Soyuz 1/50 build

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wrad

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Hi everyone

My current build experience is mostly Estes kits for low power and PML for mid/high, so I have been looking for a challenge to push my building/ rocketry to the next level.

So, whilst watching a Soyuz launch a few months back I thought how could this be done? A few well spent hours of YouTube “research” later and I came across this masterpiece.


[video=youtube;syqW2kNgLEk]https://www.youtube.com/watch?v=syqW2kNgLEk[/video]


And so, spurred on by a brother with access to laser cutting/3D printing project Soyuz was born.

The aim is to build a 1/50 scale Soyuz, using PieroAcme’s fantastic model as a guide.

New challenges to be faced will be clustering, staging, and strap on boosters (nothing to hard then he jokes) as well as scale building/ detailing.

So as i said this project has been on the go in my head for a few months with the first stages of the build started this morning so i will fill you in on the jump from conception to today

Scale reference was found here on the rtf mostly, with the majority of measurements taken from this blueprint (although I now have a small library of Soyuz/Vostoc plans/diagrams).

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Staging/ booster separation will be attempted using PieroAcme’s method which is better demonstrated by a link in the comments of his video, showing some photos of his build. (unfortunately I just checked this link and it has died in the last couple days, however I have a copy of all of the images for reference fortunately).
 
So to the good stuff, unfortunately open rocket is somewhat limited when it come strap on boosters/ so is my ability with the program, however it has served well for the "blueprinting"/designing of my Soyuz.
The rocket has been split into to .ORK's, one for the core 2 stages and one for the side boosters.

View attachment 1-50 soyuz core v4.ork
View attachment 1-50 soyuz side booster.ork

So for the eagle eyed/ those that love scale builds, my scale is slightly off, after creating a 1/50 scale drawing of the Soyuz in open rocket, i have then converted all of the straight tubes to standard tube sizes as for one, rolling my own custom tubes is for now beyond me, and secondly they all fell within 1mm or so of the desired diameter, all of the other diameters were then adjusted to better represent the new scale, so whilst the final rocket wont win a scale rocket contest for ultimate accuracy it will proportionally be correct, and thats whats important to me.

The only major other adjustment is that the motor tube for the side boosters will actually be offset in the booster by a small margin to bring the top of the motor tube flush with the edge of the transition at the top, this will bring the centre of thrust closer to the core which will also be aided by the angled mounting of the boosters.
 
Great project...susbscribed.

I like the spider system used to light the cluster in the video, plenty of information out there on that.

Looking forward to the build.
On my list as well - someday.
 
So I ordered all the standard size tubes + some spare for when i inevitably mess up, as well as some couplers and engine hooks.


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The next job was the centering rings, many of the rings are standard sizes however the boosters all have offset centre holes, as well as some custom sizes for the core stage, so i had them all laser cut by my brother.

The added bonus to this was he did me a bunch of spares as well as cutting them in several different materials.

The black/white faced ones are in a heavy card stock similar to the estes cardstock rings, these came out fantastically, fit snuggly and are plenty strong enough for the purpose of this build. He also did a few in thin plywood as well as a full set in foam board as its his material of choice for RC plane building. The foam board rings are incredibly light and strong, however the foam has some shrinkage away from the laser cutting edge, so would require a space filling glue (hot glue is the preference plane builders), also the very thin rings have warped from the heat so wont work.

The final advantage to the laser cut rings is that the booster rings have all been cut with a very faint score line through the centre for alignment purposes, which should make the build much less tricky.

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For the most part i will be using the cardstock rings however a few foam board ones may make it in to the final build.
 
And so to actual building....

I am starting with the core of the rocket first, building from the bottom up, so natural started with the 1st stage core booster.

I don't use any specific tools for cutting body tubes, so the technique that i have found works best for me is a s follow;

1. Use a thin card cutting guide taped around the body tube to provide a straight edge (same idea as the fin marking guides)
2. Measure twice (very important) (give a fraction of a mm extra for step 4), cut once.
3. Use a new scalpel blade, cut slowly and a little at a time.]
4 After cutting, gently sand away any burs/cutting imperfections to give a smooth straight cut.

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So with the tubes and couplers cut, and notches added to the rings for engine hooks everything is ready for a dry fit before glue.

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With everything mocked up for the booster, gluing of the centering rings and engine hook in place commenced. Whilst that was drying i made some motor blocks from some spare 24mm tubing, 4 5mm rings were cut then split in half the first was trimmed so it fits within a 24mm tube without any overlap the the remaining 3 were glued in a concentric spiral inside to make a thick ring ready to be glued in place.

A small slot was also cut for the sustainers engine hook to slot into, this will enable the rear of the sustainers motor to be inserted into the top of the boosters motor tube with just the engine block between the 2 motors which will hopefully make for good staging and sustainer ignition.


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With the glue drying on the booster i have moved on to the sustainers engine mount, unfortunately my tubes i fall a few cm to short so i am going to have to split the tube and add a couple, something i should have foreseen when ordering the tubes. I thought the best place for the split would be with the lower portion of the sustainer just above the motor mount and in the bt60 tube where i could support the join with extra cantering rings, so i created a short motor mount that will be couple to a long extension later.



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the sustainers motor mount was built in the same manner as the booster, however i trimmed the engine hook with a dremel to make it as low profile as posable, and used a strip of paper wrapped around the motor tube and hook 3 or so times as the tensioner as the centering ring of the sustainer doesn't overlap it like with the booster.
so heres the two drying.

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I mocked up the sustainers motor mount extension and cut it to length next and came up with a solution for the lack of tube coupler which i had overlooked. I have a yellow motor mount building tube that those familiar with estes kits will know of which is usually used to position the motor block within a tube, however it just so happens to be an almost ideal coupler, the problem is i want a rely snug fit with no movement to keep the core strong and the yellow guide is a loose wobbly fit, the solution, glue a bit of thick paper to it to make it thicker, and there you go one tight fitting coupler with no play.

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So they you have it one full length motor mount ready for the next steps of the build.

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And here is how the 2 motor tubes will align within the airframe.
 
So to introduce myself i am the brother with access to a laser and 3D printer!


While i have a fair amount of experience with 2D cad programs and laser cutting this is my first proper foray into the world of 3D modelling and 3D Printers. After a phew hours playing round yesterday i was able to model the basic nose cone and launch escape tower for the centre core as well as the nose cone for the side boosters.

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Once I achieved this i was able to test print the parts this morning and i am fairly happy with the results. The 3D printer was set to fast print as they will be sanded and painted anyway. The Centre cone and launch tower fit together really nicely. The only place that the 3D printer seems to have struggled as you can see in the pictures below is the tip of the side booster cone has gone a little wobbly, nothing a bit of filler and sanding shouldn't be able to fix.

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The parts were printed with a lattice structure in the centre which makes them very strong but a little heavier so the the nose cone and launch tower have a combined weight of 48.7g and the side booster cone has a weight of 10.6g. These parts will now make there way to my brother for fit checks ect. so we can see if any modification are required before further prints are done.
 
So i have been toying with centering ring positioning and whether to end the lower body tube at the first transition (option A) or to extend it into the transition up to the next centering ring (option B).

option A vs option B
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I decided to go with B as although it will be slightly heavier the design will also offer far more strength/ stiffness, not just relying upon the centre tube for strength.

Thinking over, I glued the motor mount tube sections together with my DIY coupler and fixed the remaining centering rings in place for the lower body tube.

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Got all the tubes cut to length now and mocked up the whole centre stage tubes, she is rather a lot taller than i expected even if new exactly how big it was going to be from the start.
 
What amazing build,Saturn V kit has nothing on this!And this is not a kit!Thanks for sharing looking forward to see the finished product!
 
So we decided to have a bit more fun with 3d printing and have a play at modeling some of the smaller parts to add detail to the build. For this we have started with the grid fins.

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These posed a bit of a challenge!

As you can see from our first effort on the left the frame printed fine but the printer ignored the internal structure. After some research and experiment we got it to work as you can see from the right grid fin. Although i damaged this one as i removed it from its support structure, and forgot to photograph the good ones before i sent them with the other printed parts to my brother for fit checks.

So the solution to our problem here is that 3d printers have a minimum wall width that they will print and if the drawing has walls smaller than this the printer will ignore them. The printer that i have been using has a 0.4mm nozzle but doesn't particular like printing single skin walls so we had no luck printing walls drawn at 0.4mm they were simply ignored. It will sometimes print walls that are drawn at 0.6mm depending on which axis it drawn in strangely. To guarantee that it printed correctly the walls were drawn at 0.8mm which leaves us with a result this isn't quite scale but still has lots of detail.
 
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To finish the core structure of the rocket upto the interstage seperation (minus the transitions) I glued the transition centring ring in place followed by the next centring ring for the final body tube before the interstage., the final centring ring was glued firstly to the body tube as it lies flush with the end of the tube and i wanted the fit to be perfect. I used white wood glue on the inside of the tube and CA on the outside which i was then able to sand to give a very smooth transition from the tube to end cap.

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once dry the upper body tube/ centring ring could be slid over the motor mount and glued in place.
 
whilst the glue on the core stage was drying i started marking out the strap on boosters motor mount tubes.I marked on the centring ring locations, an arrow for direction and a centre line using the preferred method for the estes kits i.e a door frame as the guide. the centring line will be key for the alignment of the centring rings which all have a laser engraved centre line for alignment.

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The next job was preparing the lower centring rings for the boosters. The boosters have a small flat indentation at the base which aligns with the vernier thrusters of the core stage, which i will be using as a ledge under which the 1st stage of the core will press up against in order to lock the boosters in place during the first stage of the flight.

using an exacto i cut away a flat section from 4 centring rings which will be the lower rings, then glued the offcuts to another set of 4 rings which will be the next centring rings of the booster, hopefully this will enable me to firmly glue a flat piece of card in place to simulate this feature.

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So this is where i am upto now, the core stage booster is finished, the core second stage is built upto the interstage apart from the 2 transitions and the cores upper body tube (recovery hardware compartment) has been cut to length and marked up ready for attachment to the main motor tube/ for its own transitions to be built. Finally the side boosters motor tubes have been cut and marked and the centring rings for each prepped for assembly.

Altogether not to bad for a couple of weekends tinkering.

P.s. By finished i mean the flight structure is built rather than totally finished as obviously i have a lot of detailing etc to make it look like the real thing.
 
So last night the postman delivered a parcel of 3D printed parts courtesy of my brother. I was very exited

To test out the fitting he had sent me 2 versions of the main nose cone and an escape tower, 2 side booster nose cones, and 5 grid fins.
These are the first 3D printed objects i have held personally and i was immediately impressed with the weight and solidity of the nose cones. Printed in ABS plastic they feel very comparable to the very solid cone from my PML IO kit.


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A quick test fit of all the cones in there respective tubes found they were all perfect fits, not requiring any sanding or tape apart from the main nose cone with the 1cm shoulder which we had specifically made with a looser fit just for testing.


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All the parts will require some finishing due to the nature of 3d printing however this will be far less than i expected and will be no more complex than filling the defects an a moulded nose cone. The biggest challenge will be the tips of the side boosters which are a little wobbly, however 5 mins with some squadron green putty and i had one of the test pieces looking rather good.

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Great work Wrad ! I found your post by chance and I thank you for taking reference form my model.
I'm really interested to see the progress of your building.
If you need other details or info let me know, even I see that you are proceeding very well.
Best wishes for a successful project
;-)
Piero
 
Thank you Piero, Great that you think its going well, I can only hope it flies half as well as yours in the end!
 
yesterday i took delivery of some kevlar cord that i had been waiting for in order to construct the recover harness, so was able to move on with the core stage.
With the interstage gap and only a short length of motor tube to attach the centring rings to for the upper stage (probably should have left myself some more to work with) I was a little concerned about the strength of the rings and how close together they would be. After much pondering i decided to sandwich a heavy card stock ring and a plywood ring together to make a thicker and much stiffer ring, hopefully this will strengthen up the top section of the rocket a little without adding to much weight

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My second concern was the kevlar cord as it is fairly thin, and i am sure many have discovered that it acts as cheese wire under tension, I therefor wanted to make its attachment point as strong as possible.

In the end what i settle on isn't particularly pretty but should be more than adequate, i doubled up the thread and made it into a y harness, which parses through the forward centering ring (sandwiched like the previous one) with one side looped around a small plywood ring and and the other looped around the motor mount.
The reason i ended up with this asymmetric anchoring of the y harness comes down to me being indecisive as to which would work best, so obviously i chose both.

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The final bit of progress has been to cut the slots in the side boosters centring rings for the engine hooks and test fit them before gluing.

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Its been a fairly productive weekend on the 3d printing front. I have been able to print what hopefully will be the final pieces used for the rocket as well as a full second set as spares.

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You can see from the pictures that once we fit checked the 3D printed parts with the tubes being used to build the rocket we have been able to make a phew small alterations and have had a go at adding some detail to the parts, which has worked fairly well.

For people that are interested i wanted to give a little bit more detail on how much time it has taken to print these pieces and mow much they are costing from a material point of view so here we go:

​ABS Filament Price Per KG in £**ABS Filament Price Per Gram in £Part weight in Grams*Cost in £Print Time in Minuets*
Nose Side Booster nose cone£16.18£0.0211.9£0.2054
Escape Tower£16.18£0.0214.9£0.2470
Main Booster Nose Cone£16.18£0.0250.3£0.81191
Grid Fin£16.18£0.024£0.0615
*Just to note that all Print times and weights of material used could vary massively depending on printer and the print settings used. I have been using a UP Plus 3d Printer with the following settings: layer hight 0.25mm, print quality fine and loose infill.

** Filament price also varies a lot anywhere form around £10-£30+ per KG, the filament that i have used is a white ABS made by a company called COLIDO, It is very much a mid range filament and so far i have been happy with the results.

So 4 side booster cones, 1 tower, 1 main nose cone and 4 grid fins have a total 3d printer material cost of £2.09!!
 
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Ok the build has been slow for a week or two whilst i figure some bits out.

The final body tube of the core stage (upper stage of the real thing)has been glued in place, using a piece of aluminium box section to keep everything true and straight.


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With all of the body tubes now in place I began with the card stock transition sections which have proved to be far more tricky than i could of imagined. After a few days of painful fiddling i am finally happy with the first couple of transitions, so here is my method and some of the issues i encountered.

Firstly i made patterns using a conical transition calculator online (I cant remember which I used but there are many to be found with a 30 second google search). this is where i encountered the first problem, printing the templates out resulted in slightly smaller than desired templates which didn't fit, drawing the templates myself in CAD software then printing them as a blue print had no joy ether with the printer slightly downscaling the print ( I believe this can be fixed somewhere in the printer settings however i was using a work printer with no access to print settings) I solved the template sizing issues by trial and error, by upscaling the templates manual at the expense of a large number of sheets of card, however they now fit.

Once cut out i bent the transition sections by rolling them around a body tube and pressing them into carpet to act as a soft mat to curve them, this technique worked well to give a nice curve to begin with, next i used a failed attempt of a transition taped together as a mould to bend the transition into its final shape, a tab was glued to the inside along with a zig zag tab for joining the two transitions together. Finally the surface was gently sanded before being soaked in ca glue, a final gentle sanding gave the final transitions ready to be glued in place.


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Its been a slow few weeks on the Soyuz build, with other rocket repairs taking priority, some small progress has been made.

For the side booster engine blocks i used a spent casing sliced into disks. With the engine blocks in place the all of the side booster centring rings have been glued into place. Finally the detailed nose cones have arrived from my brother and i have done some finishing work on them to smooth out any minor print defects and glued the tower in place.

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thanks everyone for the encouragement!

with a long weekend this week i have been able to move the Soyuz project build on a little. The last 3 card stock transitions have been glued in place along with centring and support rings for them. the same technique was used for the transitions as with the larger previous one. I used a little cord to bind the transitions in place as they were glued just to hold things where i wanted them. I am very pleased with the outcome with only a couple of small gaps and cracks that will be easily filled and sanded smooth at a later date.

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With the completion of the last 3 transitions all of the main structural elements of the core booster are in place, so i have moved on to do some detailing on the core. I am aiming for a good level of fine detailing, enough so that the rocket looks like a good representation from fairly close however not so much that i spend the next 2 years making it look picture perfect, its going to fly after all. The main detailing elements of the core stage are the interstage support structure, the wiring conduits along the length of the booster, any of the larger details of the payload fairing and the grid fins which have been 3D printed already. For the most part i have been using scraps of balsa for almost everything.

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so here she is so far, looking somewhat like a rocket already.

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so today i tackled the job that i have been least looking forward to, making the transitions for the side boosters. after the difficult fiddle that was the transitions on the core stage i was a little concerned about the amount of work required to make all 4 side boosters, 8 transitions in total, however things went really well dare i say.

I have revised my technique slightly for these larger transitions. the first thing i did was create a card template by wrapping one of the side booster cores in card and taping it in place, i then drew around the top and bottom, and down the centre line, enabling me to cut out a perfectly sized template for the large conical transition. 4 fresh transitions were then cut. For the lower transition which is cylindrical I simply cut the correct size rectangles and removed a notch for the ledge, and glued on connecting tabs.

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the lower transitions were then rolled around a rolling pin and banded in places to give them the desired curve. the larger transitions were the curved using the handle of a wooden spoon pressed into the palm of my hand to gently curve the transitions, which worked perfectly. thje connecting tabs were then glued in place leaving gapos for each of the centring rings.

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the large transitions were then glued into rings/ cones using ether the template or a scrap of card taped around them as forms and the cores inserted to oress from the inside, this gave nicely round and perfectly sized transitions. ready to be glued in place at a later date.

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