The flying brick AKA outback rescue.
This isn't a montage - it is hovering in front of the unfolded box it came in.
November 2005,
This is the latest and most promising model in my now year long quest for a good aerial camera/video platform. Half way through construction of my flying bucky ball - a couple of small co-axial helis began appearing in websites and (local) hobby shops. I resisted getting one because they seemed too light to do what I wanted. Fairly recently the 'outback rescue' appeared and at 410 gram it is over twice the weight of the earlier models.
I bought mine from http://www.wingsnthings.com.au/
- they were a little dearer than some other places but they had
stock. Their online shopping isn't working yet but Miles was very
helpful and seemed very enthusiastic about flying. As usual there was
an addressing problem, this seems to be the norm for some reason. I
ordered on a Friday and had it the following Wednesday.
I
already knew the transmitter would be set up in the wrong mode
because Australian brains must somehow be thought to different to US
ones. Fortunately it isn't too hard to reconfigure it. In general the
transmitter is much better than I was expecting. My JR feels better
but it is quite usable. I like having LED battery indicator because
it is very noticeable and reduces the chance of leaving the
transmitter on accidentally as I often do with the JR.
The model seems quite well built to me. It looks and feels solid and the workings are more enclosed that other models I've seen. One strange thing is the swash plate servos seem to connect at 120 deg (to each other) not 90 deg. There does not appear to be 120 deg mixing in the electronics, yet the controls seem to work properly. I haven't got my head around it yet.
Straight up I had a problem. I had several tail strikes before I ever got the thing off the floor. It seems that if the rotor isn't under load - extreme control movements will cause the lower rotor to strike the tail truss. The tips were damaged, I have spare blades but choose to leave the damaged ones on while I practice.
There are a few other minor annoyances. The throttle
and trims have “clicks”, this is fine except they are too
course and you generally want a setting in between clicks. In hover
I'm constantly moving between two clicks to stay at constant height.
The same goes for rudder trim.
I'm not trilled by the battery
clearance to ground, anything but a light landing will bang the
battery holder on the floor.
The gyro seems quite good. Out of the box with no tweaking it is quite well behaved. There is a small amount of drift but probably less than the heading hold gyros I'm used to. I quite like the having an on/off switch and ESC enable button. It is much easier to keep the model still for gryo initialization if you have a switch and not just the battery connector to enable power.
I'm very suspicious of the charger because the battery (lipo) gets warm when charged, I'll be swapping over to using my swallow charger after I change the battery connector.
As the adds and the demo videos suggest - it has a very stable hover. As usual you have to have still air and be out of ground effect. Indoors at >1.5 meters high it hangs there. However it doesn't fly like a regular heli. If you move the controls or there is a gust it will 'giggle' and take a second or two to settle. On my first few flights I was over-correcting and trying to compensate for the swaying as you normally would.
After the first day I got rid of the tail (no more tail strikes now), the nose and moved the blue LED to the back. The thing flew just as well if not better without the extra stuff, I didn't even need to re-balance. With this stuff gone the thing becomes a small yellow flying brick. In the top photo the thing is flying, it was a little hard to photograph it by myself because the thing is not far off the floor and is in ground effect.
Removing the paraphernalia lost about 40g in weight so
I strapped my 'heavy' video camera (40g) and a light transmitter on
and it flies like they weren't there.
I haven't wired the camera
in yet and it could be quite a while before the weather is good for
outdoor tests but so far so good.
I think the system isn't ideal
and something better could be made with electronic stabilization but
for an “out of the box” solution this is looking pretty
good.
Later.
I got the video camera working and made some videos in
my lounge room. The camera was held onto the front of the brick with
rubber bands. The vibration wasn't too bad but I seemed to get some
sort of interference off the motor. I also tried taking off by
viewing the video feed but this was pretty hopeless in the confined
space. You really have to get away from the floor quickly for the
heli to be stable and that is hard to do.
I then discovered an
unexpected problem – I got motion sick watching the replays. I
had to stop several times and felt ill for some time later.
Next day.
I experimented with shielding and such but found I had to move the camera away from the heli body. I put it on a block of EPP foam and rubber banded in place. The interference went away but now the vibration got bad. I then bound the camera and foam to the body with cotton to make it more rigid, this improved it but it was still pretty bad. So I replaced the damaged blades and it seemed better, both set of blades looked like they were tracking well when suddenly the flybar came off while hovering 20cm of the deck. After that I had a lot of shake and I think it was partly from the bar getting bent but the battery went dead and I haven't confirmed it.
Unlike the dragon-fly there does seem to be adjustment in the cyclic linkages as well as the single fly-bar linkage so tracking should adjustable on both blade-sets. Hopefully with careful tuning and balancing I'll tame the shake.
Nimbin outdoors,
I
went to Nimbin and flew it outdoors a few times. There was very
little breeze but I still had trouble preventing it getting blown
away. This was partly because I'd turned down the gain on the cyclic
(a trimpot on the heli). This makes indoor flyling easier at the
expense of being able to use extreme control travel. I still haven't
fixed the shake which I now think is due to a cracked outer
rotor-shaft (a 5mm carbon fibre tube). Mike took some video on his
digicam but the heli is pretty hard to see in it. If you want to
waste some bandwidth the
clip is here.
Eddie.m.