Yep, another Partizon build thread...

[jeff_j_black]

Actually this thread is an homage to the other Partizon threads. There is lots of good insight and suggestions in these threads. I'm not a great builder. I spend a lot of time reading the threads here, marveling at just how skilled the posters here are and the amazing results they get. I cherry picked the particular ideas that suit the outcome I want. 1) The third tube will be incorporated into a payload section. 2) I hate finishing fins. So I will paper them using Avery self-adhesive sheets. 3) This should be a potential platform for 29mm H or I motors, but will mostly fly the AT G reloads.

The Partizon threads:
https://www.rocketryforum.com/showt...ng-an-Estes-Partizon-Build&highlight=partizon
https://www.rocketryforum.com/showthread.php?131072-Estes-Partizon-PSII&highlight=partizon

Papering fins:
https://www.rocketryforum.com/showthread.php?134261-Biohazard-build-thread&p=1590650#post1590650
https://www.rocketryforum.com/showthread.php?134261-Biohazard-build-thread&p=1586422#post1586422

RKT Files for the Partizon:
https://www.rocketryforum.com/showthread.php?51331&mode=linear&p=503933#post503933

The kit is sold out on the Estes page where I bought it for $22.50. This was an incredible bargain!
You can still get some parts:
https://www.estesrockets.com/rockets/accessories/pro-series-ii?p=1
https://www.estesrockets.com/rockets/pro-series/parts
Though I can't find centering rings in these pages.

I did a PDF scan of the fins, and actually tested transferring it to 1/8 inch plywood using the Avery self-adhesive paper and cut one out. That essentially gave a good cutting guide and papered one side of the fin by default. I test fit it and set it aside as I didn't want to spend more time working on fins. So satisfied that I can replicate the fins easily, I went forward the the stock fins.

Again, thanks to all the great posters for the knowledge imparted in the threads above. Now on with the build...

 

[jeff_j_black]

OK for starters, don't install Part K. the thrust ring or engine block. Build the motor mount, gluing only the top and middle centering rings. This allows for internally filleting the TTW fins, installing the bottom CR afterwards. This is well depicted in the threads I linked to so no picture of that here. Instead, since I was essentially working outside if the instructions for the kit. I had to be careful not to get some step out of order.
The one that is crossed out is: 'resolve shock cord attachment'.

 

[jeff_j_black]

Yeah I really drilled down to figure out the shock cord mount that suits me best. At first I was seriously considering the baffle notions. But I really just wanted a secure mount that would essentially prevent the recovery system from falling into the booster section. This is two layers of 1/8" aircraft plywood, sandwiched. The exposed edges are CA'ed. Stainless eye bolt, washers on both sides, nut secured with epoxy.

 

[jeff_j_black]

Kevlar shock cord, 1/8" spearfishing line from Amazon. Going to loop this to just the top end of the second tube for inspection and replacement when needed.

 

[jeff_j_black]

I already discarded any notion of launch lugs for this one. Rail guides it is. I measured placement at 1/2" above the bottom centering ring and 1/2" above the first tube couple, which should be close to the center of gravity. With each of the tube marked vertically with a pencil line for alignment and the holes for the rail guides drilled. I installed the motor mount tube first, as the nut for the rail guide above the bottom centering ring would prevent this installation. I used a quarter inch dowel rod to smear glue at the two locations where the top and second centering rings would be placed.

With TTW (through the wall) fins, it is also important not to get glue or install obstructions in places that collide with the fin installation. This is something to keep in mind.

With the MMT in place, installing the backing nuts for the rail guides is next. I bent these slightly to meet the contour of inside of the tube. Neither of the locations makes it easy. This is 2.5" tube, so my hands won't get in to either place to install these. I wrapped a stick of scrap balsa with padded 2 side tape, placed the backing nut on it, applied epoxy around the flange of the backing nut and managed to get these in place. I smeared the back of that installation with epoxy to seal the deal. I hand threaded the rail guides in place to make sure I could rescue either, if they fell back in before drying.

MMT and rail guide backing nuts installed:

 

[jeff_j_black]

Papering the fins comes next. Using this paper, thin CA to seal the edges and provide a sanding surface to lightly sand smooth. I will keep the edges mostly square.

Paper one side, leaving a thin margin along the root edge to support filleting later. I ran a thin bead of CA along the line where the edge of the fin and the paper meets. Once dry, trim the excess paper away. Repeat for papering the other side. Finally run CA along the exposed edges of the fins and along the outside edge of the paper. CA of course is sticky and can get you into trouble fast. Make sure you mind what you are doing and don't let CA go where you don't want it. Also the Avery self stick paper is very sticky. Occasionally, a corner of it would catch hold of my cutting mat. Again mind what you are doing closely when working with stuff that is final or takes a great amount of MacGyver skills to back out of.

Sand the edges with 220 grit. A slight ridge of paper can develop, treat that carefully with the 220 grit. But do take it away. Follow same with 440 grit. Ready to install!

 

[jeff_j_black]

Avery comes through again with an easy fin guide that I drew in CAD, applied to the side of a 12 pack and cut out.

Fins installed:

Used this basswood strip to reinforce internal joints:

There is lots of Elmer's glue involved here. So while it was drying, I kept orienting the assembly vertically, first downwards then upwards to reflow the glue until all was dry.

 

[jeff_j_black]

The bottom CR is now installed with a fillet as well. Currently working on the fin fillets. Please note as this is paper and wood, I am allowing ample time between steps to let glue from the previous step to dry thoroughly. I'm trying not to trap wet glue on one side of things to have wet glue on the opposite side as much as possible. I just came up with the theory that this is where bubbles in fillets come from.

One thing I snuck in but didn't depict earlier, the bulkhead for the payload section and the top coupler are installed, completing the payload section.


To be posted in the future:
I will paint the booster and nose cone together, first with primer, then flat black. For the next two tube sections, I'm thinking of using the Avery stick paper to do wraps that I drew in CAD. These are trial prints. Each covers the circumference of half the length of the tubes:

After I weigh the components carefully, I might try to shorten the payload section by half, to provide a second interchangeable payload bay. Back to work tomorrow so will post next weekend hopefully.

 

[K'Tesh]

If you want to sim it, I've updated my .ork file for the Partizon, the colors won't match your custom paint, but you can always change that.

https://www.rocketryforum.com/showthread.php?123564-K-Tesh-s-OpenRocket-files&p=1443205#post1443205

 

[jeff_j_black]

Great! Thanks!

 

[jeff_j_black]

OK, so I'm resuming posts a couple of weeks later. Don't fret actual pictures of the build still on the way. But first a word about rattle can painting. To begin with, read all the other posts on TRF about spray paints. I didn't want to get this part wrong. So two Sunday's ago, I got the primer on. I applied several coats, with some sanding in between as needed. I get what I need as far as primer on there. Great. So I start reading the instructions. This is Ace Premium Spray Enamel. And much like wisdom in the other posts, it is good to know the parameters you are working within. The label for the drying times is clear. Dry to touch in 25 minutes. Recoat within two hours or after five days. Dang if I didn't already purchase the flat black I am going to apply to the fin can and the nose cone. And the way the day lines up, I would not be able to get the paint, let alone in under two hours and have time to apply it. OK, I'll let it dry until the next weekend. So what to do in the mean time?

 

[jeff_j_black]

I need an E burner to finish cooking off some Estes BP E9's and E12's. I had a lot of fun papering the fins as mentioned above. (Avery self adhesive label sheets and thin CA). I also wanted to practice the body tube wraps. So here it is: "Team America, World Police". Yeah don't bag on me as this is not any political slur. It is the title of a movie, one that probably could not be made today. Anyway, rocket name, not any sort of political bent, just something to snicker about as you burn off some Estes black powder E's.

I have some choice Christmas wrapping paper tubes on hand. A couple have a nice sturdiness to them with no outwardly visible spirals. 38mm in diameter and 36" in length. I cut the tube to 30" to accommodate three wraps printed on the Avery 8.5"x11" self adhesive paper.
Wraps came out OK, fairly easy to roll the printed Avery sheets. I drew these in Delta CAD.

One of the hatch patterns makes for good corrugation effect and I also printed the slot cutting guides right on the wrap for through the wall fins.

I also spent time rounding the leading edge and beveling the fins, while using the Avery paper and CA. I have papered over the rounding and the beveling. Apply the paper to one side, a bead of CA on the edges, making sure the paper is well attached to the bevel. You have to be careful not to crinkle things as you trim the paper away and roll it over the rounded edge, finishing the other side in the same manner. this is 3/32" basswood.

One more look at the wrap:

The third side reads: $&%@ Yeah. (Actual spelling, special characters in place of the curse word, not shown).
The rule line to align the wraps also helped with lining up the 1/4" launch lugs and engine hook. I cut the centering rings by drawing the circles in Delta CAD, printing on the Avery labels and affixing these to cardboard. (30 pack beer carton card board is my choice). I glued two layers of this cardboard together and cut out two rings for the motor mount. The nose cone is built up in a similar manner, rolled cardboard as the shoulder, centering rings to hold a short run of 24mm tube, for some reinforcement. the actual cone is 100 something pound paper. There is an 18" metal ruler in one of these photos for scale. It is a solid 3FNC, looks decent too.

 

[jeff_j_black]

So back to the Partizon.

After the five days had expired, I resumed painting. First one more touch of 400 grit on the primer to smooth a couple of spots. Next the flat black Ace Premium Enamel. Both the nose cone and the fin can came out with a nice satin appearance.

I reworked the wraps in Delta CAD. I wasn't quite happy with my first few tries. I went for a sort of Saturn Five ripoff look.

The wrap on the second section needed a small cutout to clear the rail button weld nut. but other than that the wraps went on. I used a black magic marker to fill a couple of gaps at the seams.

To finish assembly I cemented the motor retainer by roughing the interior of it and applying 5 minute epoxy to the motor mount tube after roughing it a bit as well.

I installed the coupler into the fin can, then the second section using some aluminum angle bar to line up the rail buttons before the glue on the coupler set.

That's it! I just need a clothes line to hang the laundry off of and we can go flying!

 

[jeff_j_black]

Moving this thread to the watering hole...

 

[K'Tesh]

Looking Good!

Why move it to the watering hole though?

 

[jeffjblack]

It's Throwback Thursday, so here is a blast from the past. This is the Estes Partizon at the National Association of Rocketry's National Sport Launch hosted by FLARE and SMRA in Almagordo NM. I'm estimating from the flight simulation that the Partizon got over 3000 feet. I trimmed the parachute ejection delay from 14 seconds down to 11 seconds based on the simulation. Jolly Logic Chute Release was used to allow the chute to inflate at 400 feet. I used the Aerotech H135-14a White Lightning DMS motor. Don't worry, I'm certified for this.
Check out the video here:

https://bit.ly/partizonatnsl2017

 

[Nytrunner]

Hmm, are you related to the original Jeff_j_black?

Good flight, any idea why the audio was so....jarring?

 

[jeffjblack]

Hmm, are you related to the original Jeff_j_black?

Good flight, any idea why the audio was so....jarring?

Video and Audio slowed by 50% to make things watchable. It was very windy and the camera is just taped to the side of the rocket. Not much to muffle the sound of that. Thanks for watching!