Some behind the scenes of the RC Tank Battle: Revenge video

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Run forest! Run!

I’m one of those people that can’t fall asleep for about half an hour to an hour after going to bed. One night I got the idea to make another RC tank battle video. The first one was really fun to make and you tend to forget the difficult parts after five years, so you remember it being fun and easy. The seed was planted and I started slowly constructing a story during the many attempts to catch that elusive sleep fairy.

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Christian Mogensen prepping fireworks on the tanks.

After a couple of weeks I had a story line and I decided to actually make the video. Since I now have some really cool toys, like a 3D printer and slowmotion camera I knew that I could take this video a level higher than the last one.

T-rex tank chassi

T-rex tank chassi

Hobbyking had sent me a T-rex tank chassi ages ago. It doesn’t have any kind of turret on it, so I posted a video asking for ideas for turrets that I could make. Some fantastic ideas came in and I started designing. A friend of mine, Terje (he’s on the forums here as well) Really helped out with the design. He singlehandedly designed the ED209 turret. With working gear driven tilt for the “arms”. Absolutely fantastic design. Thank you for that Terje.

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Setting up a slowmo shot

In the meantime I designed the “bad guy turret” which is based on a concept tank called the Leopard III. Man, designing stuff takes a crazy long time!

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ED209 getting ready

As soon as I had a design finished I started 3D printing. All in all it took almost a week to print all the parts that were used in the video. Really convenient though as you just start a print and then you can work with something else while the printer is regurgitating plastic.

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This is the turret Terje designed. It’s the “head” from the robot called ED209 in the famous eighties movie Robocop. Printed in ABS at 0.2mm layer hight.

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It’s designed in two main parts so that it’s possible to disassemble to get to the servo inside. Also made printing a lot easier.

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Designed in Fusion360.

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ED209 gets taken down by the “Sunlance” in the video.Screen Shot 2017-04-14 at 20.20.02

That thing was crazy bright and burned super hot.

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Poor ED. We had to light him on fire for the next scene again.

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It wasn’t really part of the plan for the GoPro to get blasted with the fire. But luckily it survived with only 3rd degree burns (you can see the PCB a bit in one of the corners now)

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The “Sunlance” was made from 150 sparklers.Screen Shot 2017-04-14 at 20.36.58

One sparkler burns pretty slow. Having multiple strapped together creates a chain reaction, making the whole stack burn in about 2-4 seconds.

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All fireworks that were mounted on the tanks were lit by hand. Timing and running like hell works a treat.
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The explosives that were placed a bit under ground were remotely activated via an RC transmitter. A receiver with 3 brushed ESC’s, each one hooked up to a detonator allowed for very precise timing of the explosions.

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3D printed canister loaded with gunpowder plus ignitor

Last time we used resistors to set off the fireworks. They are very reliable, but they take a couple of seconds to light and they vary in time. This makes it really difficult to do well timed stunts.

The igniters used in this video were made from a piece of brass wool dipped in a mixture of gunpowder and dissolved ping pong balls. Very quick, durable and reliable.

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Rockets

The missiles were propelled with the rocket part of the firework rockets. Felt like a waste not to use them. A thing fishing line was used to guide the rockets to the right place.

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It’s difficult to pin down exactly how ideas comes to you and stick. When thinking about this video I made up a small segment at a time. These segments could be like the one shown above. Using a fireworks tank as a decoy. Everyone that has fired one of these off have been severely disappointed (or was it just me that was traumatised by this as a kid?). I thought it would be a perfect segment that could work as comic relief and as a means to get into a slow pace part of the video so that I could do another build up.

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For some reason the balloons didn’t get a big part in this video. Poor things. Wonder what their side of the story is.

Screen Shot 2017-04-14 at 20.31.24The entrance of the bad guy was another segment I really wanted to have. It doesn’t quite cut well into the video as it’s shot in two very different locations on completely different surfaces and during night and day. But the heart want what the hearts wants. I think it cut acceptable enough in the end. We did about 20-30 takes of this shot in one evening. We stopped when we ran out of lighter fluid. The
tank smelled funny after that.

Thumbnail12The “Grey” tank is actually the tank from the previous video. That poor thing has been through so much. It’s incredible that we managed to get it through the whole shoot. We glued the tracks and did so many repairs on sight. In the end we tried not to try and turn with it, but rather just drive as straight as possible. This so that the tracks would be less stressed.

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This shot where Grey get’s hit on the underside by the mortar was not supposed to happen that way. It was supposed to explode in front of the tank while it was driving but I accidentally triggered the explosive too late. The tank was completely dead after the explosion and we through the whole PCB inside was destroyed. Luckily the explosion had just flipped the power switch!
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The poor GoPros really took some punishment during the filming. I didn’t want to use the protective case as i wanted them mounted as low and flat as possible. This did result in that both now have cracked front screens (but who needs those right?) They were constantly thrown in the air, hit by fireworks and being burned, but the hardest impact has to have been the one in the picture above. The final explosion hurled the whole metal drivetrain of the tank plus motor straight at the camera. But it took it like a champ. Cool shot too!

I had an absolut blast doing this video. Editing is alway tedious as it takes soooooooo much time and energy. But the end result was worth every minute of it.

Might update this post with some more info. Let me know if you want it

One thought on “Some behind the scenes of the RC Tank Battle: Revenge video

  1. Awesome Job on the video David, It looks awesome. The behind the scenes stuff is really interesting, being a someone that makes videos I really appreciate all the work you put into it!

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