Rango - Build diary

[harry hills]

We're looking at similar things now. Would using one and using the dual rates/fancy arse magic on the DX6i make those a viable choice?

[plargen]

spotted these on ebay

http://www.ebay.co.uk/itm/MODEL-BOAT...item2ec7531693

[Ellis]

The 885s are 49mm in diameter and the width between bulkheads is 100mm, so to fit larger motors (the torpedo 800, 850s, or any 900 size can) the main bulkheads would have to be pocketed a bit and the bolt pattern in the mounting plate moved/slotted to the side a few mm. So not something that can be done on the day sadly. A powerful enough 775 could work but I can't find many that are between low revving and gutless and the fast ones such as the banebots ones.

Will try the existing setup on radically reduced rates from the tx as Harry suggests and see what effect that has.

[Eventorizon]

What brushless motors could you run? There must be something with the same mounting points that you could use. Question is getting the parts in time.

[maddox10]

Unfortunatly, no 900's without gears available atm.

But, adding a few grams of dry ice to cool the TZ's can't be that big an issue.

[ChrisKazoo]

I have one I found in a box, I think it was a spare from Conker 1 that I lost. It smells fine, I will bring it to GSL.

Would something live this do? http://www.cornwallmodelboats.co.uk/...mfa1114_1.html

Here is the Data sheet: http://www.mfacomodrills.com/motors/800.html

And here are some real Speed 900's: http://www.westbourne-models.com/Mod...-2084-ext.html

I am sure if you ordered them to have them rapidly posted to the Robochallenge building that Grant could bring them in for you on the morning of the event.

I live I Cornwall and could go there and bring anything to GSL on Thursday if that's any help to anyone

[Max]

The 885s are 49mm in diameter and the width between bulkheads is 100mm, so to fit larger motors (the torpedo 800, 850s, or any 900 size can) the main bulkheads would have to be pocketed a bit and the bolt pattern in the mounting plate moved/slotted to the side a few mm. So not something that can be done on the day sadly. A powerful enough 775 could work but I can't find many that are between low revving and gutless and the fast ones such as the banebots ones.

Will try the existing setup on radically reduced rates from the tx as Harry suggests and see what effect that has.

Can you not do the machine work before you go from the dimensions on the data sheets/ from other roboteers so then its just a relatively simple case of bolting in the motors and soldering the wires when you arrive?

[overkill]

Would it be possible to pocket out the bulkheads in advance from the drawings? Going with the larger & low RPM motors would be the best remedy if you can fit them.

I had to use rate limiting in the past to stop motors melting - you are probably looking at 20% or less, which will also reduce steering control considerably. Its a good, cheap option to try first.

[Eventorizon]

I know Ellis, sling up a CAD drawing of the bulkhead as it would need to be to take 2 speed 900's. I will try printing a mount for you with 100% fill, and other people can try and work something out as well.

[Ellis]

Really, thank you so much everyone for raising your hands and trying to help. Feels good.

I can't really do much of the work before leaving, the closest thing I have to a mill is a £35 pillar drill . Unless the milling work can be done for sure then buying different motors is academic, there is no way motors larger than about 49.5mm can fit as-is.

Alex, cheers mate, but as before without the milling work too the new mounting plate holes aren't needed.

I'm up for trying dual rates, I just don't know enough about how that works - what exactly is happening there? Does it simply limit travel, so full stick is only partial throttle (or the % of full throttle that you set it)? If so I can't see it helping much, but I can try. Or is it cleverer than that? If it does anything to reduce the amount of power the motor can demand, i.e. changes the pwm shape or something, then I can see how it could get the thing through a few fights.

In the meantime, I'm permanently in the workshop bolting stuff on, all these delays because of issues mean the actual chassis has been left behind. I have now actually properly attached the base and made the drum cutout, the back armour HDPE is also now bolted on, I have done some necessary work on the drum itself, and now I'm about to attempt to make the top cover(s).

After that there's final wiring/cable paths etc, putting the edge on the scoop and making spacers so it fits as it should, making the electronics mounts, and some testing if time allows. Leave early on Tuesday. Oh and I have a lot of work to do on T2 as well.

There are worse kinds of stress, non robot kinds!

[Eventorizon]

I can print what ever shape you need, recessed, new holes, spaces, motor supports, anything

[harry hills]

You can borrow my mill and tooling if you want to. Snot great but maybe we can ghetto something.

[Max]

Or could you just file away some of the bulkhead to accodate a wider motor?
How easy is it to fit the bevel gear to a new motor?

[Mouldy]

If Alex makes you a mount, worse case I'm sure we could mill a pocket into each bulkhead one of the nights to get it running on speed 900's...

[Ellis]

That'd be cool. I'll have a look at that possibility later tonight when we do a test on reduced rates. If it functions and doesn't get too hot then then we can run as-is. Also as you suggested on FB, it's easy to lift the back wheels up, that's a pair of button head bolts somewhere near the back.

The good news is, all in sans top covers it comes to 12.1kg, so it should be possible to prevent instant death from above.