Comrades:

The .pdf is how you do it with a better chance of success:

The pic is my Soyuz and Vostok both of which are nearing ten flights each. The Soyuz cone is available at eRockets in the Semroc section. There are build postings of both here on this website.

http://oldrocketforum.com/showthread.php?t=8212

http://oldrocketforum.com/showthread.php?t=7912

Last year, the Vostok core and boosters suffered a chute melt and landed on its "feet", standing up, undamaged from about 500 Ft.

Engines are D12-3 and E12-5.

Attached Thumbnails

 

Attached Files

Art of Scale Rocketry Vostok.pdf (304.0 KB, 28 views)

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NAR 79743
NARTrek Silver
I miss being SAM 062

Awaiting First Launch: Too numerous to count
Finishing: Zooch Saturn V; Alway/Nau BioArcas; Estes Expedition; TLP Standard
Repair/Rescue: Cherokee-D (2); Centuri Nike-Smoke; MX-774
On the Bench: 2650;
Dream Stage: 1/39.37 R-7

Well, sure. Except the point of plastic model conversion (PMC) is, you know, to convert a plastic model! Hence the addition to the MPC thread.

I built the Alway Vostok several years ago, and it certainly is lightweight and it easily accommodates a 24mm motor. Just never liked the incorrect shapes on the aft ends of the strap-on boosters. The models also look naked unless you add the nozzles. Fixing those booster shapes is, in a word, non-trivial. I also really stink at making those long paper cones (I didn't use a mandrel, like Peter recommends).

If anybody ever produces a decent 1/48 scale R7, Sputnik, Vostok, Soyuz, etc, the PMC community will be in business. Until then, 3D printing the strap-on aft sections would be a good idea. Would allow some of the interesting surface detail as well.

OK, so let's stay with the MPC Vostok model. I have tried to build one of the kits using a BT-50 body tube and connected the four boosters to it like DR Zooch Vostok kit are built. Still not much room for recover device.

I have also thought about a rear motor ejection and placing a parachute or two in the boosters.

Years ago, maybe late 80s, I bought the MPC Vostok, and paid a bunch for it, around $75. Hey — it was a collectors item! A friend built one in the late 60s and I always wanted one. So, cost was really not a concern. I finally started it about a year ago. My kit is the old one with body tube and other flight conversion pieces included. At the time I also found the re-release, and it’s the identical kit, minus the flight conversion parts. I paid a little over $30, bringing my average cost per kit down considerably! (eRockets has it for $27.79). The new release has both fin sets, since the plastic parts did not change. I’m not done yet, it still needs paint, and I had planned to use the oversized fins. I’m glad to hear yours flew OK with the standard fins. I had not glued on the fins when I put the project on hold.

I was planning to fly with my 18/20 RMS with D reload, but would probably go with the Q-Jet D16 now. Recovery still has me concerned.

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Lee Reep
NAR 55948

Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor
In the Paint Shop: Nothing! Too cold!
Launch-Ready: Farside-X, Maxi Honest John, Super Scamp

Launched the MPC Vostok today on a Q-Jet C12-4. Did a big U turn and ejected on the ground. Maybe a D will work.
https://www.facebook.com/1000129240...?type=2&theater

The good news is that the laundry did eject completely out the tube.

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Based on that flight, I would not try the 13 n-sec Quest D16.
Use a full 20 n-sec Aerotech D10/13W or D21/24T.
It needs it bigg-tyme.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

Or was the U-turn a CG/CP problem?

If that is the problem, no offense to GH, but adding propellant to the back end will make it worse.

All R-7s, regardless of scale or material, balance about half-way up the flared out section of the core stage or just under the attachment point of the boosters. That's why Soyuz is a better flyer than Vostok and WAY better than Sputnik; the longer nose moment of the Soyuz allows less weight to be added farther from the balance point so the overall weight of the rocket is less.

I found one on eBay for $20. I'll have to try this out . . . .

__________________
NAR 79743
NARTrek Silver
I miss being SAM 062

Awaiting First Launch: Too numerous to count
Finishing: Zooch Saturn V; Alway/Nau BioArcas; Estes Expedition; TLP Standard
Repair/Rescue: Cherokee-D (2); Centuri Nike-Smoke; MX-774
On the Bench: 2650;
Dream Stage: 1/39.37 R-7

MarkB, I would be very interested in what you might come up with and have to say on building this rocket. All and all it's a PMC project but I think it can be made to be a reliable flyer.

It looked like a lack of thrust to me, but it could have been a CP/CG issue.

__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

it was not unstable as it did not do loops.


It arced over, but it flew pretty fast, so it does not appear to be lack of thrust.


I would guess one or more of the following:


1) Short flexible launch rod. This needs a 4 foot long 1/8" diameter steel rod.


2) Wind. It may have weathercocked. A loger rod would allow it to build up more speed and reduce weathercocking.


3) Something was not balanced. Was there weight that was not symmetrical, such as nose weight that oozed to one side or shifted?

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-Fred Shecter NAR 20117 (L2)
Southern California Rocket Association, NAR Section 430