Interpretive Arson » make

Engine test #2 CAD

raindrift — Tue, 25 Nov 2008 08:18:41 +0000

Nicole, Jonathan and I spent the evening finishing up the design for Hitodama test engine #2. It’s a cool-running liquid propane/compressed air thruster, with a theoretical thrust of 96 Newtons. We’re opting for safety over performance, which means low combustion chamber temperatures and lots of air pressure. The complete engine, including bolt flanges, is 9cm diameter. Hopefully we’ll be able to reduce that slightly for the production version. A complete set of design specifications should be forthcoming.

Next come the high-pressure air and nitrogen-pushed propane systems. Just because we said it’s safe doesn’t mean it’s simple…

Hitodama test engine #2

This is a picture of the complete engine. From left to right, you see the nozzle (including diverging and converging sections), the combustion chamber which contains a titanium flame holder, the fuel injector, and the injector cap. Air and propane enter and mix inside the flame holder. Meanwhile, a bunch more air is injected outside the flame holder. The entire mass of combustion gases are heated to about 1000C, and ejected from the engine at Mach 2.5. At least, in theory. We still have to build it.

Finger electronics rebuild

raindrift — Tue, 18 Mar 2008 09:27:54 +0000

I just spent the evening rebuilding the control system for the fire fingers. They’ll be much more reliable now (not that they had a problem before, but I was personally uncomfortable with the level of jank). I snapped a couple pics before closing up the box.

The fingers are a performance tool that hasn’t really been out much. There is, however, a photoset of Audrey using them to immolate her former uniform from the gelateria where she used to work. We’re hoping to use then at the Fire Ballet, if I can get the gloves to fit the performer.

New 2πr Platform!

nicole — Tue, 18 Mar 2008 07:34:44 +0000

2pir Layered View

Recently, Sharp introduced new extra-long-range infrared proximity sensors that rock the house better, harder, faster, and yes, stronger than any sensors like it. We got a hold of a few for testing, and decided that it was a perfect opportunity to upgrade 2πr! But we didn’t want to simply hack them in to our current setup! With the experience we’ve gained from running 2πr at various events across the western US, we decided to go right back to the drawing board and rework the whole platform. It’s now shorter, sleeker, and incorporating a swanky design accent, as well as containing the glory of the new sensors.

The first step of a project like this is to draw it out, and recently at IA, we’ve taken to drawing everything out in CAD before buying any of the materials. This leads to a lot less waste, and helps to overcome some of the possible design challenges early on. As such, the last few weeks have had numerous meetings and work sessions to really hammer down what we want this thing to be.

I’m excited to share these images with everyone, so I’ve created a flickr set with all the various layers of the file separated out into individual images.

Enjoy!