Engineering a Bigger Dragon
Last year, Heavy Meta brought Canada's 30-foot long fire-breathing dragon across the U.S./Canada border to bring the heat to Maker Faire Detroit. Over the year that has passed, one thing that always irked us was the size of the dragon's wings. In the original sketch, the wings are supposed to be as tall as the head of the dragon! However, we had never been able to solve the engineering challenge this posed until now.
We are pleased to say that Detroit will be the first Maker Faire where attendees can check out our new wings! Here's how we did it.
Designing the Wings
We had two design goals:
1. Safely engineer a system that would allow the wings to be raised and lowered using some kind of mechanical winch.
2. Prevent the wings from rusting.
The first and second parts are related in a way, and the choice was made early on to work with aluminum to keep the wings light, as well as prevent corrosion.
To accomplish the first goal, we looked for other places where this problem has already been solved in an elegant fashion, and we found two "homologous structures" in the engineering world. One is in hydraulic excavating equipment, and the other, much simpler example is a straight razor.
A straight razor has a little handle for the thumb called a tang. It is the perfect length and shape to apply just the right amount of leverage to the spine to open the razor. We asked ourselves, what if instead of the handle, we had a wing stem, and what if instead of one spine, there were three spines, each supporting wing mesh?
With this in mind, we got our friend Ryan Longo at the Apocalypse Metal Shop to CNC plasma cut four large pieces of steel that mimicked the look of a straight razor and tang combo.
Matt decided inside each spine would need to be a strong piece of steel, we would create an aluminum façade to go over each "dragon finger."
Cutting the Aluminum... Disaster Strikes!
Since we had made the dragon entirely out of steel, we didn't have a whole lot of experience with aluminum, but knew it was the right material for the job. We decided to try CNC plasma cutting it, even though we had never done it before. We loaded the design files into the computer, and it made a great test cut. Then, 20 minutes into the actual cut, everything went pear shaped. The torch depth sensor had failed to determine where it was located, and rammed the torch into the material, snapping the torch head in half. This was an expensive mistake.
Return to the CNC Table
While the torch was being repaired at the other shop, we decided to give it a shot at our own shop, which has a CNC router. With a ton of help from Alex Borins, we were able to cut out and rivet together the necessary pieces of aluminum to sheath the "dragon fingers." We were also able to repurpose some of the original wing mesh by cutting it in triangles and riveting it to the fingers.
Making the Fingers Move
Matt realized that if the wing was going to need to fold, the fingers would have to be slightly offset so each finger would slot inside each other. We also agonized for quite a bit about how to exert the downward force on the tang to make the fingers pivot upward, and decided the best tool for the job was also one of the simplest: a hand winch. This allows just about anybody to easily crank the wings up and down and makes the dragon kind of like a giant mechanical puppet. We love the effect of the slowly rising wings, and the sound is like a medieval drawbridge!
The Big Picture
We can't wait to show you our brand new wings at The Henry Ford.
Kevin Bracken is Co-Lead of Heavy Meta Entertainment.
events, engineering, making, Maker Faire Detroit, by Kevin Bracken
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