Team Invade's Build Diary

Considering the last feather we built was Explosion back in late 2007/early 2008, and we've still got all the parts for the new Invasion which never happened, I thought it was about time we made a new one.

However, this time my Dad can't be bothered, excuse was something to do with him being too busy with one heavy and two feathers to maintain, so this one I'm building by myself.

So I've already got:
2x Feather Gold motors
2x 4Ah lipos (one spare)
1x Sidewinder
3x RoboChallenge wheels (we've lost one somehow)
Various amounts of HDPE
Various amounts of Hardox

But we've already got a pusher, so I'm going to order a brushless setup and try a spinner this time :)

So, first progress:

http://i1224.photobucket.com/albums/...1564DB3430.jpg

http://i1224.photobucket.com/albums/...156DF85D50.jpg

The first thing I did was cut the 20mm bulkhead (last weekend). Back then it was going to be a drum spinner (hence why it is so long), but I've changed plan to a vertical so they'll be shortened, but I'm leaving them for now as I'll probably have changed my mind again by next weekend. I had my first go on the lathe this weekend and made the aluminium spacers, turned down the wheel and pulley and bolted them together. The outer HDPE is only 10mm but it'll be wrapped by Hardox when finished so it should be fine.

Did a quick test by plugging it into the lipo and all seemed fine. It's only running on 5S so I think the 3:1 reduction should be fine.

There are a few things left to do such as shortening the axle, shortening the screws that fasten in the motor and adding some bearings, but that shouldn't take too long so I'm hoping to start the next one next weekend :)

If that's HDPE that you are using then I would swap it to nylon.

Yes it is HDPE. The drive pod feels pretty tough though so I think it should be fine. I think I'll probably use nylon for the spinner bulkheads though as I'm going to have to buy a new sheet anyway and I think the HDPE may be too soft.

That should be fine. I was concerned that you were going to support the disc axle with hdpe

Nowt wrong with 10mm HDPE wheel protection! :uhoh:

Looking forward to this, man. Will be interesting to see how those motors perform at 3:1. I know virtually nothing about gold motors, only that the 12v model doesn't exist now? They must be low RPM if 3:1 doesn't result in silly speeds.

As for HDPE for spinner bulkheads, is nylon really that superior? Why? It's somewhat stiffer, but also more brittle, for the high speed stresses of spinner mounts is the slight give in HDPE that undesirable?

Perhaps I'm a little bias, our negative experience with brittle plastic is a little more developed than some ( :lol: ), though I have seen several instances of nylon cracking in combat.

I don't understand the bias against 10mm HDPE.

It seems that after 11 years of roboteering, and using HDPE as armor, I'm still happy with it.

The only failure we had, was against Kan-Opener, and that was with Obsidian.
And the damage there that doomed the machine, was the buckled 5mm 6082 ali baseplate and crumbled drive.

Inertia XL uses HDPE bulkheads for the disk, works pretty well it would appear

Nylon is significantly stronger and deforms much less before breaking than hdpe.
Good for critical structural components (disc mounts etc.) possibly less good for armour depending on how it's used/ what it's up against.

Yeah I agree, nylon is a lot sturdier, you can feel the difference when you work with it. The only problem I have found with nylon is that it becomes more brittle when it's cold, so you have to be more cautious when machining it outside in winter. But luckily you don't fight them out side, so it's fine.

One wheel pod finished

http://i1224.photobucket.com/albums/...ps8f978a96.jpg

http://i1224.photobucket.com/albums/...ps804990cb.jpg

I've cut down the HDPE and axle, and countersunk the screws for the motor so the belt doesn't catch on them. Now that I'm using screws that aren't too long the belt feels a lot tighter, which is good. The whole setup weighs about 1.75kg, which I think is quite good considering that there's 875g of motor and 20mm thick HDPE in it.

I've decided on using Nylon for the spinner bulkheads. I do think that HDPE would probably just about manage but it's always better to be certain. I think the drive ratio should be fine. The motors are 24v and I'm only going to be running them on 5 cell, and I did a quick test and the speed seemed fine.