Flappy Paddle System
Note. To see detailed explanation of the pneumatic system, please look on the page.
Once I managed to shoehorn a 6 speed sequential gearbox into the chassis it didn't take me long to progress to the obvious next step - Flappy paddles and full throttle gear changing :-)
Looking at the systems available, the choice was between pneumatic and electric, with staunch adherents for both systems. After much humming and harring I finally came down on the side of pneumatics as this seemed to be the gentlest system on the gearbox.
Next stage was to source a system, which is when I discovered how expensive they were, upwards of £3000! Ouch.
When I looked into what a kit comprised of, I was shocked at how much the components were sold individually for. The actuators sold for around £500 on their own! Unless there is something very special inside, this a lot money for a simple pressure powered piston.
After some thought I decided to make my own system, the rational being that if it doesn't work I can revert to a commercial system.
First item on my list were the flappy paddles. I found a pair of Mercedes paddles for £60 on good ol' eBay that I could adapt. I wanted bigger/longer paddles so I designed and cut a pair out of polycarbonate.I wasn't happy with the rigidity so I made another pair out of aluminium and these are what I used. I milled the top face of the Merc paddles flat and glued my extended paddles on top.
Now all I needed was a steering wheel to fit them to. Fortunately I was already on to that particular case so no dramas there :-)
Next part to source was the actuator and this is where AliExpress comes into the picture. This is the Chinese version of Amazon but a lot cheaper :-)
I bought a 25mm diameter actuator with 50mm stroke, thinking that this looked to be of a similar size to the £500 commercial kit one.
Before I could test my theory I had to fabricate a bracket to hold it on to the gearbox. I located suitable existing bolts on the gearbox and utilised these to fix the bracket to.
When I tested the actuator on the bench it was fine. However, once connected to the gearbox it would change up but not down. A little bit of head stratching and I decided that the problem was that the actuating piston takes up a significant percentage of the surface area of the piston, so the is less air pressure available to push the piston back in than to push it out. Doing a little maths I concluded that going up to a 40mm piston would give me more than enough pressure.
Original actuator proved to be too small.
Acuator bracket mocked up in aluminium sheet.
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Bracket finished. Note steel top hat washers preventing bolt hole from elongating.
Replacement 40mm bore actuator.
Smaller SMC solenoid under test.
Airtec Solenoid bolted to actuator.
New actuator fitted
While I was sorting out the bracket I was also sourcing an air reservoir. I settled on a carbon fibre paint ball cylinder. Certified to 5000psi this should cope as I will be using a max of 200psi.
With the help of Tony at Reef Engineering we adapted the cylinder's fittings so I could connect it to my compressor (another AliExpress purchase). Tony supplied me with a pressure regulator so a consistant pressure can be supplied to the solenoids.
Gave the cylinder a coat of matt black paint to tidy it up a bit.
Like the actuator, I bought a couple of solenoids before settling on which one to use, the smallest of course :-)
Solenoid fitted and plumbed in.
Final setup. Note that the solenoid bracket has been lightened and the aluminium fixing bolts have had their heads reduced and been centre drilled :-)
The titanium bolt securing the actuator has also been centre drilled.
Next up was the down shift throttle blipper. Again, these were silly money commercially so I made my own. If it works, great. If not there is alway sthe fall back position but at least I would have tried and it is fun.
Sourced a mini actuator with a 5mm stroke and a tiny solenoid from AliExpress (can you see a pattern emerging here?) and fabricated a support for them. From AliExpress I also bought all the 6mm push fit pneumatic connectors. For the price of one on eBay I could get 5 of the same make. Probably where the eBay sellers get them from.
