Finally caved in & built a traditional rotating actuator. Didn't like
the weight or complexity of these, but they're the only way to keep the
distance between coil & magnet constant throughout the motion. Having a
minimal distance between coil & magnet is where the maximum force comes
from.
The test article was made from balsa. Medical tape once again came in
to shield the mechanical shaft from the wire. It has 3x more wire than
actuator #1.
It certainly caused a lot more motion, but yet again, not enough force
for a full wing actuator. Forget about moving the entire wing in our
mass budget. Variable pitch is out. It can move a 1" x 13" x 1/16"
flap against gravity, for a short time. It might work in a ducted fan
VTOL.
Next, another solenoid with the 1" flap. Pretty good deflection with
this one. Quite an alignment problem. The permanent magnet needs to be
halfway down the solenoid to get the most thrust. Any lower & it's
attracted downward. Any higher & it's not deflected as far. This leads
to a gnarly wing stand.
Really disappointing to not be able to move the entire wing, but that's
why we don't have variable pitch wings on airliners.
Thus begins another round of solenoid tests with 1" flaps & another $2
of magnets. A vi ate ing does suck money even without any flying.
Efforts continue on improving radio weather resistance with
polyeurethane.
The 900Mhz Marcy 1 ground station sees daylight again.
Marcy 1 flight computer, covered in dust, insects, & polyeurethane.
New wing attachment required some fancy woodworking.
Didn't like this wing attachment, but it was the only way.
To fit the solenoid in. We do not claim any crash resistence.
This one stayed up for 6 seconds at 3.3V before the TO-220 voltage
regulator fell over. With this kind of Amp suckage, you're not likely
to get an increase in lift without a decrease in motor output. Next
comes making a more efficient actuator.
Straight from RCGroups lore, it's CA glued pieces of plastic.
This 4ohm 4g monster held for 10 seconds at 3V. It even actuates at
2V. With BJT + magnets, it probably weighs over 6g. BJT's serve us better than
MOSFETs because they can handle back EMF.
The smallest servo is the GWS Pico, weighing 5.4g. That could move the
entire wing, but burns out quickly. The only other redeeming quality of
actuators is the price.
The main drag on this operation is the fact that actuating the wing is going
to suck a lot of power.
Next, in the Marcy 1 weight reduction department, it's spray paint
stenciling. That was real unpleasant to carve out.
It's very inconsistent. We have many wings yet to crash. Should have used
transparency instead of paper. The lighter the spraying, the better. 1 pass is all it can handle
before it bleeds.
A new board for Vika 1 started.
This one's intended to minimize GPS interference. It has a shielded
oscillator at 40Mhz. 40Mhz is the dead zone. It was the 1st Vika 1
board we ever laid out. It was laid out in 2009, before Major Marcy, & before
we were confident in crystals.
There's nothing new in it. Once again, forgot to put the GPS voltage
converter on it, provide enough pins for everything, provide capacitor
pins.
It's exactly 1 year to the day since the 1 & only time Major Marcy said anything to
us in real life.
It's a dark anniversary. Now that 1 year has passed, it really is
final. There was a bet whether we'd ever be in a photo with Her.
Mathematically, it seemed likely, 1 year ago. It never happened.
While She was very reclusive, only associating with a handful of people in real life,
was really freaked out by men who didn't demonstrate traditional male dominance,
it was the laying of a very negative judgment on our work to have a heroine Air Force
Major want nothing to do with us.
Comments
Now thats sweet, did you see the micro camera focus actuator?
http://www.newscaletech.com/videos/UTAF-video-july2010.swf
Sorry if im out of place here but you could try 1 of these squiggle motors from newcscale. I've used them and they offer fantastic power/size/force.
Might be worth a play.
Might be way off here but how about using a flybar? Is that not the trim tab of the rotary wing world?
@Darren, the idea is to provide the complement of control in real time during each rotation; that servo wire stuff is way way way too slow.
Helicopters turn the whole blade for a number of reasons, beginning with complexity?
It may be just a dumb question, and I know its not diy... but would something like this be effective?
I'm not sure of the weight with the case removed? but this is the newest in servo tech (bio wire)
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=...
But given weight, torque, and control of distance of throw. I would think you would have more precise control.
But a quick Q: is it more efficient to drive a trim tab on the main blade, then to change the pitch of the blade itself. Although I imagine there is lag and limits involved with that technique, it is more predictable and relitive given the torque necessary to move the whole blade, vs a trim tab.
Not to mention the risk of intruding into the deadly cavitation angle (caused by too high AOA) is much larger isnt it? A full throw trim tab usually cant cause a wing to stall if you know what I mean
Two thought. the thimble thing you made is available as a sewing bobbin at Walmart and fine sewing shops everywhere. The second is - what you are looking for is a harddrive arm (These are available down to a CF card size harddrive.)