Rango - Build diary

[mrsam]

Ah Hobbyking brushless motors, so the magnets will be coming unstuck of their own accord fairly soon i imagine? by the looks of it you're using the same receiver as me, hopefully it'll be nicer to you

[Ellis]

Am expecting getting the rx/tx setup to agree with each other and properly failsafe to be a pain. I believe there is a workaround (Mr Weston to the rescue!) though.

The HK motor is of unknown quality. Joking aside, it feels pretty nice in the hand. I think they have improved a lot over the last 12-18 months. Many a 12lb/30lb robot has used HK or HK-based weapons with success. Reviews for its intended use are generally all positive. Only time will tell if it appreciates swinging Rango's drum around!

[mrsam]

I'll be trying out Mr Westons advice tomorrow to see if i can make the RX behave, it's starting to make me wish i'd spent the extra few pounds on a slightly better receiver but hopefully i can get it sussed

[Ellis]

Well I had heard that the true Spektrum receivers are just as temperamental, so at £7.50 each for the orangerx models I thought it's well worth the experiment.

[mrsam]

That's a fair point, in all fairness that model is not used by many roboteers, if any so it might just be that there's a lack on knowledge on using them, i'm sure once they've been cracked they're really good user friendly bits of kit

[maddox10]

Mrsam, the "cheap" HK brushless have vurnable magnets, but even the venerable Bosch GPA750 has issues with those in the arena.

I think I solved that with the application of a few grams of 2K glue and some time.

[harry hills]

Quit stalling and post pictures of today's arrival

[Ellis]

Bulkheads arrived! Major pretendobot-mode engaged! The bits attached are just those I had in the house, I will do a more complete pretendobot soon.




Scratches are just from machining and will clean up easily, they're no deeper than the colouration of the raw material.




It's diddy!

And shiny!

The bulkheads are 7075 aluminium. They were manually machined, not CNC, by Jeroen in Holland. He pumped these out quickly and exactly to my spec. He did a huge amount of work (even tapped lots of the holes that need it) for a very very reasonable price. Highly recommended, I'm chuffed as can be.

No going back now!

[mrsam]

Is It really Diddy though or is it just because Tormenta is twice the size of other bots? Joking aside those bulkheads look great

[Ellis]

I think a bit of both. T2 is perhaps on the slightly larger side of average and Rango a little on the smaller side. I had to do that, to get the thing in weight. Happily the wheelbase is only a little smaller than T2's so despite its small size, Rango should be fairly stable.

I have just half-checked belt distances for the drive and I think it's going to be just right. That's a pretty big worry mostly lifted. Of course only having the complete drive setup bolted in will present any problems, if there are any.

[daveimi]

Robot is looking really nice.

You know the metal poles that are sort of "standoffs"? What's the proper name for those, and did you make them your self or are they available off the shelf type of thing?

Dave

[harry hills]

http://www.instructables.com/id/How-...fs-and-Spacer/

He made them, but you can buy them as well. This may be helpful for you ^

[Ellis]

I made them on my small Chinese lathe. They were actually a pain to make, turning them accurately between centres on a not-that-rigid machine was difficult and took way longer than it should. Happily, though, they all nicely slip into the pockets machined (thousands of miles away!) in the bulkheads. It's amazing how rigid they are, even just finger-tight.

Tonight I finished the faces of the last wheel. Tomorrow I'll probably throw them all on a mandrel and turn the OD. I'll be glad to get past making the nylon parts of the wheels, it's a weird combination of super easy to turn and a schlep because every second pass you have to stop the machine and clear the barbie-hair.

[Max]

Did you turn down the OD of the spacers or just face off each end then drill and tap each end?

[Ellis]

Faced, drilled and tapped both ends and then turned the OD. I have 18mm rod which would fit into the pockets in the bulkheads, but my lathe's chuck is crap and the bolt holes would be eccentric to the point of the bolt not lining up once in the bulkheads.