Spinner Weapon Motor Discussion

Its a real struggle to keep microCHIP competitive against fast, well armoured, well designed and made feathers and although its made big improvements since Aberystwyth Uni earlier this year its weight is now the biggest problem. Its has always had a centrally mounted Evo Warrior run with two 7.2v 3600 mAh in series, belt driving the 1Kg blades/disk on a 1:1 ratio (see profile pic). The motor is about 65mm high and weighs about 1.3kg. It spins the blades to about 2900rpm really quickly.
Ive now got an Astroflight 940, which is 700g (big saving) but I dont want to fry it. Im thinking of a belt drive at a 5:1 ratio in the same configuration.
Any views on whether Ill get the same power/performance, is it worth modifications, experience with Astros. With the weight saving I can put in more cells or use a bigger disk.
Thanks
Rob

Hiya Rob, well you know what Scorpion Evil is like. They use their Astro flight at 24v using 3:1 ratio on their 6mm chain. So belt drive on 5:1 ratio seems quite safe. Faster spin up time as well since the more ratio used, not as fast but who needs speed if you can keep it going.
Little Spinner is only 2000rpm but keeps hitting with the diamter and weight behind it.

So yeah Rob 5:1 ratio is a good safe choice. and can run it up to 24v if you want to.

Mr Stu

Id invest the weight youve lost in extra battery cells if I were you. At 24v with 5:1 ratio the astroflight should give no load of around 3200rpm to the disc/bar - but at a push you should be able to run 4:1 giving 4000rpm or more - this is probably closer to the ratio used by scorpion jr at the moment. Currently I guess your getting about 3000rpm from the undervolted EV so you should see an increased KE with on your existing bars/discs at 4:1/5:1 ratio. As you dont want to fry your Astro, dont run it at 2:1 ratio like Ive done before :)

If youve got the weight to spare you should stick more weight into the weapon - but only if youve got enough weight after youve packed in a few more weapon battery cells. Ive seen microchip with the big long steel bar with hammer shaped bits on the end - I presume youve not had the weight to use this much but now perhaps you could use that? (is there any more weight you could take out of the ali base?)

From our bout at Norwich I think theres a big modification you should try to make with the height of the weapon bar/disc. Currently its right at the top of the axle but it should be quite easy to mount the astroflight upside-down in the middle of the chassis so that its possible to put the bar right down to the ground - maybe 2cm over the ground actually.

Thanks guys, maybe Ill go for a 4:1 @ 21.6v (3 packs) Ill need to make a new driver pulley. Ive already made some modifications to microCHIP and it will go with the 10mm ali base on top so the disk will be about 2cm off the deck. Im hoping to get it all together by the 4th Sept

Well personnally speaking, not a fan of astros. A drill motor is perfect for spinning up a disc. The astro is just overkill and as they are so small, producing so much power that they heat up rather quickly if used for a long period (a few min).

Although thats just my views......

would any body have any downloadable videos of some of these latest UK featherweight spinners. it would be nice to see some in action :)

Hi folks- I thought Id add to this thread rather than start another.
Thanks to Eds heads up back in September (cheers Ed!), Ive acquired a pair of those RS pancake motors that were being sold on ebay. Rather than reinvent the wheel (or the disc), what would experienced spinner builders suggest is a sensible size of pulley and belt, and a sensible gearing ratio for this motor (24v, 75W, 3,600rpm, 19.7Ncm torque)? Itll be spinning one of those nice 10 Hardox discs of Christians. Also, what profile of belt do most folk use? Im assuming a V belt, but I have seen feathers using round section belts too.

Hi John On the original DragonStrike I used the round belt with a gear ratio of 1 to 1 but that was with a EV warrior. The only problem I found was that when it hit the belt tended to slip. On the New DS I will be using a 2kg Disc at 1 to 1 from a EV using 6 mm chain. At the moment most spinners are using chain or like Little Spinner a converted angle grinder gear box. For your motors I would probably go for a 1 to 1 Ratio.

Thanks Tony- It may wellve been DragonStrike I was thinking of with the round section belt. The reason I was thinking V-belts was to allow a little slip and avoid stalling the motor and transmitting mechanical shock to it. So, current thinking is that these arent significant issues?

It appears to me chains are often the achilles heel of spinners. They are always coming off in battle. On microCHIP I used a V belt (as used in pillar drills actually) because I wanted a little slip to protect the motor and other components. I used a 1:1 from an 18v driven EvoWarrior with two hefty pulleys. The belt was 10mm wide. On the latest microCHIP Im using an Astro which revs at 11,000 the ratio is 3:1, but Im using the same lucky belt that Ive had from the start. The weapon system has been microCHIPS most reliable part, I just wish the drive was as tough.

The only potential issue with V-Belt is that when you put a shock through the system the V can dig into the pulley and actually transmit a lot of force - if you can found a round belt it will be a lot safer, though as people above have said - many are using V-belts without any issue.

We never had a problem with a chain on Vortex, but there are plenty of people who have so Im assuming that we just got lucky !

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

John,
I have tried virtualy every opion for spinner drive and after much experimentation I have come down to usig 6mm pitch HD Stainless Steel roller chain for the fetherweight and dual SPA V belts for the heavyweight
I have another F/W spinner under costruction that uses a 5mm pitch 9mm wide HTD timming belt. This was chosen because of the velocity of the drive train and complex belt route. HTD belts are good up to 80M/S! were 8-10M/S is about the fastest I would comfortly like to run a chain.
As for ratios, I use 3.1:1 reduction in the featherweight, 1:1 on the heavyweight and 4:1 on the new Featherweight.

LOL, Ed, on Vortex all the shock was in your opponent faces and in their featherweights, I cant recall anything stalling Vortexs disk.
BlacknBlue used twin HTD timing belts, 5mm pitch 9mm, on either side of the disk. They also worked reliably. I guess any method described above will work well as long as the engineering is sound.

The only problem with chain is if you do not get the engineering right the chain can come off. But DS and Scorpion seem to have got it right now. But that caused another prob the chain did not come off the shaft on the EV snapped which would not have happened with belt drive. Glad to know your robots up and running Rob rematch.

Thanks for the advice folks, much appreciated.

John, Our first spinner used the same pancake motors. It had a 2:1 ratio on a 600mm dia disc with the disc weighting only 500 gramms. These motors are very slow compared to an EV or Astro so a big gear ratio would make it run slower, It used a large O-ring for the belt from a car asseccory shop on 2 very deep pullies. We did have one problem with the motor as the shaft is only pressed into the disc armature and it started spinning after only a few test hits. A couple of grub screws fixed this easy enough. On testing we were actually using 240W of power once the disc got to full speed and even more spinning up, so after a fight it was red hot but we never burnt it out.

Thanks Mark- very useful to know about the need to secure the shaft before we use it! Handy to know that its normal for it to get really hot too. I hope to start making the featherweight in the next couple of weeks, although presently the main focus is getting the Roboteq and the NiCads into Ka-Pow! for Birmingham. thanks again everyone.

Im not too sure what range of cars you have in the UK, but over here in Oz, I found a 12v 75watt pancake motor which seems to handle 24v quite nicely. It came out of a Ford Telstar. It weights 750g, 110mm diameter and 40mm tall including shaft(shaft is 8mm double D shaped).

If your looking for a non-pancake style motor to suit your design better, a Mini EV is a cheap and effective weapon motor. We have one in our featherweight, Vertical Limits, which has a 3.4kg 300mm diameter flywheel which rotates at around 4000rpm. The Mini EV survives a full battle just running of two crappy 2.3amp SLAs in parallel.

You can buy Mini Evs here: http://www.robotmarketplace.com/marketplace_motorsmisc.htmlhttp://www.robotmarketplace.com/mark...otorsmisc.html

On that link, check out the HTI motors with 5mm shafts, they might be a half decent motor, but I havent personally used any.

Will let you know about the HTI motors as we are trying them out on one of our new spinners we are useing 2 to power the 2kg disc.

I believe the HTI motors will do quite nice if you run them on 12-14.4v and possibly 18v if you gear the weapon enough and share the load between two motors. Ive seen a few of them smoke at 24v, mainly in Hellbringer X (Aussie Rambot with 4 x HTI motors with SS2 gearboxes on 24v powered by 3600mAh Battlepack)

Tony: I meant to ask you- on a motor like the HTIs or the mini EVs, which have a really skinny motor shaft, whats a sensible way of attaching drive pulleys or sprockets to them securely?

Most people use grub screws but I have welded mine on to the shaft but you have to be very carefull, cover the motor so not to get any bits inside. Dont try to weld it all at once as it will get too hot and could damage the motor.

Thanks Tony. Initially Ill be using the RS pancakes, but the prices on mini EVs and HTIs are low enough to encourage experiments next year...

If the shaft is 5mm then the trantorque keyless fitting is very good. RS sell them

I didnt want to make a new thread so ill just post here , I want my wearpon motor to turn on , and i want to build a mechanical switch myself , i mnow i would need a relay , a microswtch and a servo , but how do i wire the whole thing up ? The weapon motor im using is one of the pancake motors mentioned in the for sale section , any help would be great .

Sorry for the double post , But i have had another though , would it be easier if i just got an electronize rc switcher and a relay and it woould just turn the weapon on/off , Would this be easier ?

I like your idea of an Electronize RC switch activating a relay.

On DragonStrike I use a servo connected to a toggle switch to turn the weapon on/off simple and cheap but it works.

Only problem is that it doesnt failsafe Tony ;) Easy way for me is to use a PicAXE 08M or my IBC :proud:

It does if you add a failsafe between the servo and reciever £11 for the failsafe £2.50 for the toggle switch Like I said cheap

Hi another question about weapon activating with the electronize 2 way switcher , what sort of relay would i need for my weapon , it runs off 24v so im guessing ill need a 24v relay , but what type ?
Also if somebody could draw me up a quick diagram of how i would wire the whole thing up aswell that would be great .

I have updated my design for my spinner , It is basically going to be like an old version of little spinner ,
I have recieved and old angle grinder gear box that i am going to modify to attach a gear that has the same pitch as the ones found on drill motors .
I have also bought 2 johnson motors to power the spinner and going to try and find some old pinion gear on some small motors .
I also got the elctronize 2 way switcher for the 2 johnson motors . The hole design is going to be an undercutter of some kind with a 4mm hardox bar with 8 mm hardox teeth on the ends
Any comments on the design would be great .

We used 12V relays at 24V in little spinner 2 (version 1), mainly becsue we had some spare but didnt have any problems. Actually one of these is now in Dizzy Tilly and thats working on a mag. Not bad for a relay that says its rated for 12V 10A. Little Spinner used a 75W pancake motor and belt drive.

i still have some 12v 80amp relays, that arnt bigger or heavier than the relays used to modify the 30 amp electronizes.
its the HG4185C from willow technologies, make current is 240 amps, break 80 amps. weight about 35 gr

I have some questions about pinion gear
What is the Module of a normal pinion gear on a drill motor ?
What is the pitch of the gear on a drill motor ?

What is the Module of a normal pinion gear on a drill motor ?

I think it is 0.75.

Thanks JH-Q i just figured that pitch and Module were the same thing
Can somebody please post or draw up a schematic diagram of how i would connect a 12 vlt relay to an electronize 2 way switch to turn a motor on or off

To make a motor run in forward or reverse you want a pair of SPDT (sometimes called SPCO) relays connected in an H bridge. Maplin does a good 30 amp one for £1.49. The electronize switch turns one relay coil on for forward, the other on for reverse. For each relay pair connect your motor across the common terminals, connect your battery positive to NC of both relays and your negative to NO of both relays. If this is hard to follow then wire up the relays, without the electronise switch, and turn the relay coils on and off with an ordinary switch until you are confident about how it works.

Thank you John i understand how to wire it up now thanks
I have a question about the mod size of a gear , JH-Q told me that the mod of a 9 tooth gear you find on the end of the drill motor is 0.75 , i cant find any gears with a mod of 0.75 , what do i do ?
This is my planned weapon setup
http://img521.imageshack.us/img521/4462/wepsutup8av.jpghttp://img521.imageshack.us/img521/4462/wepsutup8av.jpg
Am i right in thinking that the total ration for the setup is 9:1 ?
What do people think of this setup ?

looks like it will work ok, i would strip the angle grinder gearbox, degrease it, and replace with a light oil like wd40. thats just me though, minimizing the friction losses