5/18/12

Mach 2

One of my goals this summer is to break Mach 2. When I got back from school earlier this May, I started work on a new rocket that should be up to the job.

It's a 38mm minimum diameter rocket made of hand-laid fiberglass in my very own composites lab. Rocksim predicts a top speed of Mach 2.3 on a 6G Cesaroni J360.

It is an exercise in space/weight efficiency, construction techniques, and strength of materials.

I used the motor casing as a form and wrapped wax paper around it to protect it.

Then I went around with liberal doses of epoxy resin. I used about 2 feet of cloth.

This was the result after the wrapping. To prevent it from hardening into this bumpy matrix pattern, I wrapped a layer of wax paper around the entire thing.

For the fins I made a little fiberglass sheet with about 8 layers of cloth.

I then covered it in wax paper and pressed it with some heavy books.

(Such as an astrophysics text).

Very happy with the result. Taped on RockSim templates.

Cut them out with a jigsaw.

Sanded them even, gave them double-wedge airfoils.

Not much room for TTW fin attachment, but I did cut slots and but the fins up against the motor casing.

Used lats of epoxy.

A good view of the fillets. Used 60 minute epoxy mixed in fiberglass dust that I collected from sanding the fins. The fiberglass dust gives the epoxy more of a matrix, which increases the strength.

Recovery is going to be a little tricky, but I've got an idea that uses Kevlar shock cord. I'm planning to use a blaze-orange nylon streamer and, of course, a rocket tracker.


I'm tentatively planning on launching this June at Tripoli MN.

I am also determined to make it to either LDRS or BALLS this year, but I have to earn some money first. It'll be an interesting summer anyway.

3 comments:

Steve Finnell said...

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Alex said...

Did you use wax paper or parchment paper? In my experience, wax paper tends to stick to the epoxy and is a real PITA to use. Parchment paper doesnt stick to the epoxy (or ANYTHING for that matter). It peels off nicely, leaving a clean finish. I use it when pressing carbon fiber sheets.

DTH Rocket said...

I used wax paper which seemed to peel off okay. Good tip though, I'll see if there's any parchment paper kicking around.

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