well since the voltage on the brushless drive goes from + vbat to - Vbat I'd say you would get instant smoke ;->
which of newtons laws was it "every action has an equal yadda yadda"
I think the "just bounced off" comes from the expectation that the other bot will instantly turn into a pile of scrap ;-> _________________ Mechanical engineers build weapons, civil engineers build targets
Wed Feb 07, 2007 11:00 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
You are right on both counts Jake. When people expect a "one hit wonder" and don't get it, they mainly vote for the other guy. I'm fine with that, it just makes me try harder
Progress:
I did some more self-righting tests with more parts in the bot - the hoop works even better with the extra weight and with the beater in place, its going to be 100% effective without being any larger The final weight will be 700 to 800 grams and I can't see anything being better. I still like the friction driven wheels though, it's an interesting design challenge.
Bad news from the armoury: the thick sheet of Ti is too small to cut both Chuck's front armour and Scissorhand's blade As a compromise, I can cut two layers of thiner armour from 4.7mm sheet and double up the front like this:
I couldn't resist a little advertising . The combined thickness at the front is 9.4mm of Ti over 19mm of 2024 aluminium thicker than many super heavies. If those bearing mounts ever bend, I will be super pissed! _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Feb 07, 2007 11:50 pm
Bort Experienced Roboteer
Joined: 15 Jun 2004
Posts: 696
Location: Sydney, NSW
The friction drive wheels that Angus referred to didn't actually touch either, except when the weight of the robot pushed them that little bit further till they touched.
I really liked that approach cause it means that forward is still forward but left and right are reversed though.
Although I don't like retread and jolt being mentioned in the same sentence. Brings back bad memories. I reckon I had the match till something locked on But then thats what Jolt relies on really. Still barely any external damage to the tyre. In fact I'm using the tyre below Jolt blade height (ie ungouged section) for the new drumbot.
Thu Feb 08, 2007 6:42 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
The quote for water-jetting the beater arrived today - I can see why it took 4 weeks - $960 AUD That's blown the budget good 'n proper! Needless to say I'm looking around for a comparison...
In better news, I adjusted the side armour to something saner. there was no point having super thick sides and a bare aluminium back plate, so the sides are now 3mm (down from 4.7) and there is 3mm Ti across the back of the bot as well. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Feb 13, 2007 10:09 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
$960!? Fark that!
Someone thinks they can rip you off...
I bet even if it was made custom by whyachi it'd probably be cheaper!
The revision on the titanium sounds wise too. Roadkills old wedge took hardly any damage. In fact, the 5.5mm has taken more than the 2.5mm! _________________ ( •_•)
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Yeah, the price is astronomical - more than all the Ti I have had cut over the last 3 years and then some! Aparently it is because the steel is so thick (50mm) and the cutting head has to move extremely slowly to keep the cut even. After the waterjetting, the part goes off to Whyachi for some lathe and mill work and hardening, which I thought was going to be the expensive bit! _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
How many spares are you getting? _________________ Satisfaction is proportional to effort and results.
Wed Feb 14, 2007 6:42 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Just the one part for Chuck . Six new teeth for Jolt / Scissorhands though . These ones are keyed onto the bar and cannot fly off. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Feb 14, 2007 7:03 pm
Rotwang Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1589
Location: Vic
As the 2 teeth coming off cost you 2 fights that’s probably a good idea.
I probably missed it somewhere but what was the attraction of the beater over a conventional cylindrical drum. _________________ Satisfaction is proportional to effort and results.
Wed Feb 14, 2007 7:18 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
So true! Could you just mail me the trophy in advance for the next Robowars?
The new teeth are double ended as well, so when one cutting edge gets blunt, I can reverse the motor connections and use the sharp ends for the next match . _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Feb 14, 2007 7:22 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
quote:
I probably missed it somewhere but what was the attraction of the beater over a conventional cylindrical drum.
Beater's are hitting the US pretty hard, just like when Helios hit the scene, drumbots came out everywhere. Beaters seem to have the advantages of no end caps for spinners to smash, able to put more weight out on the very edge of the weapon, making for KE, and they seem to have a knack for beating wedges _________________ https://www.halfdonethings.com/
Wed Feb 14, 2007 7:59 pm
Rotwang Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1589
Location: Vic
quote:Originally posted by TDT:
and they seem to have a knack for beating wedges
Any idea how fast they are spinning them. _________________ Satisfaction is proportional to effort and results.
Wed Feb 14, 2007 8:34 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Too fast, if you ask me! My theory (just a guess really) is that a beater gets more bite by allowing opponents to penetrate between the teeth, where a drum's surface would stop them. The slower the RPM, the deeper the possible penetration. There were some neat calculations on the RFL forum about RPM vs bite, but they did not take into account what happens after the first hit - the weapon slows down and subsequent hits *might* penetrate deeper.
The other advantage is that the beater is a single part with a thick cross section at all points - my beater has around 4 sq cm of S7 except right at the axles, so breakage is reduced. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Feb 14, 2007 8:51 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
@ Aaron: I can't see how beaters put more weight out at the perimeter of the weapon . What they do is put a bit less weight right where all the impact energy is. They may also allow a larger diameter weapon vs a drum of the same weight, which will obviously have a big effect on the KE. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
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