One of the cooler things I've done this summer was to help out for the filming of the Tamiya Toyota Mirai promotion videos. My thumbs were required to control this revolutionary Hydrogen-fuelled Tamiya TT02 around the Old New Inn Model village in Bourton-on-the-Water.
A bit of background info
Toyota are leading the pack with their Hydrogen powered vehicle development, the new Mirai has over 400 miles of range, can be refilled in minutes and the only emission is water. With this in mind they thought it would interesting to see how the technology would scale down into a Tamiya RC car.
Step in Bramble Energy. This company makes highly scalable PCB fuel cells that can fit any shape and size. They took on the challenge to make a fuel cell that would fit into the Tamiya TT02 and within the bespoke Tamiya Toyota Mirai bodyshell.
|1. Hydrogen manifold 2. Hydrogen inlet pipe 3. Electronics control board 4. Hydrogen regulator 5. Hydrogen gas storage canister 6. Fuel cell power terminal 7. Battery pack 8. PCBFC fuel cell range extender 9. Voltage regulator 10. Rear shock absorber 11. Bespoke body-shell in the shape of a new generation Toyota Mirai|
When you remove the bodyshell, you can see it is a stock TT02. There is a basic 7.2v nimh battery installed that is then connected to the hydrogen cell. This cell powers the battery and ensures that it maintains charge.
The promotional video would cut between both the real Mirai driving around Bourton on the water, and the Tamiya version driving the replica version re-created so well in the model village.
This was going to be a fun challenge as the roads were very narrow, and most of the time I needed to be out of the shot whilst still trying to get enough visibility on the car to drive around sections of the village in a realistic manner.
The big risk is that the bodyshell is a unique part made for the filming, so I had to be careful when driving as any big scrapes or bangs could spell disaster for the filming. So unlike racing the challenge was not to cross the line first, but to ensure that I kept the car firmly away from the stone buildings and out of the flowing water of the replica river.
We fired up the car, and the hydrogen controller emits a solid beep and the green light comes on. It was now time to drive this car for the first time, with the enclosed stone walls either side. I tentatively pushed the throttle forward and the mini Mirai smoothly rolled away.
Luckily the TT02 even in stock form is stable at lower speeds, and the new Tamiya TBLE 04S esc is a refined so I instantly felt quite at ease driving the car. The H2 power unit was providing a steady 7.2v voltage so the cars speed was easy to maintain.
All of the high tech gubbings in the chassis did add a fairly significant amount of weight to the TT02. This settled the car on the kit shocks, and allowed it to soak up most the bumps in the paths around the model village. The penalty was that the extra weight did put more load on the steering. The chassis was running standard electrics and the kit servo was still able to throw the car around, but as you would expect it made it a little lazy at times when entering and exiting the corner. As you would also expect, the added weight also made the brakes work a little harder bringing the car to a halt, luckily the brakes on the 04S are more powerful and despite the occasional sharp intake of breath as the mini Mirai would be screeching to a halt at the end of chase scene towards a dead end the Mirai stayed unscathed.
As filming progressed we wanted to do some low down chase shots, to try to get a true drivers eye view of the Mirai, we decided to make a chase cam car. Step in an old TRF that I had with me in the spares. We quickly mounted GoPro camera's front and rear and we had a nice responsive chase camera car.
One of the more challenging scenes was to drive the Mirai over a bridge in the village. The replica bridge doesn't have any walls so you need to hit the bridge straight on, whilst compensating for the acute angle of attack of the base of the bridge.. (It wasn't made for a RC car to drive over it). A few tentative runs didn't help. The extra weight of the car and the steep angle of the bridge would find the chassis grounding out.. so there was only one thing for it.. full on attack.
We all took a deep breath and I hit the throttle to build up enough speed to ensure the chassis wouldn't hold me back and the car made it safely over the bridge without careering into the water which could have been disastrous for exposed circuitry of the Hydrogen Cell.
The finished result
It was a long, but fun day. The handling of this Tamiya Mini Mirai Hydrogen powered car was very similar to a standard electric powered TT02, with the exception of the extra weight. The real benefit was the length of time that the car would run with the hydrogen power units. The car would run for ages before we even had to swap out the Hydrogen canisters. Its not going to change the world of RC overnight, but it is interesting to see where hydrogen power will go in both road car and RC car development...
Here is a behind the scenes video of the making of the video and more info.
All Photos (except the TRF camera car) copyright: Rod Kirkpatrick