360 - mini hypnodisc

[Eventorizon]

Re: 360 - mini hypnodisc

What would the calculation be to go from a known voltage, known kV rating and known RPM to get the torque figure at any given speed?
And the Scorpion HK-4035-630KV has a max continuous current of 90A and Max Power of 4000w.
[Did some calculations and its possible to get 2 HK-40's in Conker 2 with two 10S lipo packs... a rough top speed of 14'000 RPM... overkill somewhat!]

[PJ-27]

Re: 360 - mini hypnodisc

I'm not all that savvy on Brushless motors, but with DC you get Max Torque at 0 Rpm and 0 Torque and Max Rpm.

[Mouldy]

Re: 360 - mini hypnodisc

What would the calculation be to go from a known voltage, known kV rating and known RPM to get the torque figure at any given speed?
And the Scorpion HK-4035-630KV has a max continuous current of 90A and Max Power of 4000w.
[Did some calculations and its possible to get 2 HK-40's in Conker 2 with two 10S lipo packs... a rough top speed of 14'000 RPM... overkill somewhat!]

Not sure of any torque figure calculations, If you have it all set up for the robochallenge open day ill show you how to use the data logging features if you have it set up on a laptop?

Dont bother with dual brushless, its more hassle then its worth mate.

[Eventorizon]

Re: 360 - mini hypnodisc

What issues did you have when running dual brushless in 360? I would guess mainly synchronisation?

[maddox10]

Re: 360 - mini hypnodisc

I guess the same issues as with multiple brushed motors driving 1 powerconsumer.

In Mantis we tried a 3 Speed 900 setup to drive the pump. After 1 fight 1 motor was toast, and the 2 others weren't in good shape.

In the past, coupling 2 IC engines to 1 propeller like this engine, wasn't a succes either.

[Mouldy]

Re: 360 - mini hypnodisc

To start with you have to power it up initialy and assemble your gearboxes powered up so they start at the same home point as eachother..

then you need a second speedo as its not suggested you run two brushless motors of one esc, although i think its been done before, on small scale.

And then no motor is totally identicle to another, one will try to accelerate harder then the other, then the other one might have a higher top speed etc etc draging the faster one down or speeding up the slower one etc, basically its just not very easy unless you had something like a one way bearing setup for each... but then the slower motor would pretty much become redundant on top speed anyhow... and getting a one way bearing to take the shocks is also quite hard (tried it)

I tried it because i was one of the first people to use brushless in the UK and high power motors werent really availible easily at the time, So i used two of the best i could find.

[Eventorizon]

Re: 360 - mini hypnodisc

The only time I have seen more than one engine joined successfully is here... though its not just as simple as bolting 2 motors together... or even 3!
[attachment=0:118a27qu]napier_deltic_animation.gif[/attachment:118a27qu]
3 opposed piston engines joined together, sharing the same 3 cranks. Used mainly in the 50's and 60's in diesel electric trains.

[Mouldy]

Re: 360 - mini hypnodisc

Found a few faults this weekend at the robochallenge open day that i wouldnt of found until the uk champs, so thanks to the RC lads for that, I welded some spikes on the sides to stop it landing on end, also i found the front ali plate that stops shrapnel going into the robot to thin, it bent from the force of slamming into stuff, and caught in the drum, so ill make a new one from titanium...

The biggest fault i found is the drum teeth werent up to the job, they snaped, pulled out and ripped all the bolts out along with it, after talking to the big nipper team and sam smith i think the way forward is to go for a T shaped tooth thats keyed into the drum and taped in from the sides, with teeth made from a high grade hardox/or toolox, ive already milled the teeth slots 16mm wide by 16mm deep, so beefy teeth are the way to go!

http://www.youtube.com/watch?v=JkRj72um ... fofx1AV82Q

[RogueTwoRobots]

Re: 360 - mini hypnodisc

Very nice. I think a dance-off is in order at our next event

[PJ-27]

Re: 360 - mini hypnodisc

Funk me is that an aerial?! Old Skool.

[RogueTwoRobots]

Re: 360 - mini hypnodisc

Looks like a long cable tie for pulling the link out.

[PJ-27]

Re: 360 - mini hypnodisc

[daveimi]

Re: 360 - mini hypnodisc

As a random aside, that animated gif of the Napier Deltic engine is cool. There's a real one cut in half in York Railway Museum.

[Mouldy]

Re: 360 - mini hypnodisc

not done much in a while, tried to engineer out the weak teeth on 720's drum... they were 10mm wide 15mm deep teeth which were key'd in 10mm and stuck out 5mm which i thought would be fine.... but the teeth riped straight out and broke into 4 pieces....

so going much bigger now... will be 16mm wide... 16mm deep and key'd in on a t slot. then secured on the ends with a retaining ring (no bolts in the teeth)

They will also be alternating like on 540's old beater... one big tooth one side, 2 small ones on the other side... pictures of the drum teeth slots;

being machined;



slot's and ring end finnished;



ill get some test teeth made up next week from en24 or something, if they work out ok ill machine some from hardox 500

[ady]

Re: 360 - mini hypnodisc

Looks impressive, wish I had access to this sort of engineering, good job Dave!