Liftoff (FW) build diary

[adz600]

3mm angle ram braces would be the way, then you can also mount armour and electronics of them also

[Liftoff]

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!!!

[Eventorizon]

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.

[Liftoff]

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)

[Ellis]

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.

[Liftoff]

Interesting...do you have to get a whole sheet or they sell smaller pieces?

[Ellis]

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.

[Eventorizon]

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.

[Liftoff]

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

[Eventorizon]

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.

[Liftoff]

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!

Top view.jpg

[Revsmin]

LF3 had 2.5mm Ti armour, and it doesn't look too mangled. Weighs very little too, might be the way to go.

[Liftoff]

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...

[Max]

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?

[Liftoff]

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?