Featherweight Discs

[ewan]

Ok, also can Scorpian JNR go through 12mm polycarb?
(Thats how thick the front armour is)

[robjones]

Also worth noting is that the motor in BlacknBlue was fully modded. The internal bearings at either end are bigger and more secure,there are extra cables to the brushes and the original shaft was carefully tapped out and replaced by an 8mm shaft that the local engineering firm gave me. They make gear for rock climbers and said that it was hot rolled high yield steel. The far end of the shaft has a thread cut in and a nyloc nut keeps it together. Nevertheless the shaft was already slightly bent at Inspire, causing more vibration. Ive since replaced it again, but Im on the look out for some chrome-moly steel which which will bend back after big hits. Another factor is how much damage occurs to the shaft when the disk is first attached - In BlacknBlue the blade is attached using the two Tarantorque fittings so no holes or flats are needed on the shaft itself. Im not that happy with the length of the shaft as this weakens it but I cant see a simple way around that.
I think 8mm is OK for big feather disks if supported at both ends but dont expect it to last that long. 12mm or 1/2 would be better.
Despite its apparent strength Ive never run the weapon indoors or in car parks/gardens etc, only in arenas, its far to dangerous. And after Inspire 2002 only if theres a roof on the arena
We build lots of feathers in the Young Engineers club at my high school but I wont allow any of the students (inc. sixth formers) to build spinners. None of my students have ever seen BlacknBlue in action - that how careful we are.

Ewan,
I have just spotted your age!€¦I had no idea you are only 12! Now I€™m even more pleased that you are so enthusiastic about robot building. This is exatly what our community needs€¦ Roboteers, The Next Generation!! It also explains a few things!.
But that said, It still doesn€™t change my advice to you regarding the dangers of this type weapon, something that you will come to learn in time and I hope its not the hard way.
Please take my, and a lot of other peoples advice and take advantage of the vast amount of knowledge out there€¦Remember, all you have to do is ask.
I€™m sorry if you thought I was being hard on you but all I€™m trying to do is promote a responsible attitude towards safety.
Keep working on that machine but be careful and do some serious work strengthening that spinner mounting.
Oh and by the way, 12 mm of poly will not save you, its not a question of thickness of armour, but how many times can your robot stand the shock of being smashed into the air and crashing down again before something vital breaks. Another thing you will learn about spinners, not all of the damage involves tearing large pieces off your opponent Sometimes the shock of impact on a robots internal parts can kill a machine far quicker than any damage you can do to the outside!
Now you know why I go on about having a rock solid drive and a strong chassis.
So take it easy, and work safely

Geoff,
Team scorpion.

If I have a workshop with a pillar drill and jig-saw machine (dont know the name) at the age of 12... I wonder what Ill have when Im 18
But still, I do take the fact that being 12 does not give you an excuse to build less safely. I will try to upgrade Big Daddy as much as possible, because I still think that it is a workable design. One of the problems about being so young is not having the money to get anything CNCed or using so many good materials. If I could afford a version of vortex, then thats what Id build. If anyone wants to send me money then do so! (yes that is a desparate call for cash!!!)
Cheers, Ewan

[s8nsmum]

If you have a bandsaw and a pillar drill you should be able to build a robot very similar to vortex. If you dont think you can machine the bulkheads and baseplate out of aluminium like vortexs then use some of that 12mm polycarb, that can be machined as if it were wood and should be plenty strong enough and a lot lighter. If you manage a copy of vortexs chassis then use a fat bar instead of the disk, dimension it to fit your speed controllers/batteries/motors etc. not Eds then it should be a very impressive robot that costs no more than Big Daddy did. The only part you may need outside help with is the axle that the disc goes on, I imagine lots of people on this forum will have access to a lathe and could whip up an axle to your specs for a small fee. CNC is a luxury not a necessity. As for the good materials I agree with you much more on this point, it can be quite depressing when you hear about the cost of decent grades of titanium but if your build quality is good a robot armoured with 6mm polycarb will be very hard to stop even with a robot like vortex. Like Geoff said above it is normaly the shock breaking the internal workings of the robot rather than cutting through the armour that ends the fight.

Joe Townsend

Its not a bandsaw its a scroll saw...
Anyway, Ive fitted a better 2.2mm titanium scoop at the back of the robot, which extends 30cm beyond the back of the bot, I might take on venom and Tantrum afterall. (but still, even at 1/16 power, I do think tantrum- with the weapon- should NOT be allowed in an arena without a roof, even though its horizontal, shrapnel could still go upwards...)
Cheers, Ewan
P.S. The bot is now fully clad in my sponsors logos (http://www.batteryworld.co.ukwww.batteryworld.co.uk) and for the logos sake, the name has gone back to Micro-Maul

[geoff]

Ewan....Remember what we agreed...never mind the Ti scoop and sponsors, what about those weapon mountings!!
Get your priorities right!!
Geoff.

As I have said before, Im only kitting it out for RC wars right now, Ill kit it out for using the weapon (at the FW smash) after Rc wars...

[craig_anto]

tools dont makethe robot the roboteer does

TX-108 Gianto V1 Gianto v2 Tanto 1 and my previous 3 heavyweights were made with a jig saw a hand drill and file and pretty much nothing else and all of them capapble of taking there own strength and surive a full on attack from all sorts
youd really be amazed what you can achive when you put your mind too it
Recently I got a milling machine and lathe but I dont personally see them as essentials more of a luxury to me

that said I did have to get somethings done outside of my garage I think we all need some help sometimes

[jamesb]

Tantrum wont be fightin at RCWars on Sunday Ewan, too busy with all the extra paperwork Ive been lumped with.

For the record by the way, as shaft sizes came up a few posts ago, Tantrum runs a 55mm thick aircraft ali shaft with 4mm titanium thrust retainer. This is in line with the expect 10% guideline on spinner supports from the FRA.

Though many current spinner come nowhere near this, I would not say that makes them unsafe.

Each robot is unique, and each solution should suit that robot. I would suggest for Ewan, as you are always trying to get so much energy in your spinners, that you have a primary support shaft of at least 10% of the disk diameter, this is to meet that expected guideline. If you had a 50mm shaft on you 500mm bar, and the motor shaft plugged in the other side, you would have pretty much the same setup as not, but its held on far better. Not too hard to do, wont compromise your robot either. If you did have this, even with a wooden chsssis Id be 90% sure of running you. Wood is underrated, remember, the Mosquito fighter bomber was wood!

spinners are a very tricky thing to convince people they are safe, if you want to make sure they minimize their critisism, maximize your mounting method.

If your robot is well built, and Im convinced the spinner will not seperate from the robot, its 90% there. The arena is more than capable of containing most spinner (featherweight) but one or two might be just the right size/shape to cause us problems.

As to the roof, again, dont make so much of it, its very close to the top of the arena, as due to feedback from the roboteers, there is now no gap. We can run verticals.