Liftoff (FW) build diary

[maddox10]

I'm not to keen to accept that setup.
Have seen how Tip Top had to be activated... scary....

[Liftoff]

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
isolation valve.jpg

The valve is similar to this:
http://www.ebay.co.uk/itm/2x-New-CO2...item3a7fc6eb43

[maddox10]

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.

[Liftoff]

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!

And you're struggling for weight as is, so adding a small motor and gear to open that valve remotely ain't an option.

Unfortunately you're right, weight does not permit that...

[maddox10]

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.

[Mouldy]

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.

[Liftoff]

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...

[Mouldy]

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)."

[Liftoff]

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.

Turning the gas on through the flipper arm wouldn't be seen as a good idea. Same goes for turning the robot over.

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).

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.

PRV-Dump valve.jpg

[Max]

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.

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!

[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?

[RogueTwoRobots]

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!

[Liftoff]

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!

[Mouldy]

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.

[Liftoff]

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...