(3-15-08) The Brushless motor arrived today so I set to work creating a new assembly arm to hold the weapon with during testing. The new motor is a bit wider and taller than originally designed so I found I had to up-scale the thickness of the arm. Since I was at it I chose to work with 1/16 thick garolite this time as I was finding the aluminum took to bending under pressure allot, and was hard to get completely straight again once bent. So I wanted something that would give, and bounce back, since this is still the testing phase I chose garolite as it has similar properties to carbon fiber at ~1/5 the cost.

The motor itself weighs in at 1.6 oz and runs at 1400 RPM/v, my current plan is to feed it off of a 6 AAA cell 1000 mAh pack, at ~7v (running) I should see about 9800 RPM with no load on the motor shaft. I am guestimating about 11A with the load of the weapon at 7v. I have no way of knowing what the end RPMs will be, I plan on running it at a 1:1 gear ratio for the first few tests, and adjust according to the test results. I have some concern that ill be melting my new ultra light battery pack,.. but I wont really know until I try. The ESC should hold up, I purchased one that can handle 30A.

I think iv missed the mark a bit on scale its feeling a little light for a 3 Lb beetle and just a little heavy for a 1 Lb ant, my old 2 Lb mind set seems to have gotten the best of me again, but I want to push forward with what I have now and see what happens. I should be able to do a powered test in a day or two and judging from that ill be able to chose to downscale, upscale, or move on.

(3-17-08)  Finally got everything together and found the time for testing,.. I am both happy and disappointed. The weapon is doing just what I designed it for, but its feeling a little under powered even for a 1lber (not to mention its way to heavy in its current build a for a 1 lber. It shatters plastic bits, tosses fire alarms across the room (.5 lb), throws off sparks on stone, and cuts through cardboard even though its designed as a blunt weapon to do concussion damage not a sharp weapon. I am thinking that iv missed the mark on hammer weight (to light to make a big impact). or my RPMs are actually to fast, not letting the bolt actually make deep purchase before transferring momentum (fancy wording for hit). I also have an issue with belt tightness, I have one belt that's a hair to loose for the motor mount location I drilled, and one belt that's a hair to tight. I am certain i am loosing power either way. The test below where done with the belt that's a hair to loose, so some slippage is occurring particularly at start up and when trying to recover from a series of strikes.

I did three materials tests and one endurance test. videos from the three materiel tests can be clicked on below.

     

One thing that really impressed me was the torque behind this little motor, this is my first time playing with brushless,.. and I for one will likely never go back,.. as you can see I had to dig rather deeply into something to stop the mill from spinning and even after a few strikes it only took a fraction of a second to get back up to a blur.

As for the stress test, I planed on running it for three minuets while tracking power, speed, and temperatures at various points including the battery and a few of the connection points I was worried about . I set up a stand with my drill press vise to hold the arm. I wired everything through my Multimeter so that I could track Amperage.

I believe my data was off by a few bad connection points, according to the meter I was only pulling 5-6 amps which according to the motor specs is not quite right for the Voltage I was feeding it. I think some less than perfect connections and possibly the fact that it was all running through the multimeter may have limited the amount of juice I was able to pull. then again I may have done better then I thought on friction points. The test only went for 1.5 minuets before I lost one of the bolts (hammers) apparently it vibrated loose, once that happened the whole rig started flailing around due to the imbalance, luckily the BR6000 shut everything down the second I killed power to the remote. As expected, if I continue to follow along this path ill need to epoxy/weld the bolts onto the collars.

Some, after the fact, expected, wear and tear. notice the scorch marks on the bolt, and the loose screw on the side view.

  

I am not sure at this time if I will continue testing on this weapon,.. I may move on to plan B and keep this one in my back pocket for a later day.