Wacky questions

[James Pancoast]

Has anyone ever put strain gauges on fins or the fin joints and gathered data during flight?

Does a small / cheap CNC machine or something similar exist that a rocketeer could buy taht can be used to precisely cut parts?

[Matt Boyles]

James,

I have always wanted to put strain gauges on my fins, but never got around to it.  If you end up doing it, I would love to see the data.  As for precisely cutting parts, have you looked into a laser engraver/cutter?  I have seen them on ebay for under $400 depending on how you option them out.

Matt B.

On Tue, Oct 29, 2024 at 11:14 AM James Pancoast <jam...@jpancoast.dev> wrote:

Has anyone ever put strain gauges on fins or the fin joints and gathered data during flight?

Does a small / cheap CNC machine or something similar exist that a rocketeer could buy taht can be used to precisely cut parts?

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[John Cantalupo]

On the second question…

Depends what you mean by “cheap”. A couple years ago I bought a Genmitsu 3020-PRO MAX (might be the previous version of what they sell now). At the time the company was doing a very good holiday special.

It’s been an introduction to CNC for me, so I still “don’t know what I don’t know”, but my son and I have used it for mainly 2D work in acrylic, polycarbonate, and plywood, including for things like fins and centering rings. It’s pretty nice and very sturdy. I’ve even done some test work with aluminum.

I also got the diode laser head for it, which is mostly just for engraving but will cut balsa and basswood. Given that the machine has no enclosure, it’s not exactly the safest thing to do. So if you go this route, do your homework and get to really understand the dangers and how to mitigate them.

In my limited experience, I’ve been very happy with it.

The company also sells some lower priced models that operate similarly. I’m sure you will see other similar options from other Chinese manufacturers on Amazon. I went with Genmitsu because there seems to be good company support, as well as a lot of user videos and such online.

- John

On Oct 29, 2024, at 11:14 AM, James Pancoast <jam...@jpancoast.dev> wrote:

Has anyone ever put strain gauges on fins or the fin joints and gathered data during flight?

Does a small / cheap CNC machine or something similar exist that a rocketeer could buy taht can be used to precisely cut parts?

[JamesR]

Yes, it has been done.  Thermistors embedded in nosecone as well. 

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[brian blueoats.net]

Instead of all the wiring and such, simplest way is just use warp 9 propellant and check for paint burning and fillet cracks!!!

GBA

BHcon

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From: crash...@googlegroups.com <crash...@googlegroups.com> on behalf of JamesR <jam...@gmail.com>
Sent: Wednesday, October 30, 2024 10:39 PM
To: Crash-Talk <crash...@googlegroups.com>
Subject: Re: [crash-talk] Wacky questions

 

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[James Pancoast]

I guess I should have asked the ACTUAL question (this is a problem with me).  What I REALLY want is something that can cut thin plywood, fiberglass, carbon fiber, etc., precisely.  Laser cutters work great for thin plywood, balsa, etc., but not sure if they'll work cutting fiberglass.  

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James Pancoast

jam...@jpancoast.dev

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[Cam Schumacher]

James,

Not sure exactly where you are located. But Castlewood Library near Lone Tree has a maker space that could probably help with the laser cutting. I don’t remember if they have any CNC routers if it was more than a laser could handle but there are definitely some other Maker Space labs around the metro area that might be able to help?

Cam

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[JamesR]

There are small table top saws and work stations like Dremel and other brands.  I have a 12in x 12in table saw that uses 3in blades. There are many different options.  I also use a small construction table saw for thicker and larger materials.  You can hand cut a lot of things and then use a belt sander to shape, straighten and smooth.  There is a lot of different things out there,  I just learned to use what I had and slowly got tools that made things easier as I went along.  Fiberglass is not hard to cut but to fast of a blade will burn it. Use high tooth count and run the tool as slow as possible and if using tools you can not very the speed, just push slower. Always use a mask, eye protection and a vacuum to pull the dust in. Wash hands and skin the dust might get on.

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[James Pancoast]

While this is indeed a great idea, I'd like to show you the piece I've had in my vehicle for a month to take to the library and get cut, but I just keep forgetting to go to the library! :)

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James Pancoast

jam...@jpancoast.dev

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