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  #11  
Old 11-28-2017, 09:28 AM
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hcmbanjo hcmbanjo is offline
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Quote:
Originally Posted by the mole
Thanks, Faithwalker I have read Chris Blog build he did on the MPC Vostok at least five or six times. It is a great read with some good tips. I liked everything about the blog build except the ending where the rocket went unstable.

Thank you dwmzmm I believe you are one of the first guys that have given an account of having this kit back in the 70s. Its good to hear you had a good experience and the flight was stable. The picture is nice to see. Thanks again. I wonder what the C6-2 motor would be equal to what motor today?


Glad you got some tips from the blog!
I would say the rocket is probably stable, it's just underpowered with todays C6-3 engines.
The older engines seemed to have more "oomph!"
A composite 18mm D might be a better choice.
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  #12  
Old 11-29-2017, 06:54 PM
BARGeezer BARGeezer is offline
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I applaud your ambition. Like you, I got a MPC Vostok (along with a MPC Titan IIIC and an OOP Estes Cosmos Mariner) with the intent of getting a good flight out of these bricks. Call me a hardhead. Anyway, some thoughts:
1. A liner tube is a good idea, not only to insulate the ejection gas heat, but also to prevent the pressure from blowing apart the glue seams. If I remember correctly I used a BT-20 + tube, which sleeve fits over a BT-20. Erockets might still have it. I think a BT-40 would also work, if you can find one.
2. RE: rear ejection/dual chutes. That would be difficult. There is a small gap between the outboard booster pods and the main body. You would have to insert a small tube to duct the gases between them. And if you use dual chutes and two pods, you would be trying to simultaneously eject both with one charge. Very iffy, ask anyone who has flown the Estes Gemini DC. If you put both chutes in the main body it would help only if the combined volume occupied by the two chutes is less than the one chute it replaces. Maybe folding the chute a little differently would help: a longer thinner package to fit the diameter of the rocket, rather than the traditional burrito style.
3. Re: Aerotech reloads. Do you already have the hardware ? It can be expensive. Reload motors require the casing, forward and aft closures, and the drilling tool to adjust the length of the delay. You will also need to do pre-flight prep (assembly) and post-flight prep (cleaning) for each motor. I used to think gun enthusiasts were a bit fanatic with their constant cleaning of their firearms, but now I know why: the residue from black powder is highly corrosive. It needs to be removed after every use, or the internal metal will pit and corrode. Originally my thinking was to save money by buying the reloads rather than the single use motors. But do the math: if you save a couple of dollars per launch, it would take 15 to 20 launches before you break even and start to save money. Can you do 20 launches and recover your rocket every time? Maybe if you live in the Kansas wheat fields or Arizona desert. Otherwise I would go single use. No assembly, no cleanup, fire and toss.
I wish I could tell you that these launched straight and true, but they have been shelf queens for the past year. The Vostok has been painted, the Titan and Mariner are still naked. One day I'll light them up, but I have to be in my "what the hell" mode. BTW best price I found for the Vostok and Titan is at Hobbylinc, at around $17 each. I'll try attaching a couple of pictures, but since I'm a newbie to posting they may not go through. Wishing you success in your endeavor.[IMG]MPC Titan next to Dr Zooch Soyuz[/IMG] [IMG]Titan IIIC[/IMG]
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  #13  
Old 11-30-2017, 09:45 AM
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the mole the mole is offline
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Thanks, BARGeezer, sorry it has taken some time to respond to you. I had to do some family business so I have been on the road for a couple days. Being on the road gives me a lot of time to think about the Vostok challenge. Your right you have to me hardheaded to continue to work on such a hard problem of getting a stable flight out of this rocket.

I'm glad you agree about using a liner tube to keep the heat away from the plastic.

My thoughts on the rear ejection I am shelving for the time being. Your right it would require a lot of work and you would be adding more weight to the rear end and that is something we don't need.

I have given the motor the most though and I agree a single use 18mm D size is the way to go. The price is a little pricey but its worth it over the cleaning hassle of the reloads.

Some more thoughts I have come to. I don't want to use the launch lug provided in the kit. I will glue the lunch lug in a different place. I would like to use the engine that is for the display model on the outer four tanks for flight. Some more rear-end weight but hoping the D motor can handle it. I would like to make the flight fins out of clear material the same size as the flight fins provided in the kit but paint the scale size fins on the clear fins for effect.
Your right Hobbylinc has the best price on this kit. In a way, I will be glad to get the holidays over so I can get started on this project. Who knows maybe I can get a little work started on it anyway.

Thank again BARGeezer for your thoughts It helps to hear from another Hardhead.
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