Estes Centuri restore/completion #3232

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Back_at_it

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This one has been in process for a little while now as I started it a few months back then got distracted by other projects. It's finally time to bring this one to a close.

This rocket was part of a collection I purchased from a high school rocketry program that went belly up when the teacher retired. There were a number of incomplete and very poorly assembled rockets all thrown in a box and sold cheap.

Here is what I started with. The rocket was never completed so no internals and what was assembled was done poorly. The upper section of the rocket was missing two fins. The transition was glued in but only inserted half way. The nose cone was glued in place but the worst part was the tube was badly crushed and twisted. Looks like someone tried a little took hard to get that transition out and twisted the tube.

The lower portion had thee of the fins attached with the forth one loose in the box. The inner 18mm motor mount was missing along with engine nozzle. Otherwise the lower section was in good shape.

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First the things you can't see. I decided to leave the 18mm motor mount out and fly this one on 24mm motors or use the adapter for 18mm. Not wanting to take chances with poor construction I decided to add an addition centering ring to the top of the motor mount. This was done by adding glue to the body tube on top of the existing centering ring. A new 50/55 centering ring was pushed down from the top of the tube into place. Next I added a motor block inside the motor mount.

Next it was time for the body. I removed the remaining fins from the lower section. They pretty much popped off without too much trouble. They were cleaned up, the tube was sanded where they attach and were glued back in place using TBII.

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Next it was time to fix the upper section. Unfortunately the tube was not salvageable so I removed the nose cone and transition and used an existing fin as a pattern to cut new fins. As luck would have it, I had a BT50 tube in the scrap box that was the exact length needed so I used it rather than cut a new one. The tube was one of the pre-colored pieces from Estes so I sanded the entire tube with 400 grit to remove the shine and hit the areas where the fins attach with 120 grit. Below we see the fins cut and the first fin attached. A piece of tape was wrapped around the tube as a guide to keep the bottom of the fins aligned.

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Here we have all 4 fins attached. The transition had the mating surface roughed up with 120 grit then glued in place with thick CA. Note that the nose cone has had the bottom of the cone removed to allow me to add nose weight at a later time. With the addition on the larger motor and the forward fins this rocket will need a little help in the stability department.

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From that point Launch lugs were installed and fillets were applied. It was at this point that the rocket got set aside and has been sitting waiting for about 6 months now.

In the last week I started the filler work in hopes to finally getting this one finished.

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I'm going to get the recovery gear sorted out today as I need to figure out the required nose weight and I'd like to fly this one before going too much further with paint. Hoping to get a stability flight in this weekend.
 
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Small update. I finished the internals with a Kevlar leader and about 4 ft. of elastic shock cord. To that I attached a 12" nylon parachute checked CG/CP using Open Rocket. SIM showed a stability of 1.84 with a D12-7 on board. While this is wildly safe I know that this rocket tends to like to wander a bit due to the forward fins when built stock. I decided that a little nose weight wouldn't hurt so I added 1/2oz using BB's and epoxy.

I managed to get out to a local field and get in a couple of quick test flights yesterday morning. First flight was a C6-3. The delay was just a tad early but no harm done. A little slow off the pad but stable and straight. Once Primer, paint and vinyl is added this one might be a touch too heavy for the C6 to get it up to speed off the pad. Might need to move up to the C5-3 when flying on 18mm

Second flight was a D12-5. This was much better. With the altimeter on board it recorded 788ft. Ejection was just about perfect from what I could see. Straight and stable. I'll feel good about flying this one at club launches.

Got it home and glued the nose cone in place with thick CA. Did some additional filler work and sanding before applying two coats of SEM high build. Letting this cure now but i can see where I need to do a little more filler work around the transition and nose cone as I'd like this to look like one solid molded piece without any seams.

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Time to wrap this one up. The weather here has been sunny and hot for the past few days so I used that to my advantage to get this one wrapped up.

Since the last post I have done some additional filler work to smooth out the transition and nosecone to appear like they are one piece. From there a final coat of white primer was applied and sanded with 600 grit. Next came four coats of Krylon Gloss White applied about 10 mins apart. With the temps as warm as they are and the sun out in full force I left the Centuri outside for a day to cure.

Next it was time to mask off and paint the black. Same deal, left it out i the sun to bake all day then brought it in for vinyl last night. I kept with the overall look of the rocket but changed the amount of Black that was applied. The changes are minor but they are what was pleasing to my eye.

Finally I cut vinyl to mimic the original. Again, close but not a direct copy. I went with thinner red vertical lines top and bottom and left off the white surround. Also went with a more retro looking font for the name. I'm happy with the results and this one has been moved to the "ready to fly" table.

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