L3 Build log-12" sonotube concrete form rocket

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tollyman

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Hello all!

I am going to be documenting my L3 build here. I have already started and had a decent portion done but I decided I would still do a build log so people can learn from what I did and I can learn from others!

This build is rather unique, it is made of fiberglassed 12 inch sonotube concrete forms. I am using two 4 ft tubes for the overall length of the body tube as well as a 3ft tall homemade nosecone.

I plan on using a "parachute cannon" design for my main 12 ft parachute which will be located inside my nosecone.

The two motors that I tentatively plan on using are a CTI M3100 or the CTI M1300. The total weight of the rocket should be around 50lbs with a predicted altitude of around 4,000 ft.

I will gladly answer any questions!

(I will get some pictures up soon, and can get specific photos upon request)

Tollyman

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Bat-mite

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You might want to contact member Tom C., who almost exclusively makes glassed Sonotube rockets. His usually weigh over 150 lbs, and he uses separate main chutes for the nose and airframe. But he'd be a great resource.
 

tollyman

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Thank you, I will look him up!

I haven't really considered doing it that way. Maybe I should have posted here before being 50% complete with construction haha
 

Bat-mite

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Well, there's no one right way! Tom uses three altimeters, and three charges of 30g each. Only one is required for separation; the other two are back-up. The charges are huge to ensure sufficient distance between the parts when the chutes inflate. NC is blasted like 40' away.

[video=youtube;Ru7ZRg0_lxs]https://www.youtube.com/watch?v=Ru7ZRg0_lxs[/video]
 

mccordmw

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I just wrapped up my fiberglassed Quickrete tube L3 rocket. It's 8" x 12', and I'm sitting on the pad at 62 lbs. You might want to take another look at the weight you'll be dealing with. I have a stupidly long and detailed build document posted. Still need to put in the finishing details in it, but the writing is 95% complete.

https://drive.google.com/open?id=1i4anunZXsiG7dyIP78nmFN7WJrSK-7uAgVvensHU9ok

There's much to consider with that large build.
 

tollyman

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Wow, truly impressive! It would be nice to do it that way but I have both my parachute cannon and electronics located in the nose cone. I knew my charges had to be big but I didn't think that big! but I can understand that youd want to make sure you have separation and redundancy.

20170806_112302.jpg
 

tollyman

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right now my nosecone is looking to be 20lbs fully loaded each tube to be 5lbs ish and then my fin can section to be another 15lbs. Like you said there is a lot of things to consider but I would say I have most of the big ticket items accounted for. I still have a long way to go including epoxying my fin can inside my body tube so I should get a better feel for the weight after that.
 
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