Yes the weight limit and dimensions, 500mm x 500mm max.
Regarding the bit of wood, it was actually quite a large piece of wood flying around - and I remember Will getting a bit concerned as the arena was not exactly spinner proof! :eek:
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Yes the weight limit and dimensions, 500mm x 500mm max.
Regarding the bit of wood, it was actually quite a large piece of wood flying around - and I remember Will getting a bit concerned as the arena was not exactly spinner proof! :eek:
So, I got the latest update on the final stages of the build which unfortunately are not looking good
Yesterday they managed to complete the robot to a working state in terms of drive, and the pneumatics were working (apart from some minor leaks!) So I was feeling confident that by today it would have been combat ready.
But this afternoon, after finalising the build and taking it out for testing it refused to move...dead! My brother is thinking the receiver went bust, but with no time to buy one looks like its grounded!
Only hope is they borrow one from I don't know where!
Guys I'm having a hard time getting this build within the weight limit!
I have gone through plans again and trimmed it further,(for now on sketchup obviously!) But I'm still off the mark by about 500 grams.
One of the heaviest pieces is the base plate which is 3mm thick Aluminium, thats 1.5kg. It is also the part which worries me most as being 1000 series Alu its soft and prone to bending with a good impact.
I was thinking of cutting some pockets in it, but not yet convinced about that, first because it will further weaken the base and secondly it will expose the internals when upside down...
Any ideas of what could be done, or maybe different materials, or maybe I should just risk it!
Attachment 4245
A 10-12mm HDPE base would save you that weight easily, and would be more than enough protection against the ram's power; we use 10mm on Skyfall, it stands up to FP fine.
10mm HDPE would actually be about 250 grams heavier than the 3mm alu. I have this problem in my machine, too, as in, the baseplate eating up a huge portion of the weight limit. It depends on how structural your base is, but I have been able to drop mine to just 1.2mm ti (only has to hold the electronics in). I wouldn't trust that to handle all of the forces of the ram on its own, unless it's supported around the base of the ram well, but point is, it'd save ~500g.
Saying that I'm not sure how much more I'd trust soft 3mm alu to support those forces, so it's probably a much for a muchness. If there is some sort of strut (some lengths of the 3mm alu on-edge perhaps) support under the ram then I'd expect it to be fine.
3mm angle ram braces would be the way, then you can also mount armour and electronics of them also
The problem with 10mm hdpe is that the base would weigh approx 1.7kg, still 200gr more than 3mm Alu. I'm not concerned about the ram's power, as its not mounted vertical, its horizontal...I'm more concerned that the whole base would warp with an impact from a spinner or from getting a good flip.
One option is going 5mm hdpe - which would be a last option as the previous build was based on that and it was too flexible for my liking...
The other option is replacing the base with thinner aluminium say 0.09" but of a stronger grade (say 2024 or 7075), problem with that is its hard to source and expensive!
Ahh bloody weight!!!:angry:
Is there anywhere else you can loose weight? It seems that your base is locked down for your design to work. You might be able to pocket out your HDPE bulkheads (I am assuming the machine is much like the one in the picture).
If Sketch up will let you, there is a tool in solidworks that allows you to view cross sections of the design, allowing you to move through and find large blobs of material that you may not need.
Its very much similar yes to that (have a look here: http://www.fightingrobots.co.uk/thre...d-diary/page15 for pictures of the internals)...
My primary concern with the base, as I mentioned is its ability(or lack of) to take punishment from external forces rather than from forces from the ram etc. It ties all the parts together taking a major part of the load, so if the base material distorts and does not spring back, then that will be the end of it!
Ellis, titanium plate at 1.2mm will of course be ideal, but I cant find a piece 500x500 in grade 5 form...apart from that, God knows how much it'll cost me!
Alex, I could probably look elsewhere for weight reduction, but I have to be careful not to weaken the whole thing... The other parts that come to mind are the hdpe sides which are 20mm thick, I could maybe drill holes in them to half their weight (they weigh 0.5kg each)
Might be worth getting a quote from these guys on the offchance: http://www.firmetal.com/titanium-sheet.asp
I got one for a conceptual Tormenta 3's 4mm titanium armour (quite a lot of material) in grade 5, and it was surprisingly "cheap" compared to other sources.
Interesting...do you have to get a whole sheet or they sell smaller pieces?
I got a quote for a specific size so yes, they'll get you a price for whatever size you want. I got a response to my email within 24 hours.
Going by this picture...
http://www.fightingrobots.co.uk/atta...0&d=1383419136
I would strategically thin out the HDPE outer armour as well as Swiss Cheesing (Yes that is a technical term ;-) )the internal wall of the aluminium box section. Inertia XL and NSW couldn't get more than 10mm into my 20mm armour on Conker 1.
People also have skimmed off their buffer tanks if they are desperate to save some weight. I have read that 1/6th of an inch is sensible in the Hanibalito 4 build diary.
Thought about skimming the buffer, the walls are 3.4mm thick and was considering taking off 1.4mm off, but I'll leave that as a last option...
Don't know if its an overkill (probably it is from your comment Alex) the side armour is 20mm hdpe with 4mm gr5Ti bolted on, a precautionary measure after seeing LS4, NST, InertiaXL and all the spinning rest in action...
Maybe halving the 20mm hdpe to 10mm I'll still be safe
If you have 4mm of grade 5 Ti firmly bolted to the side I would drop the HDPE all together! LF3 had 3mm of ti on it and I dont think anything really got through. Little hitter has 3mm G5 on the front and 1.5mm on the sides. But theirs is sloped quite heavily.
You could keep maybe 6mm on the side to absorb some impacts and slow weapons before the reach the Ti but 4mm of grade 5 is more than most machines have.
I would like to have something in between the Ti and the alu box section as that's where the tracks stay,will reduce to 10mm. Everything is sitting tight there so I cant risk anything getting distorted in there!
I have "re-sketchedup" Blastoff, a chopped off, starved version of the current build...and its now looking much smaller... yep reduced the hdpe sides from 20 to 10mm as well, that was a bit excessive,true...this means I have to place another order from direct plastics!
Attachment 4247
LF3 had 2.5mm Ti armour, and it doesn't look too mangled. Weighs very little too, might be the way to go.
Need some clarification on the build rules regarding positioning and access to the manual isolation valve on the main tank. The rules say it has to be accessible from outside, can the access be from a cutout in the bottom (baseplate) of the robot? That is, to turn on the gas supply the robot will have to be upside down...
I wouldn't want to turn the robot upside down to turn it on, I'd be worried it would self right and so jump up and hit me in the face. Lots of people turn it on and off with a tool through the side of the robot- would this be possible? Maybe have both options of tool and access from underneath to be safe?
Hmm I see, the problem is that the valve is at the fwd end of the robot, just under the flipper plate. To the side there's no access, so it can either be the bottom (easiest) or through the flipper...which is not ideal as I'll have to tear quite a large hole in it!
Might be wrong about this, but I think there's no danger in having the robot upside down as long as the flipper plate is locked no? What I mean is, you have the robot disconnected ( link removed so no elec power), flipper arm locked, so when I open the valve nothing should happen. Then I put the robot upright, insert the link and power up, and finally remove the locking pin... would that be an acceptable procedure?
I'm not to keen to accept that setup.
Have seen how Tip Top had to be activated... scary....
Got no idea how TipTop was activated, but from what I found out on the net its a HW petrol driven spinner, quite different from a FW flipper to handle...anyway wont argue with that, if its seen as dangerous way of activation I'll have to figure out another way :?
Any ideas apart from putting a hole in the flipper plate?
The valve is the one marked with an arrow
Attachment 4263
The valve is similar to this:
http://www.ebay.co.uk/itm/2x-New-CO2...item3a7fc6eb43
Argh, you're using a pin valve, not an on/off valve.
With an on/off it would have been easy enough.
Mount a nut or so in place of the knob, and use a socket to open the bottle from the top. Unfortunatly, it ain't an option here.
And you're struggling for weight as is, so adding a small motor and gear to open that valve remotely ain't an option.
On/Off you mean something like this?
http://www.ebay.co.uk/itm/New-paintb...item5af8b37a3f
I think it would still be an issue even if I had to mount a nut in place of the knob...the flipper plate stays on top of the valve so I'd still have to cut a hole through it...
Will try to play around with the cad model to see if can somehow reposition the bottle to get the bloody valve accessible from the top or side, other than that I don't know what to do!
Unfortunately you're right, weight does not permit that...Quote:
And you're struggling for weight as is, so adding a small motor and gear to open that valve remotely ain't an option.
Yep, that's an on/off.
And I was thinking of angling the knob at 75° or so. Wat means you can cut a hole in the non flipper top armor and reach it that way.
cant you turn the bottle 180, and mount it on an angle, could access it from the top at the back of the robot then.
That could be a possibility, the only issue is that (according to my sketch up model) the valve will be close to the drive motor, very close (1.4mm). Otherwise its the best solution I can get as the valve will be accessible from the backend without the need of opening anything...
Turning the gas on through the flipper arm wouldnt be seen as a good idea. Same goes for turning the robot over.
Have you considered the position of your dump valve? You mayaswell mount that next to your bottle by a hole in the back so it can be easily accessed.
"9.12 Dump Valve
All pneumatic systems must incorporate a pressure dump valve accessible from outside of the robot. This
dump valve shall quickly and reliably exhaust all gas downstream of the gas cylinder isolation (or remote
isolation) valve including systems with a maximum operating pressure of less than 50psi (3.4bar)."
For the dump valve I was going to use the PRV as its got a pull type manual override (http://www.ebay.co.uk/itm/Safety-Val...item1c34534bd6)
It will have a dual function, its installed on the buffer tank so all the system will be depressurised when open.
True, its a real headache to try getting everything in its ideal location when space is limited! (and tbh this build isn't on of the smallest).Quote:
Turning the gas on through the flipper arm wouldn't be seen as a good idea. Same goes for turning the robot over.
I've yet to figure out how to keep the PRV open to act as a dump valve, but it will be some sort of toggle mechanism...should not be too difficult to devise...still can do a normal valve if this idea is not acceptable, can put another Tee at the pressure gauge and dump from there.
Attachment 4264
You don't need a pressure guage so you could just replace it altogether with a dump valve if you need to. May even save a little bit of weight and space getting rid of the pressure guage!Quote:
Originally Posted by Liftoff
Under normal circumstances I'd agree with you that you don't need the gauge, I use it mainly as the regulator sometimes does not give a constant pressure and needs some minor adjustment...without it I wouldn't know what pressure I'm running, and it only weighs around 10g its very small :http://www.conrad.com/ce/en/product/...f=searchDetail
What type of dump valves do you normally use, ball valves?
Is your flipper physically attached to the ram, or does the ram just push against it?
Reason I ask is that there was a discussion not too long ago on arming up with the flipper in the 'up' position. Not sure what the consensus was but the way I see it with your current configuration, if the flipper is not physically attached, you could lift it up and hold it in place (or even use a bar or hook or something), then use a tool to open your valve. I suppose you could use your hand as well but with a tool it means you can open it from slightly further away, reducing potential risks.
Worst case scenario, if you open it slowly, the ram gradually extends if the firing valve is 'on' for whatever reason.
Not sure how acceptable that is for tech-checking/arming up though (Dave will be able to shed some light) so there may not be much validity in what I've just said!
No it's not attached, the ram just pushes on the flipper and it comes back again through bungees.
"Flipper up" arming would surely work on it, but as you pointed out Jamie, I still would not know where I stand re rules etc.
Maybe someone like an EO or a tech-checker can illuminate me on this, honestly I'd be really disappointed if I had to travel over to the UK only to find out the robot is out of specs. Ideally I'd have it checked before I leave but I know its impossible!
Then again, I might have an alternative as it seems that if I rotate the bottle by 180deg I can access the valve through the rear, but will need to put all things physically together to confirm as from a cad model to reality there could be some differences in mm!
I tech check at the champs... with your bottle being turned on through the arm i wouldnt pass it, it means putting yourself in harms way to gas up/ shut of the gas.
I also dont like the idea of pulling on your relief valve to act as a dump... your dump needs to be open at all times up until the point you gas up in the arena... put a ball valve in there. You can get cheap, lightweight, plastic push in ones easily to put on your low pressure side.
Ideally your gas on/off valve, the ball valve, LED and link should all be in close proximity, so if you can mount them all closely on the rear of your robot, this would be prefered as it makes things easy for the arena marshall when the time comes to shut your robot down.
Hope this makes it clear.
Clear enough, turning on the gas through the flipper is out of question, taking your advice as you mentioned in a post above and placing the valve at the back. All the rest of the stuff will also be at the back.
I get your point re. dump valve, but I'm not sure if I'm making myself understood...what I'm trying to explain is that the PRV will be open all the time, not through myself pulling on it though, but through a mechanism which will hold it open for as long as is required, ie I'll close it just before I pressure up the system... I'll post a sketch to explain myself better.
Obviously, if you straight away tell me its not allowed, then no problem, I'll find a place to squeeze in a separate dump...
I understand what you mean and technically there's nothing in the rules that states "it must be a ball valve" however this is the standard here.
For the weight of the mechanism your planning you could easily fit a low pressure ball valve.
Ok point taken, separate valve it will be.
On a different note, started building the gearboxes, look good so far...
Can someone to do some double checking for me please - I want to use a 9oz Co2 main tank and would like to know the max number of flips it can possibly give.
I want to regulate the operating pressure to a range from 19 to 24 bar max. I'm using two rams with a combined volume of 0.436 Lt.
I calculated this would give me a max of approx 13 flips at 24bar...is this close to reality, and would that be near enough for a round?
9oz carries 138 liters of gas @1 bar. @24 bar that is 5.75 liters.
5.75/0.436=13 actions.
But, you're fogetting losses in the setup, and inefficiencies. If you get 10 decent flips, the setup is well done.
And I doubt that it will be enough in a fight with an experienced opponent.
What would you rate as a decent amount of flips? Keeping in mind it's a feather and constrained by weight and space, that's why I was drifting towards a 9oz tank, a 12oz tank would be the maximum I could go up to. ..