Hexxus beetleweight in progress

So after coming dead last at robogames in the beetle class...

im out for revenge! Heres what im working with:

Chassis: 1/4 6061 with topographic cuts after components are placed

Electronics:
b16's with timing belts driving two inch wheels
fingertech tiny escs for drive
castle hv50amp esc for weapon motor
e flight power 15 outrunner for weapon motor
thunderpower 850mah 45c 3s lipo

Overview:
It's going to be a horizontal bar spinner to put all of these verticle discs in check
so im going to overdrive it from the outrunner to my bar pulley by about 10% so under load with the 8" bar im shooting for 10k rpm
so the bar weighs 7oz
if I spin it to 10k with an 8" dia I have 238mph or 349 fps
applying these two I am left with
1069joules or 785 foot pounds


heres where im at so far

8" long 1-1/8" wide by 1/4" grade 5 titanium bar
7075 aluminum hubs
22mm bearings
8mm grade 5 titanium deadshaft




and the rough layout with the bottom plate

Cross bracing is the key to that style frame. Take a look into Thomas Kenny's Misdirected Aggresion for some ideas

thanks cody I had seen a hobbyweight that looked similar to last rites but wow that beetle is badass I like how he used his motor mouts as frame struts

I was going to use a little bit of woodworking tricks to get the frame stiff like cutting pockets and threading into the side and top but he seems to have gotten away with only using top and bottom mounting the plates

research i must....

good point alex i vaporized a magnet in my 400 motor testing it against a brick with my old ant forgetting the magnets are factory stamp licked in place... also i noticed e flight switched to a lower grade neodymium on thier outrunners my old park 480 produces 278 watts on a 3 cell with a 10x5 prop
the new one produces 247

so for my power 15.... idk yet I dont have the right prop to meter it yet but im ready to be sad, if i can make weight I have a mean old power 25 that I know makes a real 700 watts on 4s

I was testing with 4s before combat and competed with 3s i used the 6110e and ran one fingertech with a bec and one without and also ran the bec from my castle hv50 so i had something like 4-5amps to the reciever at 6 volts pwm output i should have disable one of the tiny escs bec but i overlooked it and it didnt seem to hurt anything thankfully

lol yes ice 50 I get all the casle air stuff mixed up.

what did you and kurtis figure out?

ahhh interesting.... i usually disable the bec's on the tiny escs and use the castle esc bec so I never had that quirk but I can totally see how that would make for some gremlins.

I wish people would post what setups they used in the website reviews. I'd love to compile a list so that we could say "your setup matches the one this guy has, except for that one component" and thus figure out what combinations cause trouble and why!

FingerTech wrote:

I wish people would post what setups they used in the website reviews. I'd love to compile a list so that we could say "your setup matches the one this guy has, except for that one component" and thus figure out what combinations cause trouble and why!

of course kurtis

TADA!

A BIG thanks to dan for helping finish my blade hub !!!!

made some more progress today,

cut 20 something inches of 1/4 6061 with a jigsaw and a dull wood blade it wasnt fun but the results are nice after some dremeling.




things changed
1. no more heavy b16's instead I will be running silver spark motors
2. wheels wont be direct to motor shaft but instead will have thier own shaft and bearings
3.motors will have 3rd bearing blocks incorperated into mounts and will drive wheels through inverted timing belts to reduce shock loads

things left to do...
1. lose 6-8 ounces on each 15 ounce plate
2. make bearings blocks for wheels and motors
3. cut delrin for motor mounts in conjunction with polulu mounts
4. isolate weapon motor with thin carbon fiber so theres no rotating belt near my electronics in case the belt gets cut
5. make side plates out of aluminum or lexan
6. shock mount all electronics
7. mount belt tensioner
8. drill and tap 40 something m3 holes
9. if I still have weight I will use a 1/16 s7 plate to armor the sides and the front pulley

and heres a new rough layout teaser

Looking good. I look forward to fighting(and watching) the horizontals this coming GCRS.

SamM wrote:

Looking good. I look forward to fighting(and watching) the horizontals this coming GCRS.

thanks sam im drawing some of my inspiration from lefty with the pully running directly on the motor can, it's almost foolproof with how simple it makes things.

I should warn you that one of the problems we're running into is magnet survival. We went through two cans at NRL nationals on Brain which has a nearly identical set up to Leftie. Filling in between the magnets as Alex suggested may help with this.

Did the can flex? And did the magnets come unglued or sheer ?

As best I can tell, the can flexed and the magnets hit the stator. Some shattered and some just came unglued. While the simplicity is nice, if the survivability problem isn't solved it may not be a good way to do things. That being said it likely depends alot on the construction of the motor, and your motor is the same diameter and shaft size that we're running in The Brain but in a 3lber.

well that makes me feel somewhat better.... ill still 24hour epoxy the magnets for good luck.

the brain hits freaking hard for a motor with a 5mm shaft

made some more progress tonight. I mounted the weapon motor and the deadshaft and did a small spin test, well at 1/3 throttle im at 4700 rpm so im thinking it may be alot smoother through the air than I anticipated leaving me with a higher top speed

everything spins super smooth too im really happy with how this is working out

wouldn't it suck to drop your camera while it was spinning?

it definatly would lol its scary just to be around I wont even try it beyond 1/3rd throttle incase it explodes

ha i tested a version of szalor like that before, took it to full throttle fine, when i let off it freaked out, flexed and ate the frame. my bar dead stopped in the cf about 1 1/2" in =P

Koolaid64 wrote:

ha i tested a version of szalor like that before, took it to full throttle fine, when i let off it freaked out, flexed and ate the frame. my bar dead stopped in the cf about 1 1/2" in =P

thats exactly what I was afraid of when I let off the throttle the belt started jumping I can totally see how it would try to eat itself if it was just a little faster I shure as hell dont want the 9oz titanium bar flying off my worktable at those speeds that would need some serious super glue and peroxide attention for the puncture it would leave in my leg lol

made some more progress this afternoon i broke out the jigsaw and some fresh blades, some saftey glasses and went to town...


kitty for scale

No pulley on the motor can? Looks great!

-Jamo