)

 

[neil_w]

maybe someone has already asked, but what's with the Pangolin Avatar? (Of course, since I don't even HAVE an Avatar, maybe I shouldn't be the one asking!)

Just some nonsense.

 

[kuririn]

Just some nonsense.

So what are Tenet Rocketry's tenets?
My #1 tenet is to have fun.

 

[Raptor 2]

Maybe Neil is an endangered species.

 

[neil_w]

So what are Tenet Rocketry's tenets?
My #1 tenet is to have fun.

Honestly, Tenet Rocketry is all about the pangolins. I mean, just look at that thing.

 

[neil_w]

Maybe Neil is an endangered species.

A fair characterization, since there is only one known instance of me left in the wild.

 

[Cape Byron]

A fair characterization, since there is only one known instance of me left in the wild.

Not married then?

 

[BABAR]

A fair characterization, since there is only one known instance of me left in the wild.

Wow, I never thought of Northern New Jersey as ”the wild.” Clearly I can clip my Kenya safari off my bucket list and just head out your way.

 

[neil_w]

Wow, I never thought of Northern New Jersey as ”the wild.”

You have no idea.

 

[jqavins]

That's quite a bit of virtually unbroken green, with a mountain range running up the middle.

 

[neil_w]

To say nothing of the area where this guy lives....

 

[boatgeek]

View attachment 485317
That's quite a bit of virtually unbroken green, with a mountain range running up the middle.

I'm going to have to weigh in with some Western US mountain chauvinism. If it doesn't have a tree line, it's a hill. Unfortunately, climate change is killing my earlier definition--that a mountain has to have permanent snow.

 

[teepot]

It snowed in the mountains last night. 8 to 12,000'.

 

[neil_w]

This rocket flew again on a D12-5. Another really nice flight. I intended to fly with an altimeter but I couldn't get it to connect to my phone... then I realized it was a new phone since the last time I used it, and didn't want to spend any time trying to figure it out, so I still don't have much clue how high it went.

3 flights in, no damage, and no parachute snags on the fin pointy things.

 

[mbeels]

Glad to hear it is still flying and you got another opportunity to launch rockets. Was this at your usual club, or did you find another place to fly?

 

[neil_w]

Nice to see you back here Marten.

This is GSSS, which is my most local club now that RadRocks is in hibernation. It’s a relatively small field but enough to get some satisfying flying in. Unfortunately the pad location is pointlessly located towards one edge of the field, so wind direction is a dominant factor in determining what kind of flying you can do.

On a more positive note, it’s a public park with restrooms so that’s nice.

 

[mbeels]

This is GSSS, which is my most local club now that RadRocks is in hibernation.

I didn't know RadRocks was in hibernation. Hopefully that is temporary, I do have some "fond" memories of "interesting" recovery escapades through that dense growth and drainage ditches.

 

[neil_w]

They lost the farm, so the club is basically dissolved, unless something changes.