It should make the whole thing a lot more stable but we shall see how that goes.
I was struggling to work out how to even draw it with RHS so construction might be a bit of a challenge as well. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Tue Nov 24, 2015 11:55 am
Thomas AIC
Joined: 22 Jun 2009
Posts: 151
Location: Canberra
Here's the concept with more probable proportions. It's hard to get a good viewpoint of the model.
1.8m * 1.8m by 600mm high. Base angle is 15% off of vertical. The roof panel is 1.478*1.478m
What do you think - Too much angle? Not enough angle?
I will be working on implementation shortly. I have some ideas. The increase in construction difficulty should be reasonable for the improved performance.
Wed Nov 25, 2015 4:02 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
It looks good and 15 deg. is probably about right. Apart from the roof being smaller and less saggy, I don't see how sloped walls are any more stable, but its your arena.
If you are going make the wall panels with a square steel tube border, you will need to add some brackets to bridge the odd angle at each corner ans since the tubes will not but up against each other at 90 deg. the arena might actually be
less
stable.
An easier compromise might be to make two opposite sides vertical and two angled. That gives you a smaller roof and the sides will be so much easier to bolt together. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Nov 25, 2015 4:45 pm
Thomas AIC
Joined: 22 Jun 2009
Posts: 151
Location: Canberra
Here we are with RHS on the wall panels. It's a bit thin top and bottom, but that's because I'll be splitting the walls in half anyway, as I obviously can't listen to reason.
This geometric stuff fries my brain, so I'm still wrapping my head around what's parallel and what's not. In the CAD some areas are a couple of degrees off of parallel, but I think I may have messed up a mate somewhere in the assembly.
Construction is still pretty easy for the above, but a mitre saw is now non-negotiable!
@Nick, definitely working out the joints might prove too difficult, all I can say is thank goodness for CAD!
Wed Nov 25, 2015 5:39 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
if you want an "ideal" angle, stick a "standard" person standing outside it and angle it such that with them standing 60cm away from the wall when they look in to say the far third of the arena the poly is normal to their viewing angle. _________________ Mechanical engineers build weapons, civil engineers build targets
Wed Nov 25, 2015 6:02 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
The arena shape is called a pyrimidal frustum and the important thing to know is the dihedral angle, the angle between adjoining faces. There are probably some on-line calculators to figure that out.
Whatever the final shape is, the most important thing is to make up some cutting & welding jigs so that all the side panels come out identically. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Nov 25, 2015 6:03 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
We could probably just ask them for the plans. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Tue Dec 15, 2015 11:41 am
Thomas AIC
Joined: 22 Jun 2009
Posts: 151
Location: Canberra
Dusting this off as I went well and truly into holiday mode for a while there!
Basically I'm planning to head off and buy a sufficient amount of aluminium RHS for the design I posted on 25/11/15. I plan to assemble that, and then depending on results, split each wall section in two. As always I already have the polycarb sitting around.
The only real problem with just stitching the angle together was that the base wouldn't be flush to the floor but at a 15 degree angle. I'm just going to run with it digging into the floor like that for now, Any place it's set up should have some carpet or resilient layer underneath so it wouldn't matter. Could always put little wooden triangular feet to easily make it flat if it is shown to be necessary.
I'd hate to move forward on this if you're already building something marto, so let me know if you are or have any particular ideas.
If anyone wants to throw strong criticisms at the plan now is the time! I figure if I don't get started on it (even if it's not perfect) I will never get it done.
Mon Feb 08, 2016 11:30 pm
Thomas AIC
Joined: 22 Jun 2009
Posts: 151
Location: Canberra
So the Gross requirement for good old 4 panel design is:
16 m of 25*25 RHS @ $5.25 p/m
6.5m of 50*25 RHS @ $8.31 p/m
-----------------------------------
$138 total which is cheap as.
Making sure I can store all the parts tonight, then hitting up the store tomorrow. Watch this space!
I appreciate the gesture Steve! No rush with that, I'm sure it'll pay for itself in the many profitable events we will hold using the arena
A kind friend has granted me use of a Ute so things definitely going ahead at full speed now. The key hurdle will be the welding but I have some options for that.
With regards to storage, I have a home for it, but for ease of use and access I'm happy for the arena to live with you whenever you want it.
Wed Feb 10, 2016 1:12 am
Thomas AIC
Joined: 22 Jun 2009
Posts: 151
Location: Canberra
Got the aluminium, ended up at $98!
I don't know why it was cheaper, but really appreciating fyshwick right now over bunnings.
Getting started tomorrow! Cutting all the angles first up, should have a mock up of the frame by the end of the day.
heheheh.... I lost my key to Make Hack Void a couple days after getting it. Then uni got in the way
Got one wall mockup made and everything fit together very well. Been pretty busy but let me know if you have any plans that might need it and I'll get it done. Happy to hand the parts/designs over if you want as well.
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