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Friday, January 3, 2014

Centuri Flutter-By Build, Part 9, Paint & Trim


The instructions say to use bright silver on the upper half.
If you've ever used silver on a rocket you know that fingerprints show through and the finish quickly turns  dull.
Looking at the Centuri catalog page on Ninfinger's site it almost looks like a light blue was used.
I decided to compromise and use aluminum.
I still have some chrome Monokote for the trim piece that wasn't included in the Estes kit.



The lower half was easy enough, just make sure to mask off the green coupler.

Any paint left on the metal hook will probably blister up from the heat of  the engine flame. I scrape the paint off the engine hook with the backside of a knife blade. Think of it as some chrome trim on a car.




The Monokote chrome trim piece was .9" tall and 3.2" wide.
The upper edge followed the top end of the body tube. The joining seam was centered right above the launch lug.

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2 comments:

  1. Eero FlugeSeptember 25, 2014 at 1:58 AM

    I was concerned that the lower half of the rocket does not have a solid stop as it is inserted into the top half. When the motor burns, the thrust is transferred to the top through the two small places where the bottom fins contact the upper body tube. Seems bad to me. Also, the bottom half has no positive alignment in roll with the top half.
    To fix these shortcomings, I added a 20/50 centering ring inside the top half body tube to form a stop for the large green center ring of the lower half. This is essentially a thrust ring for the lower half motor mount. I also carved a shallow notch in this thrust ring to accept the engine hook. By hardening this notch with some CA, it serves as a very nice alignment guide so that the lower half always mates with the top half at the right clock angle, and with a positive stop.

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  2. Chris MichielssenSeptember 25, 2014 at 12:22 PM

    Hi Eero,
    I didn't think the lack of a "solid stop" was a concern. I have a pretty good fillet at the bottom of the lower fins where they root edge touches the 20/50 ring. But, time and a few dozen launches might prove me wrong.
    You are right, there is nothing to align the fins when the model halves are slid together. You have the right solution there.

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