Few questions about Motors, Esc’s, HDPE

[MattLampitt]

hi all, my prototype build has been going great and coming along well. Until I weighed it tonight. Lol. it’s currently made from 12mm ply wood which will be replaced with HDPE when I make the final version. Anyway it’s coming in at just under 10 KG and still have about 5kg I need to put in and on which isn’t going to work out.

so I’m thinking of scrapping the brushed motor from the 18v circular saw and contactor setup I have for the weapon and going for the convenisonal brushless Motor and Esc instead.
this will be lighter and much smaller and would enable a pretty radiacal chassi redesign resulting in saving weight.

so the questions I have..
will this motor: https://hobbyking.com/en_us/propdriv...E&gclsrc=aw.ds

and this ESC: https://hobbyking.com/en_us/turnigy-...ontroller.html

be a good matchup and wil setting up be a pain etc?


Then HDPE, iv looked into the grades most common etc and seems grade500 is the way forward but I wondered if you guys had noticed any change in characteristics with the different colours?? I know it might be a daft question but thought id ask as experience is always good to tap into.

Cheers
Matt

[Al_]

Re: the HDPE. I've only ever had stuff from Direct Plastics, but the black HDPE definitely machines differently to the white natural HDPE. I guess that it's something to do with the dye in it. There is not real difference if you are working it with standard wood working tools and I've never notice any difference between the two in combat.

I don't know much about the different grades of HDPE, but some people use UHMWPE instead which is a little stronger but considerably more expensive. I would say that its far more important to make sure you attach the pieces of HDPE together really securely, than it is what grade they are made of.

[Ocracoke]

Re: the HDPE. I've only ever had stuff from Direct Plastics, but the black HDPE definitely machines differently to the white natural HDPE.

I've not experienced any difference in machining black and white HDPE on The Honey Badger.

The motor and ESC look OK to me but it is important to note that the motor can technically run at a higher voltage (8S) over the ESC (max 7S LiPo) so I wouldn't exceed that. There is also the thing to note about saws (and rotational weapons in general) in the rules as well:

12.3 Rotating Weapons
The speed of any rotating weapons - e.g. circular saws, carbon or steel cutting discs - must not exceed the manufacturer's specification. The manufacturer's specification must be available for inspection.

[MattLampitt]

Thanks for the info guys. The rules in that respect shouldn’t be a problem however it’s good to know so thanks.

Im running 18v motors for drive powered by a
Makita 18v LI-ON at the moment so will probably end up powering it all with a 6 cell LI-PO. May get this motor instead then: https://hobbyking.com/en_us/propdriv...ner-motor.html

[Maxamuslead]

most people run 5060s on 6s as it is cheaper than spending money on higher end ESCs and is simpler then VESCs. Also, it has the added benefit of a lower KV and being physically larger and able to take more heat. this is ignoring the fact you need to Flash the Redbrick 200a (the ESC most people use for 50XX drive in FW) which isn't hard but I wouldn't like to do it as a first build. TBH I would work with Brushed motors for your first bots. 775s motors are powerful and on the correct ratio work great and maybe people still use them, IIRC Explosion uses 775 and Shrapnel the vert runs 550s. Do not overvolt 775 to 6s 22.2v they do not like and become all smoky

[Ocracoke]

775s motors are powerful and on the correct ratio work great and maybe people still use them, IIRC Explosion uses 775 and Shrapnel the vert runs 550s (and voltage DO NOT OVERVOLT them to 6s 22.2v)

Kaizen uses 4x 775 motors in it's drive system. From experience, I wouldn't recommend going past ~24v or so on them. I run them on 8S LiFe batteries (26.4v nominal) and, unsurprisingly, they'll cook under high load for long periods of time. I would agree that 550s are probably not going to work beyond 14-16v or so. I seem to recall a post on here at one stage about how much you can overvolt a motor, might be worth finding.

[Al_]

I don't think you'll have too many issues with your 18v motors on 6s. At a full charge of 4.2V/cell, at 6s battery should be 25.2V, that's only about a 40% over voltage. Lots of people run the 12V 550 motors on 4s which is 16.8V, also about a 40% overvolt.

[Maxamuslead]

there is also 18v 550s which run at 6s no problem. It just 18000 rpm 775s which dont like 24v. 9000 rpm 775s dont mind 24v but due to them being 24v motors

[MattLampitt]

The brushless motors and esc I’m on about is is for the weapon motor. No way do I want to dive into brushless drive for a first build hahahaha... I already have 4 x 18v 550’s on a hacked turngy85’s.
To be honest... if the rules say I can use these Makita LI-on ones then I’ll use them. (Need to check that)
so regarding the Propdrive 50/50 580kv motor with the Turnigy plush 100a ESC. Is it a good way to go?? And easy enough to get working etc,?

[Maxamuslead]

redbrick 200a. side note what is the weapon?

about the battery. I cannot see it being an issue if you got a charger Plus a lipo bag/metal box ( you shouldn't need it using a battery like that BUT EO may want it)

[Ocracoke]

about the battery. I cannot see it being an issue if you got a charger Plus a lipo bag/metal box ( you shouldn't need it using a battery like that BUT EO may want it)

I'd play it safe and assume that the same restrictions for Li-Po batteries apply to Li-Ion batteries as they are not specifically mentioned in the section which details the specific battery chemistries in which "no specific precautions" are noted. Then again, I follow the Li-Po rules for my Li-Fe batteries and they are listed. Best be safe than sorry.

[Maxamuslead]

Lipo rules apply to Li ion But due to them being in a drill battery I do not know if they still apply

[Ocracoke]

Yes, I assumed they would but in the same context, just because they are in a hard shell doesn't mean they wouldn't apply, that shell will probably be plastic and offer no fire resistance.

[MattLampitt]

Weapon will be a shrapnel style disk of ar500 between 2&3 kg ish.. diameter at 230mm one at 300. Depending on opponent.

[MattLampitt]

redbrick 200a. side note what is the weapon?

Isn’t that quite a big ESC considering it says 100amp on the motor specs?

Weapon will be a shrapnel style disk of ar500 between 2&3 kg ish.. diameter at 230mm one at 300. Depending on opponent.