Circuits as fins?

The Rocketry Forum

Help Support The Rocketry Forum:

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
I have a surplus of circuit boards and RAM sticks, I thought it would be cool to chop them up and use for fins, maybe even as UFO sides.
However NAR safety code says no metal for fins. my immediate thought is that this should be ok since the base is fiberglass but then what about the lead/copper content? Would that make it too heavy or too hard a material for rockets?
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
388
Reaction score
121
Maybe not as good, but could you take a picture of the circuit boards, and print them on label adhesive paper and put that on the balsa fins?
 

Funkworks

Well-Known Member
Joined
Jul 28, 2018
Messages
692
Reaction score
297
Doesn’t seem very aerodynamic. Unless you can ensure symmetry, rocket might spin, spiral or curve.

No comment on the NAR/legal side. I leave that to RSOs.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
I suppose a scan would do, but I work in IT and have enough of the darn things to side my home with them. No one want 256 mb sticks anymore. I'd rather use the real deal.

Aerodynamics shouldn't be an issue but I'll keep it in mind. I'd be using them in pairs so spin should either be constant from all opposing fins or both sides of the chips will be the same and no spin will be induced. I like to launch mostly A's and B's in my park right now so if it only goes 100ft up its still a win.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
Build a desoldering oven out of a toaster oven. Presto, free very high quality fiberglass with some holes in it! Nobody's going to mind the copper foil layers.
I can't tell if this is genius or insanity.
 

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
5,963
Reaction score
1,335
I have a surplus of circuit boards and RAM sticks, I thought it would be cool to chop them up and use for fins, maybe even as UFO sides.
However NAR safety code says no metal for fins. my immediate thought is that this should be ok since the base is fiberglass but then what about the lead/copper content? Would that make it too heavy or too hard a material for rockets?
Don’t see why it wouldn’t work.

It’ll be heavy, draggy, meaning you’ll need nose weight and a bigger motor.

It will make a unique rocket. The extra time it takes to construct may or may not be worth the time saved by standard building. If it “sparks” your fancy, go for it.
 

PatD

Well-Known Member
TRF Supporter
Joined
Jul 25, 2015
Messages
328
Reaction score
181
Draw patterns of your choice on the circuit boards with a resist pen and etch it. Lets you reduce rear weight and after you neverdull polish the remnants and clearcoat it. Oh that is an idea. I have some 1/8 double sided copper boards. The sky is the limit for designs.
 

OverTheTop

Well-Known Member
Joined
Jul 10, 2007
Messages
3,866
Reaction score
1,162
Location
Melbourne Australia
I like the idea. I don't think the RSO would have any trouble with this. As others have said it will be draggy and craggy and need some nose weight.

Very ingenious! :)
 

TXWalker

Member
Joined
Dec 10, 2019
Messages
16
Reaction score
4
Location
Texas
Recycled PCB for fiberglass fins. Just filled the holes and sanded smooth. I did an extra layer of fiberglass tip to tip after mounting to the airframe. I’ve done this on other rockets. Super strong.
 

JoePfeiffer

Well-Known Member
Joined
Jun 15, 2013
Messages
46
Reaction score
26
Not enough metal to worry about -- less than an eye bolt, and in a form that isn't going to increase damage if the rocket hits something (that and shrapnel after a CATO being the reasons for the metal prohibition). As others have said, heavy so watch your CG and draggy, but a nice cyberpunk esthetic. I'd probably only use them on a rocket with a fiberglass airframe.
 

jrap330

Retired Engineer, NAR # 76940
TRF Supporter
Joined
Jan 25, 2020
Messages
293
Reaction score
81
Location
NJ
I have a surplus of circuit boards and RAM sticks, I thought it would be cool to chop them up and use for fins, maybe even as UFO sides.
However NAR safety code says no metal for fins. my immediate thought is that this should be ok since the base is fiberglass but then what about the lead/copper content? Would that make it too heavy or too hard a material for rockets?
Someone years ago did this, not sure if model or MPR or HPR. Was done 15-20 years ago. Also did it with old CDs....
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
Ooh, maybe a cd as the hub with the RAM sticks as my drag component on a UFO. Or 3.5 floppies... if they can hold together.
 

Dugway

Well-Known Member
Joined
Jan 23, 2015
Messages
188
Reaction score
42
Location
Draper, UT
I used CD halves as fins on a competition Super Roc. They aren't as strong as you might think, one shattered on landing after a nominal recovery.
 

Rktman

Eric
Joined
Mar 5, 2017
Messages
1,015
Reaction score
72
I think it's a brilliant idea, especially considering you're goal isn't altitude/performance but rather the visual impact. As others have noted, you need to pay special attention to stability, but you get to recycle and put those circuit boards to good use, they're plenty strong for LPR use (probably even for midpower rockets) and the coolness factor is off the charts, especially for UFOs/saucers as you mentioned. It definitely would make for some truly unique designs.
 

ThirstyBarbarian

Well-Known Member
TRF Supporter
Joined
Feb 11, 2013
Messages
8,215
Reaction score
704
There is a guy in one of my clubs who has a rocket with circuit board fins.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
Snagged these from work, and they were in different colors too! I'm definitely leaning towards a saucer with these layered as the sides. Thanks for the encouragement and ideas everyone.
 

Attachments

vcp

Well-Known Member
TRF Supporter
Joined
Jan 28, 2009
Messages
1,074
Reaction score
184
Location
Meridian, ID
I have stacks of old blank PCB's that are about 4 inches square. I keep them around for windshield ice scrapers. Each board effectively has eight very sharp fiberglass edges and you can flex the board to conform to any mild curve. The cost is zero (originally ~$50 each) and I often give them away when I see someone scraping a windshield with a credit card.
 

Greg Furtman

Well-Known Member
TRF Supporter
Joined
Nov 10, 2018
Messages
1,222
Reaction score
582
Location
Webster, Wisconsin
I have stacks of old blank PCB's that are about 4 inches square. I keep them around for windshield ice scrapers. Each board effectively has eight very sharp fiberglass edges and you can flex the board to conform to any mild curve. The cost is zero (originally ~$50 each) and I often give them away when I see someone scraping a windshield with a credit card.
@vcp Micron's headquarters is in Boise isn't it? Been buying their memory for years now because I found out that they had donated a large amount of memory to SETI in its early years.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
Ok, so I finally got around to putting this concept into play.
The final product will be a flying saucer with a good bit of induced spin, probably on a C6-0. The blue sticks will be glued to the fan blades matching their cant for drag/spin stabilization. I'm undecided if I'll use the green cut pieces here for added strength or save them for a 4fnc rocket. I also got some Windows 2000 floppy disks that would be fun to incorporate somehow but that will likely throw the mass over what an estes 18mm will do.
The hub is a 3 bladed hp server fan. everything will be computer parts except the motor mount.

The next question is; how on earth to I check this thing for stability? OR or Rocksim are out... would a swing test even be useful for such a weird shape?
 

Attachments

vcp

Well-Known Member
TRF Supporter
Joined
Jan 28, 2009
Messages
1,074
Reaction score
184
Location
Meridian, ID
@vcp Micron's headquarters is in Boise isn't it? Been buying their memory for years now because I found out that they had donated a large amount of memory to SETI in its early years.
It's funny I haven't heard a word about Micron in years - I couldn't tell you if they're still there or not.
 

Greg Furtman

Well-Known Member
TRF Supporter
Joined
Nov 10, 2018
Messages
1,222
Reaction score
582
Location
Webster, Wisconsin
It's funny I haven't heard a word about Micron in years - I couldn't tell you if they're still there or not.
Micron is still in business. Crucial is their memory company. Crucial also sells SSDs. And Micron is manufacturing memory & storage memory for other companies. Plus they do a lot of R&D.
 

afadeev

Well-Known Member
TRF Supporter
Joined
Sep 21, 2017
Messages
1,227
Reaction score
506
I have a surplus of circuit boards and RAM sticks, I thought it would be cool to chop them up and use for fins, maybe even as UFO sides.
However NAR safety code says no metal for fins. my immediate thought is that this should be ok since the base is fiberglass but then what about the lead/copper content? Would that make it too heavy or too hard a material for rockets?
It will be perfectly fine. Metal content is minimal, and modern RAM sticks are fairly low-profile.
The fins will not be optimally aerodynamic, thus they will induce more drag than you would expect from a regular fin.

Fins don't have to be perfectly smooth and aerodynamic to be effective. The rocket may not fly as high with "bumpy" fins full of holes, but it will be stable.
If modeling in OR, just enter the actual weight of each fin, and the average thickness across all cross sections.

The final product will be a flying saucer [...] how on earth to I check this thing for stability? OR or Rocksim are out...
There is a thread on saucer stability here: https://www.rocketryforum.com/threads/saucer-secrets-stability-simulation.77120/
 

vcp

Well-Known Member
TRF Supporter
Joined
Jan 28, 2009
Messages
1,074
Reaction score
184
Location
Meridian, ID
Micron is still in business. Crucial is their memory company. Crucial also sells SSDs. And Micron is manufacturing memory & storage memory for other companies. Plus they do a lot of R&D.
Yeah, that was sort of tongue-in-cheek; I worked there 22 years. Designed a number of Micron products, spent most time designing dram testers, and product EMC testing. Behind me now.
 
Last edited:

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
Those parts were the hardest thing I've ever tried to glue in my life. Pretty sure sure the joints will fail...
I did not think through my clamping process with the curved surfaces.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
55
Reaction score
38
As for OR I suppose I can run them as highly canted fins. I know there was a 'trick' method with adding a tailcone that I will look into.
 
Top