RadicalRC Stinger Kit

I'm having a bit of trouble bending blogspot to my will regarding captioning and photos... I'll get some more words and pictures up shortly!

Here's the start of the Arcticopter 3, which will be as light and as small as we can make it.  After we get the full-size build flying reliably, I'll try trimming the arms down and see if it will still be stable in the air.

3/8 inch is almost 10mm

An interesting observation for Radical RC parts, which are based around 10mm arms... 3/8 inch basswood sticks from the art supply store are a pretty good fill-in if you need some arms in a pinch.

It's not a super-snug fit, but I think it could work pretty well if glued or shimmed.


3/8 inch = 9.52500 millimeters

Arcticopter II: test videos

Hooray, the Arcticopter II looks like it's going to be a fine flyer.  Powerful motors, it can probably shoot to a hundred feet in a couple of seconds.

More test results to come, but here's a couple of shots of the first test session.

 Here are the original flight tests.  We've substituted the wiffle ball landing gear... it's really nice if you can handle the weight.  As you can see from the videos, weight is not a problem for this model... it took all the control we had not to shoot it straight up into the trees and beyond.  One thing to investigate: using heli mode on the radio so as to set a throttle curve.  We fiddled with that a little bit, but then couldn't take the unit off of safety because we had displaced the zero setting off the power curve.

Here was our very first test.  Notice how the rightmost leg seems to stick to the ground?  That's the sure sign you've got a motor running backwards!  This also shows the original wire legs.

Before we did all of this of course we tested the electronics without blades.  It always sounds like an assembly line of dentists to my ears.

Arcticopter II: Build part 2

Picking up the build the next day.

We used an extra platter to keep the wiring together.   We used four extra standoffs (is that what these things are called?)  Here's some notes about how they're attached.

The tabs have been trimmed from two of the standoffs, so that they're acting as spacers but don't need to be attached to the platter.  this makes it easier to set up and remove.

Note that we cut off the tabs on two of the standoffs.  Originally we did this because they were two-tab standoffs lining up with three-tab holes, but it turned out to be a very nice setup.

We filed out the tab holes on the top platter so that it seats and unseats smoothly.  We'll use some thin bolts to hold things together.

We'll try putting another platter on top (or below?) to cover up the stabilization board.

The standoffs are placed in the holes that are offset from the arms, allowing unobstructed access for the wiring.

We got lucky... the motor wiring, the ESC wiring, and the Wago connectors were the perfect size so that everything fit without having to add any extra wir

The KKBoard is being moved between the Arcticopters 1, 2, and (soon) 3 until some more boards arrive, so it's attached to a carrier board.

The KKBoard is sitting on a double layer of 3M doublesided foam tape, and attached to the carrier with zip ties.







For now we've got everything taped together, but we'll figure out how to attach it so that it's stable, firm, and easy to move.











HINT: don't mess up and mount your board at 90 degrees to what it should be.  As soon as you apply the smallest amount of power it will attempt to correct itself by instantly flipping upside down!










We didn't have a lot of luck with the music wire legs... Since the weight should not be an issue with the motors we've got, we tried zip-tying wiffle balls under the motors.  The motor mounts make a natural cradle that holds it in place.  Use some pliers to pull the zip tie tight and it's very stable.  This worked pretty well.  I'll get some numbers on the wiffle ball weight.

I'll try the music wire legs on Arcticopter III which will be much smaller and as light as I can get it.

A KFC bowl is the perfect size for covering the platter.  Thanks Colonel, this flight's for you!












Flight videos in the next post!

Arcticopter II: Build part 1

Here's the basic RadicalRC kit assembly.  It's really nice. We're using the carbon fiber arms.  Everything fit together nicely, and we glued it up with medium CA.  Hot glue seems to be just fine to center the arms.

 

Wago connectors for power distribution, as noted here.  These have been great on the Arcticopter I.  These motors are a lot bigger, so it will be interesting to see the power draw through the connector.  The motors max out at 375 watts each, but this thing will be at airliner altitudes if you keep that much power for too long.







Here's the basic frame with motors attached.  It's very light and solid.  I had originally been a bit skeptical about the 10mm arms but am now a big fan.

The motor had an extended shaft.  Drilling through the carbon fiber arm was a no-go, so Andreas tried every saw in his shop to cut off the motor shaft.  None of them even scratched the shaft, which is why every RC toolbox should include an angle grinder with cutoff wheel.

Cover it up with tape to keep crud out of the windings and bearings, and clamp onto the motor shaft.

Dont' forget safety goggles!  Next time I'm going to try it with a (much smaller) Dremel cutoff wheel.  If that doesn't work then I'll just borrow Andreas' big cutting wheel.

There's a little sliver left on the shaft.  You can trim it off if you're so minded, but it's not necessary.

A lovely fit!  This is a shot of the lower arm, where the shaft came close to fitting... it was a bit easier to get a good picture.











Here's how the motors are mounted.  The bolts have "blue" removable threadlock.

Say hello to our little 4S friend.  One goal of Arcticopter II is to measure the payload size that can be reasonably handled.  The final Arcticopter will need to carry Josh's full-sized Canon DSLR... we probably should find out the target weight.

As you'll see in the flight videos, there's no problem blasting into the air.  Andreas has told me it's pretty good with 3S as well.





For some unknown reason, the Hobby King shipment did not include the expected fasteners.  Fortunately the local Ace has a nice selection of metric fasteners.  Judging by the price, they're made from an allow of platinum, iridium and gold.








The build went really smoothly, and the Radical RC kit was nice to work with. Andreas had glued up the  pieces and attached the motors... Everything on this page we did in an evening.

Continued in next post...