i like it! are you still using fuses>?
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Creative Instigation - Build Something Awesome!

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Yes, I didn't change any of the electrical bits as they worked 100% during the UK event. I have really warmed up to using power links rather than a switch; they are easier to make and adapt to fit in almost any position.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

i used powerlinks at nats last year and i am most certainly converted
_________________
Creative Instigation - Build Something Awesome!

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Motor maintenance:

After Mr Mangle's motor upgrades proved reliable in the UK, I started on all the spares for Mangle and Shiny:



So far I have only epoxied the windings in to place - messy but easy. The larger motors for Shiny have a problem I didn't notice before; the back plate is very thin and has large vents, which has allowed them to bow outwards. They will probably fail completely after more impacts, so they have to be replaced with something stronger.

Magnesium, again:

Mr Mangle needs some weight savings to make up for the larger wheels and other upgrades, so I am going to try replacing aluminium parts with custom magnesium. The last time I tried that was a total fail as the 'mystery magnesium' proved as soft as butter. This time I have found two suppliers that stock AZ31B-H24 and ZK60A, which are comparable to 6061 aluminium at only 65% of the weight. Still waiting for quotes but if I get a reply next week, its all on for replacement motor mounts, bearing blocks and pulleys!

Sportsman:

After messing about with the actuator and a 4-bar arm made of scraps, I am pretty disappointed. Without major upgrades, its either going to be lame or unreliable, or both . After reading up on pneumatics (mostly Glen's Citizen Flips build) and talking to Mario, I am going to try a full pressure CO2 flipper.

The first step is a test ram powered by the shop compressor while I get familiar with pneumatics and buy all the parts, then its on to something that hopefully bounces opponents off the roof. If the magnesium supplier works out, the ram and buffer will be made of ZK60A for some major weight savings.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Pneumatics:

The test ram and buffer are taking shape; I found some thick-walled tube and bored it out to 50mm to make a short ram. The remaining tube will be a buffer with around 2.4 times the ram volume:



Imagine a 5404 Burkert valve connecting those two and that's the heart of my test system. According to an on-line calculator, the 50 x 65mm ram's ideal CV is just a fraction less than the CV of the 5404 so they are a perfect match for each other .
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

More CO2 use. That's bad for the enviroment, ain't it?

Al Gore's next movie. An Inconvenient Flipper.

Can't wait to see your flipper, Nick.
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So even the rain that falls isn't actually going to fill our dams and our river systems

good one, Philip! I haven't thought of a name yet, perhaps the flipper should be called Mr Gore?

These parts are just for learning about pneumatics; everyone says not to make a FP flipper until you know what you are doing and I gotta start somewhere. Apart from the valve and a few O rings, the set-up is all from on-hand parts. That tube has been lying out in the rain for almost a decade.

Here is a noob question: the piston will be aluminium with two O rings; What is a typical clearance between the piston and the cylinder wall?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

An Inconvenient Flipper.

Best. Name. Ever.
I have a C02 fill station and a couple of small paint ball tanks that I'll never get around to using.
Available if you need some gear to get you off the ground before Vivid
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https://www.halfdonethings.com/

What sized tanks are they? Also interested in the fill station.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Flipper progress:

There has been major progress on the sportsman today; the valve and many of the small fittings are ordered and parts have been drawn, prototyped and made. The ram is mostly designed and I printed the top and piston to see what y'all think about the design:



The assembled ram. the orange bushing attached to the front of the ram with M3 screws (not shown) and is 36mm long. The rod is 2024 aluminium with a 20mm diameter. The 12mm thick end cap is held on with eight 10-24 screws.



The piston is 25mm long and will have two O rings. It has a 15mm deep recess that fits over the bushing when the ram is fully extended. The idea behind that design is to eliminate any side-play that might cause the ram to seize at full extension.



There will be a number of vents around the end of the cylinder. The ones on the left are to exhaust air from the front chamber of the ram as the piston rises. The vents to the right are to quickly exhaust the CO2 at the end of the stroke; they are positioned so the piston just clears them as it reaches the top of the cylinder. The idea here is to maximise the efficiency of the smaller diameter bore by having a very small bleed hole. The extra vents will exhaust most of the CO2 so that the bungee cord can pull the arm down quickly while the remaining gas exits the bleed hole.

Those vents would normally waste a huge amount of gas, but I plan to use an MCU to time the valve and close it before the piston has travelled far enough to vent and CO2.

The buffer tanks is also taking shape, its almost too long to mount on the lathe:



The tube is too wide to fit in the steady so I had to be REALLY careful facing the ends. Its probably going to be too long to fit on the mill withthe rotary table as well.

Temporary name:

I thought up a fun and topical name for the Vivid event: Flippy McBotface
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I appreciate the name
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Steven Martin
Twisted Constructions
http://www.botbitz.com

If its a piloted valve it'll have a minimum on time so be wary of that with your vents.

Also venting the front of the piston seems pretty useless, at least for plan-C the force back due to air in that space was pretty much nothing at least until millimetres from the end.
It also means you can't use active gas to push back the piston should you choose to.
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Mechanical engineers build weapons, civil engineers build targets

I only put the vents at the front as many other bots have them; perhaps I will leave them out and see how the ram performs. The same goes for the CO2 exhaust vents; I can see how fast the bungee retracts with just a small bleed hole and only add the vents if the retract time is too long.

The valve is the same Burkert 5404 that Glen used in Citizen flips and he seemed to get good control over it when he was datalogging the pressure. I am going to wind a new low voltage coil for the valve that will hopefully open it faster. If that works out, would changing the return spring for a slightly stiffer one close the valve any faster?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

quote:

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Originally posted by Nick:
What sized tanks are they? Also interested in the fill station.

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