Quote from: courthousedoc on July 18, 2012, 06:01:16 PMWhere does that compare to say RedRumsSimilar size. It looks like Redrum has a 24" drum.Actually, part of my inspiration for the design in the first place was Redrum (the other part was an Ork Battlewagon from Warhammer 40,000, which with a Death Roller looks a lot like a giant version of Redrum crossed with a military half-track and covered with armour plates).
Where does that compare to say RedRums
Welll than that's one huge drum. Could make for some very impressive gyro dances
a 24" drum is like twice the height of your average 220. sewer snake is only 8" high last rites is less 10" high.
The bigger it is the harder it hits right?
Quote from: courthousedoc on July 18, 2012, 09:16:12 PMThe bigger it is the harder it hits right?Rotational kinetic energy is 0.5*(moment of inertia)*(Angular Velocity^2)What that means is doubling MOI doubles energy, doubling angular velocity quadruples energy. I'm personally a fan of the compact, dense drum geared for high rpm, but both have their benefits.
Quote from: MikeNCR on July 18, 2012, 09:34:50 PMQuote from: courthousedoc on July 18, 2012, 09:16:12 PMThe bigger it is the harder it hits right?Rotational kinetic energy is 0.5*(moment of inertia)*(Angular Velocity^2)What that means is doubling MOI doubles energy, doubling angular velocity quadruples energy. I'm personally a fan of the compact, dense drum geared for high rpm, but both have their benefits.Exactly.My reasons for using a large drum rather than a small are three-fold. 1. It looks awesome. 2. As you said, 24" drum spinning at 1000 RPM has twice the power as a 12" drum spinning at 2000 RPM. This way I can take advantage of using a brushless motor designed for 1/5th scale RC car electric conversions (at least until I upgrade to a PERM PMG-132) without worrying about whether it can keep up the massive RPMs needed for an effective drum. 3. Smaller drums don't seem to have that killer uppercut I'm looking for.
That's not quite an accurate reading of what I said.For the sake of simplicity, let's pretend that the 24" drum has exactly twice the MOI of the 12" drum. We'll call them 1 and 2, since it doesn't really matter as energy is linear for MOI increases.We'll say the big drum is at 2500rpm, little drum is at 5000rpm5000rpm gives an angular velocity of 523.6 radians per second2500rpm gives an angular velocity of 261.8 radians per secondSo, for the 24" drum, you have (0.5)(2)(261.8^2), which is 68,539JSo, for the 12" drum, you have (0.5)(1)(523.6^2), which is 137,078JThose numbers are way, way high, as the MOI would be lower in reality, but for illustrative purposes it works. This is why there's been a trend recently to spin a lighter single toothed disk/bar/etc at a much higher speed for spinning weapons.
Let's see what's left on the to-do list...Get batteries Already done.Get Speed Control for drive motors Already done.Preliminary wiring for test purposes Already done.Find weapon motor and componentsInstall power distribution circuit (Y harnesses, cutoff link, fuses and main power switch)Go to scrap yard in search of some still-useful plate metal for armour and some spiky bits for decorationFind another HW builder in the area for practiceEnter first competition
http://www.ebay.com/itm/DC-MOTOR-GENERATOR-10-hp-12-24-48-Volt-Etek-MT-Electric-Car-Permanent-Mag-/300764013728?pt=LH_DefaultDomain_0&hash=item4606eea4a0etek for $270 gogogogoogogo
it's AC. DC doesn't have a switching frequency. 1/2 a horse for an almost 30lb motor at 115v is comically weak. a chinadrill at 18v produces nearly 1/2 a horse. a Inexpensive Chinese Brushless Motor or ICBM at 37v will produce just under 4 hp, weighs 2 1/2 lbs and it costs $70.
Might I recommend this:http://www.hobbyking.com/hobbyking/store/__4935__KB45_11XL_1000kv_Brushless_Inrunner.htmlAt 36 volts it will out put about 3.5 horse power. Use two for extra fun!
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Topic: Da Mekboyz (Read 20893 times)