Im new

Hey-everybody!Im Dan im 14 and i am going to build a featherweight.Its going to have 14.4v drill motors,polycarb and titanium armour,aliminuim box section chassis and 25a speedos.It will be based around the weapon as this seems the best thing to do.The weapon will be a single headed pneumatic axe.The thing is i know nothing about pneumatics-so any help welcome.I would like to know the approx weight,where i can the the bits,what size co2 bottle and everything else i will need to make a pneumatic axe mechanism.The axe will be similar to little hitters and terrorhurtzs with the same type of mechanism.I would not like to spend over £200 on pneumatics and keep it under £150 if possible.I think i will need a big ram because the axe will be making a 180 degree movement.

Thanks Everybody.

Dan.

Hi Dan,

Welcome to the forum. Your robot will need a ram with sufficient stroke, the size is a different issue. There are indeed several axes in the featherweight field (im glad there are) so I am sure several people can help you out.

Hi Dan and welcome,
£200 is very tight for a good pneumatic system but can be done.
Firstly for your axe you need a rack and pinion (HPC gears do this but its expensive - If you want some cheap rack I may have some spare)
Depending on what size and MOD the rack and pinion are will depend on the stroke you need for your ram. for example- if you have a rack and pinion of 10mm pitch teeth and a 12 tooth pinion, to get 180 degrees of movement you will need a ram with 60mm stroke. The bore of the ram will depend on what you like, but i would recomend something between 60-70mm for low pressure pneumatics.
After this is sorted, you need the rest of the system.
600g/20oz bottle, 5/3 valve, regulator, 1000psi pressure relief, 16bar pressure relief, dump valve (small ball valve), rc switcher (gimsonrobotics.com - pico switch). You can add a buffer tank to get that little extra umppff out of the axe, but i would test without first.
You would also need fittings and piping to join them all together but thats usually done after you have the components.
If you want any help with this system of how to link them all together and where to get the components from drop me an e-mail (I have helped built the newest featherweight axe BASHER! which has the potential to be the most powerful yet).

Good Luck

What Kind of batteries are best?(Ni-Cads or Ni-mhs)

Thanks

from what i can gather there isnt much difference but, i think it would be personal preference and how much you want to spend

I dont know how much a decent battery pack is.Any ideas?Links?

Thanks

Dan

Sorry,one thing i forgot!I bought the 4ch 40mhz transmitter off technobots.It comes with no servo or reciver-what type of these will i need?

Does anybody have any for sale?

Thanks.

Dan.

I suggest the best thing to do is order Ni-Cads from technobots, but if you are looking for reasonably good and cheap Ni-Mhs, http://www.modelpower.co.ukwww.modelpower.co.uk is where a lot of featherweight roboteers get their batteries from and they seem to do the trick.

Hope this was some help
Tom

did you know it didnt come with a reciever? was it a technobots own one? and unless you are using the servos for something special you wont need them, except for perphaps testing
alex

Either Model Power or Overlander. I recomend the Sanyo 2400Ah Nicads, just what I use and have so far been reliable. Sanyo and GP are generally good cells.

@Alex

Yeah i did know it came without a reciver.Its called a sky sports 4.Link-

http://www.technobots.co.uk/acatalog/Online_Catalogue_4_Channel_Technobots_40MHz_251.ht mlhttp://www.technobots.co.uk/acatalog...chnobots_40MHz _251.html

Thanks.

Dan.

Dan, firstly, welcome to the club!

There is a difference between nicads and nimh. It is to with performance.

Basically if you are going to be going heavy on the current draw then go for nicads, they are far better at delivering large amounts of current in a hurry. Nimh will probably be better for your application as you wont be using your drive heavily in a flipper.

Nimh weigh less for the same voltage and capacity as well however they have one flaw. They have a memory. All cells have some form of memory, this means that they remember what level they were discharged to. So if you only discharge cells half way and then charge them and repeat this over and over then your cells will slowly lose their capacity.

This is removed by fully cycling the cells, ie running them flat and then charging them fully.

Dont worry about half discharging cells during competitions etc as they will take a bit of abuse but whenever you can, you should always fully cycle your cells.

Just to clarrify a point:

NiMH suffer from very little memory effect. More so, NiCds need to be cycled to prevent the memory effect.

NiCds are the only cell you should cycle. Other cells can be damaged by frequent cycling. NiMHs can benefit from cycling once in a while.

hi i just brought some batteries of ebay on monday they arrived today quite cheap and work there 7.2v ni-mh 3300 mah take about a week but they are from america
comes to about £38

http://cgi.ebay.co.uk/4-RC-7-2V-3300mAh-NiMH-Battery-For-Tamiya-E-Maxx-7-2_W0QQitemZ300142602285QQihZ020QQcategoryZ44022QQt cZphotoQQcmdZViewItemhttp://cgi.ebay.co.uk/4-RC-7-2V-3300...Maxx-7-2_W0QQi temZ300142602285QQihZ020QQcategoryZ44022QQtcZphoto QQcmdZViewItem

http://www.modelpower.co.ukwww.modelpower.co.uk 7.2 niMhs 3.9 amps

2 for £30

I have 25a viper marine speedos with the drill motors off gimson robotics-

http://www.gimsonrobotics.com/shop_dc-electric-motors.htmlhttp://www.gimsonrobotics.com/shop_d...ic-motors.html

I want some ni-mhs for this but how much power will i need?

Will i need just one battery or two?

Thanks.

Dan.

Fantastic, good to see another person about my age doing robots. Im still stuck in design stage, money = tight ROFL.

yeah, i think money is the biggest problem when you building robots at our age. Although i managed to build 2FWs and now building my first HW on a very tight budget.

LOL!Your right,money is the biggest problem!I think it will be a bit easier for me,because my dad is paying half and im paying half!Still a problem though!

What are your design ideas David?

Any pics of your feathers Erik?

Thanks.

Dan.

the best thing to do i found is plan then save, always have spare money for repairs

but i agree it is certainly hard at our age!:)

alex

yeah, i send them on your email Dan.

Instead of making several new threads Im gonna hijack this one.

Im not quite new to the Robot Wars sport, been doing Antweights for many years now, but recently I started up my Featherweight project again.

Specs:
Name: Accident
Speed: About 10km/h
Power: 2x 12V NICD packs
Drive: 2x 18V drill motors
Weapon: Vertical 180mm Hardox disc unknown motor.
Armour: Polycarbonate 10mm sides and HDPE 5mm top/bottom
http://i3.photobucket.com/albums/y89...nt20076.jpgCAD

Hey Joacim,

10mm lexan is still pretty strong, but like with the antweights it all also depends heavily on the way you mount it. As a rigid construction polycarb is not able to withstand as much punishment as it would when it has a litte flex in it.

Still, 10mm will take some serious abuse.

Does lexon shatter or just crack?

Ok, but will some 5mm HDPE sheet bolted on the side amour be able to take some punishment?

Hi there,

I just bought some 12v drill motors from that site thats just closing down. When I take the torque control off loads of ball bearing fall out. Are they used solely for the torque control? do I need to stick them back in, somehow?

Thanks - Simon

simon,i just leave them out.

The ball bearings need to be replaced with locking screws or or youll get NO drive.
Some 5mm grub screws threaded down the holes are ideal for this.

Ady .....See me after class for some extra homework!:crazy:

OK thanks, so two balls per hole and screw them in?

Simon

Nope .....no need..... just replace the balls with a 5mm crub screw.
Tap the holes 5mm first and screw in a 5mm grub screw till it contacts the gear inside.

http://www.robowars.org/guides/guides-drill-hacking.htmlhttp://www.robowars.org/guides/guide...l-hacking.html

Simon,what site is closing down?

Thanks Woody, thats absolutely marvellous.

Dan, the site is http://www.gimsonrobotics.com/http://www.gimsonrobotics.com/

Simon

Ewan has a sale on ....but isnt to the best of my knowledge closing.

sorry only read bits ball bearings fell out,do i need to stick them back in :crazy:

I dont think its closing down.Its just a sale.

OK my mistake. Apologies to Ewan.

Simon

hes only removing wheels and dril motors from his site once there sold out. also starter kits are no longer available. hes going to sell more electronic stuff. I think.

Yup, Toms hit the nail on the head. New speed controllers and relay switches should be among the new stocks replacing drill motors and wheels. Less than ten drills now remain for those of you looking to grab a last minute motor!

Oh bugger!!!!I really needed those wheels!!!!