Team Aggregat's Build Diaries

[duff]

Cheers for the comments guys. I realised the rectangle thing just as I was filing down the motor mounts. But I guess its only a one off job, so I didn't mind spending some time getting it right.

Marco, its been ages! I think you were at my last featherweight event all those years ago! I think the last time I saw you was at AWS 18 or something like that. So I take it you're coming to Newport too then? And as for the electronize, mine had a dodgy relay a few times, hence the external relay mod. The botbitz look in a different league though and are much cheaper. I think I'll wait for these to die first though.

[Gaseraki]

I think the last time I saw you was at AWS 18 or something like that. So I take it you're coming to Newport too then? And as for the electronize, mine had a dodgy relay a few times, hence the external relay mod. The botbitz look in a different league though and are much cheaper. I think I'll wait for these to die first though.

Yeah it might of been Debenham that I last saw you, I built a featherweight ram bot which I dropped on the way to the event and broke an electronize. Or the giant wooden skateboard robot? I have also been out of the loop till recently. Havnt built a new robot in 4 years.
I havnt got my 85a bot bitz speedos yet so cant recomend but if they do the job then I cant see the need for a scorpion XXL.
Yes I will be a newport. Liz and I will be there a week after my marriage funny enough so its my honeymoon!

[duff]

Convince her to spend another week there and you can cone to the AWS too!

[duff]

Not sure if this belongs in a build diary, as I've not actually built anything yet, but all my Beetleweight parts arrived today! Very exciting. Pictured below, from left to right:

- 4mm steel plate, which the disc will be cut from.
- This 815w brushless motor
- 4s 1300mah 25-50C nanotech battery
- 60a Brushless ESC for spinner motor
- 2 x 20a brushless ESCs. I'm hoping to hack these myself to run the brushed drive motors.
- 2 x 12v 500rpm motors from ebay

Coin, ruler and antweight are all just there for an idea of scale. :P



I'm still unsure as to how to mount the disc. I was considering mounting it onto the motor shaft directly with a prop adapter, as I've always done with my ants. I've never had any problems, but I know there's much more energy in a robot of this size. Ideally I'd like a timing pulley system, but that's a extra expense, weight and call for tools and expertise that I don't have.

The drive motors look promising considering they were pretty cheap. Here's a quick comparison with the standard sanyo type antweight motor:



They're rated for 12v, so I'm hopeful they'll be ok on 4 cells. They're only £6 each with free P&P from china, and they only took 8 days to arrive. Fingers crossed they're decent as they look about perfect size for Bettleweights. Building won't start for a few weeks yet as I'm busy finishing my feather and getting antweights ready for the next AWS. But as anything gets done, I'll post it here.

[harry hills]

Looking good. We've gone for similar sized motors, although mine is slightly more powerful and has a higher KV. That should make for some interesting weapons! I'm really interested in what you end up building. Any chance of making it to Deeside?

[duff]

I should have it built by then, its just a case of if my car will be able to make it that far. Its being a bit of a t**t at the moment, and I suspect it might be dead by then. But I'm starting the build as soon as AWS 41 is over, so that should give me plenty of time. I went for the lower kv as I was thinking of going direct drive. If I do end up going for a pulley it will likely be 1:1, or something very close.

[psychostorm]

I could pick you up on the way through if you want?

[duff]

I could pick you up on the way through if you want?

Ah, really? That would be awesome, cheers mate.

[duff]

Progress has been slow, but I've finally got Enormole all wired up and working. I'm not the best at soldering, and I'm pretty slow at it, so I had to clear an entire evening to get it all done. The worst part was getting the external relays on the electonizes all wired up. It seems like such a waste of time as I know I'm going to use TZ85as some time in the near future, but I guess I need something for the interim. I was going to solder new wires onto the motors, but lost patience and just left the standard drill wires on there. Maybe that'll be a job before the next event. At the moment I just want to get it ready for Newport.






It's starting to look a bit more like a proper robot now. There's still loads to do before Newport though. First off, the 3 cell battery is geting replaced. I fancied a 5 cell, but looking at its current performance on 11.1v, I dont think 18.5v is necessary. I may just get a 4 cell pack now. Judging from the video, what do people think?

Then I need to build a case for the lipo. Am I right in thinking that we now need a metal cover all around the battery? Is 2mm ali going to be enough? I really don't have the tools to do much steel work. I also need a link, fuse and LED, but these should be easy enough to sort. The side panels are already cut and just need screwing on. Same goes for the scoop and front wedge, and it'll be done. I'm not expecting much in my first event, a wheel came loose even in testing tonight. But I've learnt so much already, and I've not even made it into the arena yet, so I'm hopeful for my 'proper' featherweight, which will be started at some point after next years FW championships.

It doesn't drive too bad for something I've kocked up in a few afternoons. It certainly had a bit more punch than I was expecting (hence potentially dropping the 5 cell idea). But I guess you can't judge much in a small space like this, I'm sure it'll seem underpowered when it comes to a real fight.



As usual, comments/criticisms greatly welcomed!

[RogueTwoRobots]

A nice POP, best of luck with the ESC hacking.

I don't think direct drive is the best option in this weightclass due to the greater forces that you mentioned, though it may be worth trying it to see (just stand well back incase it fails). As an alternative to timing pulleys, what about mounting the brushless motor vertically, attaching a wheel to it and running friction drive?

Don't think it's been done in that orientation before and doesn't call for as accurate a setup as traditional transmission methods; just have the motor mounted to a hinge that's sprung in such a way that it keeps a constant pressure on the disc (to account for wobble in the disc or wheel). You can then adjust the speed/ratio by varying the wheel size or how close to the disc's centre you put it.