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Semroc Cyber III clone

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JAL3

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The Semroc Cyber III was one of my earliest attempts at cloning. It is a three stage, minimum diameter rocket from days long past at Semroc. I documented the build and the first 2 flights under the old TRF and am indebted to the people at Semroc for helping me out with it.

The first flight was fine and used the sustainer only. The second flight was in the 2 stage configuration and even with a B/A combination, I lost sight of it. The booster recovered fine but I had a hard time finding the sustainer. When I did, one fin was missing. As it bounced around in the rocket box in the months since, it also suffered the loss of part of a second fin.

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JAL3

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I decided completely replace both fins. To do this, I needed to remain the root of one and most of a second. This was done by "shaving" off the old balsa with a razor knife.

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JAL3

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I took a piece of 1/16" balsa that already had quite a bit cut out of it at one end. I then trimmed the cut out edge in a straight line at the angle I wanted the grain to run. The sheet balsa was then put behind an undamaged fin and held flush against the BT and fin and a pencil was used to trace the outline. This was done a second time for the second fin and then the fins were cut out with a razor knife. I held up the new fins against an old fin and the profiles matched so I called it done. The edges were then rounded with sandpaper and Elmer's filler was applied to both sides and set aside to dry.

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JAL3

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I sanded down the filler and got things nice and smooth. I then took a piece of cardboard and put some tape down, sticky side up. The two replacement fins were placed with their root edges on the tape and they were put in the spraybooth. They were then primed with Kilz.

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JAL3

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The primed fins were taken down and given a sanding with #400 sandpaper. The were then re-mounted on some fresh tape and taken to the spray booth. There, they were give 6 coats of the flourescent yellow paint used in the rest of the rocket. I learned that this stuff goes on best in very light coats.

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JAL3

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The fins were then placed on the sustainer with double joints of yellow glue.

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JAL3

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After the glue joints had dried, I used white glue to run fillets along the new fins.

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JAL3

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After the fillets had dried, I could still see the "cracks" where the new fins had been applied. I looked around and found what was left of the original flourescent yellow paint and decided to try and spruce the rocket up a bit. I taped off the orange fin and began spraying. I wuickly ran out of paint in the rattle can and had no more of this color. It was going to takes MANY coats to cover up the seam and I decided to let it go at that point.

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JAL3

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The masking came off and the Cyber III is now awaiting an opportunity to take to the skies again.

I hope Estes really does bring back the A8-0. I almost lost it on a B6/A8 ride and have never done the three stage configuration.

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JAL3

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I got to go out to a large launch field today. I decided to try my Cyber III which had not flown since its repair job. It had never flown on all three stages before and I decided that today was the day. I was overly optimistic. I should have loaded it with B6-0/B6-0/halfA6-2. What I did load was C6-0/C6-0/B6-4.

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JAL3

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I took it out to the pad and set it up. I thought it looked nice and I asked everyone to help me spot the boosters.

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JAL3

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I thought it looked even better when it boosted off the pad.

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JAL3

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It kept right on looking nice as it climbed.

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JAL3

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It kept looking nice for so long that I began to wonder if it had suffered a staging failure.

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JAL3

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...and kept going like the Energizer Bunny.

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JAL3

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It kept right on going to the point where I started worrying about staging failure again, but it eventually did stage. I kind of saw it far away and heard the pop.

It must have staged because I got both boosters back and I saw the sustainer keep going until it got out of sight. Some of the younger eyes think they saw it eject but who knows. The sustainer was never seen again.

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Bone Daddy

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Hey JAL3

Great pixs.

I love staged rockets.

Have you tried a 1/2A in the last stage?

I too am hoping they bring back an A booster. As it is now, I usually use a B6 to a 1/2 A. I'm more interested in seeing and hearing the staging than in altitude.
 

JAL3

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Hey JAL3

Great pixs.

I love staged rockets.

Have you tried a 1/2A in the last stage?

I too am hoping they bring back an A booster. As it is now, I usually use a B6 to a 1/2 A. I'm more interested in seeing and hearing the staging than in altitude.
I generally agree with you on the altitude thing. The field we had was so much bigger than what we normally have that I just wanted to try out ALL THE WAY.

O Well.
 

Fred22

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I generally agree with you on the altitude thing. The field we had was so much bigger than what we normally have that I just wanted to try out ALL THE WAY.

O Well.
Done the same thing with a estes mongoose which landed near brisbane I think :)
 
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