360 - mini hypnodisc

[Eventorizon]

Re: 360 - mini hypnodisc

15'000 RPM!!! That is completely insane How on earth will you combat that gyroscopic forces? I just cant see you you will keep it on the ground... super-strong neodymium magnets?

[Mouldy]

Re: 360 - mini hypnodisc

Just makes it more of a challenge to drive... Can't be any worse then 360 to control

[jonny]

Re: 360 - mini hypnodisc

that drum looks slick, what's the diameter? also are you not worried about engagement issues at such high rpm?

[Laser]

Re: 360 - mini hypnodisc

brushless inrunner.... intresting.

[Eventorizon]

Re: 360 - mini hypnodisc

Just makes it more of a challenge to drive... Can't be any worse then 360 to control

Good point

[Mouldy]

Re: 360 - mini hypnodisc

Jonny - 95mm OD, don't really know about engagement.... Might be a bit crap.. But when it does grip it should be pretty impressive...

No idea on the KE it will deliver, but from what Gary has told me... It'll make bonner look like a toy :P

And yeah... In runner... Castle creations neu 2200kv... I used to be the only person using scorpion motors... Now everyone has them... So thought I'd try something else.

[Eventorizon]

Re: 360 - mini hypnodisc

what kind of reduction are you running, you dont need as big a reduction with say a 120mm a drum as you do with 200mm disc? If they weigh the same... ummm I dont know...

[Mouldy]

Re: 360 - mini hypnodisc

Thats right yeah... using a scorpion hk4025 890kv on 6s in 540 proved that... the beater on that was close to 2kg and it span up to 8000rpm in 1 second on 2.5:1 and pulled like 40a....

Gone for around 2.9:1 in this one, with a higher KV (2200) depending on how charged the lipo is i guess it'll spin upto 14-15k in 3 seconds ish.

[typhoon_driver]

Re: 360 - mini hypnodisc

Drums and beaters are able to spin up far quicker simply because they have a lower moment of intertia (essentially more of the mass is closer to the center of rotation than a comparible weighted disc). This has advantages and disadvantages. Advantage is that it spins up quicker however you have to spin it to a higher speed to get the same kinetic energy as a comparible weighted disc.

Spinning at such a high RPM will be an interesting experiment certainly but you will have to be careful that bearings etc are rated for such speeds and whilst it won't be an issue for you Dave, the machining has to be top notch as any misalignment or friction in the system will cause a spectacular premature failure.

[Eventorizon]

Re: 360 - mini hypnodisc

Yeah, we are going to have to be extremely careful that everything lines up properly!

What is the difference between the HK-40's and the HK-50's? [Besides 200g and $150!] I am guessing the 50's provide more torque but I know that you cant give a maximum torque for a brushless motor as the torque drops the faster it spin's.

Or could you drop to a 1100kV HK 30 to save some money and still be able to make an effective weapon out of it?

[Mouldy]

Re: 360 - mini hypnodisc

your going to have to be careful with your design.... my bulkheads are 20mm Alumec89, there not going anywhere :P Also the bearings im using are taper bearings rated to 18,000rpm...not cheapo ones.

With all scorpions the numbers dirrectly after the letters corrispond to the motors diamater... also... the bigger the motor, the more power it has generally... the data sheets for the motors are on the scorpion power site.

[Eventorizon]

Re: 360 - mini hypnodisc

Sorry, forgive me for being thick but where are the data sheets on the website, I can only find the dimensions at the bottom of each motor page, and there doesn't seem to be anything in downloads

[Mouldy]

Re: 360 - mini hypnodisc

http://www.scorpionsystem.com/catalog/m ... 890-12N8P/

scroll down..same for all there motors...all the info you should need.

[Eventorizon]

Re: 360 - mini hypnodisc

So there is no start up torque figures or acceleration graphs? We just have to guess our pulley ratios and disc/drum weights... I thought it would be more accurate than that but its obviously worked for everyone else.

Are these suitable bearings for the drum? http://uk.rs-online.com/web/p/roller-bearings/0514120/

And these as part of the tensioning system? http://uk.rs-online.com/web/p/roller-bearings/0513868/

I am looking at their oiled speeds and their dynamic loading numbers

edit: sorry for all the questions

[Mouldy]

Re: 360 - mini hypnodisc

There ok, but a 12mm shaft is a bit small...id go for 17mm minimum..

im using these (RS Number 506-236) as i wanted something to take exstreme loading- for instance if NST hits it side on....verticles are weak to a good horizontal, with one hit on 360 i hit a verticle once, ruined his 10mm solid aluminium bulkheads and bent his 12mm thick hardox disc, bent the axle and smashed his disc motor...totaled his disc setup due to the weakness in his bulkheads....which apeared strong enough.

Because of this ive gone for a small diamater (less leverage to smash the bearings/bulkheads) a thick shaft (20mm solid stainless) and beefy bulkheads (20mm solid alumec) my bearings will be compressed up to the bulkheads, so the drum and bearings will be a perfect fit in the chassis....

If you plan on using that honey comb ali for your bulkheads id strongly reccomend otherwise.

Will and jamie seem to do well with HDPE bulkheads as they flex quite well.