Speaking of rockets… I just discovered that my Maker Faire talk on 3D-printing, disposable rocketry and the democratization of matter went online: http://youtu.be/IBMMPBpZeHo?t=9m29s
We have had a lot of fun with this approach, pushing all of the complexity and most of the build time into a 3D-print. Now that the rocket costs less than $10, and takes less than 10 minutes to build, we don’t worry so much about losing it in the neighborhood trees or ocean. With over 20 supersonic flights under our belt, (most at Mach 1.8 with H, I and J motors in a 6 oz. rocket), we have recovered all but two of the rockets with the simple solution of writing our name and phone number on the side. This includes rockets found by skinny-dippers in Santa Barbara, the golf course supervisor at the Ritz HMB, and a guy who saw the 650 area code and figured we must be based near Menlo Park, not out in the field, and so he brought it back there waiting for my call (sure enough, that is where I work).
When I shared this with the MakerBot people at MakerFaire, they were amazed that their cheap, biodegradable PLA could survive supersonic flight. That use case was new to them. I do a standard print with the cheapest Replicator 2 and lather excess 5-minute epoxy on the fins when gluing it to the Blue Tube. That combination strengthens the fins and makes an smooth surface. As I have learned taking a large carbon fiber rocket to Mach 2.5, fin alignment to 0.1° of precision is critical. 3D-printing gives perfect fin alignment every time. And I integrate into the build the fin fillets and launch rail guides. After a one-time design effort, the complexity of the rocket comes for free in each print. I am currently trying to print a 4” fin can making full use of the maximum print volume of the Replicator 2.
Here is a video of a supersonic launch with the same 38mm airframe. The single-use Aerotech J270 takes it from 0 to 1,363 MPH in 2.6 seconds, pulling 74g’s according to RockSim: https://www.youtube.com/watch?v=wb3EU7ndUp8
Here are my print files for anyone who wants to use them:
• 29mm http://www.thingiverse.com/thing:630069
• 38mm http://www.thingiverse.com/thing:630086
More launch photos: https://www.flickr.com/search/?text=3d%20print%20rocket&sort=date-posted-desc&user_id=44124348109%40N01
Blue Tube supplier: http://www.alwaysreadyrocketry.com/about-us/blue-tube-2-0/
For 38mm flights, I also add a cheap aluminum GLR rail guide to the upper part of the motor/body tube (don’t use a rod for I or J motors; when I did, it snapped two legs off of my Aerotech Mantis launch pad, laying it flat! That’s some serious whiplash!): https://giantleaprocketry.com/products/components_launch_systems.aspx#Acme_Conformal_Launch_Guides
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