Soyuz build from Cosmodrome Vostok

Looks good, I can't wait to see the finished product. How much nose weight will you need to make it stable? The stock kit came with 10 ounces and even that seems to be riiiight on the edge of safe, I can't imagine what this'd need...:y:

Great project .... following this one closely! Really like the 24mm mounts in the pods. Someone should "sub-kit" the parts needed to convert the Cosmodrome Vostok to a Soyuz, complete with nice photo-etched launch escape grid fins.

delta22 said:

Thanks. I figure that with about 60-80 hours into the build so far, it is about halfway done. Will definitely complete this and fly it this spring. I will not start any other complex project until this flies.

With slow epoxy curing and project planning and complexity this build will take months to complete.

There was a beautiful Soyuz pictured flying in the latest Sport Rocketry.

A number of websites have interesting information on the Soyuz including this one:
https://www.spacelaunchreport.com/soyuz.html

I already have the motors for the Soyuz' first flight:
1x ProX 29mm 3grain G125 Red
16x Estes D11-P

total impulse: 477 Ns
average thrust: 301 N
= I-301

Estimating flight weight around 8lbs, including 2lbs of motors and 1+lb nose weight. Nose weight will be dialed in when I can weight the completed rocket and more accurately model it.

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Is that central G125 enough?

Doesn't it call for an H?

I assume you simmed it. Even with the D12's I wouldn't think it would get much altitude.

Not being critical, just curious.

wilsotr said:

Great project .... following this one closely! Really like the 24mm mounts in the pods. Someone should "sub-kit" the parts needed to convert the Cosmodrome Vostok to a Soyuz, complete with nice photo-etched launch escape grid fins.

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Mike Kruger of Cosmodrome Rocketry mentioned that he would like to offer options on the Vostok kit for rocketeers interested in building other variants in the R7 family. As he produces the kits himself, the time involved in designing and kitting these would be a formidable undertaking.

sandman said:

Is that central G125 enough?

Doesn't it call for an H?

I assume you simmed it. Even with the D12's I wouldn't think it would get much altitude.

Not being critical, just curious.

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A very fair question, and one I smile to think about....mmmm... all that fire and smoke....

While I greatly appreciate RockSim's help modeling stability, I find it is frequently very optimistic when it comes to estimating altitude.

Comparing to similar recent projects provides insight.

1) British Electric Thunderbird (2x FlisKits Thunderbird)
11x 24mm motors, 7lb flight weight, 4 flights, thread: https://www.rocketryforum.com/showthread.php?t=8817
Mid to full H impulse flights produced altitudes of 650 to 900ft.

2) Hell Boy (2x Fat Boy)
19x 24mm motors, 8lb flight weight, 2 flights, thread: https://www.rocketryforum.com/showthread.php?t=15812
Low I impulse flights produced altitudes of around 800ft.

The Soyuz will likely be marginally heavier than these and have moderately more drag.

The Estes motors have a delightful thrust spike at the beginning of their burn which is perfect for getting good speed off the rod and dramatic initial liftoff pictures.

The 16x D motors all by themselves are a solid H motor equivalent, and the G125 is a full G, so the combination is a mid I. I expect between 700 and 900 ft altitude with an initial acceleration of 10+Gs.

Will have to complete the rest of the build before finalizing nose weight and determining final build weight. I expect flight weight will be about 8lbs, if it comes in well over this, will re-evaluate the motor choice. The beauty of the central 38mm motor mount is that a very wide range of motors are possible.

On several Internet videos of Soyuz launches there is a red tinge to the long central flame...so the natural conclusion is that the Soviets are using Redlines....

I agree with you that Rocksim is often very optimistic.

Regardless, this is a cool "little" project you've got going on, and I can't wait to see the final result!

Really looking forward to photos of it in flight.

-Kevin

OK, then.

It looks like you're covered.

Any chance you are coming to Red Glare? And if you are, is that beast going to be ready by then?

n3tjm said:

Any chance you are coming to Red Glare? And if you are, is that beast going to be ready by then?

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Not planning on Red Glare at this time. Time and money budget is limited.

Targeting first CMASS launch of the season, tentatively set for April 30th, for the first flight of the Soyuz.

Somewhat related, I got a good chuckle out of this pic:

https://img442.imageshack.us/img442/9841/00ztteda.jpg

Maybe you should give them a call prior to launching yours, see if they'll make a quick trip over.

Installed a thick tubular Kevlar loop for a recovery attachment point for the lower part of the rocket. I was considering different options as the core was going together and installed the loop after the core was mostly complete.

Epoxied part of a popcicle stick inside one end of the loop and the bottom of both ends together first. This allowed me to then stick both loop ends through a slot in top CR so that they touched bottom CR.

Then four more applications of thin, slow epoxy, targeting bottom, each side and top bonding points for loop ends, anchoring them to two centering rings and two body tubes. Used syringe to put epoxy exactly where I wanted it.

The very thick tubular Kevlar (from Top Flight Recovery) will be more than strong enough and not likely to cause a zipper.

Painted the inside of the core with thin, slow epoxy and sanded. Then repeated. In order to fire harden cardboard tubes against ejection charges.

To sand the inside of 2.5" lower core tube, wrapped 1/2" soft foam around a 38mm tube and then securely taped one edge of 120 grit sandpaper. Twisting one way loosened the fit, twisting the other way tightened while sanding.

Formed the core conduit from 1/8" basswood instead of the supplied balsa for more resistance to wear and tear.

Glued conduit pieces on with 5 minute epoxy. After a light clean-up sanding painted conduit and immediate area with slow epoxy, then wiped off all excess with gloved fingertip.

your on a roll , Keep the pics coming !

I want to ask is there a reason your using up that good(and pricey) painters mask for general taping down purposes ? I see a roll of plain ole tape in the background is why I ask.

Stymye said:

your on a roll , Keep the pics coming !

I want to ask is there a reason your using up that good(and pricey) painters mask for general taping down purposes ? I see a roll of plain ole tape in the background is why I ask.

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It comes up clean with no residue. Other tapes are more likely to leave gummy residue which could be an issue with later gluing or painting.

With the investment of time going into this project, I'm not taking any shortcuts with materials.

As the boosters and core are reinforced with fiberglass, I plan to directly surface bond them without using the internal reinforcements the kit specifies.

As an alternative to some of the kit detail, formed small braces to fill the gap between the lower part of the boosters and the core. These will also provide side to side strength to the booster-core attachments.

The pictured braces are formed from 1/4" basswood 1 1/4" wide and are positioned on the core at the same point where the core is internally reinforced with a centering ring.

As I was double checking my alignment lines, I was very disappointed to find that I had epoxied the conduit not in perfect alignment with the axis of the core. I didn't spot it until I dry fitted the boosters. So I cut, scraped, and sanded the conduit off the core and formed and attached a new one.

After checking all my alignment lines at least five times! Drawing straight lines across the transitions was much more difficult than I had anticipated.

Got started on the upper rocket core, starting with the section where the two halves will separate.

Used the kit centering ring and 1" body tube. Substituted a 4" piece of coupler internally reinforced with a 3.875" stiffy.

This allowed for the separation point to be much stronger, and 3" deep instead of 2". Necessary due to the fact that my build will likely be twice the weight of the kit.

Building this project as a Soyuz requires scratch building the upper part of the rocket.

I have decided to follow the kit design for recovery, splitting the rocket at apogee and recovering the two halves on separate chutes. Initially I considered attempting a dual deploy setup but would prefer to simplify this aspect of the build and also of flight prep.

The upper section of the rocket (above the inter-stage lattice) will be an altimeter bay. Wires will run down through the lattice assembly, and there will be an ejection charge in the lower part of the rocket. Electronic ejection will be backed up by motor ejection set for a couple seconds after expected apogee.

The upper body starts at 3.2" OD. As this is not a standard tubing size, I built it up by wrapping one LOC 3.1" tube with another one that was slit. Filled the now expanded slit with a strip of tubing.

I will use this approach to build up the bulge present near the top of the Soyuz. It will create extra weight, but it will be well forward of the CG and there will be 17 motors pushing this into the sky.

sodmeister said:

That makes two of us !!! I finally bought (or rather snapped one up) last spring when they became available.....almost a dream come true.

I have this bookmarked.....thankyou !

Paul

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You bought one of these ? When ? It`s Jim bye the way , Gov.

Ammonium Perchlorate said:

You bought one of these ? When ? It`s Jim bye the way , Gov.

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I think I finally got one in summer ,when Mike made a new batch of kits.It`s got like a million parts in the box...and a large box at that.

Paul

The one inch band of tube that sits just below the inter-stage lattice needed to be a slightly larger OD, both to match the top of the lower core (pictured in the next post) and for scale accuracy. To make it exactly match the lower core it mates to, wrapped it with 6 wraps of 1.3oz FG.

It would have been easier to finish this if I had applied the FG before assembling this part, but some planning is happening the same time as the building. An exciting but imperfect process

I will probably see it on its first flight at CMASS! Looks like it is the exact opposite of a 3FNC!

Considered different options regarding launch rail/rod.

While I would have preferred to go with a rail, the boosters made this a challenge. Rail buttons would have had to sit on pylons at least 2 inches tall to clear the boosters at the tail of the rocket.

Decided to go with the 1/2 inch rod lugs supplied with the kit, as these can be mounted closer to the rocket body.

In the first picture, the near edge of the popcicle stick sitting on top of the core is aligned with 2 alignment marks on the core and the center of the rod.

Then filleted rod lug pylons with the Locktite 5 minute epoxy I like to use for quick bonding, upper right second pic.

Finally 3 layers of 1.3 FG to hopefully prevent ever popping off a launch lug during flight prep.

Can see part of the (yellow) Turbine Rocket Saucer in the last two pics. Part of the reason the build is going slowly now is that I just wrote and submitted an article to Sport Rocketry on this.
TRF thread: https://www.rocketryforum.com/showthread.php?t=13727

Also considered many options for building the nose cone and escape tower, but was not satisfied with any of the approaches I could build myself.

So I sent Gordon Agnello (aka Sandman) this diagram and he is building it for a very reasonable cost. He even improved on the drawing before doing the build.

Thank you Gordon.

It is a big relief knowing I will have a nicely crafted NC assembly sitting at the top of the rocket.

The scratch builder in me feels like I cheated, however the part of me that wants to complete this build this Spring is very pleased! Someday I would like to have a lathe and learn how to use it.

I plan to carve the form of the motor nozzles from the two "features" and coat the entire piece in a thin shell of epoxy.

delta22 said:

Finally 3 layers of 1.3 FG to hopefully prevent ever popping off a launch lug during flight prep.

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Looks good! Did you extend the FG down onto the body tube to give the lug stanchions some support, or was the FG just meant to keep the lugs secured to the stanchions? Your FG work always looks so clean & precise compared to mine... :blush:

eggplant said:

I will probably see it on its first flight at CMASS! Looks like it is the exact opposite of a 3FNC!

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Yes, this is a long way from 3FNC. I've been working on developing a philosophical level of patience as this project progresses.

Spurkey said:

Looks good! Did you extend the FG down onto the body tube to give the lug stanchions some support, or was the FG just meant to keep the lugs secured to the stanchions? Your FG work always looks so clean & precise compared to mine... :blush:

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Yes, the FG extends about an inch onto the core body tube. It was particularly the pylon to tube bond I was concerned about separating due to the leverage at that point.

Thanks. Practice and good supplies are key. Also, please keep in mind that I am using very thin FG (1.3oz), which tends to go on clean and flat. Also do a fair amount of sanding, mostly with 220 grit, to clean up FG work.

Received the Soyuz nose cone and escape tower from Gordon "Sandman".

Remarkably fast turnaround, ordered Sunday, shipped Tuesday, received Thursday.

The part I received was closer to my drawing than what I could have produced and more quickly too. Thanks again Gordon.

Originally I thought that me carving the form of the lower escape tower nozzles from a larger bell was a good idea. After seeing how big that "bell" really was, I removed it and plan to form the nozzles from dowels.

After working out the planned build for the upper section of the Soyuz, made some progress on the lower part of that assembly. This is the middle of the rocket and includes the inter-stage lattice.

Pictures show the rocket's recovery separation coupler and the hardware that goes into it. The eyebolt will connect to the chute for the upper section of the rocket, the 1/4" threaded rod at the top will hold the altimeter sled, and the small holes in the centering rings and fender washers allow the ejection charge wiring to pass to the lower part of the rocket.

Second picture also shows a 1" piece of 29mm tube reinforced with 7 wraps of thin FG. This both provides a conduit for ejection wiring and stiffens the mid-section of rocket.

Bolted and epoxied these together, forming a tight strong bond.

Later more inter-stage detail, including lattice will be added.

First picture shows terminal block for ejection charge. Formed a block of basswood behind this so recovery harness has no chance to snag on it.

Last picture looks really suspicious, but I assure everybody it really is just a rocket part

The 1" gap between CRs is where the lattice will go.

Above the currently free standing CR will go the alt bay and 29" more rocket.

Will use more short sections of threaded rod and rod couplers to screw upper rocket sections together.

Built up up the upper body section of the Soyuz that transitions out to 3.55" and back. Started with a doubled up 6.8" section of body tube to get a 3.2" base OD.

Then built up three more sections (5.3", 4.0" and 3.2") of body tube to form the underlying structure for the wider section. Each time splitting the tube and adding in an extra section to expand the OD.

Used epoxy mixed with sawdust, Mr. Fixit epoxy putty, spot bondo and paper wraps over 5 minute epoxy, all in multiple passes followed by lots of sanding to finally achieve smooth transitions.