PET Bottle Nosecone

Discussions about rockets, construction materials, adhesives, nozzles, nosecones and fin design.
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bugwubber
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PET Bottle Nosecone

Post by bugwubber »

I was looking for a durable nosecone and came up with a method to make them using only the top PET bottle.

Instead of cutting off the neck, I simply used my bench grinder to lightly grind off the ring handle and threads.

This process heats up the neck to the point it becomes very pliable.

Continuing to spin the bottle lightly against the grinder, I switched to the side of the grinding wheel.

Once I had the shape right, the bottle cooled and hardened. A little PLP was used to fill in a couple rough spots. Then I sanded smooth.

The picture below shows finished and right after I finished grinding but before and filler or sanding was done.
CAM01153.jpg
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Finished rocket Lucy:
CAM01093.jpg
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Re: PET Bottle Nosecone

Post by U.S. Water Rockets1 »

Hey Bugwubber!

Is that your clockworks version of the Radial Deploy system you have on that rocket? It looks like it from the pictures. The deploy is definitely the radial style, but it's not clear what the mechanism is. Also, what are you illuminating the nose with??? It looks great. Let us know how it flies!
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Re: PET Bottle Nosecone

Post by bugwubber »

U.S. Water Rockets1 wrote:Hey Bugwubber!

Is that your clockworks version of the Radial Deploy system you have on that rocket? It looks like it from the pictures. The deploy is definitely the radial style, but it's not clear what the mechanism is. Also, what are you illuminating the nose with??? It looks great. Let us know how it flies!
Right this was the nosecone for Lucy which is clockworks/radial parachute deploy upper module for my 1 liter widemouth pressure bottle. The Texas Express is the water ballast upper module version. The screw on modules make it easy to swap out.

Nosecone and fins have reflective tape. Saving my leds for another rocket...
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Re: PET Bottle Nosecone

Post by Blenderite »

Can you explain how "The Texas Express" works? Sounds interesting.
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Re: PET Bottle Nosecone

Post by bugwubber »

DogLover wrote:Can you explain how "The Texas Express" works? Sounds interesting.
Sure, here's a rundown...
1. No moving parts to reduce points of failure.
2. Rocket dumps extra ballast weight at apogee.
(To not be dangerous, this means the ballast should be free water, not rocks or balloons).
3. Rocket is balanced so that it naturally falls sideways.
(I use 1/4" plywood for fins on the 3-bottle rockets and this appears to be close to ideal without needing to add more weight. 2-bottle rockets naturally achieve this balance).
4. The simplest way to dump the water is to leave the top of the nosecone open. Ballast water is pulled out by centrifugal force as the rocket rotates around at apogee. Gravity can also pull some out.

The Texas Express is made from 3 bottles and some additional fairing material.
Pressure Vessel: 1 liter with cap glued on top
Cargo Bay: 24oz
Ballist Carrying Nosecone: 16oz (ring handle cut off)

The fairing is only glued to the cargo bottle. The ballast bottle is friction fit, the pressure bottle screws on.
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Re: PET Bottle Nosecone

Post by Blenderite »

Hmm, this makes me wonder if there is a way to use water to hold a parachute in place.
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Re: PET Bottle Nosecone

Post by bugwubber »

DogLover wrote:Hmm, this makes me wonder if there is a way to use water to hold a parachute in place.
Don't know but the force is fairly weak. If the water stays in the rocket long enough to point it down, it's gonna lawn dart. Perhaps a streamer tied to a ball could pull a parachute out? Wouldn't need water for that.
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Re: PET Bottle Nosecone

Post by U.S. Water Rockets1 »

bugwubber wrote:
U.S. Water Rockets1 wrote:Hey Bugwubber!

Is that your clockworks version of the Radial Deploy system you have on that rocket? It looks like it from the pictures. The deploy is definitely the radial style, but it's not clear what the mechanism is. Also, what are you illuminating the nose with??? It looks great. Let us know how it flies!
Right this was the nosecone for Lucy which is clockworks/radial parachute deploy upper module for my 1 liter widemouth pressure bottle. The Texas Express is the water ballast upper module version. The screw on modules make it easy to swap out.

Nosecone and fins have reflective tape. Saving my leds for another rocket...

So, you just sort of melt the bottle necks and make the nose from fusing the plastic together and then sanding and painting it? That's pretty clever. It looks pretty good too.
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Re: PET Bottle Nosecone

Post by bugwubber »

Yes the plastic gets very hot as I spin it against the grinding wheel. Here's another one fresh off the wheel. A little filler and some sanding and it will be ready to paint.
CAM01194.jpg
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Re: PET Bottle Nosecone

Post by U.S. Water Rockets1 »

bugwubber wrote:Yes the plastic gets very hot as I spin it against the grinding wheel. Here's another one fresh off the wheel. A little filler and some sanding and it will be ready to paint.
CAM01194.jpg
Looks like a Mountain Dew bottle!
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Re: PET Bottle Nosecone

Post by Jamie5335 »

Nice job bugwubber! That looks like a good idea because the bottles I use are too short and stubby to glue a ping pong ball into. This method could easily be adapted for almost any bottle shape!

Cheers, Jamie B
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Website: www.jsbrocketry.webs.com
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Jamie Bignell,
jamie.s.bignell@gmail.com
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