HardWired II

[Flag Captured]

HardWired 3 update

So, Jarvis made me a little mockup of HardWired 3, and it looks absolutely awesome.
HardWired 3.jpg

The disc on this one is 150mm, running on a 2:1 ratio from this motor http://www.hobbyking.co.uk/hobbyking...tor_730KV.html which is frankly huge, but big motors are always better, and that'll be a heck of a lot of torque behind the disc.

Dimensions are actually close enough the same as HardWired 2, which is impressive with everything in there, two 270 kv 50mm outrunners for drive (200A brushless ESCs) and batteries for it all. At the minute I think it's all running on 8s, and drive is 100mm wheels on a 5:1 ratio, gives a theoretical top speed of about 21mph, call it about 17 which is fast enough for what I'd need! Small amount of magnetic downforce too, about 5-10kg to help put the power down and prevent it from gyro-dancing with that disc

The armour's all 3.2mm Hardox, and 10mm HDPE on top so should be a brick, with Alumec bulkheads, lands it at about 13kg. Only change I'm thinking of making is the disc being a single-tooth rather than a dual tooth, but I need to learn to single tooth disc a lot better first before attempting that. I also need sleep, so fair warning, I may have misquoted a couple of numbers quite horribly here.

Thanks again to Jarvis/MicroGravity100 for the sketchup model, it's a real hand!

[overkill]

The low gearing on those drive motors is going to be a problem - you will have poor start-up torque and very jerky low speed driving - Mario's new bot Calliope has this problem with 6:1 gearing. I recommend changing to sensored motors or using much more reduction with the sensorless motors. The other advantage with sensored motors is that you don't need so much power, which saves weight and money.

[maddox10]

The NTM42's do the job nicely tough after the change over, even on a 6-1 gearratio. The slower running, but way bigger 50mm versions should laugh at the strain. if I see how Caliopes and Valkiri2's 4 kg bearingless disks spin up with only a 1.5-1 gearratio I don't have any doubt these motors will make any featherweight in a unguided rocket.

But yes, Sensored seems a better bet for such low gearratio's.

[overkill]

Hi Mario, you mentioned on the Aussie forum that the outrunners went from stopped to turning at slightly different throttle points and that the dead-band was much wider - did the larger motors fix that? On my ESCs I have a dead-band adjustment and turning it to the minimum helped quite a bit.

[Flag Captured]

These are sensored, the 2000w alien power sensored outrunners with the silver and gold cases - I did initially plan to use the NTMs but that little bit of startup torque is ideal. No idea how sensored outrunners actually perform, but I can't imagine it'd be too different to what you'd expect... Time will tell I suppose!

[overkill]

Well that's different then! Sensored outrunners should have excellent start-up torque and you can likely get more than you need from the 42mm, 1500w model. With it's higher KV, you can gear down a little more and get smoother steering as well. Given that my 95W inrunners can spin the wheels in Mr Mangle, 1,500W motors should be more than adequate.

[mrsam]

Loving that Sketchup model looks exactly how i pictured it would when you were talking about it at the champs, if you get this all working how you want i can see it being a properly good machine, tough as a brick, powerful drive and that disc on the front. Man stay away from Hatchet!

[Revsmin]

Yeah, 8S. Managed to shoehorn one of these into the back. You'd probably only get one fight out of it, but 8S batteries are big, and space was a concern. On 8S and 2:1 the disc speed is ~12,000rpm, and on that 150mm diameter disc tooth speed is ~215mph. That plus the wedge underneath means big hits every time. Disc weight is about 1.2kg. Weight-wise, I made a calculation error and factored in the weapon ESC twice, so realistically weight is about 12.8kg. And that's with basically the same shape as HWII, but half the thickness (all the way around) with 10mm HDPE instead of the stainless. Baseplate is also stainless, 3mm, which is 0.5mm thicker than the stainless base on HWII I believe. Put magnets in and it'd make for one heavy hitter! Drive-wise, this is the one being used, and if anyone else wants to use them I can upload the model to the workshop. On 5:1 top speed is as Matt said, 21mph. I reckon gearing down a little more for a bit more control and torque is a good idea, maybe just to 6:1. So yeah, should be a total brick with a hard hitting weapon and decent rambot drive as a plan B. What's not to love ?

[Eventorizon]

It looks just like I imagined it too. Space is going to be tight but I guess you are used to that.

As for the Lipo, you should only be doing 1 fight on a battery anyway. Conker 3's drive can last about 6 minutes but the weapon will die after about 4 minutes. They both cut off when the low voltage cut out activates at 3.5V, above the minimum 3.2V with a bit to spare.

The battery should be sized that you can run flat out with everything for 4 minutes; 3:30 if you are feeling frisky. Else you are carting around more weight than you need too and taking up more space. Of course you need a safety margin, hence the extra minute but by the sounds of things that 3.3Ah 8S should do it just right.

EDIT: where is the safety link going btw?

[Revsmin]

Thought of how I can do scale in Sketchup